/ 
Block-NamedVar-0.009
River stage zero No dependents
/ Block::NamedVar

NAME

Block::NamedVar - Named variables for grep and map, for with multiple named list elements.

DESCRIPTION

Gives you nmap and ngrep which are new keywords that let you do a map or grep. The difference is you can name the block variable instead of relying on $_. You can also turn custom map/grep like functions into keywords that act like nmap and ngrep.

Gives you nfor which is like 'for' except you can loop over multiple elements of the array at once. If given a hash you can get the key and the value each iteration. Implemented such that it does not suffer the problems of each().

SYNOPSIS

#!/usr/bin/perl
use strict;
use warnings;

use Block::NamedVar;

my %a_hash = ( a => 1, b => 2 );
my @stuff = qw/a 1 b 2 c 3/

nfor my ( $key, $value ) ( %a_hash ) {
    print $key, " = ", $value, "\n";
}

my @list = ngrep my $x { $x =~ m/^[a-zA-Z]$/ } @stuff;

@list = nmap my $x { "updated_$x" } @stuff;

EXPORTED FUNCTIONS

nfor my ( $vara, $varb, ... ) ( @list ) { ... }

like 'for', except that you can take any number of elements from the array per iteration. Loop controls like 'next' and 'last' work as expected.

nfor ( key => 'value' ) { $a == 'key', $b == 'value' }

Special case of nfor, if no variables are specified $a and $b will be used, and 2 elements will be taken per iteration. Useful for iterating hashes. $a and $b are localized to your block.

@out = ngrep var { $var ... } @list
@out = ngrep $var { $var ... } @list
@out = ngrep my $var { $var ... } @list
@out = ngrep our $var { $var ... } @list

Works just like grep except you specify a variable instead of using $_.

# grep with lexical $x.
@list = ngrep my $x { $x =~ m/^[a-zA-Z]$/ } @stuff;

# grep with package variable $v
$count = ngrep our $v { $v =~ m/^[a-zA-Z]$/ } @stuff;

# grep with closure over existing $y
my $y;
$count = ngrep $y { $y =~ m/^[a-zA-Z]$/ } @stuff;

# Shortcut for lexical variable
# must be bareword.
$count = ngrep thing { $thing =~ m/^[a-zA-Z]$/ } @stuff;
@out = nmap var { $var ... } @list
@out = nmap $var { $var ... } @list
@out = nmap my $var { $var ... } @list
@out = nmap our $var { $var ... } @list

Works just like map except you specify a variable instead of using $_.

# map with lexical $x
@list = nmap my $x { "updated_$x" } @stuff;

AUTHORS

Chad Granum exodist7@gmail.com

COPYRIGHT

Copyright (C) 2010 Chad Granum

Block-NamedVar is free software; Standard perl licence.

Block-NamedVar is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the license for more details.