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 have been replaced by '?'.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.