NAME¶
Data::Munge - various utility functions
SYNOPSIS¶
use Data::Munge;
my $re = list2re qw/foo bar baz/;
print byval { s/foo/bar/ } $text;
foo(mapval { chomp } @lines);
print replace('Apples are round, and apples are juicy.', qr/apples/i, 'oranges', 'g');
print replace('John Smith', qr/(\w+)\s+(\w+)/, '$2, $1');
DESCRIPTION¶
This module defines a few generally useful utility functions. I got tired of
redefining or working around them, so I wrote this module.
Functions¶
- list2re LIST
- Converts a list of strings to a regex that matches any of
the strings. Especially useful in combination with "keys".
Example:
my $re = list2re keys %hash;
$str =~ s/($re)/$hash{$1}/g;
- byval BLOCK SCALAR
- Takes a code block and a value, runs the block with $_ set
to that value, and returns the final value of $_. The global value of $_
is not affected. $_ isn't aliased to the input value either, so modifying
$_ in the block will not affect the passed in value. Example:
foo(byval { s/!/?/g } $str);
# Calls foo() with the value of $str, but all '!' have been replaced by '?'.
# $str itself is not modified.
- mapval BLOCK LIST
- Works like a combination of "map" and
"byval"; i.e. it behaves like "map", but $_ is a copy,
not aliased to the current element, and the return value is taken from $_
again (it ignores the value returned by the block). Example:
my @foo = mapval { chomp } @bar;
# @foo contains a copy of @bar where all elements have been chomp'd.
# This could also be written as chomp(my @foo = @bar); but that's not
# always possible.
- submatches
- Returns a list of the strings captured by the last
successful pattern match. Normally you don't need this function because
this is exactly what "m//" returns in list context. However,
"submatches" also works in other contexts such as the RHS of
"s//.../e".
- replace STRING, REGEX, REPLACEMENT, FLAG
- replace STRING, REGEX, REPLACEMENT
- A clone of javascript's
"String.prototype.replace". It works almost the same as
"byval { s/REGEX/REPLACEMENT/FLAG } STRING", but with a few
important differences. REGEX can be a string or a compiled
"qr//" object. REPLACEMENT can be a string or a subroutine
reference. If it's a string, it can contain the following replacement
patterns:
- $$
- Inserts a '$'.
- $&
- Inserts the matched substring.
- $`
- Inserts the substring preceding the match.
- $'
- Inserts the substring following the match.
- $N (where N is a digit)
- Inserts the substring matched by the Nth capturing
group.
- ${N} (where N is one or more digits)
- Inserts the substring matched by the Nth capturing
group.
Note that these aren't variables; they're character sequences interpreted by
"replace".
If REPLACEMENT is a subroutine reference, it's called with the following
arguments: First the matched substring (like $& above), then the contents
of the capture buffers (as returned by "submatches"), then the
offset where the pattern matched (like "$-[0]", see "@-"
in perlvar), then the STRING. The return value will be inserted in place of
the matched substring.
Normally only the first occurrence of REGEX is replaced. If FLAG is present, it
must be 'g' and causes all occurrences to be replaced.
AUTHOR¶
Lukas Mai, "<l.mai at web.de>"
COPYRIGHT & LICENSE¶
Copyright 2009-2011 Lukas Mai.
This program is free software; you can redistribute it and/or modify it under
the terms of either: the GNU General Public License as published by the Free
Software Foundation; or the Artistic License.
See
http://dev.perl.org/licenses/ for more information.
