Positron::Environment - container class for template parameters
version v0.0.3
use Positron::Environment; my $env = Positron::Environment->new({ key1 => 'value 1', key2 => 'value 2'}); my $child = Positron::Environment->new({ key1 => 'value 3'}, { parent => $env }); say $env->get('key1'); # value 1 say $env->get('key2'); # value 2 say $child->get('key1'); # value 3 say $child->get('key2'); # value 2 $child->set( key2 => 'value 4' ); say $child->get('key2'); # value 4 say $env->get('key2'); # value 2
Positron::Environment is basically a thin wrapper around hashes (key-value mappings) with hierarchy extensions. It is used internally by the Positron template systems to store template variables.
Positron::Environment
Positron
Positron::Environment provides getters and setters for values. It can also optionally refer to a parent environment. If the environment does not contain anything for an asked-for key, it will ask its parent in turn. Note that if a key refers to undef as its value, this counts as "containing something", and the parent will not be asked.
undef
my $env = Positron::Environment->new( \%data, \%options );
Creates a new environment which serves the data passed in a hash reference. The following options are supported:
If set to a true value, the constructed environment will be immutable; calling the set method will raise an exception.
set
A reference to another environment. If the newly constructed environment does not contain a key when asked with get, it will ask this parent environment (which can have a parent in turn).
get
my $value = $env->get('key');
Returns the value stored under the key key in the data of this environment. This is very much like a standard hash ref. If this environment does not know about this key (i.e. it does not exist in the data hash), it returns undef, unless a parent environment is set. In this case, it will recursively query its parent for the key.
key
my $value = $env->set('key', 'value');
Sets the key to the given value in this environment's data hash. This call will croak if the environment has been marked as immutable. Setting the value to undef will effectively mask any parent; a get call will return undef even if the parent has a defined value.
Returns the value again (this may change in future versions).
Ben Deutsch, <ben at bendeutsch.de>
<ben at bendeutsch.de>
None known so far, though keep in mind that this is alpha software.
Please report any bugs or feature requests to bug-positron at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Positron. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
bug-positron at rt.cpan.org
This module is part of the Positron distribution.
You can find documentation for this distribution with the perldoc command.
perldoc Positron
You can also look for information at:
RT: CPAN's request tracker (report bugs here)
http://rt.cpan.org/NoAuth/Bugs.html?Dist=Positron
AnnoCPAN: Annotated CPAN documentation
http://annocpan.org/dist/Positron
CPAN Ratings
http://cpanratings.perl.org/d/Positron
Search CPAN
http://search.cpan.org/dist/Positron/
Copyright 2013 Ben Deutsch. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See http://dev.perl.org/licenses/ for more information.
To install Positron, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Positron
CPAN shell
perl -MCPAN -e shell install Positron
For more information on module installation, please visit the detailed CPAN module installation guide.