
  [;1m-spec float(Number) -> float() when Number :: number().[0m

  Returns a float by converting [;;4mNumber[0m to a float, for example:

    > float(55).
    55.0

  Allowed in guard tests.

  Note:
    If used on the top level in a guard, it tests whether the
    argument is a floating point number; for clarity, use [;;4m[0m
    [;;4mis_float/1[0m instead.

    When [;;4mfloat/1[0m is used in an expression in a guard, such as '[;;4m[0m
    [;;4mfloat(A) == 4.0[0m', it converts a number as described earlier.
