diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..8e607e4 --- /dev/null +++ b/.gitignore @@ -0,0 +1 @@ +SOURCES/Pod-Perldoc-3.28.tar.gz diff --git a/.perl-Pod-Perldoc.metadata b/.perl-Pod-Perldoc.metadata new file mode 100644 index 0000000..924d2b1 --- /dev/null +++ b/.perl-Pod-Perldoc.metadata @@ -0,0 +1 @@ +eca1954ea46fb2dbc87043f43e8f0a8f74a1d652 SOURCES/Pod-Perldoc-3.28.tar.gz diff --git a/SOURCES/Pod-Perldoc-3.28-Add-a-test-for-a-truncated-perldoc-f-tr-output.patch b/SOURCES/Pod-Perldoc-3.28-Add-a-test-for-a-truncated-perldoc-f-tr-output.patch new file mode 100644 index 0000000..8d4f6c2 --- /dev/null +++ b/SOURCES/Pod-Perldoc-3.28-Add-a-test-for-a-truncated-perldoc-f-tr-output.patch @@ -0,0 +1,3736 @@ +From 0729324bcb3f8186541fcc7fabadf474b86a7411 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= +Date: Wed, 14 Aug 2019 17:35:22 +0200 +Subject: [PATCH 1/2] Add a test for a truncated perldoc -f "tr" output +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Please note that it bundles perlop POD from Perl 5.30.0 to have +a non-moving test target. + +CPAN RT#86506 + +Signed-off-by: Petr Písař +--- + MANIFEST | 2 + + Makefile.PL | 1 + + corpus/perlop.pod | 3610 +++++++++++++++++++++++++++++++++++++ + t/03_builtin_pod_output.t | 59 + + 4 files changed, 3672 insertions(+) + create mode 100644 corpus/perlop.pod + create mode 100644 t/03_builtin_pod_output.t + +diff --git a/MANIFEST b/MANIFEST +index 8350f18..8e1dbae 100644 +--- a/MANIFEST ++++ b/MANIFEST +@@ -1,6 +1,7 @@ + Changes + corpus/no-head.pod + corpus/perlfunc.pod ++corpus/perlop.pod + corpus/utf8.pod + lib/Pod/Perldoc.pm + lib/Pod/Perldoc/BaseTo.pm +@@ -28,3 +29,4 @@ t/man/_get_columns.t + t/pod.t + t/01_about_verbose.t + t/02_module_pod_output.t ++t/03_builtin_pod_output.t +diff --git a/Makefile.PL b/Makefile.PL +index f76d364..8f5b159 100644 +--- a/Makefile.PL ++++ b/Makefile.PL +@@ -15,6 +15,7 @@ WriteMakefile( + + 'PREREQ_PM' => { + # Are there any hard dependencies not covered here? ++ 'blib' => '0', + 'Config' => '0', + 'Encode' => '0', + 'Fcntl' => '0', +diff --git a/corpus/perlop.pod b/corpus/perlop.pod +new file mode 100644 +index 0000000..dd658bf +--- /dev/null ++++ b/corpus/perlop.pod +@@ -0,0 +1,3610 @@ ++=head1 NAME ++X ++ ++perlop - Perl operators and precedence ++ ++=head1 DESCRIPTION ++ ++In Perl, the operator determines what operation is performed, ++independent of the type of the operands. For example S> ++is always a numeric addition, and if C<$x> or C<$y> do not contain ++numbers, an attempt is made to convert them to numbers first. ++ ++This is in contrast to many other dynamic languages, where the ++operation is determined by the type of the first argument. It also ++means that Perl has two versions of some operators, one for numeric ++and one for string comparison. For example S> compares ++two numbers for equality, and S> compares two strings. ++ ++There are a few exceptions though: C can be either string ++repetition or list repetition, depending on the type of the left ++operand, and C<&>, C<|>, C<^> and C<~> can be either string or numeric bit ++operations. ++ ++=head2 Operator Precedence and Associativity ++X X X ++ ++Operator precedence and associativity work in Perl more or less like ++they do in mathematics. ++ ++I means some operators group more tightly than others. ++For example, in C<2 + 4 * 5>, the multiplication has higher precedence, so C<4 ++* 5> is grouped together as the right-hand operand of the addition, rather ++than C<2 + 4> being grouped together as the left-hand operand of the ++multiplication. It is as if the expression were written C<2 + (4 * 5)>, not ++C<(2 + 4) * 5>. So the expression yields C<2 + 20 == 22>, rather than ++C<6 * 5 == 30>. ++ ++I defines what happens if a sequence of the same ++operators is used one after another: whether they will be grouped at the left ++or the right. For example, in C<9 - 3 - 2>, subtraction is left associative, ++so C<9 - 3> is grouped together as the left-hand operand of the second ++subtraction, rather than C<3 - 2> being grouped together as the right-hand ++operand of the first subtraction. It is as if the expression were written ++C<(9 - 3) - 2>, not C<9 - (3 - 2)>. So the expression yields C<6 - 2 == 4>, ++rather than C<9 - 1 == 8>. ++ ++For simple operators that evaluate all their operands and then combine the ++values in some way, precedence and associativity (and parentheses) imply some ++ordering requirements on those combining operations. For example, in C<2 + 4 * ++5>, the grouping implied by precedence means that the multiplication of 4 and ++5 must be performed before the addition of 2 and 20, simply because the result ++of that multiplication is required as one of the operands of the addition. But ++the order of operations is not fully determined by this: in C<2 * 2 + 4 * 5> ++both multiplications must be performed before the addition, but the grouping ++does not say anything about the order in which the two multiplications are ++performed. In fact Perl has a general rule that the operands of an operator ++are evaluated in left-to-right order. A few operators such as C<&&=> have ++special evaluation rules that can result in an operand not being evaluated at ++all; in general, the top-level operator in an expression has control of ++operand evaluation. ++ ++Perl operators have the following associativity and precedence, ++listed from highest precedence to lowest. Operators borrowed from ++C keep the same precedence relationship with each other, even where ++C's precedence is slightly screwy. (This makes learning Perl easier ++for C folks.) With very few exceptions, these all operate on scalar ++values only, not array values. ++ ++ left terms and list operators (leftward) ++ left -> ++ nonassoc ++ -- ++ right ** ++ right ! ~ \ and unary + and - ++ left =~ !~ ++ left * / % x ++ left + - . ++ left << >> ++ nonassoc named unary operators ++ nonassoc < > <= >= lt gt le ge ++ nonassoc == != <=> eq ne cmp ~~ ++ left & ++ left | ^ ++ left && ++ left || // ++ nonassoc .. ... ++ right ?: ++ right = += -= *= etc. goto last next redo dump ++ left , => ++ nonassoc list operators (rightward) ++ right not ++ left and ++ left or xor ++ ++In the following sections, these operators are covered in detail, in the ++same order in which they appear in the table above. ++ ++Many operators can be overloaded for objects. See L. ++ ++=head2 Terms and List Operators (Leftward) ++X X X ++ ++A TERM has the highest precedence in Perl. They include variables, ++quote and quote-like operators, any expression in parentheses, ++and any function whose arguments are parenthesized. Actually, there ++aren't really functions in this sense, just list operators and unary ++operators behaving as functions because you put parentheses around ++the arguments. These are all documented in L. ++ ++If any list operator (C, etc.) or any unary operator (C, etc.) ++is followed by a left parenthesis as the next token, the operator and ++arguments within parentheses are taken to be of highest precedence, ++just like a normal function call. ++ ++In the absence of parentheses, the precedence of list operators such as ++C, C, or C is either very high or very low depending on ++whether you are looking at the left side or the right side of the operator. ++For example, in ++ ++ @ary = (1, 3, sort 4, 2); ++ print @ary; # prints 1324 ++ ++the commas on the right of the C are evaluated before the C, ++but the commas on the left are evaluated after. In other words, ++list operators tend to gobble up all arguments that follow, and ++then act like a simple TERM with regard to the preceding expression. ++Be careful with parentheses: ++ ++ # These evaluate exit before doing the print: ++ print($foo, exit); # Obviously not what you want. ++ print $foo, exit; # Nor is this. ++ ++ # These do the print before evaluating exit: ++ (print $foo), exit; # This is what you want. ++ print($foo), exit; # Or this. ++ print ($foo), exit; # Or even this. ++ ++Also note that ++ ++ print ($foo & 255) + 1, "\n"; ++ ++probably doesn't do what you expect at first glance. The parentheses ++enclose the argument list for C which is evaluated (printing ++the result of S>). Then one is added to the return value ++of C (usually 1). The result is something like this: ++ ++ 1 + 1, "\n"; # Obviously not what you meant. ++ ++To do what you meant properly, you must write: ++ ++ print(($foo & 255) + 1, "\n"); ++ ++See L for more discussion of this. ++ ++Also parsed as terms are the S> and S> constructs, as ++well as subroutine and method calls, and the anonymous ++constructors C<[]> and C<{}>. ++ ++See also L toward the end of this section, ++as well as L. ++ ++=head2 The Arrow Operator ++X X X<< -> >> ++ ++"C<< -> >>" is an infix dereference operator, just as it is in C ++and C++. If the right side is either a C<[...]>, C<{...}>, or a ++C<(...)> subscript, then the left side must be either a hard or ++symbolic reference to an array, a hash, or a subroutine respectively. ++(Or technically speaking, a location capable of holding a hard ++reference, if it's an array or hash reference being used for ++assignment.) See L and L. ++ ++Otherwise, the right side is a method name or a simple scalar ++variable containing either the method name or a subroutine reference, ++and the left side must be either an object (a blessed reference) ++or a class name (that is, a package name). See L. ++ ++The dereferencing cases (as opposed to method-calling cases) are ++somewhat extended by the C feature. For the ++details of that feature, consult L. ++ ++=head2 Auto-increment and Auto-decrement ++X X X<++> X X X<--> ++ ++C<"++"> and C<"--"> work as in C. That is, if placed before a variable, ++they increment or decrement the variable by one before returning the ++value, and if placed after, increment or decrement after returning the ++value. ++ ++ $i = 0; $j = 0; ++ print $i++; # prints 0 ++ print ++$j; # prints 1 ++ ++Note that just as in C, Perl doesn't define B the variable is ++incremented or decremented. You just know it will be done sometime ++before or after the value is returned. This also means that modifying ++a variable twice in the same statement will lead to undefined behavior. ++Avoid statements like: ++ ++ $i = $i ++; ++ print ++ $i + $i ++; ++ ++Perl will not guarantee what the result of the above statements is. ++ ++The auto-increment operator has a little extra builtin magic to it. If ++you increment a variable that is numeric, or that has ever been used in ++a numeric context, you get a normal increment. If, however, the ++variable has been used in only string contexts since it was set, and ++has a value that is not the empty string and matches the pattern ++C, the increment is done as a string, preserving each ++character within its range, with carry: ++ ++ print ++($foo = "99"); # prints "100" ++ print ++($foo = "a0"); # prints "a1" ++ print ++($foo = "Az"); # prints "Ba" ++ print ++($foo = "zz"); # prints "aaa" ++ ++C is always treated as numeric, and in particular is changed ++to C<0> before incrementing (so that a post-increment of an undef value ++will return C<0> rather than C). ++ ++The auto-decrement operator is not magical. ++ ++=head2 Exponentiation ++X<**> X X ++ ++Binary C<"**"> is the exponentiation operator. It binds even more ++tightly than unary minus, so C<-2**4> is C<-(2**4)>, not C<(-2)**4>. ++(This is ++implemented using C's C function, which actually works on doubles ++internally.) ++ ++Note that certain exponentiation expressions are ill-defined: ++these include C<0**0>, C<1**Inf>, and C. Do not expect ++any particular results from these special cases, the results ++are platform-dependent. ++ ++=head2 Symbolic Unary Operators ++X X ++ ++Unary C<"!"> performs logical negation, that is, "not". See also ++L|/Logical Not> for a lower precedence version of this. ++X ++ ++Unary C<"-"> performs arithmetic negation if the operand is numeric, ++including any string that looks like a number. If the operand is ++an identifier, a string consisting of a minus sign concatenated ++with the identifier is returned. Otherwise, if the string starts ++with a plus or minus, a string starting with the opposite sign is ++returned. One effect of these rules is that C<-bareword> is equivalent ++to the string C<"-bareword">. If, however, the string begins with a ++non-alphabetic character (excluding C<"+"> or C<"-">), Perl will attempt ++to convert ++the string to a numeric, and the arithmetic negation is performed. If the ++string cannot be cleanly converted to a numeric, Perl will give the warning ++B. ++X<-> X ++ ++Unary C<"~"> performs bitwise negation, that is, 1's complement. For ++example, S> is 0640. (See also L and ++L.) Note that the width of the result is ++platform-dependent: C<~0> is 32 bits wide on a 32-bit platform, but 64 ++bits wide on a 64-bit platform, so if you are expecting a certain bit ++width, remember to use the C<"&"> operator to mask off the excess bits. ++X<~> X ++ ++Starting in Perl 5.28, it is a fatal error to try to complement a string ++containing a character with an ordinal value above 255. ++ ++If the "bitwise" feature is enabled via S> or C, then unary ++C<"~"> always treats its argument as a number, and an ++alternate form of the operator, C<"~.">, always treats its argument as a ++string. So C<~0> and C<~"0"> will both give 2**32-1 on 32-bit platforms, ++whereas C<~.0> and C<~."0"> will both yield C<"\xff">. Until Perl 5.28, ++this feature produced a warning in the C<"experimental::bitwise"> category. ++ ++Unary C<"+"> has no effect whatsoever, even on strings. It is useful ++syntactically for separating a function name from a parenthesized expression ++that would otherwise be interpreted as the complete list of function ++arguments. (See examples above under L.) ++X<+> ++ ++Unary C<"\"> creates references. If its operand is a single sigilled ++thing, it creates a reference to that object. If its operand is a ++parenthesised list, then it creates references to the things mentioned ++in the list. Otherwise it puts its operand in list context, and creates ++a list of references to the scalars in the list provided by the operand. ++See L ++and L. Do not confuse this behavior with the behavior of ++backslash within a string, although both forms do convey the notion ++of protecting the next thing from interpolation. ++X<\> X X ++ ++=head2 Binding Operators ++X X X<=~> X ++ ++Binary C<"=~"> binds a scalar expression to a pattern match. Certain operations ++search or modify the string C<$_> by default. This operator makes that kind ++of operation work on some other string. The right argument is a search ++pattern, substitution, or transliteration. The left argument is what is ++supposed to be searched, substituted, or transliterated instead of the default ++C<$_>. When used in scalar context, the return value generally indicates the ++success of the operation. The exceptions are substitution (C) ++and transliteration (C) with the C (non-destructive) option, ++which cause the Beturn value to be the result of the substitution. ++Behavior in list context depends on the particular operator. ++See L for details and L for ++examples using these operators. ++ ++If the right argument is an expression rather than a search pattern, ++substitution, or transliteration, it is interpreted as a search pattern at run ++time. Note that this means that its ++contents will be interpolated twice, so ++ ++ '\\' =~ q'\\'; ++ ++is not ok, as the regex engine will end up trying to compile the ++pattern C<\>, which it will consider a syntax error. ++ ++Binary C<"!~"> is just like C<"=~"> except the return value is negated in ++the logical sense. ++ ++Binary C<"!~"> with a non-destructive substitution (C) or transliteration ++(C) is a syntax error. ++ ++=head2 Multiplicative Operators ++X ++ ++Binary C<"*"> multiplies two numbers. ++X<*> ++ ++Binary C<"/"> divides two numbers. ++X X ++ ++Binary C<"%"> is the modulo operator, which computes the division ++remainder of its first argument with respect to its second argument. ++Given integer ++operands C<$m> and C<$n>: If C<$n> is positive, then S> is ++C<$m> minus the largest multiple of C<$n> less than or equal to ++C<$m>. If C<$n> is negative, then S> is C<$m> minus the ++smallest multiple of C<$n> that is not less than C<$m> (that is, the ++result will be less than or equal to zero). If the operands ++C<$m> and C<$n> are floating point values and the absolute value of ++C<$n> (that is C) is less than S>, only ++the integer portion of C<$m> and C<$n> will be used in the operation ++(Note: here C means the maximum of the unsigned integer type). ++If the absolute value of the right operand (C) is greater than ++or equal to S>, C<"%"> computes the floating-point remainder ++C<$r> in the equation S> where C<$i> is a certain ++integer that makes C<$r> have the same sign as the right operand ++C<$n> (B as the left operand C<$m> like C function C) ++and the absolute value less than that of C<$n>. ++Note that when S> is in scope, C<"%"> gives you direct access ++to the modulo operator as implemented by your C compiler. This ++operator is not as well defined for negative operands, but it will ++execute faster. ++X<%> X X X ++ ++Binary C is the repetition operator. In scalar context, or if the ++left operand is neither enclosed in parentheses nor a C list, ++it performs a string repetition. In that case it supplies scalar ++context to the left operand, and returns a string consisting of the ++left operand string repeated the number of times specified by the right ++operand. If the C is in list context, and the left operand is either ++enclosed in parentheses or a C list, it performs a list repetition. ++In that case it supplies list context to the left operand, and returns ++a list consisting of the left operand list repeated the number of times ++specified by the right operand. ++If the right operand is zero or negative (raising a warning on ++negative), it returns an empty string ++or an empty list, depending on the context. ++X ++ ++ print '-' x 80; # print row of dashes ++ ++ print "\t" x ($tab/8), ' ' x ($tab%8); # tab over ++ ++ @ones = (1) x 80; # a list of 80 1's ++ @ones = (5) x @ones; # set all elements to 5 ++ ++ ++=head2 Additive Operators ++X ++ ++Binary C<"+"> returns the sum of two numbers. ++X<+> ++ ++Binary C<"-"> returns the difference of two numbers. ++X<-> ++ ++Binary C<"."> concatenates two strings. ++X X ++X X X X<.> ++ ++=head2 Shift Operators ++X X X<<< << >>> ++X<<< >> >>> X X X ++X X X X ++ ++Binary C<<< "<<" >>> returns the value of its left argument shifted left by the ++number of bits specified by the right argument. Arguments should be ++integers. (See also L.) ++ ++Binary C<<< ">>" >>> returns the value of its left argument shifted right by ++the number of bits specified by the right argument. Arguments should ++be integers. (See also L.) ++ ++If S> (see L) is in force then ++signed C integers are used (I), otherwise unsigned C ++integers are used (I), even for negative shiftees. ++In arithmetic right shift the sign bit is replicated on the left, ++in logical shift zero bits come in from the left. ++ ++Either way, the implementation isn't going to generate results larger ++than the size of the integer type Perl was built with (32 bits or 64 bits). ++ ++Shifting by negative number of bits means the reverse shift: left ++shift becomes right shift, right shift becomes left shift. This is ++unlike in C, where negative shift is undefined. ++ ++Shifting by more bits than the size of the integers means most of the ++time zero (all bits fall off), except that under S> ++right overshifting a negative shiftee results in -1. This is unlike ++in C, where shifting by too many bits is undefined. A common C ++behavior is "shift by modulo wordbits", so that for example ++ ++ 1 >> 64 == 1 >> (64 % 64) == 1 >> 0 == 1 # Common C behavior. ++ ++but that is completely accidental. ++ ++If you get tired of being subject to your platform's native integers, ++the S> pragma neatly sidesteps the issue altogether: ++ ++ print 20 << 20; # 20971520 ++ print 20 << 40; # 5120 on 32-bit machines, ++ # 21990232555520 on 64-bit machines ++ use bigint; ++ print 20 << 100; # 25353012004564588029934064107520 ++ ++=head2 Named Unary Operators ++X ++ ++The various named unary operators are treated as functions with one ++argument, with optional parentheses. ++ ++If any list operator (C, etc.) or any unary operator (C, etc.) ++is followed by a left parenthesis as the next token, the operator and ++arguments within parentheses are taken to be of highest precedence, ++just like a normal function call. For example, ++because named unary operators are higher precedence than C<||>: ++ ++ chdir $foo || die; # (chdir $foo) || die ++ chdir($foo) || die; # (chdir $foo) || die ++ chdir ($foo) || die; # (chdir $foo) || die ++ chdir +($foo) || die; # (chdir $foo) || die ++ ++but, because C<"*"> is higher precedence than named operators: ++ ++ chdir $foo * 20; # chdir ($foo * 20) ++ chdir($foo) * 20; # (chdir $foo) * 20 ++ chdir ($foo) * 20; # (chdir $foo) * 20 ++ chdir +($foo) * 20; # chdir ($foo * 20) ++ ++ rand 10 * 20; # rand (10 * 20) ++ rand(10) * 20; # (rand 10) * 20 ++ rand (10) * 20; # (rand 10) * 20 ++ rand +(10) * 20; # rand (10 * 20) ++ ++Regarding precedence, the filetest operators, like C<-f>, C<-M>, etc. are ++treated like named unary operators, but they don't follow this functional ++parenthesis rule. That means, for example, that C<-f($file).".bak"> is ++equivalent to S>. ++X<-X> X X ++ ++See also L. ++ ++=head2 Relational Operators ++X X ++ ++Perl operators that return true or false generally return values ++that can be safely used as numbers. For example, the relational ++operators in this section and the equality operators in the next ++one return C<1> for true and a special version of the defined empty ++string, C<"">, which counts as a zero but is exempt from warnings ++about improper numeric conversions, just as S> is. ++ ++Binary C<< "<" >> returns true if the left argument is numerically less than ++the right argument. ++X<< < >> ++ ++Binary C<< ">" >> returns true if the left argument is numerically greater ++than the right argument. ++X<< > >> ++ ++Binary C<< "<=" >> returns true if the left argument is numerically less than ++or equal to the right argument. ++X<< <= >> ++ ++Binary C<< ">=" >> returns true if the left argument is numerically greater ++than or equal to the right argument. ++X<< >= >> ++ ++Binary C<"lt"> returns true if the left argument is stringwise less than ++the right argument. ++X<< lt >> ++ ++Binary C<"gt"> returns true if the left argument is stringwise greater ++than the right argument. ++X<< gt >> ++ ++Binary C<"le"> returns true if the left argument is stringwise less than ++or equal to the right argument. ++X<< le >> ++ ++Binary C<"ge"> returns true if the left argument is stringwise greater ++than or equal to the right argument. ++X<< ge >> ++ ++=head2 Equality Operators ++X X X X ++ ++Binary C<< "==" >> returns true if the left argument is numerically equal to ++the right argument. ++X<==> ++ ++Binary C<< "!=" >> returns true if the left argument is numerically not equal ++to the right argument. ++X ++ ++Binary C<< "<=>" >> returns -1, 0, or 1 depending on whether the left ++argument is numerically less than, equal to, or greater than the right ++argument. If your platform supports C's (not-a-numbers) as numeric ++values, using them with C<< "<=>" >> returns undef. C is not ++C<< "<" >>, C<< "==" >>, C<< ">" >>, C<< "<=" >> or C<< ">=" >> anything ++(even C), so those 5 return false. S>> returns ++true, as does S I>. If your platform doesn't ++support C's then C is just a string with numeric value 0. ++X<< <=> >> ++X ++ ++ $ perl -le '$x = "NaN"; print "No NaN support here" if $x == $x' ++ $ perl -le '$x = "NaN"; print "NaN support here" if $x != $x' ++ ++(Note that the L, L, and L pragmas all ++support C<"NaN">.) ++ ++Binary C<"eq"> returns true if the left argument is stringwise equal to ++the right argument. ++X ++ ++Binary C<"ne"> returns true if the left argument is stringwise not equal ++to the right argument. ++X ++ ++Binary C<"cmp"> returns -1, 0, or 1 depending on whether the left ++argument is stringwise less than, equal to, or greater than the right ++argument. ++X ++ ++Binary C<"~~"> does a smartmatch between its arguments. Smart matching ++is described in the next section. ++X<~~> ++ ++C<"lt">, C<"le">, C<"ge">, C<"gt"> and C<"cmp"> use the collation (sort) ++order specified by the current C locale if a S> form that includes collation is in effect. See L. ++Do not mix these with Unicode, ++only use them with legacy 8-bit locale encodings. ++The standard C> and ++C> modules offer much more powerful ++solutions to collation issues. ++ ++For case-insensitive comparisons, look at the L case-folding ++function, available in Perl v5.16 or later: ++ ++ if ( fc($x) eq fc($y) ) { ... } ++ ++=head2 Smartmatch Operator ++ ++First available in Perl 5.10.1 (the 5.10.0 version behaved differently), ++binary C<~~> does a "smartmatch" between its arguments. This is mostly ++used implicitly in the C construct described in L, although ++not all C clauses call the smartmatch operator. Unique among all of ++Perl's operators, the smartmatch operator can recurse. The smartmatch ++operator is L and its behavior is ++subject to change. ++ ++It is also unique in that all other Perl operators impose a context ++(usually string or numeric context) on their operands, autoconverting ++those operands to those imposed contexts. In contrast, smartmatch ++I contexts from the actual types of its operands and uses that ++type information to select a suitable comparison mechanism. ++ ++The C<~~> operator compares its operands "polymorphically", determining how ++to compare them according to their actual types (numeric, string, array, ++hash, etc.). Like the equality operators with which it shares the same ++precedence, C<~~> returns 1 for true and C<""> for false. It is often best ++read aloud as "in", "inside of", or "is contained in", because the left ++operand is often looked for I the right operand. That makes the ++order of the operands to the smartmatch operand often opposite that of ++the regular match operator. In other words, the "smaller" thing is usually ++placed in the left operand and the larger one in the right. ++ ++The behavior of a smartmatch depends on what type of things its arguments ++are, as determined by the following table. The first row of the table ++whose types apply determines the smartmatch behavior. Because what ++actually happens is mostly determined by the type of the second operand, ++the table is sorted on the right operand instead of on the left. ++ ++ Left Right Description and pseudocode ++ =============================================================== ++ Any undef check whether Any is undefined ++ like: !defined Any ++ ++ Any Object invoke ~~ overloading on Object, or die ++ ++ Right operand is an ARRAY: ++ ++ Left Right Description and pseudocode ++ =============================================================== ++ ARRAY1 ARRAY2 recurse on paired elements of ARRAY1 and ARRAY2[2] ++ like: (ARRAY1[0] ~~ ARRAY2[0]) ++ && (ARRAY1[1] ~~ ARRAY2[1]) && ... ++ HASH ARRAY any ARRAY elements exist as HASH keys ++ like: grep { exists HASH->{$_} } ARRAY ++ Regexp ARRAY any ARRAY elements pattern match Regexp ++ like: grep { /Regexp/ } ARRAY ++ undef ARRAY undef in ARRAY ++ like: grep { !defined } ARRAY ++ Any ARRAY smartmatch each ARRAY element[3] ++ like: grep { Any ~~ $_ } ARRAY ++ ++ Right operand is a HASH: ++ ++ Left Right Description and pseudocode ++ =============================================================== ++ HASH1 HASH2 all same keys in both HASHes ++ like: keys HASH1 == ++ grep { exists HASH2->{$_} } keys HASH1 ++ ARRAY HASH any ARRAY elements exist as HASH keys ++ like: grep { exists HASH->{$_} } ARRAY ++ Regexp HASH any HASH keys pattern match Regexp ++ like: grep { /Regexp/ } keys HASH ++ undef HASH always false (undef can't be a key) ++ like: 0 == 1 ++ Any HASH HASH key existence ++ like: exists HASH->{Any} ++ ++ Right operand is CODE: ++ ++ Left Right Description and pseudocode ++ =============================================================== ++ ARRAY CODE sub returns true on all ARRAY elements[1] ++ like: !grep { !CODE->($_) } ARRAY ++ HASH CODE sub returns true on all HASH keys[1] ++ like: !grep { !CODE->($_) } keys HASH ++ Any CODE sub passed Any returns true ++ like: CODE->(Any) ++ ++Right operand is a Regexp: ++ ++ Left Right Description and pseudocode ++ =============================================================== ++ ARRAY Regexp any ARRAY elements match Regexp ++ like: grep { /Regexp/ } ARRAY ++ HASH Regexp any HASH keys match Regexp ++ like: grep { /Regexp/ } keys HASH ++ Any Regexp pattern match ++ like: Any =~ /Regexp/ ++ ++ Other: ++ ++ Left Right Description and pseudocode ++ =============================================================== ++ Object Any invoke ~~ overloading on Object, ++ or fall back to... ++ ++ Any Num numeric equality ++ like: Any == Num ++ Num nummy[4] numeric equality ++ like: Num == nummy ++ undef Any check whether undefined ++ like: !defined(Any) ++ Any Any string equality ++ like: Any eq Any ++ ++ ++Notes: ++ ++=over ++ ++=item 1. ++Empty hashes or arrays match. ++ ++=item 2. ++That is, each element smartmatches the element of the same index in the other array.[3] ++ ++=item 3. ++If a circular reference is found, fall back to referential equality. ++ ++=item 4. ++Either an actual number, or a string that looks like one. ++ ++=back ++ ++The smartmatch implicitly dereferences any non-blessed hash or array ++reference, so the C> and C> entries apply in those cases. ++For blessed references, the C> entries apply. Smartmatches ++involving hashes only consider hash keys, never hash values. ++ ++The "like" code entry is not always an exact rendition. For example, the ++smartmatch operator short-circuits whenever possible, but C does ++not. Also, C in scalar context returns the number of matches, but ++C<~~> returns only true or false. ++ ++Unlike most operators, the smartmatch operator knows to treat C ++specially: ++ ++ use v5.10.1; ++ @array = (1, 2, 3, undef, 4, 5); ++ say "some elements undefined" if undef ~~ @array; ++ ++Each operand is considered in a modified scalar context, the modification ++being that array and hash variables are passed by reference to the ++operator, which implicitly dereferences them. Both elements ++of each pair are the same: ++ ++ use v5.10.1; ++ ++ my %hash = (red => 1, blue => 2, green => 3, ++ orange => 4, yellow => 5, purple => 6, ++ black => 7, grey => 8, white => 9); ++ ++ my @array = qw(red blue green); ++ ++ say "some array elements in hash keys" if @array ~~ %hash; ++ say "some array elements in hash keys" if \@array ~~ \%hash; ++ ++ say "red in array" if "red" ~~ @array; ++ say "red in array" if "red" ~~ \@array; ++ ++ say "some keys end in e" if /e$/ ~~ %hash; ++ say "some keys end in e" if /e$/ ~~ \%hash; ++ ++Two arrays smartmatch if each element in the first array smartmatches ++(that is, is "in") the corresponding element in the second array, ++recursively. ++ ++ use v5.10.1; ++ my @little = qw(red blue green); ++ my @bigger = ("red", "blue", [ "orange", "green" ] ); ++ if (@little ~~ @bigger) { # true! ++ say "little is contained in bigger"; ++ } ++ ++Because the smartmatch operator recurses on nested arrays, this ++will still report that "red" is in the array. ++ ++ use v5.10.1; ++ my @array = qw(red blue green); ++ my $nested_array = [[[[[[[ @array ]]]]]]]; ++ say "red in array" if "red" ~~ $nested_array; ++ ++If two arrays smartmatch each other, then they are deep ++copies of each others' values, as this example reports: ++ ++ use v5.12.0; ++ my @a = (0, 1, 2, [3, [4, 5], 6], 7); ++ my @b = (0, 1, 2, [3, [4, 5], 6], 7); ++ ++ if (@a ~~ @b && @b ~~ @a) { ++ say "a and b are deep copies of each other"; ++ } ++ elsif (@a ~~ @b) { ++ say "a smartmatches in b"; ++ } ++ elsif (@b ~~ @a) { ++ say "b smartmatches in a"; ++ } ++ else { ++ say "a and b don't smartmatch each other at all"; ++ } ++ ++ ++If you were to set S>, then instead of reporting that "a and b ++are deep copies of each other", it now reports that C<"b smartmatches in a">. ++That's because the corresponding position in C<@a> contains an array that ++(eventually) has a 4 in it. ++ ++Smartmatching one hash against another reports whether both contain the ++same keys, no more and no less. This could be used to see whether two ++records have the same field names, without caring what values those fields ++might have. For example: ++ ++ use v5.10.1; ++ sub make_dogtag { ++ state $REQUIRED_FIELDS = { name=>1, rank=>1, serial_num=>1 }; ++ ++ my ($class, $init_fields) = @_; ++ ++ die "Must supply (only) name, rank, and serial number" ++ unless $init_fields ~~ $REQUIRED_FIELDS; ++ ++ ... ++ } ++ ++However, this only does what you mean if C<$init_fields> is indeed a hash ++reference. The condition C<$init_fields ~~ $REQUIRED_FIELDS> also allows the ++strings C<"name">, C<"rank">, C<"serial_num"> as well as any array reference ++that contains C<"name"> or C<"rank"> or C<"serial_num"> anywhere to pass ++through. ++ ++The smartmatch operator is most often used as the implicit operator of a ++C clause. See the section on "Switch Statements" in L. ++ ++=head3 Smartmatching of Objects ++ ++To avoid relying on an object's underlying representation, if the ++smartmatch's right operand is an object that doesn't overload C<~~>, ++it raises the exception "C". That's because one has no business digging ++around to see whether something is "in" an object. These are all ++illegal on objects without a C<~~> overload: ++ ++ %hash ~~ $object ++ 42 ~~ $object ++ "fred" ~~ $object ++ ++However, you can change the way an object is smartmatched by overloading ++the C<~~> operator. This is allowed to ++extend the usual smartmatch semantics. ++For objects that do have an C<~~> overload, see L. ++ ++Using an object as the left operand is allowed, although not very useful. ++Smartmatching rules take precedence over overloading, so even if the ++object in the left operand has smartmatch overloading, this will be ++ignored. A left operand that is a non-overloaded object falls back on a ++string or numeric comparison of whatever the C operator returns. That ++means that ++ ++ $object ~~ X ++ ++does I invoke the overload method with C> as an argument. ++Instead the above table is consulted as normal, and based on the type of ++C>, overloading may or may not be invoked. For simple strings or ++numbers, "in" becomes equivalent to this: ++ ++ $object ~~ $number ref($object) == $number ++ $object ~~ $string ref($object) eq $string ++ ++For example, this reports that the handle smells IOish ++(but please don't really do this!): ++ ++ use IO::Handle; ++ my $fh = IO::Handle->new(); ++ if ($fh ~~ /\bIO\b/) { ++ say "handle smells IOish"; ++ } ++ ++That's because it treats C<$fh> as a string like ++C<"IO::Handle=GLOB(0x8039e0)">, then pattern matches against that. ++ ++=head2 Bitwise And ++X X X<&> ++ ++Binary C<"&"> returns its operands ANDed together bit by bit. Although no ++warning is currently raised, the result is not well defined when this operation ++is performed on operands that aren't either numbers (see ++L) nor bitstrings (see L). ++ ++Note that C<"&"> has lower priority than relational operators, so for example ++the parentheses are essential in a test like ++ ++ print "Even\n" if ($x & 1) == 0; ++ ++If the "bitwise" feature is enabled via S> or ++C, then this operator always treats its operands as numbers. ++Before Perl 5.28 this feature produced a warning in the ++C<"experimental::bitwise"> category. ++ ++=head2 Bitwise Or and Exclusive Or ++X X X<|> X ++X X<^> ++ ++Binary C<"|"> returns its operands ORed together bit by bit. ++ ++Binary C<"^"> returns its operands XORed together bit by bit. ++ ++Although no warning is currently raised, the results are not well ++defined when these operations are performed on operands that aren't either ++numbers (see L) nor bitstrings (see L). ++ ++Note that C<"|"> and C<"^"> have lower priority than relational operators, so ++for example the parentheses are essential in a test like ++ ++ print "false\n" if (8 | 2) != 10; ++ ++If the "bitwise" feature is enabled via S> or ++C, then this operator always treats its operands as numbers. ++Before Perl 5.28. this feature produced a warning in the ++C<"experimental::bitwise"> category. ++ ++=head2 C-style Logical And ++X<&&> X X ++ ++Binary C<"&&"> performs a short-circuit logical AND operation. That is, ++if the left operand is false, the right operand is not even evaluated. ++Scalar or list context propagates down to the right operand if it ++is evaluated. ++ ++=head2 C-style Logical Or ++X<||> X ++ ++Binary C<"||"> performs a short-circuit logical OR operation. That is, ++if the left operand is true, the right operand is not even evaluated. ++Scalar or list context propagates down to the right operand if it ++is evaluated. ++ ++=head2 Logical Defined-Or ++X X ++ ++Although it has no direct equivalent in C, Perl's C operator is related ++to its C-style "or". In fact, it's exactly the same as C<||>, except that it ++tests the left hand side's definedness instead of its truth. Thus, ++S>> returns the value of C<< EXPR1 >> if it's defined, ++otherwise, the value of C<< EXPR2 >> is returned. ++(C<< EXPR1 >> is evaluated in scalar context, C<< EXPR2 >> ++in the context of C<< // >> itself). Usually, ++this is the same result as S>> (except that ++the ternary-operator form can be used as a lvalue, while S>> ++cannot). This is very useful for ++providing default values for variables. If you actually want to test if ++at least one of C<$x> and C<$y> is defined, use S>. ++ ++The C<||>, C and C<&&> operators return the last value evaluated ++(unlike C's C<||> and C<&&>, which return 0 or 1). Thus, a reasonably ++portable way to find out the home directory might be: ++ ++ $home = $ENV{HOME} ++ // $ENV{LOGDIR} ++ // (getpwuid($<))[7] ++ // die "You're homeless!\n"; ++ ++In particular, this means that you shouldn't use this ++for selecting between two aggregates for assignment: ++ ++ @a = @b || @c; # This doesn't do the right thing ++ @a = scalar(@b) || @c; # because it really means this. ++ @a = @b ? @b : @c; # This works fine, though. ++ ++As alternatives to C<&&> and C<||> when used for ++control flow, Perl provides the C and C operators (see below). ++The short-circuit behavior is identical. The precedence of C<"and"> ++and C<"or"> is much lower, however, so that you can safely use them after a ++list operator without the need for parentheses: ++ ++ unlink "alpha", "beta", "gamma" ++ or gripe(), next LINE; ++ ++With the C-style operators that would have been written like this: ++ ++ unlink("alpha", "beta", "gamma") ++ || (gripe(), next LINE); ++ ++It would be even more readable to write that this way: ++ ++ unless(unlink("alpha", "beta", "gamma")) { ++ gripe(); ++ next LINE; ++ } ++ ++Using C<"or"> for assignment is unlikely to do what you want; see below. ++ ++=head2 Range Operators ++X X X<..> X<...> ++ ++Binary C<".."> is the range operator, which is really two different ++operators depending on the context. In list context, it returns a ++list of values counting (up by ones) from the left value to the right ++value. If the left value is greater than the right value then it ++returns the empty list. The range operator is useful for writing ++S> loops and for doing slice operations on arrays. In ++the current implementation, no temporary array is created when the ++range operator is used as the expression in C loops, but older ++versions of Perl might burn a lot of memory when you write something ++like this: ++ ++ for (1 .. 1_000_000) { ++ # code ++ } ++ ++The range operator also works on strings, using the magical ++auto-increment, see below. ++ ++In scalar context, C<".."> returns a boolean value. The operator is ++bistable, like a flip-flop, and emulates the line-range (comma) ++operator of B, B, and various editors. Each C<".."> operator ++maintains its own boolean state, even across calls to a subroutine ++that contains it. It is false as long as its left operand is false. ++Once the left operand is true, the range operator stays true until the ++right operand is true, I which the range operator becomes false ++again. It doesn't become false till the next time the range operator ++is evaluated. It can test the right operand and become false on the ++same evaluation it became true (as in B), but it still returns ++true once. If you don't want it to test the right operand until the ++next evaluation, as in B, just use three dots (C<"...">) instead of ++two. In all other regards, C<"..."> behaves just like C<".."> does. ++ ++The right operand is not evaluated while the operator is in the ++"false" state, and the left operand is not evaluated while the ++operator is in the "true" state. The precedence is a little lower ++than || and &&. The value returned is either the empty string for ++false, or a sequence number (beginning with 1) for true. The sequence ++number is reset for each range encountered. The final sequence number ++in a range has the string C<"E0"> appended to it, which doesn't affect ++its numeric value, but gives you something to search for if you want ++to exclude the endpoint. You can exclude the beginning point by ++waiting for the sequence number to be greater than 1. ++ ++If either operand of scalar C<".."> is a constant expression, ++that operand is considered true if it is equal (C<==>) to the current ++input line number (the C<$.> variable). ++ ++To be pedantic, the comparison is actually S>, ++but that is only an issue if you use a floating point expression; when ++implicitly using C<$.> as described in the previous paragraph, the ++comparison is S> which is only an issue when C<$.> ++is set to a floating point value and you are not reading from a file. ++Furthermore, S> or S> will not do what ++you want in scalar context because each of the operands are evaluated ++using their integer representation. ++ ++Examples: ++ ++As a scalar operator: ++ ++ if (101 .. 200) { print; } # print 2nd hundred lines, short for ++ # if ($. == 101 .. $. == 200) { print; } ++ ++ next LINE if (1 .. /^$/); # skip header lines, short for ++ # next LINE if ($. == 1 .. /^$/); ++ # (typically in a loop labeled LINE) ++ ++ s/^/> / if (/^$/ .. eof()); # quote body ++ ++ # parse mail messages ++ while (<>) { ++ $in_header = 1 .. /^$/; ++ $in_body = /^$/ .. eof; ++ if ($in_header) { ++ # do something ++ } else { # in body ++ # do something else ++ } ++ } continue { ++ close ARGV if eof; # reset $. each file ++ } ++ ++Here's a simple example to illustrate the difference between ++the two range operators: ++ ++ @lines = (" - Foo", ++ "01 - Bar", ++ "1 - Baz", ++ " - Quux"); ++ ++ foreach (@lines) { ++ if (/0/ .. /1/) { ++ print "$_\n"; ++ } ++ } ++ ++This program will print only the line containing "Bar". If ++the range operator is changed to C<...>, it will also print the ++"Baz" line. ++ ++And now some examples as a list operator: ++ ++ for (101 .. 200) { print } # print $_ 100 times ++ @foo = @foo[0 .. $#foo]; # an expensive no-op ++ @foo = @foo[$#foo-4 .. $#foo]; # slice last 5 items ++ ++The range operator (in list context) makes use of the magical ++auto-increment algorithm if the operands are strings. You ++can say ++ ++ @alphabet = ("A" .. "Z"); ++ ++to get all normal letters of the English alphabet, or ++ ++ $hexdigit = (0 .. 9, "a" .. "f")[$num & 15]; ++ ++to get a hexadecimal digit, or ++ ++ @z2 = ("01" .. "31"); ++ print $z2[$mday]; ++ ++to get dates with leading zeros. ++ ++If the final value specified is not in the sequence that the magical ++increment would produce, the sequence goes until the next value would ++be longer than the final value specified. ++ ++As of Perl 5.26, the list-context range operator on strings works as expected ++in the scope of L<< S>|feature/The ++'unicode_strings' feature >>. In previous versions, and outside the scope of ++that feature, it exhibits L: its behavior ++depends on the internal encoding of the range endpoint. ++ ++If the initial value specified isn't part of a magical increment ++sequence (that is, a non-empty string matching C), ++only the initial value will be returned. So the following will only ++return an alpha: ++ ++ use charnames "greek"; ++ my @greek_small = ("\N{alpha}" .. "\N{omega}"); ++ ++To get the 25 traditional lowercase Greek letters, including both sigmas, ++you could use this instead: ++ ++ use charnames "greek"; ++ my @greek_small = map { chr } ( ord("\N{alpha}") ++ .. ++ ord("\N{omega}") ++ ); ++ ++However, because there are I other lowercase Greek characters than ++just those, to match lowercase Greek characters in a regular expression, ++you could use the pattern C (or the ++L C>). ++ ++Because each operand is evaluated in integer form, S> will ++return two elements in list context. ++ ++ @list = (2.18 .. 3.14); # same as @list = (2 .. 3); ++ ++=head2 Conditional Operator ++X X X X ++ ++Ternary C<"?:"> is the conditional operator, just as in C. It works much ++like an if-then-else. If the argument before the C is true, the ++argument before the C<:> is returned, otherwise the argument after the ++C<:> is returned. For example: ++ ++ printf "I have %d dog%s.\n", $n, ++ ($n == 1) ? "" : "s"; ++ ++Scalar or list context propagates downward into the 2nd ++or 3rd argument, whichever is selected. ++ ++ $x = $ok ? $y : $z; # get a scalar ++ @x = $ok ? @y : @z; # get an array ++ $x = $ok ? @y : @z; # oops, that's just a count! ++ ++The operator may be assigned to if both the 2nd and 3rd arguments are ++legal lvalues (meaning that you can assign to them): ++ ++ ($x_or_y ? $x : $y) = $z; ++ ++Because this operator produces an assignable result, using assignments ++without parentheses will get you in trouble. For example, this: ++ ++ $x % 2 ? $x += 10 : $x += 2 ++ ++Really means this: ++ ++ (($x % 2) ? ($x += 10) : $x) += 2 ++ ++Rather than this: ++ ++ ($x % 2) ? ($x += 10) : ($x += 2) ++ ++That should probably be written more simply as: ++ ++ $x += ($x % 2) ? 10 : 2; ++ ++=head2 Assignment Operators ++X X X<=> X<**=> X<+=> X<*=> X<&=> ++X<<< <<= >>> X<&&=> X<-=> X X<|=> X<<< >>= >>> X<||=> X X<.=> ++X<%=> X<^=> X X<&.=> X<|.=> X<^.=> ++ ++C<"="> is the ordinary assignment operator. ++ ++Assignment operators work as in C. That is, ++ ++ $x += 2; ++ ++is equivalent to ++ ++ $x = $x + 2; ++ ++although without duplicating any side effects that dereferencing the lvalue ++might trigger, such as from C. Other assignment operators work similarly. ++The following are recognized: ++ ++ **= += *= &= &.= <<= &&= ++ -= /= |= |.= >>= ||= ++ .= %= ^= ^.= //= ++ x= ++ ++Although these are grouped by family, they all have the precedence ++of assignment. These combined assignment operators can only operate on ++scalars, whereas the ordinary assignment operator can assign to arrays, ++hashes, lists and even references. (See L<"Context"|perldata/Context> ++and L, and L.) ++ ++Unlike in C, the scalar assignment operator produces a valid lvalue. ++Modifying an assignment is equivalent to doing the assignment and ++then modifying the variable that was assigned to. This is useful ++for modifying a copy of something, like this: ++ ++ ($tmp = $global) =~ tr/13579/24680/; ++ ++Although as of 5.14, that can be also be accomplished this way: ++ ++ use v5.14; ++ $tmp = ($global =~ tr/13579/24680/r); ++ ++Likewise, ++ ++ ($x += 2) *= 3; ++ ++is equivalent to ++ ++ $x += 2; ++ $x *= 3; ++ ++Similarly, a list assignment in list context produces the list of ++lvalues assigned to, and a list assignment in scalar context returns ++the number of elements produced by the expression on the right hand ++side of the assignment. ++ ++The three dotted bitwise assignment operators (C<&.=> C<|.=> C<^.=>) are new in ++Perl 5.22. See L. ++ ++=head2 Comma Operator ++X X X<,> ++ ++Binary C<","> is the comma operator. In scalar context it evaluates ++its left argument, throws that value away, then evaluates its right ++argument and returns that value. This is just like C's comma operator. ++ ++In list context, it's just the list argument separator, and inserts ++both its arguments into the list. These arguments are also evaluated ++from left to right. ++ ++The C<< => >> operator (sometimes pronounced "fat comma") is a synonym ++for the comma except that it causes a ++word on its left to be interpreted as a string if it begins with a letter ++or underscore and is composed only of letters, digits and underscores. ++This includes operands that might otherwise be interpreted as operators, ++constants, single number v-strings or function calls. If in doubt about ++this behavior, the left operand can be quoted explicitly. ++ ++Otherwise, the C<< => >> operator behaves exactly as the comma operator ++or list argument separator, according to context. ++ ++For example: ++ ++ use constant FOO => "something"; ++ ++ my %h = ( FOO => 23 ); ++ ++is equivalent to: ++ ++ my %h = ("FOO", 23); ++ ++It is I: ++ ++ my %h = ("something", 23); ++ ++The C<< => >> operator is helpful in documenting the correspondence ++between keys and values in hashes, and other paired elements in lists. ++ ++ %hash = ( $key => $value ); ++ login( $username => $password ); ++ ++The special quoting behavior ignores precedence, and hence may apply to ++I of the left operand: ++ ++ print time.shift => "bbb"; ++ ++That example prints something like C<"1314363215shiftbbb">, because the ++C<< => >> implicitly quotes the C immediately on its left, ignoring ++the fact that C is the entire left operand. ++ ++=head2 List Operators (Rightward) ++X X ++ ++On the right side of a list operator, the comma has very low precedence, ++such that it controls all comma-separated expressions found there. ++The only operators with lower precedence are the logical operators ++C<"and">, C<"or">, and C<"not">, which may be used to evaluate calls to list ++operators without the need for parentheses: ++ ++ open HANDLE, "< :encoding(UTF-8)", "filename" ++ or die "Can't open: $!\n"; ++ ++However, some people find that code harder to read than writing ++it with parentheses: ++ ++ open(HANDLE, "< :encoding(UTF-8)", "filename") ++ or die "Can't open: $!\n"; ++ ++in which case you might as well just use the more customary C<"||"> operator: ++ ++ open(HANDLE, "< :encoding(UTF-8)", "filename") ++ || die "Can't open: $!\n"; ++ ++See also discussion of list operators in L. ++ ++=head2 Logical Not ++X X ++ ++Unary C<"not"> returns the logical negation of the expression to its right. ++It's the equivalent of C<"!"> except for the very low precedence. ++ ++=head2 Logical And ++X X ++ ++Binary C<"and"> returns the logical conjunction of the two surrounding ++expressions. It's equivalent to C<&&> except for the very low ++precedence. This means that it short-circuits: the right ++expression is evaluated only if the left expression is true. ++ ++=head2 Logical or and Exclusive Or ++X X ++X ++X X ++ ++Binary C<"or"> returns the logical disjunction of the two surrounding ++expressions. It's equivalent to C<||> except for the very low precedence. ++This makes it useful for control flow: ++ ++ print FH $data or die "Can't write to FH: $!"; ++ ++This means that it short-circuits: the right expression is evaluated ++only if the left expression is false. Due to its precedence, you must ++be careful to avoid using it as replacement for the C<||> operator. ++It usually works out better for flow control than in assignments: ++ ++ $x = $y or $z; # bug: this is wrong ++ ($x = $y) or $z; # really means this ++ $x = $y || $z; # better written this way ++ ++However, when it's a list-context assignment and you're trying to use ++C<||> for control flow, you probably need C<"or"> so that the assignment ++takes higher precedence. ++ ++ @info = stat($file) || die; # oops, scalar sense of stat! ++ @info = stat($file) or die; # better, now @info gets its due ++ ++Then again, you could always use parentheses. ++ ++Binary C<"xor"> returns the exclusive-OR of the two surrounding expressions. ++It cannot short-circuit (of course). ++ ++There is no low precedence operator for defined-OR. ++ ++=head2 C Operators Missing From Perl ++X X<&> X<*> ++X X<(TYPE)> ++ ++Here is what C has that Perl doesn't: ++ ++=over 8 ++ ++=item unary & ++ ++Address-of operator. (But see the C<"\"> operator for taking a reference.) ++ ++=item unary * ++ ++Dereference-address operator. (Perl's prefix dereferencing ++operators are typed: C<$>, C<@>, C<%>, and C<&>.) ++ ++=item (TYPE) ++ ++Type-casting operator. ++ ++=back ++ ++=head2 Quote and Quote-like Operators ++X X X X X X X ++X X X X<'> X<''> X<"> X<""> X X<`> X<``> X<<< << >>> ++X X ++ ++While we usually think of quotes as literal values, in Perl they ++function as operators, providing various kinds of interpolating and ++pattern matching capabilities. Perl provides customary quote characters ++for these behaviors, but also provides a way for you to choose your ++quote character for any of them. In the following table, a C<{}> represents ++any pair of delimiters you choose. ++ ++ Customary Generic Meaning Interpolates ++ '' q{} Literal no ++ "" qq{} Literal yes ++ `` qx{} Command yes* ++ qw{} Word list no ++ // m{} Pattern match yes* ++ qr{} Pattern yes* ++ s{}{} Substitution yes* ++ tr{}{} Transliteration no (but see below) ++ y{}{} Transliteration no (but see below) ++ <> module (standard as of v5.8, ++and from CPAN before then) is able to do this properly. ++ ++There can (and in some cases, must) be whitespace between the operator ++and the quoting ++characters, except when C<#> is being used as the quoting character. ++C is parsed as the string C, while S> is the ++operator C followed by a comment. Its argument will be taken ++from the next line. This allows you to write: ++ ++ s {foo} # Replace foo ++ {bar} # with bar. ++ ++The cases where whitespace must be used are when the quoting character ++is a word character (meaning it matches C): ++ ++ q XfooX # Works: means the string 'foo' ++ qXfooX # WRONG! ++ ++The following escape sequences are available in constructs that interpolate, ++and in transliterations whose delimiters aren't single quotes (C<"'">). ++X<\t> X<\n> X<\r> X<\f> X<\b> X<\a> X<\e> X<\x> X<\0> X<\c> X<\N> X<\N{}> ++X<\o{}> ++ ++ Sequence Note Description ++ \t tab (HT, TAB) ++ \n newline (NL) ++ \r return (CR) ++ \f form feed (FF) ++ \b backspace (BS) ++ \a alarm (bell) (BEL) ++ \e escape (ESC) ++ \x{263A} [1,8] hex char (example: SMILEY) ++ \x1b [2,8] restricted range hex char (example: ESC) ++ \N{name} [3] named Unicode character or character sequence ++ \N{U+263D} [4,8] Unicode character (example: FIRST QUARTER MOON) ++ \c[ [5] control char (example: chr(27)) ++ \o{23072} [6,8] octal char (example: SMILEY) ++ \033 [7,8] restricted range octal char (example: ESC) ++ ++=over 4 ++ ++=item [1] ++ ++The result is the character specified by the hexadecimal number between ++the braces. See L below for details on which character. ++ ++Only hexadecimal digits are valid between the braces. If an invalid ++character is encountered, a warning will be issued and the invalid ++character and all subsequent characters (valid or invalid) within the ++braces will be discarded. ++ ++If there are no valid digits between the braces, the generated character is ++the NULL character (C<\x{00}>). However, an explicit empty brace (C<\x{}>) ++will not cause a warning (currently). ++ ++=item [2] ++ ++The result is the character specified by the hexadecimal number in the range ++0x00 to 0xFF. See L below for details on which character. ++ ++Only hexadecimal digits are valid following C<\x>. When C<\x> is followed ++by fewer than two valid digits, any valid digits will be zero-padded. This ++means that C<\x7> will be interpreted as C<\x07>, and a lone C<"\x"> will be ++interpreted as C<\x00>. Except at the end of a string, having fewer than ++two valid digits will result in a warning. Note that although the warning ++says the illegal character is ignored, it is only ignored as part of the ++escape and will still be used as the subsequent character in the string. ++For example: ++ ++ Original Result Warns? ++ "\x7" "\x07" no ++ "\x" "\x00" no ++ "\x7q" "\x07q" yes ++ "\xq" "\x00q" yes ++ ++=item [3] ++ ++The result is the Unicode character or character sequence given by I. ++See L. ++ ++=item [4] ++ ++S}>> means the Unicode character whose Unicode code ++point is I. ++ ++=item [5] ++ ++The character following C<\c> is mapped to some other character as shown in the ++table: ++ ++ Sequence Value ++ \c@ chr(0) ++ \cA chr(1) ++ \ca chr(1) ++ \cB chr(2) ++ \cb chr(2) ++ ... ++ \cZ chr(26) ++ \cz chr(26) ++ \c[ chr(27) ++ # See below for chr(28) ++ \c] chr(29) ++ \c^ chr(30) ++ \c_ chr(31) ++ \c? chr(127) # (on ASCII platforms; see below for link to ++ # EBCDIC discussion) ++ ++In other words, it's the character whose code point has had 64 xor'd with ++its uppercase. C<\c?> is DELETE on ASCII platforms because ++S> is 127, and ++C<\c@> is NULL because the ord of C<"@"> is 64, so xor'ing 64 itself produces 0. ++ ++Also, C<\c\I> yields S">> for any I, but cannot come at the ++end of a string, because the backslash would be parsed as escaping the end ++quote. ++ ++On ASCII platforms, the resulting characters from the list above are the ++complete set of ASCII controls. This isn't the case on EBCDIC platforms; see ++L for a full discussion of the ++differences between these for ASCII versus EBCDIC platforms. ++ ++Use of any other character following the C<"c"> besides those listed above is ++discouraged, and as of Perl v5.20, the only characters actually allowed ++are the printable ASCII ones, minus the left brace C<"{">. What happens ++for any of the allowed other characters is that the value is derived by ++xor'ing with the seventh bit, which is 64, and a warning raised if ++enabled. Using the non-allowed characters generates a fatal error. ++ ++To get platform independent controls, you can use C<\N{...}>. ++ ++=item [6] ++ ++The result is the character specified by the octal number between the braces. ++See L below for details on which character. ++ ++If a character that isn't an octal digit is encountered, a warning is raised, ++and the value is based on the octal digits before it, discarding it and all ++following characters up to the closing brace. It is a fatal error if there are ++no octal digits at all. ++ ++=item [7] ++ ++The result is the character specified by the three-digit octal number in the ++range 000 to 777 (but best to not use above 077, see next paragraph). See ++L below for details on which character. ++ ++Some contexts allow 2 or even 1 digit, but any usage without exactly ++three digits, the first being a zero, may give unintended results. (For ++example, in a regular expression it may be confused with a backreference; ++see L.) Starting in Perl 5.14, you may ++use C<\o{}> instead, which avoids all these problems. Otherwise, it is best to ++use this construct only for ordinals C<\077> and below, remembering to pad to ++the left with zeros to make three digits. For larger ordinals, either use ++C<\o{}>, or convert to something else, such as to hex and use C<\N{U+}> ++(which is portable between platforms with different character sets) or ++C<\x{}> instead. ++ ++=item [8] ++ ++Several constructs above specify a character by a number. That number ++gives the character's position in the character set encoding (indexed from 0). ++This is called synonymously its ordinal, code position, or code point. Perl ++works on platforms that have a native encoding currently of either ASCII/Latin1 ++or EBCDIC, each of which allow specification of 256 characters. In general, if ++the number is 255 (0xFF, 0377) or below, Perl interprets this in the platform's ++native encoding. If the number is 256 (0x100, 0400) or above, Perl interprets ++it as a Unicode code point and the result is the corresponding Unicode ++character. For example C<\x{50}> and C<\o{120}> both are the number 80 in ++decimal, which is less than 256, so the number is interpreted in the native ++character set encoding. In ASCII the character in the 80th position (indexed ++from 0) is the letter C<"P">, and in EBCDIC it is the ampersand symbol C<"&">. ++C<\x{100}> and C<\o{400}> are both 256 in decimal, so the number is interpreted ++as a Unicode code point no matter what the native encoding is. The name of the ++character in the 256th position (indexed by 0) in Unicode is ++C. ++ ++An exception to the above rule is that S}>> is ++always interpreted as a Unicode code point, so that C<\N{U+0050}> is C<"P"> even ++on EBCDIC platforms. ++ ++=back ++ ++B: Unlike C and other languages, Perl has no C<\v> escape sequence for ++the vertical tab (VT, which is 11 in both ASCII and EBCDIC), but you may ++use C<\N{VT}>, C<\ck>, C<\N{U+0b}>, or C<\x0b>. (C<\v> ++does have meaning in regular expression patterns in Perl, see L.) ++ ++The following escape sequences are available in constructs that interpolate, ++but not in transliterations. ++X<\l> X<\u> X<\L> X<\U> X<\E> X<\Q> X<\F> ++ ++ \l lowercase next character only ++ \u titlecase (not uppercase!) next character only ++ \L lowercase all characters till \E or end of string ++ \U uppercase all characters till \E or end of string ++ \F foldcase all characters till \E or end of string ++ \Q quote (disable) pattern metacharacters till \E or ++ end of string ++ \E end either case modification or quoted section ++ (whichever was last seen) ++ ++See L for the exact definition of characters that ++are quoted by C<\Q>. ++ ++C<\L>, C<\U>, C<\F>, and C<\Q> can stack, in which case you need one ++C<\E> for each. For example: ++ ++ say"This \Qquoting \ubusiness \Uhere isn't quite\E done yet,\E is it?"; ++ This quoting\ Business\ HERE\ ISN\'T\ QUITE\ done\ yet\, is it? ++ ++If a S> form that includes C is in effect (see ++L), the case map used by C<\l>, C<\L>, C<\u>, and C<\U> is ++taken from the current locale. If Unicode (for example, C<\N{}> or code ++points of 0x100 or beyond) is being used, the case map used by C<\l>, ++C<\L>, C<\u>, and C<\U> is as defined by Unicode. That means that ++case-mapping a single character can sometimes produce a sequence of ++several characters. ++Under S>, C<\F> produces the same results as C<\L> ++for all locales but a UTF-8 one, where it instead uses the Unicode ++definition. ++ ++All systems use the virtual C<"\n"> to represent a line terminator, ++called a "newline". There is no such thing as an unvarying, physical ++newline character. It is only an illusion that the operating system, ++device drivers, C libraries, and Perl all conspire to preserve. Not all ++systems read C<"\r"> as ASCII CR and C<"\n"> as ASCII LF. For example, ++on the ancient Macs (pre-MacOS X) of yesteryear, these used to be reversed, ++and on systems without a line terminator, ++printing C<"\n"> might emit no actual data. In general, use C<"\n"> when ++you mean a "newline" for your system, but use the literal ASCII when you ++need an exact character. For example, most networking protocols expect ++and prefer a CR+LF (C<"\015\012"> or C<"\cM\cJ">) for line terminators, ++and although they often accept just C<"\012">, they seldom tolerate just ++C<"\015">. If you get in the habit of using C<"\n"> for networking, ++you may be burned some day. ++X X X X ++X<\n> X<\r> X<\r\n> ++ ++For constructs that do interpolate, variables beginning with "C<$>" ++or "C<@>" are interpolated. Subscripted variables such as C<$a[3]> or ++C<< $href->{key}[0] >> are also interpolated, as are array and hash slices. ++But method calls such as C<< $obj->meth >> are not. ++ ++Interpolating an array or slice interpolates the elements in order, ++separated by the value of C<$">, so is equivalent to interpolating ++S>. "Punctuation" arrays such as C<@*> are usually ++interpolated only if the name is enclosed in braces C<@{*}>, but the ++arrays C<@_>, C<@+>, and C<@-> are interpolated even without braces. ++ ++For double-quoted strings, the quoting from C<\Q> is applied after ++interpolation and escapes are processed. ++ ++ "abc\Qfoo\tbar$s\Exyz" ++ ++is equivalent to ++ ++ "abc" . quotemeta("foo\tbar$s") . "xyz" ++ ++For the pattern of regex operators (C, C and C), ++the quoting from C<\Q> is applied after interpolation is processed, ++but before escapes are processed. This allows the pattern to match ++literally (except for C<$> and C<@>). For example, the following matches: ++ ++ '\s\t' =~ /\Q\s\t/ ++ ++Because C<$> or C<@> trigger interpolation, you'll need to use something ++like C to match them literally. ++ ++Patterns are subject to an additional level of interpretation as a ++regular expression. This is done as a second pass, after variables are ++interpolated, so that regular expressions may be incorporated into the ++pattern from the variables. If this is not what you want, use C<\Q> to ++interpolate a variable literally. ++ ++Apart from the behavior described above, Perl does not expand ++multiple levels of interpolation. In particular, contrary to the ++expectations of shell programmers, back-quotes do I interpolate ++within double quotes, nor do single quotes impede evaluation of ++variables when used within double quotes. ++ ++=head2 Regexp Quote-Like Operators ++X ++ ++Here are the quote-like operators that apply to pattern ++matching and related activities. ++ ++=over 8 ++ ++=item C/msixpodualn> ++X X X X X X X

++ ++This operator quotes (and possibly compiles) its I as a regular ++expression. I is interpolated the same way as I ++in C/>. If C<"'"> is used as the delimiter, no variable ++interpolation is done. Returns a Perl value which may be used instead of the ++corresponding C/msixpodualn> expression. The returned value is a ++normalized version of the original pattern. It magically differs from ++a string containing the same characters: C returns "Regexp"; ++however, dereferencing it is not well defined (you currently get the ++normalized version of the original pattern, but this may change). ++ ++ ++For example, ++ ++ $rex = qr/my.STRING/is; ++ print $rex; # prints (?si-xm:my.STRING) ++ s/$rex/foo/; ++ ++is equivalent to ++ ++ s/my.STRING/foo/is; ++ ++The result may be used as a subpattern in a match: ++ ++ $re = qr/$pattern/; ++ $string =~ /foo${re}bar/; # can be interpolated in other ++ # patterns ++ $string =~ $re; # or used standalone ++ $string =~ /$re/; # or this way ++ ++Since Perl may compile the pattern at the moment of execution of the C ++operator, using C may have speed advantages in some situations, ++notably if the result of C is used standalone: ++ ++ sub match { ++ my $patterns = shift; ++ my @compiled = map qr/$_/i, @$patterns; ++ grep { ++ my $success = 0; ++ foreach my $pat (@compiled) { ++ $success = 1, last if /$pat/; ++ } ++ $success; ++ } @_; ++ } ++ ++Precompilation of the pattern into an internal representation at ++the moment of C avoids the need to recompile the pattern every ++time a match C is attempted. (Perl has many other internal ++optimizations, but none would be triggered in the above example if ++we did not use C operator.) ++ ++Options (specified by the following modifiers) are: ++ ++ m Treat string as multiple lines. ++ s Treat string as single line. (Make . match a newline) ++ i Do case-insensitive pattern matching. ++ x Use extended regular expressions; specifying two ++ x's means \t and the SPACE character are ignored within ++ square-bracketed character classes ++ p When matching preserve a copy of the matched string so ++ that ${^PREMATCH}, ${^MATCH}, ${^POSTMATCH} will be ++ defined (ignored starting in v5.20) as these are always ++ defined starting in that release ++ o Compile pattern only once. ++ a ASCII-restrict: Use ASCII for \d, \s, \w and [[:posix:]] ++ character classes; specifying two a's adds the further ++ restriction that no ASCII character will match a ++ non-ASCII one under /i. ++ l Use the current run-time locale's rules. ++ u Use Unicode rules. ++ d Use Unicode or native charset, as in 5.12 and earlier. ++ n Non-capture mode. Don't let () fill in $1, $2, etc... ++ ++If a precompiled pattern is embedded in a larger pattern then the effect ++of C<"msixpluadn"> will be propagated appropriately. The effect that the ++C modifier has is not propagated, being restricted to those patterns ++explicitly using it. ++ ++The C, C, C, and C modifiers (added in Perl 5.14) ++control the character set rules, but C is the only one you are likely ++to want to specify explicitly; the other three are selected ++automatically by various pragmas. ++ ++See L for additional information on valid syntax for I, and ++for a detailed look at the semantics of regular expressions. In ++particular, all modifiers except the largely obsolete C are further ++explained in L. C is described in the next section. ++ ++=item C/msixpodualngc> ++X X ++X X X X ++X X X X X

X X X ++ ++=item C/msixpodualngc> ++ ++Searches a string for a pattern match, and in scalar context returns ++true if it succeeds, false if it fails. If no string is specified ++via the C<=~> or C operator, the C<$_> string is searched. (The ++string specified with C<=~> need not be an lvalue--it may be the ++result of an expression evaluation, but remember the C<=~> binds ++rather tightly.) See also L. ++ ++Options are as described in C above; in addition, the following match ++process modifiers are available: ++ ++ g Match globally, i.e., find all occurrences. ++ c Do not reset search position on a failed match when /g is ++ in effect. ++ ++If C<"/"> is the delimiter then the initial C is optional. With the C ++you can use any pair of non-whitespace (ASCII) characters ++as delimiters. This is particularly useful for matching path names ++that contain C<"/">, to avoid LTS (leaning toothpick syndrome). If C<"?"> is ++the delimiter, then a match-only-once rule applies, ++described in C?> below. If C<"'"> (single quote) is the delimiter, ++no variable interpolation is performed on the I. ++When using a delimiter character valid in an identifier, whitespace is required ++after the C. ++ ++I may contain variables, which will be interpolated ++every time the pattern search is evaluated, except ++for when the delimiter is a single quote. (Note that C<$(>, C<$)>, and ++C<$|> are not interpolated because they look like end-of-string tests.) ++Perl will not recompile the pattern unless an interpolated ++variable that it contains changes. You can force Perl to skip the ++test and never recompile by adding a C (which stands for "once") ++after the trailing delimiter. ++Once upon a time, Perl would recompile regular expressions ++unnecessarily, and this modifier was useful to tell it not to do so, in the ++interests of speed. But now, the only reasons to use C are one of: ++ ++=over ++ ++=item 1 ++ ++The variables are thousands of characters long and you know that they ++don't change, and you need to wring out the last little bit of speed by ++having Perl skip testing for that. (There is a maintenance penalty for ++doing this, as mentioning C constitutes a promise that you won't ++change the variables in the pattern. If you do change them, Perl won't ++even notice.) ++ ++=item 2 ++ ++you want the pattern to use the initial values of the variables ++regardless of whether they change or not. (But there are saner ways ++of accomplishing this than using C.) ++ ++=item 3 ++ ++If the pattern contains embedded code, such as ++ ++ use re 'eval'; ++ $code = 'foo(?{ $x })'; ++ /$code/ ++ ++then perl will recompile each time, even though the pattern string hasn't ++changed, to ensure that the current value of C<$x> is seen each time. ++Use C if you want to avoid this. ++ ++=back ++ ++The bottom line is that using C is almost never a good idea. ++ ++=item The empty pattern C ++ ++If the I evaluates to the empty string, the last ++I matched regular expression is used instead. In this ++case, only the C and C flags on the empty pattern are honored; ++the other flags are taken from the original pattern. If no match has ++previously succeeded, this will (silently) act instead as a genuine ++empty pattern (which will always match). ++ ++Note that it's possible to confuse Perl into thinking C (the empty ++regex) is really C (the defined-or operator). Perl is usually pretty ++good about this, but some pathological cases might trigger this, such as ++C<$x///> (is that S> or S>?) and S> ++(S> or S>?). In all of these examples, Perl ++will assume you meant defined-or. If you meant the empty regex, just ++use parentheses or spaces to disambiguate, or even prefix the empty ++regex with an C (so C becomes C). ++ ++=item Matching in list context ++ ++If the C option is not used, C in list context returns a ++list consisting of the subexpressions matched by the parentheses in the ++pattern, that is, (C<$1>, C<$2>, C<$3>...) (Note that here C<$1> etc. are ++also set). When there are no parentheses in the pattern, the return ++value is the list C<(1)> for success. ++With or without parentheses, an empty list is returned upon failure. ++ ++Examples: ++ ++ open(TTY, "+ =~ /^y/i && foo(); # do foo if desired ++ ++ if (/Version: *([0-9.]*)/) { $version = $1; } ++ ++ next if m#^/usr/spool/uucp#; ++ ++ # poor man's grep ++ $arg = shift; ++ while (<>) { ++ print if /$arg/o; # compile only once (no longer needed!) ++ } ++ ++ if (($F1, $F2, $Etc) = ($foo =~ /^(\S+)\s+(\S+)\s*(.*)/)) ++ ++This last example splits C<$foo> into the first two words and the ++remainder of the line, and assigns those three fields to C<$F1>, C<$F2>, and ++C<$Etc>. The conditional is true if any variables were assigned; that is, ++if the pattern matched. ++ ++The C modifier specifies global pattern matching--that is, ++matching as many times as possible within the string. How it behaves ++depends on the context. In list context, it returns a list of the ++substrings matched by any capturing parentheses in the regular ++expression. If there are no parentheses, it returns a list of all ++the matched strings, as if there were parentheses around the whole ++pattern. ++ ++In scalar context, each execution of C finds the next match, ++returning true if it matches, and false if there is no further match. ++The position after the last match can be read or set using the C ++function; see L. A failed match normally resets the ++search position to the beginning of the string, but you can avoid that ++by adding the C modifier (for example, C). Modifying the target ++string also resets the search position. ++ ++=item C<\G I> ++ ++You can intermix C matches with C, where C<\G> is a ++zero-width assertion that matches the exact position where the ++previous C, if any, left off. Without the C modifier, the ++C<\G> assertion still anchors at C as it was at the start of ++the operation (see L), but the match is of course only ++attempted once. Using C<\G> without C on a target string that has ++not previously had a C match applied to it is the same as using ++the C<\A> assertion to match the beginning of the string. Note also ++that, currently, C<\G> is only properly supported when anchored at the ++very beginning of the pattern. ++ ++Examples: ++ ++ # list context ++ ($one,$five,$fifteen) = (`uptime` =~ /(\d+\.\d+)/g); ++ ++ # scalar context ++ local $/ = ""; ++ while ($paragraph = <>) { ++ while ($paragraph =~ /\p{Ll}['")]*[.!?]+['")]*\s/g) { ++ $sentences++; ++ } ++ } ++ say $sentences; ++ ++Here's another way to check for sentences in a paragraph: ++ ++ my $sentence_rx = qr{ ++ (?: (?<= ^ ) | (?<= \s ) ) # after start-of-string or ++ # whitespace ++ \p{Lu} # capital letter ++ .*? # a bunch of anything ++ (?<= \S ) # that ends in non- ++ # whitespace ++ (?) { ++ say "NEW PARAGRAPH"; ++ my $count = 0; ++ while ($paragraph =~ /($sentence_rx)/g) { ++ printf "\tgot sentence %d: <%s>\n", ++$count, $1; ++ } ++ } ++ ++Here's how to use C with C<\G>: ++ ++ $_ = "ppooqppqq"; ++ while ($i++ < 2) { ++ print "1: '"; ++ print $1 while /(o)/gc; print "', pos=", pos, "\n"; ++ print "2: '"; ++ print $1 if /\G(q)/gc; print "', pos=", pos, "\n"; ++ print "3: '"; ++ print $1 while /(p)/gc; print "', pos=", pos, "\n"; ++ } ++ print "Final: '$1', pos=",pos,"\n" if /\G(.)/; ++ ++The last example should print: ++ ++ 1: 'oo', pos=4 ++ 2: 'q', pos=5 ++ 3: 'pp', pos=7 ++ 1: '', pos=7 ++ 2: 'q', pos=8 ++ 3: '', pos=8 ++ Final: 'q', pos=8 ++ ++Notice that the final match matched C instead of C

, which a match ++without the C<\G> anchor would have done. Also note that the final match ++did not update C. C is only updated on a C match. If the ++final match did indeed match C

, it's a good bet that you're running an ++ancient (pre-5.6.0) version of Perl. ++ ++A useful idiom for C-like scanners is C. You can ++combine several regexps like this to process a string part-by-part, ++doing different actions depending on which regexp matched. Each ++regexp tries to match where the previous one leaves off. ++ ++ $_ = <<'EOL'; ++ $url = URI::URL->new( "http://example.com/" ); ++ die if $url eq "xXx"; ++ EOL ++ ++ LOOP: { ++ print(" digits"), redo LOOP if /\G\d+\b[,.;]?\s*/gc; ++ print(" lowercase"), redo LOOP ++ if /\G\p{Ll}+\b[,.;]?\s*/gc; ++ print(" UPPERCASE"), redo LOOP ++ if /\G\p{Lu}+\b[,.;]?\s*/gc; ++ print(" Capitalized"), redo LOOP ++ if /\G\p{Lu}\p{Ll}+\b[,.;]?\s*/gc; ++ print(" MiXeD"), redo LOOP if /\G\pL+\b[,.;]?\s*/gc; ++ print(" alphanumeric"), redo LOOP ++ if /\G[\p{Alpha}\pN]+\b[,.;]?\s*/gc; ++ print(" line-noise"), redo LOOP if /\G\W+/gc; ++ print ". That's all!\n"; ++ } ++ ++Here is the output (split into several lines): ++ ++ line-noise lowercase line-noise UPPERCASE line-noise UPPERCASE ++ line-noise lowercase line-noise lowercase line-noise lowercase ++ lowercase line-noise lowercase lowercase line-noise lowercase ++ lowercase line-noise MiXeD line-noise. That's all! ++ ++=item C?msixpodualngc> ++X X ++ ++This is just like the C/> search, except that it matches ++only once between calls to the C operator. This is a useful ++optimization when you want to see only the first occurrence of ++something in each file of a set of files, for instance. Only C ++patterns local to the current package are reset. ++ ++ while (<>) { ++ if (m?^$?) { ++ # blank line between header and body ++ } ++ } continue { ++ reset if eof; # clear m?? status for next file ++ } ++ ++Another example switched the first "latin1" encoding it finds ++to "utf8" in a pod file: ++ ++ s//utf8/ if m? ^ =encoding \h+ \K latin1 ?x; ++ ++The match-once behavior is controlled by the match delimiter being ++C; with any other delimiter this is the normal C operator. ++ ++In the past, the leading C in C?> was optional, but omitting it ++would produce a deprecation warning. As of v5.22.0, omitting it produces a ++syntax error. If you encounter this construct in older code, you can just add ++C. ++ ++=item C/I/msixpodualngcer> ++X X X X X ++X X X X X X

X X X X X ++ ++Searches a string for a pattern, and if found, replaces that pattern ++with the replacement text and returns the number of substitutions ++made. Otherwise it returns false (a value that is both an empty string (C<"">) ++and numeric zero (C<0>) as described in L). ++ ++If the C (non-destructive) option is used then it runs the ++substitution on a copy of the string and instead of returning the ++number of substitutions, it returns the copy whether or not a ++substitution occurred. The original string is never changed when ++C is used. The copy will always be a plain string, even if the ++input is an object or a tied variable. ++ ++If no string is specified via the C<=~> or C operator, the C<$_> ++variable is searched and modified. Unless the C option is used, ++the string specified must be a scalar variable, an array element, a ++hash element, or an assignment to one of those; that is, some sort of ++scalar lvalue. ++ ++If the delimiter chosen is a single quote, no variable interpolation is ++done on either the I or the I. Otherwise, if the ++I contains a C<$> that looks like a variable rather than an ++end-of-string test, the variable will be interpolated into the pattern ++at run-time. If you want the pattern compiled only once the first time ++the variable is interpolated, use the C option. If the pattern ++evaluates to the empty string, the last successfully executed regular ++expression is used instead. See L for further explanation on these. ++ ++Options are as with C with the addition of the following replacement ++specific options: ++ ++ e Evaluate the right side as an expression. ++ ee Evaluate the right side as a string then eval the ++ result. ++ r Return substitution and leave the original string ++ untouched. ++ ++Any non-whitespace delimiter may replace the slashes. Add space after ++the C when using a character allowed in identifiers. If single quotes ++are used, no interpretation is done on the replacement string (the C ++modifier overrides this, however). Note that Perl treats backticks ++as normal delimiters; the replacement text is not evaluated as a command. ++If the I is delimited by bracketing quotes, the I has ++its own pair of quotes, which may or may not be bracketing quotes, for example, ++C or C<< s/bar/ >>. A C will cause the ++replacement portion to be treated as a full-fledged Perl expression ++and evaluated right then and there. It is, however, syntax checked at ++compile-time. A second C modifier will cause the replacement portion ++to be Ced before being run as a Perl expression. ++ ++Examples: ++ ++ s/\bgreen\b/mauve/g; # don't change wintergreen ++ ++ $path =~ s|/usr/bin|/usr/local/bin|; ++ ++ s/Login: $foo/Login: $bar/; # run-time pattern ++ ++ ($foo = $bar) =~ s/this/that/; # copy first, then ++ # change ++ ($foo = "$bar") =~ s/this/that/; # convert to string, ++ # copy, then change ++ $foo = $bar =~ s/this/that/r; # Same as above using /r ++ $foo = $bar =~ s/this/that/r ++ =~ s/that/the other/r; # Chained substitutes ++ # using /r ++ @foo = map { s/this/that/r } @bar # /r is very useful in ++ # maps ++ ++ $count = ($paragraph =~ s/Mister\b/Mr./g); # get change-cnt ++ ++ $_ = 'abc123xyz'; ++ s/\d+/$&*2/e; # yields 'abc246xyz' ++ s/\d+/sprintf("%5d",$&)/e; # yields 'abc 246xyz' ++ s/\w/$& x 2/eg; # yields 'aabbcc 224466xxyyzz' ++ ++ s/%(.)/$percent{$1}/g; # change percent escapes; no /e ++ s/%(.)/$percent{$1} || $&/ge; # expr now, so /e ++ s/^=(\w+)/pod($1)/ge; # use function call ++ ++ $_ = 'abc123xyz'; ++ $x = s/abc/def/r; # $x is 'def123xyz' and ++ # $_ remains 'abc123xyz'. ++ ++ # expand variables in $_, but dynamics only, using ++ # symbolic dereferencing ++ s/\$(\w+)/${$1}/g; ++ ++ # Add one to the value of any numbers in the string ++ s/(\d+)/1 + $1/eg; ++ ++ # Titlecase words in the last 30 characters only ++ substr($str, -30) =~ s/\b(\p{Alpha}+)\b/\u\L$1/g; ++ ++ # This will expand any embedded scalar variable ++ # (including lexicals) in $_ : First $1 is interpolated ++ # to the variable name, and then evaluated ++ s/(\$\w+)/$1/eeg; ++ ++ # Delete (most) C comments. ++ $program =~ s { ++ /\* # Match the opening delimiter. ++ .*? # Match a minimal number of characters. ++ \*/ # Match the closing delimiter. ++ } []gsx; ++ ++ s/^\s*(.*?)\s*$/$1/; # trim whitespace in $_, ++ # expensively ++ ++ for ($variable) { # trim whitespace in $variable, ++ # cheap ++ s/^\s+//; ++ s/\s+$//; ++ } ++ ++ s/([^ ]*) *([^ ]*)/$2 $1/; # reverse 1st two fields ++ ++ $foo !~ s/A/a/g; # Lowercase all A's in $foo; return ++ # 0 if any were found and changed; ++ # otherwise return 1 ++ ++Note the use of C<$> instead of C<\> in the last example. Unlike ++B, we use the \> form only in the left hand side. ++Anywhere else it's $>. ++ ++Occasionally, you can't use just a C to get all the changes ++to occur that you might want. Here are two common cases: ++ ++ # put commas in the right places in an integer ++ 1 while s/(\d)(\d\d\d)(?!\d)/$1,$2/g; ++ ++ # expand tabs to 8-column spacing ++ 1 while s/\t+/' ' x (length($&)*8 - length($`)%8)/e; ++ ++=back ++ ++=head2 Quote-Like Operators ++X ++ ++=over 4 ++ ++=item C/> ++X X X<'> X<''> ++ ++=item C<'I'> ++ ++A single-quoted, literal string. A backslash represents a backslash ++unless followed by the delimiter or another backslash, in which case ++the delimiter or backslash is interpolated. ++ ++ $foo = q!I said, "You said, 'She said it.'"!; ++ $bar = q('This is it.'); ++ $baz = '\n'; # a two-character string ++ ++=item C/> ++X X X<"> X<""> ++ ++=item "I" ++ ++A double-quoted, interpolated string. ++ ++ $_ .= qq ++ (*** The previous line contains the naughty word "$1".\n) ++ if /\b(tcl|java|python)\b/i; # :-) ++ $baz = "\n"; # a one-character string ++ ++=item C/> ++X X<`> X<``> X ++ ++=item C<`I`> ++ ++A string which is (possibly) interpolated and then executed as a ++system command with F or its equivalent. Shell wildcards, ++pipes, and redirections will be honored. The collected standard ++output of the command is returned; standard error is unaffected. In ++scalar context, it comes back as a single (potentially multi-line) ++string, or C if the command failed. In list context, returns a ++list of lines (however you've defined lines with C<$/> or ++C<$INPUT_RECORD_SEPARATOR>), or an empty list if the command failed. ++ ++Because backticks do not affect standard error, use shell file descriptor ++syntax (assuming the shell supports this) if you care to address this. ++To capture a command's STDERR and STDOUT together: ++ ++ $output = `cmd 2>&1`; ++ ++To capture a command's STDOUT but discard its STDERR: ++ ++ $output = `cmd 2>/dev/null`; ++ ++To capture a command's STDERR but discard its STDOUT (ordering is ++important here): ++ ++ $output = `cmd 2>&1 1>/dev/null`; ++ ++To exchange a command's STDOUT and STDERR in order to capture the STDERR ++but leave its STDOUT to come out the old STDERR: ++ ++ $output = `cmd 3>&1 1>&2 2>&3 3>&-`; ++ ++To read both a command's STDOUT and its STDERR separately, it's easiest ++to redirect them separately to files, and then read from those files ++when the program is done: ++ ++ system("program args 1>program.stdout 2>program.stderr"); ++ ++The STDIN filehandle used by the command is inherited from Perl's STDIN. ++For example: ++ ++ open(SPLAT, "stuff") || die "can't open stuff: $!"; ++ open(STDIN, "<&SPLAT") || die "can't dupe SPLAT: $!"; ++ print STDOUT `sort`; ++ ++will print the sorted contents of the file named F<"stuff">. ++ ++Using single-quote as a delimiter protects the command from Perl's ++double-quote interpolation, passing it on to the shell instead: ++ ++ $perl_info = qx(ps $$); # that's Perl's $$ ++ $shell_info = qx'ps $$'; # that's the new shell's $$ ++ ++How that string gets evaluated is entirely subject to the command ++interpreter on your system. On most platforms, you will have to protect ++shell metacharacters if you want them treated literally. This is in ++practice difficult to do, as it's unclear how to escape which characters. ++See L for a clean and safe example of a manual C and C ++to emulate backticks safely. ++ ++On some platforms (notably DOS-like ones), the shell may not be ++capable of dealing with multiline commands, so putting newlines in ++the string may not get you what you want. You may be able to evaluate ++multiple commands in a single line by separating them with the command ++separator character, if your shell supports that (for example, C<;> on ++many Unix shells and C<&> on the Windows NT C shell). ++ ++Perl will attempt to flush all files opened for ++output before starting the child process, but this may not be supported ++on some platforms (see L). To be safe, you may need to set ++C<$|> (C<$AUTOFLUSH> in C>) or call the C method of ++C> on any open handles. ++ ++Beware that some command shells may place restrictions on the length ++of the command line. You must ensure your strings don't exceed this ++limit after any necessary interpolations. See the platform-specific ++release notes for more details about your particular environment. ++ ++Using this operator can lead to programs that are difficult to port, ++because the shell commands called vary between systems, and may in ++fact not be present at all. As one example, the C command under ++the POSIX shell is very different from the C command under DOS. ++That doesn't mean you should go out of your way to avoid backticks ++when they're the right way to get something done. Perl was made to be ++a glue language, and one of the things it glues together is commands. ++Just understand what you're getting yourself into. ++ ++Like C, backticks put the child process exit code in C<$?>. ++If you'd like to manually inspect failure, you can check all possible ++failure modes by inspecting C<$?> like this: ++ ++ if ($? == -1) { ++ print "failed to execute: $!\n"; ++ } ++ elsif ($? & 127) { ++ printf "child died with signal %d, %s coredump\n", ++ ($? & 127), ($? & 128) ? 'with' : 'without'; ++ } ++ else { ++ printf "child exited with value %d\n", $? >> 8; ++ } ++ ++Use the L pragma to control the I/O layers used when reading the ++output of the command, for example: ++ ++ use open IN => ":encoding(UTF-8)"; ++ my $x = `cmd-producing-utf-8`; ++ ++C can also be called like a function with L. ++ ++See L for more discussion. ++ ++=item C/> ++X X X ++ ++Evaluates to a list of the words extracted out of I, using embedded ++whitespace as the word delimiters. It can be understood as being roughly ++equivalent to: ++ ++ split(" ", q/STRING/); ++ ++the differences being that it only splits on ASCII whitespace, ++generates a real list at compile time, and ++in scalar context it returns the last element in the list. So ++this expression: ++ ++ qw(foo bar baz) ++ ++is semantically equivalent to the list: ++ ++ "foo", "bar", "baz" ++ ++Some frequently seen examples: ++ ++ use POSIX qw( setlocale localeconv ) ++ @EXPORT = qw( foo bar baz ); ++ ++A common mistake is to try to separate the words with commas or to ++put comments into a multi-line C-string. For this reason, the ++S> pragma and the B<-w> switch (that is, the C<$^W> variable) ++produces warnings if the I contains the C<","> or the C<"#"> character. ++ ++=item C/I/cdsr> ++X X X X X X ++ ++=item C/I/cdsr> ++ ++Transliterates all occurrences of the characters found (or not found ++if the C modifier is specified) in the search list with the ++positionally corresponding character in the replacement list, possibly ++deleting some, depending on the modifiers specified. It returns the ++number of characters replaced or deleted. If no string is specified via ++the C<=~> or C operator, the C<$_> string is transliterated. ++ ++For B devotees, C is provided as a synonym for C. ++ ++If the C (non-destructive) option is present, a new copy of the string ++is made and its characters transliterated, and this copy is returned no ++matter whether it was modified or not: the original string is always ++left unchanged. The new copy is always a plain string, even if the input ++string is an object or a tied variable. ++ ++Unless the C option is used, the string specified with C<=~> must be a ++scalar variable, an array element, a hash element, or an assignment to one ++of those; in other words, an lvalue. ++ ++If the characters delimiting I and I ++are single quotes (C'I'>), the only ++interpolation is removal of C<\> from pairs of C<\\>. ++ ++Otherwise, a character range may be specified with a hyphen, so ++C does the same replacement as ++C. ++ ++If the I is delimited by bracketing quotes, the ++I must have its own pair of quotes, which may or may ++not be bracketing quotes; for example, C or ++C. ++ ++Characters may be literals, or (if the delimiters aren't single quotes) ++any of the escape sequences accepted in double-quoted strings. But ++there is never any variable interpolation, so C<"$"> and C<"@"> are ++always treated as literals. A hyphen at the beginning or end, or ++preceded by a backslash is also always considered a literal. Escape ++sequence details are in L. ++ ++Note that C does B do regular expression character classes such as ++C<\d> or C<\pL>. The C operator is not equivalent to the C> ++utility. C will uppercase the 26 letters "a" through "z", ++but for case changing not confined to ASCII, use ++L|perlfunc/lc>, L|perlfunc/uc>, ++L|perlfunc/lcfirst>, L|perlfunc/ucfirst> ++(all documented in L), or the ++LIEIE>|/sEPATTERNEREPLACEMENTEmsixpodualngcer> ++(with C<\U>, C<\u>, C<\L>, and C<\l> string-interpolation escapes in the ++I portion). ++ ++Most ranges are unportable between character sets, but certain ones ++signal Perl to do special handling to make them portable. There are two ++classes of portable ranges. The first are any subsets of the ranges ++C, C, and C<0-9>, when expressed as literal characters. ++ ++ tr/h-k/H-K/ ++ ++capitalizes the letters C<"h">, C<"i">, C<"j">, and C<"k"> and nothing ++else, no matter what the platform's character set is. In contrast, all ++of ++ ++ tr/\x68-\x6B/\x48-\x4B/ ++ tr/h-\x6B/H-\x4B/ ++ tr/\x68-k/\x48-K/ ++ ++do the same capitalizations as the previous example when run on ASCII ++platforms, but something completely different on EBCDIC ones. ++ ++The second class of portable ranges is invoked when one or both of the ++range's end points are expressed as C<\N{...}> ++ ++ $string =~ tr/\N{U+20}-\N{U+7E}//d; ++ ++removes from C<$string> all the platform's characters which are ++equivalent to any of Unicode U+0020, U+0021, ... U+007D, U+007E. This ++is a portable range, and has the same effect on every platform it is ++run on. In this example, these are the ASCII ++printable characters. So after this is run, C<$string> has only ++controls and characters which have no ASCII equivalents. ++ ++But, even for portable ranges, it is not generally obvious what is ++included without having to look things up in the manual. A sound ++principle is to use only ranges that both begin from, and end at, either ++ASCII alphabetics of equal case (C, C), or digits (C<1-4>). ++Anything else is unclear (and unportable unless C<\N{...}> is used). If ++in doubt, spell out the character sets in full. ++ ++Options: ++ ++ c Complement the SEARCHLIST. ++ d Delete found but unreplaced characters. ++ r Return the modified string and leave the original string ++ untouched. ++ s Squash duplicate replaced characters. ++ ++If the C modifier is specified, any characters specified by ++I not found in I are deleted. (Note that ++this is slightly more flexible than the behavior of some B programs, ++which delete anything they find in the I, period.) ++ ++If the C modifier is specified, sequences of characters, all in a ++row, that were transliterated to the same character are squashed down to ++a single instance of that character. ++ ++ my $a = "aaaba" ++ $a =~ tr/a/a/s # $a now is "aba" ++ ++If the C modifier is used, the I is always interpreted ++exactly as specified. Otherwise, if the I is shorter ++than the I, the final character, if any, is replicated until ++it is long enough. There won't be a final character if and only if the ++I is empty, in which case I is ++copied from I. An empty I is useful ++for counting characters in a class, or for squashing character sequences ++in a class. ++ ++ tr/abcd// tr/abcd/abcd/ ++ tr/abcd/AB/ tr/abcd/ABBB/ ++ tr/abcd//d s/[abcd]//g ++ tr/abcd/AB/d (tr/ab/AB/ + s/[cd]//g) - but run together ++ ++If the C modifier is specified, the characters to be transliterated ++are the ones NOT in I, that is, it is complemented. If ++C and/or C are also specified, they apply to the complemented ++I. Recall, that if I is empty (except ++under C) a copy of I is used instead. That copy is made ++after complementing under C. I is sorted by code point ++order after complementing, and any I is applied to ++that sorted result. This means that under C, the order of the ++characters specified in I is irrelevant. This can ++lead to different results on EBCDIC systems if I ++contains more than one character, hence it is generally non-portable to ++use C with such a I. ++ ++Another way of describing the operation is this: ++If C is specified, the I is sorted by code point order, ++then complemented. If I is empty and C is not ++specified, I is replaced by a copy of I (as ++modified under C), and these potentially modified lists are used as ++the basis for what follows. Any character in the target string that ++isn't in I is passed through unchanged. Every other ++character in the target string is replaced by the character in ++I that positionally corresponds to its mate in ++I, except that under C, the 2nd and following characters ++are squeezed out in a sequence of characters in a row that all translate ++to the same character. If I is longer than ++I, characters in the target string that match a ++character in I that doesn't have a correspondence in ++I are either deleted from the target string if C is ++specified; or replaced by the final character in I if ++C isn't specified. ++ ++Some examples: ++ ++ $ARGV[1] =~ tr/A-Z/a-z/; # canonicalize to lower case ASCII ++ ++ $cnt = tr/*/*/; # count the stars in $_ ++ $cnt = tr/*//; # same thing ++ ++ $cnt = $sky =~ tr/*/*/; # count the stars in $sky ++ $cnt = $sky =~ tr/*//; # same thing ++ ++ $cnt = $sky =~ tr/*//c; # count all the non-stars in $sky ++ $cnt = $sky =~ tr/*/*/c; # same, but transliterate each non-star ++ # into a star, leaving the already-stars ++ # alone. Afterwards, everything in $sky ++ # is a star. ++ ++ $cnt = tr/0-9//; # count the ASCII digits in $_ ++ ++ tr/a-zA-Z//s; # bookkeeper -> bokeper ++ tr/o/o/s; # bookkeeper -> bokkeeper ++ tr/oe/oe/s; # bookkeeper -> bokkeper ++ tr/oe//s; # bookkeeper -> bokkeper ++ tr/oe/o/s; # bookkeeper -> bokkopor ++ ++ ($HOST = $host) =~ tr/a-z/A-Z/; ++ $HOST = $host =~ tr/a-z/A-Z/r; # same thing ++ ++ $HOST = $host =~ tr/a-z/A-Z/r # chained with s///r ++ =~ s/:/ -p/r; ++ ++ tr/a-zA-Z/ /cs; # change non-alphas to single space ++ ++ @stripped = map tr/a-zA-Z/ /csr, @original; ++ # /r with map ++ ++ tr [\200-\377] ++ [\000-\177]; # wickedly delete 8th bit ++ ++ $foo !~ tr/A/a/ # transliterate all the A's in $foo to 'a', ++ # return 0 if any were found and changed. ++ # Otherwise return 1 ++ ++If multiple transliterations are given for a character, only the ++first one is used: ++ ++ tr/AAA/XYZ/ ++ ++will transliterate any A to X. ++ ++Because the transliteration table is built at compile time, neither ++the I nor the I are subjected to double quote ++interpolation. That means that if you want to use variables, you ++must use an C: ++ ++ eval "tr/$oldlist/$newlist/"; ++ die $@ if $@; ++ ++ eval "tr/$oldlist/$newlist/, 1" or die $@; ++ ++=item C<< < >> ++X X X X<<< << >>> ++ ++A line-oriented form of quoting is based on the shell "here-document" ++syntax. Following a C<< << >> you specify a string to terminate ++the quoted material, and all lines following the current line down to ++the terminating string are the value of the item. ++ ++Prefixing the terminating string with a C<~> specifies that you ++want to use L (see below). ++ ++The terminating string may be either an identifier (a word), or some ++quoted text. An unquoted identifier works like double quotes. ++There may not be a space between the C<< << >> and the identifier, ++unless the identifier is explicitly quoted. The terminating string ++must appear by itself (unquoted and with no surrounding whitespace) ++on the terminating line. ++ ++If the terminating string is quoted, the type of quotes used determine ++the treatment of the text. ++ ++=over 4 ++ ++=item Double Quotes ++ ++Double quotes indicate that the text will be interpolated using exactly ++the same rules as normal double quoted strings. ++ ++ print < ++being treated as two backslashes and not one as they would in every ++other quoting construct. ++ ++Just as in the shell, a backslashed bareword following the C<<< << >>> ++means the same thing as a single-quoted string does: ++ ++ $cost = <<'VISTA'; # hasta la ... ++ That'll be $10 please, ma'am. ++ VISTA ++ ++ $cost = <<\VISTA; # Same thing! ++ That'll be $10 please, ma'am. ++ VISTA ++ ++This is the only form of quoting in perl where there is no need ++to worry about escaping content, something that code generators ++can and do make good use of. ++ ++=item Backticks ++ ++The content of the here doc is treated just as it would be if the ++string were embedded in backticks. Thus the content is interpolated ++as though it were double quoted and then executed via the shell, with ++the results of the execution returned. ++ ++ print << `EOC`; # execute command and get results ++ echo hi there ++ EOC ++ ++=back ++ ++=over 4 ++ ++=item Indented Here-docs ++ ++The here-doc modifier C<~> allows you to indent your here-docs to make ++the code more readable: ++ ++ if ($some_var) { ++ print <<~EOF; ++ This is a here-doc ++ EOF ++ } ++ ++This will print... ++ ++ This is a here-doc ++ ++...with no leading whitespace. ++ ++The delimiter is used to determine the B whitespace to ++remove from the beginning of each line. All lines B have ++at least the same starting whitespace (except lines only ++containing a newline) or perl will croak. Tabs and spaces can ++be mixed, but are matched exactly. One tab will not be equal to ++8 spaces! ++ ++Additional beginning whitespace (beyond what preceded the ++delimiter) will be preserved: ++ ++ print <<~EOF; ++ This text is not indented ++ This text is indented with two spaces ++ This text is indented with two tabs ++ EOF ++ ++Finally, the modifier may be used with all of the forms ++mentioned above: ++ ++ <<~\EOF; ++ <<~'EOF' ++ <<~"EOF" ++ <<~`EOF` ++ ++And whitespace may be used between the C<~> and quoted delimiters: ++ ++ <<~ 'EOF'; # ... "EOF", `EOF` ++ ++=back ++ ++It is possible to stack multiple here-docs in a row: ++ ++ print <<"foo", <<"bar"; # you can stack them ++ I said foo. ++ foo ++ I said bar. ++ bar ++ ++ myfunc(<< "THIS", 23, <<'THAT'); ++ Here's a line ++ or two. ++ THIS ++ and here's another. ++ THAT ++ ++Just don't forget that you have to put a semicolon on the end ++to finish the statement, as Perl doesn't know you're not going to ++try to do this: ++ ++ print <. ++ ++ chomp($string = <<'END'); ++ This is a string. ++ END ++ ++If you want your here-docs to be indented with the rest of the code, ++use the C<<< <<~FOO >>> construct described under L: ++ ++ $quote = <<~'FINIS'; ++ The Road goes ever on and on, ++ down from the door where it began. ++ FINIS ++ ++If you use a here-doc within a delimited construct, such as in C, ++the quoted material must still come on the line following the ++C<<< <>> marker, which means it may be inside the delimited ++construct: ++ ++ s/this/<, C, and the like are not ++supported in place of C<''> and C<"">, and the only interpolation is for ++backslashing the quoting character: ++ ++ print << "abc\"def"; ++ testing... ++ abc"def ++ ++Finally, quoted strings cannot span multiple lines. The general rule is ++that the identifier must be a string literal. Stick with that, and you ++should be safe. ++ ++=back ++ ++=head2 Gory details of parsing quoted constructs ++X ++ ++When presented with something that might have several different ++interpretations, Perl uses the B (that's "Do What I Mean") ++principle to pick the most probable interpretation. This strategy ++is so successful that Perl programmers often do not suspect the ++ambivalence of what they write. But from time to time, Perl's ++notions differ substantially from what the author honestly meant. ++ ++This section hopes to clarify how Perl handles quoted constructs. ++Although the most common reason to learn this is to unravel labyrinthine ++regular expressions, because the initial steps of parsing are the ++same for all quoting operators, they are all discussed together. ++ ++The most important Perl parsing rule is the first one discussed ++below: when processing a quoted construct, Perl first finds the end ++of that construct, then interprets its contents. If you understand ++this rule, you may skip the rest of this section on the first ++reading. The other rules are likely to contradict the user's ++expectations much less frequently than this first one. ++ ++Some passes discussed below are performed concurrently, but because ++their results are the same, we consider them individually. For different ++quoting constructs, Perl performs different numbers of passes, from ++one to four, but these passes are always performed in the same order. ++ ++=over 4 ++ ++=item Finding the end ++ ++The first pass is finding the end of the quoted construct. This results ++in saving to a safe location a copy of the text (between the starting ++and ending delimiters), normalized as necessary to avoid needing to know ++what the original delimiters were. ++ ++If the construct is a here-doc, the ending delimiter is a line ++that has a terminating string as the content. Therefore C<< is ++terminated by C immediately followed by C<"\n"> and starting ++from the first column of the terminating line. ++When searching for the terminating line of a here-doc, nothing ++is skipped. In other words, lines after the here-doc syntax ++are compared with the terminating string line by line. ++ ++For the constructs except here-docs, single characters are used as starting ++and ending delimiters. If the starting delimiter is an opening punctuation ++(that is C<(>, C<[>, C<{>, or C<< < >>), the ending delimiter is the ++corresponding closing punctuation (that is C<)>, C<]>, C<}>, or C<< > >>). ++If the starting delimiter is an unpaired character like C or a closing ++punctuation, the ending delimiter is the same as the starting delimiter. ++Therefore a C terminates a C construct, while a C<]> terminates ++both C and C constructs. ++ ++When searching for single-character delimiters, escaped delimiters ++and C<\\> are skipped. For example, while searching for terminating C, ++combinations of C<\\> and C<\/> are skipped. If the delimiters are ++bracketing, nested pairs are also skipped. For example, while searching ++for a closing C<]> paired with the opening C<[>, combinations of C<\\>, C<\]>, ++and C<\[> are all skipped, and nested C<[> and C<]> are skipped as well. ++However, when backslashes are used as the delimiters (like C and ++C), nothing is skipped. ++During the search for the end, backslashes that escape delimiters or ++other backslashes are removed (exactly speaking, they are not copied to the ++safe location). ++ ++For constructs with three-part delimiters (C, C, and ++C), the search is repeated once more. ++If the first delimiter is not an opening punctuation, the three delimiters must ++be the same, such as C and C, ++in which case the second delimiter ++terminates the left part and starts the right part at once. ++If the left part is delimited by bracketing punctuation (that is C<()>, ++C<[]>, C<{}>, or C<< <> >>), the right part needs another pair of ++delimiters such as C and C. In these cases, whitespace ++and comments are allowed between the two parts, although the comment must follow ++at least one whitespace character; otherwise a character expected as the ++start of the comment may be regarded as the starting delimiter of the right part. ++ ++During this search no attention is paid to the semantics of the construct. ++Thus: ++ ++ "$hash{"$foo/$bar"}" ++ ++or: ++ ++ m/ ++ bar # NOT a comment, this slash / terminated m//! ++ /x ++ ++do not form legal quoted expressions. The quoted part ends on the ++first C<"> and C, and the rest happens to be a syntax error. ++Because the slash that terminated C was followed by a C, ++the example above is not C, but rather C with no C ++modifier. So the embedded C<#> is interpreted as a literal C<#>. ++ ++Also no attention is paid to C<\c\> (multichar control char syntax) during ++this search. Thus the second C<\> in C is interpreted as a part ++of C<\/>, and the following C is not recognized as a delimiter. ++Instead, use C<\034> or C<\x1c> at the end of quoted constructs. ++ ++=item Interpolation ++X ++ ++The next step is interpolation in the text obtained, which is now ++delimiter-independent. There are multiple cases. ++ ++=over 4 ++ ++=item C<<<'EOF'> ++ ++No interpolation is performed. ++Note that the combination C<\\> is left intact, since escaped delimiters ++are not available for here-docs. ++ ++=item C, the pattern of C ++ ++No interpolation is performed at this stage. ++Any backslashed sequences including C<\\> are treated at the stage ++to L. ++ ++=item C<''>, C, C, C, the replacement of C ++ ++The only interpolation is removal of C<\> from pairs of C<\\>. ++Therefore C<"-"> in C and C is treated literally ++as a hyphen and no character range is available. ++C<\1> in the replacement of C does not work as C<$1>. ++ ++=item C, C ++ ++No variable interpolation occurs. String modifying combinations for ++case and quoting such as C<\Q>, C<\U>, and C<\E> are not recognized. ++The other escape sequences such as C<\200> and C<\t> and backslashed ++characters such as C<\\> and C<\-> are converted to appropriate literals. ++The character C<"-"> is treated specially and therefore C<\-> is treated ++as a literal C<"-">. ++ ++=item C<"">, C<``>, C, C, C<< >>, C<<<"EOF"> ++ ++C<\Q>, C<\U>, C<\u>, C<\L>, C<\l>, C<\F> (possibly paired with C<\E>) are ++converted to corresponding Perl constructs. Thus, C<"$foo\Qbaz$bar"> ++is converted to S> internally. ++The other escape sequences such as C<\200> and C<\t> and backslashed ++characters such as C<\\> and C<\-> are replaced with appropriate ++expansions. ++ ++Let it be stressed that I and C<\E>> ++is interpolated in the usual way. Something like C<"\Q\\E"> has ++no C<\E> inside. Instead, it has C<\Q>, C<\\>, and C, so the ++result is the same as for C<"\\\\E">. As a general rule, backslashes ++between C<\Q> and C<\E> may lead to counterintuitive results. So, ++C<"\Q\t\E"> is converted to C, which is the same ++as C<"\\\t"> (since TAB is not alphanumeric). Note also that: ++ ++ $str = '\t'; ++ return "\Q$str"; ++ ++may be closer to the conjectural I of the writer of C<"\Q\t\E">. ++ ++Interpolated scalars and arrays are converted internally to the C and ++C<"."> catenation operations. Thus, S> becomes: ++ ++ $foo . " XXX '" . (join $", @arr) . "'"; ++ ++All operations above are performed simultaneously, left to right. ++ ++Because the result of S \E">> has all metacharacters ++quoted, there is no way to insert a literal C<$> or C<@> inside a ++C<\Q\E> pair. If protected by C<\>, C<$> will be quoted to become ++C<"\\\$">; if not, it is interpreted as the start of an interpolated ++scalar. ++ ++Note also that the interpolation code needs to make a decision on ++where the interpolated scalar ends. For instance, whether ++S {c}" >>> really means: ++ ++ "a " . $x . " -> {c}"; ++ ++or: ++ ++ "a " . $x -> {c}; ++ ++Most of the time, the longest possible text that does not include ++spaces between components and which contains matching braces or ++brackets. because the outcome may be determined by voting based ++on heuristic estimators, the result is not strictly predictable. ++Fortunately, it's usually correct for ambiguous cases. ++ ++=item the replacement of C ++ ++Processing of C<\Q>, C<\U>, C<\u>, C<\L>, C<\l>, C<\F> and interpolation ++happens as with C constructs. ++ ++It is at this step that C<\1> is begrudgingly converted to C<$1> in ++the replacement text of C, in order to correct the incorrigible ++I hackers who haven't picked up the saner idiom yet. A warning ++is emitted if the S> pragma or the B<-w> command-line flag ++(that is, the C<$^W> variable) was set. ++ ++=item C in C, C, C, C, ++ ++Processing of C<\Q>, C<\U>, C<\u>, C<\L>, C<\l>, C<\F>, C<\E>, ++and interpolation happens (almost) as with C constructs. ++ ++Processing of C<\N{...}> is also done here, and compiled into an intermediate ++form for the regex compiler. (This is because, as mentioned below, the regex ++compilation may be done at execution time, and C<\N{...}> is a compile-time ++construct.) ++ ++However any other combinations of C<\> followed by a character ++are not substituted but only skipped, in order to parse them ++as regular expressions at the following step. ++As C<\c> is skipped at this step, C<@> of C<\c@> in RE is possibly ++treated as an array symbol (for example C<@foo>), ++even though the same text in C gives interpolation of C<\c@>. ++ ++Code blocks such as C<(?{BLOCK})> are handled by temporarily passing control ++back to the perl parser, in a similar way that an interpolated array ++subscript expression such as C<"foo$array[1+f("[xyz")]bar"> would be. ++ ++Moreover, inside C<(?{BLOCK})>, S>, and ++a C<#>-comment in a C-regular expression, no processing is ++performed whatsoever. This is the first step at which the presence ++of the C modifier is relevant. ++ ++Interpolation in patterns has several quirks: C<$|>, C<$(>, C<$)>, C<@+> ++and C<@-> are not interpolated, and constructs C<$var[SOMETHING]> are ++voted (by several different estimators) to be either an array element ++or C<$var> followed by an RE alternative. This is where the notation ++C<${arr[$bar]}> comes handy: C is interpreted as ++array element C<-9>, not as a regular expression from the variable ++C<$arr> followed by a digit, which would be the interpretation of ++C. Since voting among different estimators may occur, ++the result is not predictable. ++ ++The lack of processing of C<\\> creates specific restrictions on ++the post-processed text. If the delimiter is C, one cannot get ++the combination C<\/> into the result of this step. C will ++finish the regular expression, C<\/> will be stripped to C on ++the previous step, and C<\\/> will be left as is. Because C is ++equivalent to C<\/> inside a regular expression, this does not ++matter unless the delimiter happens to be character special to the ++RE engine, such as in C, C, or C; or an ++alphanumeric char, as in: ++ ++ m m ^ a \s* b mmx; ++ ++In the RE above, which is intentionally obfuscated for illustration, the ++delimiter is C, the modifier is C, and after delimiter-removal the ++RE is the same as for S>. There's more than one ++reason you're encouraged to restrict your delimiters to non-alphanumeric, ++non-whitespace choices. ++ ++=back ++ ++This step is the last one for all constructs except regular expressions, ++which are processed further. ++ ++=item parsing regular expressions ++X ++ ++Previous steps were performed during the compilation of Perl code, ++but this one happens at run time, although it may be optimized to ++be calculated at compile time if appropriate. After preprocessing ++described above, and possibly after evaluation if concatenation, ++joining, casing translation, or metaquoting are involved, the ++resulting I is passed to the RE engine for compilation. ++ ++Whatever happens in the RE engine might be better discussed in L, ++but for the sake of continuity, we shall do so here. ++ ++This is another step where the presence of the C modifier is ++relevant. The RE engine scans the string from left to right and ++converts it into a finite automaton. ++ ++Backslashed characters are either replaced with corresponding ++literal strings (as with C<\{>), or else they generate special nodes ++in the finite automaton (as with C<\b>). Characters special to the ++RE engine (such as C<|>) generate corresponding nodes or groups of ++nodes. C<(?#...)> comments are ignored. All the rest is either ++converted to literal strings to match, or else is ignored (as is ++whitespace and C<#>-style comments if C is present). ++ ++Parsing of the bracketed character class construct, C<[...]>, is ++rather different than the rule used for the rest of the pattern. ++The terminator of this construct is found using the same rules as ++for finding the terminator of a C<{}>-delimited construct, the only ++exception being that C<]> immediately following C<[> is treated as ++though preceded by a backslash. ++ ++The terminator of runtime C<(?{...})> is found by temporarily switching ++control to the perl parser, which should stop at the point where the ++logically balancing terminating C<}> is found. ++ ++It is possible to inspect both the string given to RE engine and the ++resulting finite automaton. See the arguments C/C ++in the S>> pragma, as well as Perl's B<-Dr> command-line ++switch documented in L. ++ ++=item Optimization of regular expressions ++X ++ ++This step is listed for completeness only. Since it does not change ++semantics, details of this step are not documented and are subject ++to change without notice. This step is performed over the finite ++automaton that was generated during the previous pass. ++ ++It is at this stage that C silently optimizes C to ++mean C. ++ ++=back ++ ++=head2 I/O Operators ++X X X X X ++X<< <> >> X<< <<>> >> X<@ARGV> ++ ++There are several I/O operators you should know about. ++ ++A string enclosed by backticks (grave accents) first undergoes ++double-quote interpolation. It is then interpreted as an external ++command, and the output of that command is the value of the ++backtick string, like in a shell. In scalar context, a single string ++consisting of all output is returned. In list context, a list of ++values is returned, one per line of output. (You can set C<$/> to use ++a different line terminator.) The command is executed each time the ++pseudo-literal is evaluated. The status value of the command is ++returned in C<$?> (see L for the interpretation of C<$?>). ++Unlike in B, no translation is done on the return data--newlines ++remain newlines. Unlike in any of the shells, single quotes do not ++hide variable names in the command from interpretation. To pass a ++literal dollar-sign through to the shell you need to hide it with a ++backslash. The generalized form of backticks is C, or you can ++call the L function. (Because ++backticks always undergo shell expansion as well, see L for ++security concerns.) ++X X<`> X<``> X X ++ ++In scalar context, evaluating a filehandle in angle brackets yields ++the next line from that file (the newline, if any, included), or ++C at end-of-file or on error. When C<$/> is set to C ++(sometimes known as file-slurp mode) and the file is empty, it ++returns C<''> the first time, followed by C subsequently. ++ ++Ordinarily you must assign the returned value to a variable, but ++there is one situation where an automatic assignment happens. If ++and only if the input symbol is the only thing inside the conditional ++of a C statement (even if disguised as a C loop), ++the value is automatically assigned to the global variable C<$_>, ++destroying whatever was there previously. (This may seem like an ++odd thing to you, but you'll use the construct in almost every Perl ++script you write.) The C<$_> variable is not implicitly localized. ++You'll have to put a S> before the loop if you want that ++to happen. Furthermore, if the input symbol or an explicit assignment ++of the input symbol to a scalar is used as a C/C condition, ++then the condition actually tests for definedness of the expression's ++value, not for its regular truth value. ++ ++Thus the following lines are equivalent: ++ ++ while (defined($_ = )) { print; } ++ while ($_ = ) { print; } ++ while () { print; } ++ for (;;) { print; } ++ print while defined($_ = ); ++ print while ($_ = ); ++ print while ; ++ ++This also behaves similarly, but assigns to a lexical variable ++instead of to C<$_>: ++ ++ while (my $line = ) { print $line } ++ ++In these loop constructs, the assigned value (whether assignment ++is automatic or explicit) is then tested to see whether it is ++defined. The defined test avoids problems where the line has a string ++value that would be treated as false by Perl; for example a "" or ++a C<"0"> with no trailing newline. If you really mean for such values ++to terminate the loop, they should be tested for explicitly: ++ ++ while (($_ = ) ne '0') { ... } ++ while () { last unless $_; ... } ++ ++In other boolean contexts, C<< > >> without an ++explicit C test or comparison elicits a warning if the ++S> pragma or the B<-w> ++command-line switch (the C<$^W> variable) is in effect. ++ ++The filehandles STDIN, STDOUT, and STDERR are predefined. (The ++filehandles C, C, and C will also work except ++in packages, where they would be interpreted as local identifiers ++rather than global.) Additional filehandles may be created with ++the C function, amongst others. See L and ++L for details on this. ++X X X ++ ++If a C<< > >> is used in a context that is looking for ++a list, a list comprising all input lines is returned, one line per ++list element. It's easy to grow to a rather large data space this ++way, so use with care. ++ ++C<< > >> may also be spelled C)>. ++See L. ++ ++The null filehandle C<< <> >> is special: it can be used to emulate the ++behavior of B and B, and any other Unix filter program ++that takes a list of filenames, doing the same to each line ++of input from all of them. Input from C<< <> >> comes either from ++standard input, or from each file listed on the command line. Here's ++how it works: the first time C<< <> >> is evaluated, the C<@ARGV> array is ++checked, and if it is empty, C<$ARGV[0]> is set to C<"-">, which when opened ++gives you standard input. The C<@ARGV> array is then processed as a list ++of filenames. The loop ++ ++ while (<>) { ++ ... # code for each line ++ } ++ ++is equivalent to the following Perl-like pseudo code: ++ ++ unshift(@ARGV, '-') unless @ARGV; ++ while ($ARGV = shift) { ++ open(ARGV, $ARGV); ++ while () { ++ ... # code for each line ++ } ++ } ++ ++except that it isn't so cumbersome to say, and will actually work. ++It really does shift the C<@ARGV> array and put the current filename ++into the C<$ARGV> variable. It also uses filehandle I ++internally. C<< <> >> is just a synonym for C<< >>, which ++is magical. (The pseudo code above doesn't work because it treats ++C<< >> as non-magical.) ++ ++Since the null filehandle uses the two argument form of L ++it interprets special characters, so if you have a script like this: ++ ++ while (<>) { ++ print; ++ } ++ ++and call it with S>, it actually opens a ++pipe, executes the C command and reads C's output from that pipe. ++If you want all items in C<@ARGV> to be interpreted as file names, you ++can use the module C from CPAN, or use the double bracket: ++ ++ while (<<>>) { ++ print; ++ } ++ ++Using double angle brackets inside of a while causes the open to use the ++three argument form (with the second argument being C<< < >>), so all ++arguments in C are treated as literal filenames (including C<"-">). ++(Note that for convenience, if you use C<< <<>> >> and if C<@ARGV> is ++empty, it will still read from the standard input.) ++ ++You can modify C<@ARGV> before the first C<< <> >> as long as the array ends up ++containing the list of filenames you really want. Line numbers (C<$.>) ++continue as though the input were one big happy file. See the example ++in L for how to reset line numbers on each file. ++ ++If you want to set C<@ARGV> to your own list of files, go right ahead. ++This sets C<@ARGV> to all plain text files if no C<@ARGV> was given: ++ ++ @ARGV = grep { -f && -T } glob('*') unless @ARGV; ++ ++You can even set them to pipe commands. For example, this automatically ++filters compressed arguments through B: ++ ++ @ARGV = map { /\.(gz|Z)$/ ? "gzip -dc < $_ |" : $_ } @ARGV; ++ ++If you want to pass switches into your script, you can use one of the ++C modules or put a loop on the front like this: ++ ++ while ($_ = $ARGV[0], /^-/) { ++ shift; ++ last if /^--$/; ++ if (/^-D(.*)/) { $debug = $1 } ++ if (/^-v/) { $verbose++ } ++ # ... # other switches ++ } ++ ++ while (<>) { ++ # ... # code for each line ++ } ++ ++The C<< <> >> symbol will return C for end-of-file only once. ++If you call it again after this, it will assume you are processing another ++C<@ARGV> list, and if you haven't set C<@ARGV>, will read input from STDIN. ++ ++If what the angle brackets contain is a simple scalar variable (for example, ++C<$foo>), then that variable contains the name of the ++filehandle to input from, or its typeglob, or a reference to the ++same. For example: ++ ++ $fh = \*STDIN; ++ $line = <$fh>; ++ ++If what's within the angle brackets is neither a filehandle nor a simple ++scalar variable containing a filehandle name, typeglob, or typeglob ++reference, it is interpreted as a filename pattern to be globbed, and ++either a list of filenames or the next filename in the list is returned, ++depending on context. This distinction is determined on syntactic ++grounds alone. That means C<< <$x> >> is always a C from ++an indirect handle, but C<< <$hash{key}> >> is always a C. ++That's because C<$x> is a simple scalar variable, but C<$hash{key}> is ++not--it's a hash element. Even C<< <$x > >> (note the extra space) ++is treated as C, not C. ++ ++One level of double-quote interpretation is done first, but you can't ++say C<< <$foo> >> because that's an indirect filehandle as explained ++in the previous paragraph. (In older versions of Perl, programmers ++would insert curly brackets to force interpretation as a filename glob: ++C<< <${foo}> >>. These days, it's considered cleaner to call the ++internal function directly as C, which is probably the right ++way to have done it in the first place.) For example: ++ ++ while (<*.c>) { ++ chmod 0644, $_; ++ } ++ ++is roughly equivalent to: ++ ++ open(FOO, "echo *.c | tr -s ' \t\r\f' '\\012\\012\\012\\012'|"); ++ while () { ++ chomp; ++ chmod 0644, $_; ++ } ++ ++except that the globbing is actually done internally using the standard ++C> extension. Of course, the shortest way to do the above is: ++ ++ chmod 0644, <*.c>; ++ ++A (file)glob evaluates its (embedded) argument only when it is ++starting a new list. All values must be read before it will start ++over. In list context, this isn't important because you automatically ++get them all anyway. However, in scalar context the operator returns ++the next value each time it's called, or C when the list has ++run out. As with filehandle reads, an automatic C is ++generated when the glob occurs in the test part of a C, ++because legal glob returns (for example, ++a file called F<0>) would otherwise ++terminate the loop. Again, C is returned only once. So if ++you're expecting a single value from a glob, it is much better to ++say ++ ++ ($file) = ; ++ ++than ++ ++ $file = ; ++ ++because the latter will alternate between returning a filename and ++returning false. ++ ++If you're trying to do variable interpolation, it's definitely better ++to use the C function, because the older notation can cause people ++to become confused with the indirect filehandle notation. ++ ++ @files = glob("$dir/*.[ch]"); ++ @files = glob($files[$i]); ++ ++If an angle-bracket-based globbing expression is used as the condition of ++a C or C loop, then it will be implicitly assigned to C<$_>. ++If either a globbing expression or an explicit assignment of a globbing ++expression to a scalar is used as a C/C condition, then ++the condition actually tests for definedness of the expression's value, ++not for its regular truth value. ++ ++=head2 Constant Folding ++X X ++ ++Like C, Perl does a certain amount of expression evaluation at ++compile time whenever it determines that all arguments to an ++operator are static and have no side effects. In particular, string ++concatenation happens at compile time between literals that don't do ++variable substitution. Backslash interpolation also happens at ++compile time. You can say ++ ++ 'Now is the time for all' ++ . "\n" ++ . 'good men to come to.' ++ ++and this all reduces to one string internally. Likewise, if ++you say ++ ++ foreach $file (@filenames) { ++ if (-s $file > 5 + 100 * 2**16) { } ++ } ++ ++the compiler precomputes the number which that expression ++represents so that the interpreter won't have to. ++ ++=head2 No-ops ++X X ++ ++Perl doesn't officially have a no-op operator, but the bare constants ++C<0> and C<1> are special-cased not to produce a warning in void ++context, so you can for example safely do ++ ++ 1 while foo(); ++ ++=head2 Bitwise String Operators ++X X<&.> X<|.> X<^.> X<~.> ++ ++Bitstrings of any size may be manipulated by the bitwise operators ++(C<~ | & ^>). ++ ++If the operands to a binary bitwise op are strings of different ++sizes, B<|> and B<^> ops act as though the shorter operand had ++additional zero bits on the right, while the B<&> op acts as though ++the longer operand were truncated to the length of the shorter. ++The granularity for such extension or truncation is one or more ++bytes. ++ ++ # ASCII-based examples ++ print "j p \n" ^ " a h"; # prints "JAPH\n" ++ print "JA" | " ph\n"; # prints "japh\n" ++ print "japh\nJunk" & '_____'; # prints "JAPH\n"; ++ print 'p N$' ^ " E bitwise operation. You may explicitly show which type of ++operation you intend by using C<""> or C<0+>, as in the examples below. ++ ++ $foo = 150 | 105; # yields 255 (0x96 | 0x69 is 0xFF) ++ $foo = '150' | 105; # yields 255 ++ $foo = 150 | '105'; # yields 255 ++ $foo = '150' | '105'; # yields string '155' (under ASCII) ++ ++ $baz = 0+$foo & 0+$bar; # both ops explicitly numeric ++ $biz = "$foo" ^ "$bar"; # both ops explicitly stringy ++ ++This somewhat unpredictable behavior can be avoided with the "bitwise" ++feature, new in Perl 5.22. You can enable it via S> or C. Before Perl 5.28, it used to emit a warning ++in the C<"experimental::bitwise"> category. Under this feature, the four ++standard bitwise operators (C<~ | & ^>) are always numeric. Adding a dot ++after each operator (C<~. |. &. ^.>) forces it to treat its operands as ++strings: ++ ++ use feature "bitwise"; ++ $foo = 150 | 105; # yields 255 (0x96 | 0x69 is 0xFF) ++ $foo = '150' | 105; # yields 255 ++ $foo = 150 | '105'; # yields 255 ++ $foo = '150' | '105'; # yields 255 ++ $foo = 150 |. 105; # yields string '155' ++ $foo = '150' |. 105; # yields string '155' ++ $foo = 150 |.'105'; # yields string '155' ++ $foo = '150' |.'105'; # yields string '155' ++ ++ $baz = $foo & $bar; # both operands numeric ++ $biz = $foo ^. $bar; # both operands stringy ++ ++The assignment variants of these operators (C<&= |= ^= &.= |.= ^.=>) ++behave likewise under the feature. ++ ++It is a fatal error if an operand contains a character whose ordinal ++value is above 0xFF, and hence not expressible except in UTF-8. The ++operation is performed on a non-UTF-8 copy for other operands encoded in ++UTF-8. See L. ++ ++See L for information on how to manipulate individual bits ++in a bit vector. ++ ++=head2 Integer Arithmetic ++X ++ ++By default, Perl assumes that it must do most of its arithmetic in ++floating point. But by saying ++ ++ use integer; ++ ++you may tell the compiler to use integer operations ++(see L for a detailed explanation) from here to the end of ++the enclosing BLOCK. An inner BLOCK may countermand this by saying ++ ++ no integer; ++ ++which lasts until the end of that BLOCK. Note that this doesn't ++mean everything is an integer, merely that Perl will use integer ++operations for arithmetic, comparison, and bitwise operators. For ++example, even under S>, if you take the C, you'll ++still get C<1.4142135623731> or so. ++ ++Used on numbers, the bitwise operators (C<&> C<|> C<^> C<~> C<< << >> ++C<< >> >>) always produce integral results. (But see also ++L.) However, S> still has meaning for ++them. By default, their results are interpreted as unsigned integers, but ++if S> is in effect, their results are interpreted ++as signed integers. For example, C<~0> usually evaluates to a large ++integral value. However, S> is C<-1> on two's-complement ++machines. ++ ++=head2 Floating-point Arithmetic ++ ++X X X X ++ ++While S> provides integer-only arithmetic, there is no ++analogous mechanism to provide automatic rounding or truncation to a ++certain number of decimal places. For rounding to a certain number ++of digits, C or C is usually the easiest route. ++See L. ++ ++Floating-point numbers are only approximations to what a mathematician ++would call real numbers. There are infinitely more reals than floats, ++so some corners must be cut. For example: ++ ++ printf "%.20g\n", 123456789123456789; ++ # produces 123456789123456784 ++ ++Testing for exact floating-point equality or inequality is not a ++good idea. Here's a (relatively expensive) work-around to compare ++whether two floating-point numbers are equal to a particular number of ++decimal places. See Knuth, volume II, for a more robust treatment of ++this topic. ++ ++ sub fp_equal { ++ my ($X, $Y, $POINTS) = @_; ++ my ($tX, $tY); ++ $tX = sprintf("%.${POINTS}g", $X); ++ $tY = sprintf("%.${POINTS}g", $Y); ++ return $tX eq $tY; ++ } ++ ++The POSIX module (part of the standard perl distribution) implements ++C, C, and other mathematical and trigonometric functions. ++The C> module (part of the standard perl distribution) ++defines mathematical functions that work on both the reals and the ++imaginary numbers. C is not as efficient as POSIX, but ++POSIX can't work with complex numbers. ++ ++Rounding in financial applications can have serious implications, and ++the rounding method used should be specified precisely. In these ++cases, it probably pays not to trust whichever system rounding is ++being used by Perl, but to instead implement the rounding function you ++need yourself. ++ ++=head2 Bigger Numbers ++X ++ ++The standard C>, C>, and ++C> modules, ++along with the C, C, and C pragmas, provide ++variable-precision arithmetic and overloaded operators, although ++they're currently pretty slow. At the cost of some space and ++considerable speed, they avoid the normal pitfalls associated with ++limited-precision representations. ++ ++ use 5.010; ++ use bigint; # easy interface to Math::BigInt ++ $x = 123456789123456789; ++ say $x * $x; ++ +15241578780673678515622620750190521 ++ ++Or with rationals: ++ ++ use 5.010; ++ use bigrat; ++ $x = 3/22; ++ $y = 4/6; ++ say "x/y is ", $x/$y; ++ say "x*y is ", $x*$y; ++ x/y is 9/44 ++ x*y is 1/11 ++ ++Several modules let you calculate with unlimited or fixed precision ++(bound only by memory and CPU time). There ++are also some non-standard modules that ++provide faster implementations via external C libraries. ++ ++Here is a short, but incomplete summary: ++ ++ Math::String treat string sequences like numbers ++ Math::FixedPrecision calculate with a fixed precision ++ Math::Currency for currency calculations ++ Bit::Vector manipulate bit vectors fast (uses C) ++ Math::BigIntFast Bit::Vector wrapper for big numbers ++ Math::Pari provides access to the Pari C library ++ Math::Cephes uses the external Cephes C library (no ++ big numbers) ++ Math::Cephes::Fraction fractions via the Cephes library ++ Math::GMP another one using an external C library ++ Math::GMPz an alternative interface to libgmp's big ints ++ Math::GMPq an interface to libgmp's fraction numbers ++ Math::GMPf an interface to libgmp's floating point numbers ++ ++Choose wisely. ++ ++=cut +diff --git a/t/03_builtin_pod_output.t b/t/03_builtin_pod_output.t +new file mode 100644 +index 0000000..70f8549 +--- /dev/null ++++ b/t/03_builtin_pod_output.t +@@ -0,0 +1,59 @@ ++ ++use File::Spec; ++use FindBin qw($Bin); ++ ++use IPC::Open3; ++use Test::More; ++use Config; ++ ++my $pid = undef; ++my $stdout = undef; ++my $stderr = undef; ++ ++# get path to perldoc exec in a hopefully platform neutral way.. ++my ($volume, $bindir, undef) = File::Spec->splitpath($Bin); ++my $perldoc = File::Spec->catpath($volume,$bindir, File::Spec->catfile(qw(blib script perldoc))); ++if ($ENV{PERL_CORE}) { ++ $perldoc = File::Spec->catfile('..','..','utils', ++ ($Config{usecperl}?'c':'').'perldoc'); ++} ++ ++# Hash of builtin => [output_start_regexp, output_end_regexp] ++my %builtins = ( ++ 'tr' => [ # CPAN RT#86506 ++ qr/\A\s+"tr\/\*SEARCHLIST\*\/\*REPLACEMENTLIST\*\/cdsr"\n/, ++ qr/\n\s+eval "tr\/\$oldlist\/\$newlist\/, 1" or die \$\@;\n\n\z/ ++ ], ++); ++ ++plan tests => 5 * scalar keys %builtins; ++ ++for my $builtin (sort keys %builtins) { ++ my ($pid, $stdout, $stderr); ++ ++ eval { ++ $pid = open3(\*CHLD_IN, \*CHLD_OUT1, \*CHLD_ERR1, ++ $^X, '-Mblib', '-Icorpus', $perldoc, '-T', '-t', '-f', $builtin); ++ }; ++ ++ is(length($@), 0, "open for $builtin succeeded"); # returns '' not undef ++ ok(defined($pid), "got process ID for $builtin"); ++ ++ # gather STDERR ++ while(){ ++ $stderr .= $_; ++ } ++ ++ # check STDERR ++ is($stderr, undef, "no STDERR for $builtin"); ++ ++ # gather STDOUT ++ while(){ ++ $stdout .= $_; ++ } ++ ++ # check STDOUT ++ like($stdout, $builtins{$builtin}->[0], "output for $builtin starts as expected"); ++ like($stdout, $builtins{$builtin}->[1], "output for $builtin ends as expected"); ++} ++ +-- +2.21.0 + diff --git a/SOURCES/Pod-Perldoc-3.28-Search-for-X-in-the-whole-perlop-document.patch b/SOURCES/Pod-Perldoc-3.28-Search-for-X-in-the-whole-perlop-document.patch new file mode 100644 index 0000000..316be5b --- /dev/null +++ b/SOURCES/Pod-Perldoc-3.28-Search-for-X-in-the-whole-perlop-document.patch @@ -0,0 +1,205 @@ +From aa7a2c99bff2a8d02d75f6b9f7155483cc94318c Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= +Date: Tue, 13 Aug 2019 16:49:21 +0200 +Subject: [PATCH 2/2] Search for X<> in the whole perlop document +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +perlop documents many operators before "Regexp Quote-Like Operators" +(X) section. A change introduced with "Refactor +search_perlop RT#86506" (d8b23dcb1a) commit started to ignore those +operators. E.g. A search for '==' did not found anything. A search for +'<>' returned too many text and broke POD syntax. + +This patch searches for X<> index entries in all sections and +considers =head keywords in addition to =item as section delimeters. + +Because some X<> entries exists on more places, this patch implements +this strategy: First =item section that contains the X<> entry is +returned. If there is no =item sections, last =head section is +returned. If the =item entry is empty (like for 'tr'), the the output +continues up to and including a next non-empty =item. This strategy is +implemented in one pass. + +Signed-off-by: Petr Písař +--- + lib/Pod/Perldoc.pm | 116 ++++++++++++++++++++++++++------------ + t/03_builtin_pod_output.t | 8 +++ + 2 files changed, 89 insertions(+), 35 deletions(-) + +diff --git a/lib/Pod/Perldoc.pm b/lib/Pod/Perldoc.pm +index cd52aa2..b54cc23 100644 +--- a/lib/Pod/Perldoc.pm ++++ b/lib/Pod/Perldoc.pm +@@ -1153,6 +1153,20 @@ sub search_perlvar { + + #.......................................................................... + ++# Check whether an item POD section contains any documentation text. The POD ++# section is passed as refernce to list of lines. ++# If there is no text, return true; otherwise false. ++sub item_has_no_text { ++ for (@{$_[0]}) { ++ next if /^=over\s/; ++ next if /^=item\s/; ++ next if /^Xopt_f; + +- my $previous_line; ++ my @previous_lines; ++ my $stop_line; ++ my $wrap_into_over; + my $push = 0; +- my $seen_item = 0; +- my $skip = 1; ++ my $pod_candidate = []; + + while( my $line = <$fh> ) { + $line =~ /^=encoding\s+(\S+)/ && $self->set_encoding($fh, $1); +- # only start search after we hit the operator section +- if ($line =~ m!^X!) { +- $skip = 0; +- } + +- next if $skip; +- +- # strategy is to capture the previous line until we get a match on X<$thingy> +- # if the current line contains X<$thingy>, then we push "=over", the previous line, +- # the current line and keep pushing current line until we see a ^X, +- # then we chop off final line from @$pod and add =back ++ # A strategy is to capture the previous lines from =head or =item until we ++ # get a match on X<$thing>. If the current line contains X<$thing>, then ++ # we push "=over" (in case of =item), the previous lines, the current line ++ # and keep pushing current line until we see a terminating POD keyworkd ++ # (=head, =item, =over, corrsponding to the starting POD keyword). Then we ++ # append =back (in case of =item). + # +- # At that point, Bob's your uncle. +- +- if ( $line =~ m!X<+\s*\Q$thing\E\s*>+!) { +- if ( $previous_line ) { +- push @$pod, "=over 8\n\n", $previous_line; +- $previous_line = ""; ++ # If this was =item, we are done. If the =item was empty (like two ++ # consequtive =item-s documented at once) we continue gathering other ++ # =item-s until we get some content. Then we are done. ++ # ++ # If this was a =head, we stash the POD section and do another search in ++ # hope we will found =item section. (=item sections tends to be more ++ # focused on =X<$thing> than =head sections.) If did not found any =item ++ # section, we will return the last found =head section. ++ ++ if ( $line =~ m!X<+\s*\Q$thing\E\s*>+! ) { ++ if ( @previous_lines ) { ++ push @$pod_candidate, "=over 8\n\n" if $wrap_into_over; ++ push @$pod_candidate, @previous_lines; ++ @previous_lines = (); + } +- push @$pod, $line; ++ push @$pod_candidate, $line; + $push = 1; + + } +- elsif ( $push and $line =~ m!^=item\s*.*$! ) { +- $seen_item = 1; +- } +- elsif ( $push and $seen_item and $line =~ m!^X<+\s*[ a-z,?-]+\s*>+!) { ++ elsif ( $push and $line =~ m/$stop_line/ ) { + $push = 0; +- $seen_item = 0; +- last; ++ ++ # X exists twice in perlop. Prefer =item location over =head ++ # location. We assume =item is more specific. ++ if ($wrap_into_over) { ++ # However, the X =item section is empty (except of bunch of ++ # X<> kewords) and documented in the next =item section. Thus ++ # continue until the so far gathered text looks empty. ++ if ($line =~ /^=item\s/ && item_has_no_text($pod_candidate)) { ++ $push = 1; ++ push @$pod_candidate, $line; ++ # and continue appending following =item section ++ } else { ++ # We have an =item with a content. ++ push @$pod_candidate, "\n\n=back\n"; ++ # Replace pod with the candidate ++ @$pod = @$pod_candidate; ++ last; ++ } ++ } else { ++ # Copy the candidate to pod ++ push @$pod, @$pod_candidate; ++ $pod_candidate = []; ++ # And search for another occurance of the X<> reference with the ++ # prospect it will be an =item. ++ } + } + elsif ( $push ) { +- push @$pod, $line; +- } +- +- else { +- $previous_line = $line; ++ push @$pod_candidate, $line; ++ } ++ ++ if ( !$push ) { ++ # Gather a smallest block starting with "=head" or "=item" ++ if ($line =~ /^=head([1234])\s/) { ++ $stop_line = join('', 1..$1); ++ $stop_line = qr/^=head[$stop_line]\s/; ++ $wrap_into_over = 0; ++ @previous_lines = (); ++ } elsif ($line =~ /^=item\s/) { ++ $stop_line = qr/^=(?:item\s|back\b)/; ++ $wrap_into_over = 1; ++ @previous_lines = (); ++ } ++ push @previous_lines, $line; + } + + } #end while + + # we overfilled by 1 line, so pop off final array element if we have any + if ( scalar @$pod ) { +- pop @$pod; +- +- # and add the =back +- push @$pod, "\n\n=back\n"; + DEBUG > 8 and print "PERLOP POD --->" . (join "", @$pod) . "<---\n"; + } + else { +diff --git a/t/03_builtin_pod_output.t b/t/03_builtin_pod_output.t +index 70f8549..d42a242 100644 +--- a/t/03_builtin_pod_output.t ++++ b/t/03_builtin_pod_output.t +@@ -24,6 +24,14 @@ my %builtins = ( + qr/\A\s+"tr\/\*SEARCHLIST\*\/\*REPLACEMENTLIST\*\/cdsr"\n/, + qr/\n\s+eval "tr\/\$oldlist\/\$newlist\/, 1" or die \$\@;\n\n\z/ + ], ++ '==' => [ # CPAN RT#126015 ++ qr/\A\s+Equality Operators\n/, ++ qr/\n\s+if \( fc\(\$x\) eq fc\(\$y\) \) \{ \.\.\. \}\n\n\z/ ++ ], ++ '<>' => [ # CPAN RT#126015 ++ qr/\A\s+I\/O Operators\n/, ++ qr/\n\s+for its regular truth value\.\n\n\z/ ++ ] + ); + + plan tests => 5 * scalar keys %builtins; +-- +2.21.0 + diff --git a/SOURCES/Pod-Perldoc-3.28-Upgrade-to-3.2801.patch b/SOURCES/Pod-Perldoc-3.28-Upgrade-to-3.2801.patch new file mode 100644 index 0000000..e33a3ed --- /dev/null +++ b/SOURCES/Pod-Perldoc-3.28-Upgrade-to-3.2801.patch @@ -0,0 +1,49 @@ +From d469b8609b566b972c7cc3ed74029cdddea50eee Mon Sep 17 00:00:00 2001 +From: Jitka Plesnikova +Date: Thu, 24 May 2018 10:48:47 +0200 +Subject: [PATCH] Upgrade to 3.2801 + +--- + lib/Pod/Perldoc.pm | 12 +----------- + 1 file changed, 1 insertion(+), 11 deletions(-) + +diff --git a/lib/Pod/Perldoc.pm b/lib/Pod/Perldoc.pm +index 8d695b2..bb6ffc8 100644 +--- a/lib/Pod/Perldoc.pm ++++ b/lib/Pod/Perldoc.pm +@@ -12,7 +12,7 @@ use File::Spec::Functions qw(catfile catdir splitdir); + use vars qw($VERSION @Pagers $Bindir $Pod2man + $Temp_Files_Created $Temp_File_Lifetime + ); +-$VERSION = '3.28'; ++$VERSION = '3.2801'; + + #.......................................................................... + +@@ -486,11 +486,6 @@ sub init_formatter_class_list { + + $self->opt_M_with('Pod::Perldoc::ToPod'); # the always-there fallthru + $self->opt_o_with('text'); +- $self->opt_o_with('term') +- unless $self->is_mswin32 || $self->is_dos || $self->is_amigaos +- || !($ENV{TERM} && ( +- ($ENV{TERM} || '') !~ /dumb|emacs|none|unknown/i +- )); + + return; + } +@@ -1937,11 +1932,6 @@ sub page { # apply a pager to the output file + } elsif($self->is_amigaos) { + last if system($pager, $output) == 0; + } else { +- my $formatter = $self->{'formatter_class'}; +- if ( $formatter->can('pager_configuration') ) { +- $self->aside("About to call $formatter" . "->pager_configuration(\"$pager\")\n"); +- $formatter->pager_configuration($pager, $self); +- } + last if system("$pager \"$output\"") == 0; + } + } +-- +2.14.3 + diff --git a/SPECS/perl-Pod-Perldoc.spec b/SPECS/perl-Pod-Perldoc.spec new file mode 100644 index 0000000..278b59d --- /dev/null +++ b/SPECS/perl-Pod-Perldoc.spec @@ -0,0 +1,301 @@ +# Optional features +# Run Tk tests +%bcond_without perl_Pod_Perldoc_enables_tk_test +# Support for groff +%bcond_without perl_enables_groff + +%global base_version 3.28 +Name: perl-Pod-Perldoc +# let's overwrite the module from perl.srpm +Version: 3.28.01 +Release: 442%{?dist} +Summary: Look up Perl documentation in Pod format +License: GPL+ or Artistic +URL: https://metacpan.org/release/Pod-Perldoc +Source0: https://cpan.metacpan.org/authors/id/M/MA/MALLEN/Pod-Perldoc-%{base_version}.tar.gz +# Unbundled from perl 5.28.0-RC1 +Patch0: Pod-Perldoc-3.28-Upgrade-to-3.2801.patch +# 1/2 Fix searching for builtins in perlop POD, bug #1739463, CPAN RT#126015 +Patch1: Pod-Perldoc-3.28-Add-a-test-for-a-truncated-perldoc-f-tr-output.patch +# 1/2 Fix searching for builtins in perlop POD, bug #1739463, CPAN RT#126015 +Patch2: Pod-Perldoc-3.28-Search-for-X-in-the-whole-perlop-document.patch +BuildArch: noarch +BuildRequires: make +BuildRequires: perl-generators +BuildRequires: perl-interpreter +BuildRequires: perl(ExtUtils::MakeMaker) >= 6.76 +BuildRequires: perl(strict) +BuildRequires: perl(warnings) +# Run-time: +%if %{with perl_enables_groff} +# Pod::Perldoc::ToMan executes roff +BuildRequires: groff-base +%endif +BuildRequires: perl(Carp) +BuildRequires: perl(Config) +BuildRequires: perl(Encode) +BuildRequires: perl(Fcntl) +BuildRequires: perl(File::Basename) +BuildRequires: perl(File::Spec::Functions) +# File::Temp 0.22 not used by tests +# HTTP::Tiny not used by tests +# IO::Handle not used by tests +BuildRequires: perl(IO::Select) +# IPC::Open3 not used by tests +BuildRequires: perl(parent) +# POD2::Base is optional +# Pod::Checker is not needed if Pod::Simple::Checker is available +BuildRequires: perl(Pod::Man) >= 2.18 +BuildRequires: perl(Pod::Simple::Checker) +BuildRequires: perl(Pod::Simple::RTF) >= 3.16 +BuildRequires: perl(Pod::Simple::XMLOutStream) >= 3.16 +BuildRequires: perl(Pod::Text) +BuildRequires: perl(Pod::Text::Color) +BuildRequires: perl(Pod::Text::Termcap) +# Symbol not used by tests +# Text::ParseWords not used by tests +BuildRequires: perl(vars) +# Tests: +BuildRequires: perl(blib) +BuildRequires: perl(Test::More) +# Optional tests: +%if !%{defined perl_bootstrap} +%if !( 0%{?rhel} >= 7 ) +%if %{with perl_Pod_Perldoc_enables_tk_test} +BuildRequires: perl(Tk) +# Tk::FcyEntry is optional +BuildRequires: perl(Tk::Pod) +%endif +%endif +%endif +%if %{with perl_enables_groff} +# Pod::Perldoc::ToMan executes roff +Requires: groff-base +%endif +Requires: perl(:MODULE_COMPAT_%(eval "`perl -V:version`"; echo $version)) +Requires: perl(File::Temp) >= 0.22 +Requires: perl(HTTP::Tiny) +Requires: perl(IO::Handle) +Requires: perl(IPC::Open3) +# POD2::Base is optional +# Pod::Checker is not needed if Pod::Simple::Checker is available +Requires: perl(Pod::Simple::Checker) +Requires: perl(Pod::Simple::RTF) >= 3.16 +Requires: perl(Pod::Simple::XMLOutStream) >= 3.16 +Requires: perl(Text::ParseWords) +# Tk is optional +Requires: perl(Symbol) + +# Remove underspecified dependencies +%global __requires_exclude %{?__requires_exclude:%__requires_exclude|}^perl\\((Pod::Man|Pod::Simple::XMLOutStream|Pod::Simple::RTF)\\)$ + +%description +perldoc looks up a piece of documentation in POD format that is embedded +in the perl installation tree or in a Perl script, and displays it via +"groff -man | $PAGER". This is primarily used for the documentation for +the Perl library modules. + +%prep +%setup -q -n Pod-Perldoc-%{base_version} +%patch0 -p1 +%patch1 -p1 +%patch2 -p1 + +%build +perl Makefile.PL INSTALLDIRS=vendor NO_PACKLIST=1 NO_PERLLOCAL=1 +%{make_build} + +%install +%{make_install} +%{_fixperms} $RPM_BUILD_ROOT/* + +%check +make test + +%files +%doc Changes README +%{_bindir}/perldoc +%{perl_vendorlib}/* +%{_mandir}/man1/* +%{_mandir}/man3/* + +%changelog +* Fri Aug 16 2019 Petr Pisar - 3.28.01-442 +- Build-require blib module for tests (bug #1739463) + +* Thu Aug 15 2019 Petr Pisar - 3.28.01-441 +- Fix searching for builtins in perlop POD (bug #1739463) + +* Fri Jul 26 2019 Fedora Release Engineering - 3.28.01-440 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_31_Mass_Rebuild + +* Sun Jun 02 2019 Jitka Plesnikova - 3.28.01-439 +- Perl 5.30 re-rebuild of bootstrapped packages + +* Thu May 30 2019 Jitka Plesnikova - 3.28.01-438 +- Increase release to favour standalone package + +* Fri Feb 01 2019 Fedora Release Engineering - 3.28.01-419 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_30_Mass_Rebuild + +* Fri Jul 13 2018 Fedora Release Engineering - 3.28.01-418 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_29_Mass_Rebuild + +* Sat Jun 30 2018 Jitka Plesnikova - 3.28.01-417 +- Perl 5.28 re-rebuild of bootstrapped packages + +* Wed Jun 27 2018 Jitka Plesnikova - 3.28.01-416 +- Increase release to favour standalone package + +* Thu May 24 2018 Jitka Plesnikova - 3.28.01-1 +- Upgrade to 3.2801 as provided in perl-5.28.0-RC1 + +* Fri Feb 09 2018 Fedora Release Engineering - 3.28-396 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild + +* Thu Jul 27 2017 Fedora Release Engineering - 3.28-395 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_27_Mass_Rebuild + +* Wed Jun 07 2017 Jitka Plesnikova - 3.28-394 +- Perl 5.26 re-rebuild of bootstrapped packages + +* Sat Jun 03 2017 Jitka Plesnikova - 3.28-393 +- Perl 5.26 rebuild + +* Mon Apr 03 2017 Petr Pisar - 3.28-2 +- Introduce a build-condition on groff +- Rename a _without_tk build-condition to + _without_perl_Pod_Perldoc_enables_tk_test + +* Thu Mar 16 2017 Petr Pisar - 3.28-1 +- 3.28 bump + +* Sat Feb 11 2017 Fedora Release Engineering - 3.27-2 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_26_Mass_Rebuild + +* Tue Aug 09 2016 Jitka Plesnikova - 3.27-1 +- 3.27 bump + +* Fri Jul 29 2016 Petr Pisar - 3.26-1 +- 3.26 bump + +* Wed May 18 2016 Jitka Plesnikova - 3.25-366 +- Perl 5.24 re-rebuild of bootstrapped packages + +* Sat May 14 2016 Jitka Plesnikova - 3.25-365 +- Increase release to favour standalone package + +* Thu Feb 04 2016 Fedora Release Engineering - 3.25-349 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_24_Mass_Rebuild + +* Mon Sep 21 2015 Petr Pisar - 3.25-348 +- Current generator detects dependency on Encode and Pod::Man properly + +* Thu Jun 18 2015 Fedora Release Engineering - 3.25-347 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_23_Mass_Rebuild + +* Wed Jun 10 2015 Jitka Plesnikova - 3.25-346 +- Perl 5.22 re-rebuild of bootstrapped packages + +* Thu Jun 04 2015 Jitka Plesnikova - 3.25-345 +- Increase release to favour standalone package + +* Wed Jun 03 2015 Jitka Plesnikova - 3.25-2 +- Perl 5.22 rebuild + +* Fri Feb 13 2015 Petr Pisar - 3.25-1 +- 3.25 bump + +* Mon Sep 15 2014 Petr Pisar - 3.24-4 +- Enable perl(Tk) tests + +* Sun Sep 07 2014 Jitka Plesnikova - 3.24-3 +- Perl 5.20 re-rebuild of bootstrapped packages +- Disable Perl(Tk) tests temporarily until Perl-Tk works with perl-5.20 + +* Tue Aug 26 2014 Jitka Plesnikova - 3.24-2 +- Perl 5.20 rebuild + +* Fri Aug 22 2014 Petr Pisar - 3.24-1 +- 3.24 bump + +* Sat Jun 07 2014 Fedora Release Engineering - 3.23-2 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_21_Mass_Rebuild + +* Tue Feb 25 2014 Petr Pisar - 3.23-1 +- 3.23 bump + +* Mon Jan 06 2014 Petr Pisar - 3.21-1 +- 3.21 bump + +* Mon Oct 07 2013 Petr Pisar - 3.20-7 +- Correct perldoc.pod location (bug #1010057) + +* Wed Aug 14 2013 Jitka Plesnikova - 3.20-6 +- Perl 5.18 re-rebuild of bootstrapped packages + +* Sun Aug 04 2013 Fedora Release Engineering - 3.20-5 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_20_Mass_Rebuild + +* Wed Jul 31 2013 Petr Pisar - 3.20-4 +- Specify all dependencies + +* Fri Jul 12 2013 Petr Pisar - 3.20-3 +- Link minimal build-root packages against libperl.so explicitly + +* Thu May 23 2013 Petr Pisar - 3.20-2 +- Specify all dependencies + +* Mon Apr 29 2013 Petr Pisar - 3.20-1 +- 3.20 bump + +* Tue Jan 29 2013 Petr Pisar - 3.19.01-1 +- 3.19_01 bump + +* Mon Jan 28 2013 Petr Pisar - 3.19.00-1 +- 3.19 bump + +* Wed Aug 15 2012 Petr Pisar - 3.17.00-241 +- Do not build-require perl(Tk) on RHEL >= 7 +- Depend on perl(HTTP::Tiny) + +* Mon Aug 13 2012 Marcela Mašláňová - 3.17.00-240 +- Bump release to override sub-package from perl.spec + +* Fri Jul 20 2012 Fedora Release Engineering - 3.17-9 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_18_Mass_Rebuild + +* Tue Jul 10 2012 Petr Pisar - 3.17-8 +- Perl 5.16 re-rebuild of bootstrapped packages + +* Wed Jun 27 2012 Petr Pisar - 3.17-7 +- Perl 5.16 rebuild + +* Wed Jun 27 2012 Petr Pisar - 3.17-6 +- Require groff-base because Pod::Perldoc::ToMan executes roff + +* Wed Jun 06 2012 Petr Pisar - 3.17-5 +- Perl 5.16 rebuild + +* Fri Jun 01 2012 Petr Pisar - 3.17-4 +- Omit optional Tk tests on bootstrap + +* Wed May 30 2012 Marcela Mašláňová - 3.17-3 +- conditionalize optional BR tests + +* Tue May 15 2012 Petr Pisar - 3.17-2 +- Fix perldoc synopsis (bug #821632) + +* Mon Mar 19 2012 Petr Pisar - 3.17-1 +- 3.17 bump +- Fix displaying long POD in groff + +* Fri Jan 13 2012 Fedora Release Engineering - 3.15.10-2 +- Rebuilt for https://fedoraproject.org/wiki/Fedora_17_Mass_Rebuild + +* Mon Nov 21 2011 Petr Pisar 3.15-1 +- Specfile autogenerated by cpanspec 1.78. +- Remove BuildRoot and defattr from spec code. +- perl(Config) BR removed +- Source URL fixed to point to BDFOY author +- Do not require unversioned perl(Pod::Simple::RTF)