Template::Plugin::String
Author: Andy Wardley

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#### Template::Plugin::Scalar

call object methods in scalar context Up

#### Template::Plugin::* Modules

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#### Template::Plugin::Table

Plugin to present data in a table

# Template::Plugin::String

## Object oriented interface for string manipulation

# Contents

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# SYNOPSIS

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    # create String objects via USE directive
    [% USE String %]
    [% USE String 'initial text' %]
    [% USE String text => 'initial text' %]

    # or from an existing String via new()
    [% newstring = String.new %]
    [% newstring = String.new('newstring text') %]
    [% newstring = String.new( text => 'newstring text' ) %]

    # or from an existing String via copy()
    [% newstring = String.copy %]

    # append text to string
    [% String.append('text to append') %]

    # format left, right or center/centre padded
    [% String.left(20) %]
    [% String.right(20) %]
    [% String.center(20) %]   # American spelling
    [% String.centre(20) %]   # European spelling

    # and various other methods...

# DESCRIPTION

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This module implements a `String` class for doing stringy things to text in an object-oriented way.

You can create a `String` object via the `USE` directive, adding any initial text value as an argument or as the named parameter `text`.

    [% USE String %]
    [% USE String 'initial text' %]
    [% USE String text='initial text' %]

The object created will be referenced as `String` by default, but you can provide a different variable name for the object to be assigned to:

    [% USE greeting = String 'Hello World' %]

Once you've got a `String` object, you can use it as a prototype to create other `String` objects with the `new()` method.

    [% USE String %]
    [% greeting = String.new('Hello World') %]

The `new()` method also accepts an initial text string as an argument or the named parameter `text`.

    [% greeting = String.new( text => 'Hello World' ) %]

You can also call `copy()` to create a new `String` as a copy of the original.

    [% greet2 = greeting.copy %]

The `String` object has a `text()` method to return the content of the string.

    [% greeting.text %]

However, it is sufficient to simply print the string and let the overloaded stringification operator call the `text()` method automatically for you.

    [% greeting %]

Thus, you can treat `String` objects pretty much like any regular piece of text, interpolating it into other strings, for example:

    [% msg = "It printed '$greeting' and then dumped core\n" %]

You also have the benefit of numerous other methods for manipulating the string.

    [% msg.append("PS  Don't eat the yellow snow") %]

Note that all methods operate on and mutate the contents of the string itself. If you want to operate on a copy of the string then simply take a copy first:

    [% msg.copy.append("PS  Don't eat the yellow snow") %]

These methods return a reference to the `String` object itself. This allows you to chain multiple methods together.

    [% msg.copy.append('foo').right(72) %]

It also means that in the above examples, the `String` is returned which causes the `text()` method to be called, which results in the new value of the string being printed. To suppress printing of the string, you can use the `CALL` directive.

    [% foo = String.new('foo') %]

    [% foo.append('bar') %]         # prints "foobar"

    [% CALL foo.append('bar') %]    # nothing

# CONSTRUCTOR METHODS

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These methods are used to create new `String` objects.

## new()

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Creates a new string using an initial value passed as a positional argument or the named parameter `text`.

    [% USE String %]
    [% msg = String.new('Hello World') %]
    [% msg = String.new( text => 'Hello World' ) %]

## copy()

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Creates a new `String` object which contains a copy of the original string.

    [% msg2 = msg.copy %]

# INSPECTOR METHODS

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These methods are used to examine the string.

## text()

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Returns the internal text value of the string. The stringification operator is overloaded to call this method. Thus the following are equivalent:

    [% msg.text %]
    [% msg %]

## length()

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Returns the length of the string.

    [% USE String("foo") %]
    [% String.length %]   # => 3

## search($pattern)

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Searches the string for the regular expression specified in `$pattern` returning true if found or false otherwise.

    [% item = String.new('foo bar baz wiz waz woz') %]
    [% item.search('wiz') ? 'WIZZY! :-)' : 'not wizzy :-(' %]

## split($pattern, $limit)

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Splits the string based on the delimiter `$pattern` and optional `$limit`. Delegates to Perl's internal `split()` so the parameters are exactly the same.

    [% FOREACH item.split %]
         ...
    [% END %]

    [% FOREACH item.split('baz|waz') %]
         ...
    [% END %]

# MUTATOR METHODS

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These methods modify the internal value of the string. For example:

    [% USE str=String('foobar') %]
    [% str.append('.html') %]   # str => 'foobar.html'

The value of `str` is now '`foobar.html`'. If you don't want to modify the string then simply take a copy first.

    [% str.copy.append('.html') %]

These methods all return a reference to the `String` object itself. This has two important benefits. The first is that when used as above, the `String` object '`str`' returned by the `append()` method will be stringified with a call to its `text()` method. This will return the newly modified string content. In other words, a directive like:

    [% str.append('.html') %]

will update the string and also print the new value. If you just want to update the string but not print the new value then use `CALL`.

    [% CALL str.append('.html') %]

The other benefit of these methods returning a reference to the `String` is that you can chain as many different method calls together as you like. For example:

    [% String.append('.html').trim.format(href) %]

Here are the methods:

## push($suffix, ...) / append($suffix, ...)

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Appends all arguments to the end of the string. The `append()` method is provided as an alias for `push()`.

    [% msg.push('foo', 'bar') %]
    [% msg.append('foo', 'bar') %]

## pop($suffix)

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Removes the suffix passed as an argument from the end of the String.

    [% USE String 'foo bar' %]
    [% String.pop(' bar')   %]   # => 'foo'

## unshift($prefix, ...) / prepend($prefix, ...)

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Prepends all arguments to the beginning of the string. The `prepend()` method is provided as an alias for `unshift()`.

    [% msg.unshift('foo ', 'bar ') %]
    [% msg.prepend('foo ', 'bar ') %]

## shift($prefix)

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Removes the prefix passed as an argument from the start of the String.

    [% USE String 'foo bar' %]
    [% String.shift('foo ') %]   # => 'bar'

## left($pad)

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If the length of the string is less than `$pad` then the string is left formatted and padded with spaces to `$pad` length.

    [% msg.left(20) %]

## right($pad)

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As per left() but right padding the `String` to a length of `$pad`.

    [% msg.right(20) %]

## center($pad) / centre($pad)

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As per left() and right() but formatting the `String` to be centered within a space padded string of length `$pad`. The `centre()` method is provided as an alias for `center()`.

    [% msg.center(20) %]    # American spelling
    [% msg.centre(20) %]    # European spelling

## format($format)

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Apply a format in the style of `sprintf()` to the string.

    [% USE String("world") %]
    [% String.format("Hello %s\n") %]  # => "Hello World\n"

## upper()

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Converts the string to upper case.

    [% USE String("foo") %]
    [% String.upper %]  # => 'FOO'

## lower()

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Converts the string to lower case

    [% USE String("FOO") %]
    [% String.lower %]  # => 'foo'

## capital()

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Converts the first character of the string to upper case.

    [% USE String("foo") %]
    [% String.capital %]  # => 'Foo'

The remainder of the string is left untouched. To force the string to be all lower case with only the first letter capitalised, you can do something like this:

    [% USE String("FOO") %]
    [% String.lower.capital %]  # => 'Foo'

## chop()

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Removes the last character from the string.

    [% USE String("foop") %]
    [% String.chop %]   # => 'foo'

## chomp()

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Removes the trailing newline from the string.

    [% USE String("foo\n") %]
    [% String.chomp %]  # => 'foo'

## trim()

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Removes all leading and trailing whitespace from the string

    [% USE String("   foo   \n\n ") %]
    [% String.trim %]   # => 'foo'

## collapse()

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Removes all leading and trailing whitespace and collapses any sequences of multiple whitespace to a single space.

    [% USE String(" \n\r  \t  foo   \n \n bar  \n") %]
    [% String.collapse %]   # => "foo bar"

## truncate($length, $suffix)

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Truncates the string to `$length` characters.

    [% USE String('long string') %]
    [% String.truncate(4) %]  # => 'long'

If `$suffix` is specified then it will be appended to the truncated string. In this case, the string will be further shortened by the length of the suffix to ensure that the newly constructed string complete with suffix is exactly `$length` characters long.

    [% USE msg = String('Hello World') %]
    [% msg.truncate(8, '...') %]   # => 'Hello...'

## replace($search, $replace)

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Replaces all occurences of `$search` in the string with `$replace`.

    [% USE String('foo bar foo baz') %]
    [% String.replace('foo', 'wiz')  %]  # => 'wiz bar wiz baz'

## remove($search)

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Remove all occurences of `$search` in the string.

    [% USE String('foo bar foo baz') %]
    [% String.remove('foo ')  %]  # => 'bar baz'

## repeat($count)

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Repeats the string `$count` times.

    [% USE String('foo ') %]
    [% String.repeat(3)  %]  # => 'foo foo foo '

# AUTHOR

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Andy Wardley <abw@wardley.org> http://wardley.org/

# COPYRIGHT

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Copyright (C) 1996-2007 Andy Wardley. All Rights Reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

# SEE ALSO

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Template::Plugin

http://template-toolkit.org/docs/modules/Template/Plugin/String.html