NAME

List::MapList - map lists through a list of subs, not just one

VERSION

version 1.124

SYNOPSIS

Contrived heterogenous transform

use List::MapList;

my $code = [
  sub { $_ + 1 },
  sub { $_ + 2 },
  sub { $_ + 3 },
  sub { $_ + 4 }
];

my @mapped_1 = maplist( $code, qw(1 2 3 4 5 6 7 8 9));
# @mapped_1 is qw(2 4 6 8)

my @mapped_2 = mapcycle( $code, qw(1 2 3 4 5 6 7 8 9));
# @mapped_2 is qw(2 4 6 8 6 8 10 12 13)

Ultra-secure partial rot13:

my $rotsome = [
 sub { tr/a-zA-Z/n-za-mN-ZA-M/; $_ },
 sub { tr/a-zA-Z/n-za-mN-ZA-M/; $_ },
 sub { $_ },
];

my $plaintext  = "Too many secrets.";
my $cyphertext = join '', mapcycle($rotsome, split //, $plaintext);

DESCRIPTION

List::MapList provides methods to map a list through a list of transformations, instead of just one. The transformations are not chained together on each element; only one is used, alternating sequentially.

Here's a contrived example: given the transformations { $_ = 0 } and { $_ = 1 }, the list (1, 2, 3, "Good morning", undef) would become (0, 1, 0, 1, 0) or, without cycling, (0, 1).;

(I use this code to process a part number in which each digit maps to a set of product attributes.)

PERL VERSION

This library should run on perls released even a long time ago. It should work on any version of perl released in the last five years.

Although it may work on older versions of perl, no guarantee is made that the minimum required version will not be increased. The version may be increased for any reason, and there is no promise that patches will be accepted to lower the minimum required perl.

FUNCTIONS

maplist

my @results = maplist(\@coderefs, LIST);

This routine acts much like a normal map, but uses the list of code references in $coderefs in parallel with the list members. First first code reference is used for the first list member, the next for the second, and so on. Once the last code reference has been used, all further elements will be mapped to ().

mapcycle

my @results = mapcycle($coderefs, LIST);

This routine is identical to maplist, but will cycle through the passed coderefs over and over as needed.

AUTHOR

Ricardo SIGNES <cpan@semiotic.systems>

CONTRIBUTORS

• Ricardo SIGNES <rjbs@codesimply.com>

• Ricardo Signes <rjbs@semiotic.systems>

COPYRIGHT AND LICENSE

This software is copyright (c) 2004 by Ricardo SIGNES.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.