NAME
List::Gather - Construct lists procedurally without temporary variables
SYNOPSIS
use List::Gather;
my @list = gather {
# Try to extract odd numbers and odd number names...
for (@data) {
if (/(one|three|five|seven|nine)$/) {
take qq{'$_'};
}
elsif (/^\d+$/ && $_ %2) {
take $_;
}
}
# But use the default set if there aren't any of either...
take @defaults unless gathered;
}DESCRIPTION
This module provides a gather keyword that allows lists to be constructed procedurally, without the need for a temporary variable.
Within the block controlled by a gather any call to take pushes that call's argument list to an implicitly created array.
gather returns the list of values taken during its block's execution.
FUNCTIONS
gather
gather { ... };
gather({ ... });Executes the block it has been provided with, collecting all arguments passed to take calls within it. After execution, the list of values collected is returned.
Parens around the gather block are optional.
take
take LIST;Collects a LIST of values within the currently executing gather block.
take returns no meaningful value.
take calls outside of the lexical scope of a gather block are compile time errors. Calling take is only legal within the dynamic scope its associated gather block.
gathered
gathered;Returns the list of items collected so far during the execution of a gather block.
gathered calls outside of the lexical scope of a gather block are compile time errors. Calling gathered outside of the dynamic scope of its associated gather block is legal.
SEE ALSO
- Syntax::Keyword::Gather
-
A non-lexical gather/take implementation that's otherwise very similar to this one
- Perl6::GatherTake
-
An experimental implementation of a lazily evaluating gather/take
- Perl6::Take
-
A very simple gather/take implementation without lexical scoping
- Perl6::Gather
-
Like Syntax::Keyword::Gather, but reliant on Perl6::Export
- List::Gen
-
A comprehensive suit list generation functions featuring a non-lexical gather/take
ACKNOWLEDGEMENTS
Andrew Main (Zefram) <zefram@fysh.org>
for providing his input in both the design and implementation of this module, and writing much of the infrastructure that made this module possible in the first place
Arthur Axel "fREW" Schmidt <frioux+cpan@gmail.com>
for his input on various aspects of this module as well as the many tests of his Syntax::Keyword::Gather module that this module shamelessly stole
AUTHOR
Florian Ragwitz <rafl@debian.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2012 by Florian Ragwitz.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.