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Data-Phrasebook-Loader-JSON-0.02
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/ Data::Phrasebook::Loader::JSON

NAME

Data::Phrasebook::Loader::JSON - Absract your phrases with JSON.

SYNOPSIS

use Data::Phrasebook;

my $q = Data::Phrasebook->new(
    class  => 'Fnerk',
    loader => 'JSON',
    file   => 'phrases.json',
);

$q->delimiters( qr{ \[% \s* (\w+) \s* %\] }x );
my $phrase = $q->fetch($keyword);

DESCRIPTION

This class loader implements phrasebook patterns using JSON.

Phrases can be contained within one or more dictionaries, with each phrase accessible via a unique key. Phrases may contain placeholders, please see Data::Phrasebook for an explanation of how to use these. Groups of phrases are kept in a dictionary. In this implementation a single file is one complete dictionary.

An example JSON file:

{ 
  "dictionary1": { "key1": "value1", "key2": "value2" },
  "dictionary2": { "key3": "value3", "key4": "value4" }
}

Within the phrase text placeholders can be used, which are then replaced with the appropriate values once the get() method is called. The default style of placeholders can be altered using the delimiters() method.

INHERITANCE

Data::Phrasebook::Loader::JSON inherits from the base class Data::Phrasebook::Loader::Base. See that module for other available methods and documentation.

METHODS

load

Given a file, load it. file must contain a JSON map.

$loader->load( $file, @dict );

This method is used internally by Data::Phrasebook::Generic's data method, to initialise the data store.

It must take a file (be it a scalar, or something more complex) and return a handle. The dict is optional, should you wish to use the dictionary support.

get

Returns the phrase stored in the phrasebook, for a given keyword.

my $value = $loader->get( $key );

If one or more named dictionaries have been previously selected, they will be searched in order, followed by the default dictionary. The first hit on key will be returned, otherwise undef is returned.

dicts

Returns the list of dictionaries available.

my @dicts = $loader->dicts();

This is the list of all dictionaries available in the source file. If multiple dictionaries are not being used, then an empty list will be returned.

keywords

Returns the list of keywords available. List is lexically sorted.

my @keywords = $loader->keywords( $dict );

If one or more named dictionaries have been previously selected, they will be farmed for keywords, followed by the default dictionary.

The dict argument is optional, and may be used to override the search to a single named dictionary, or a list of dictionaries if passed by reference, plus the default dictionary of course.

To find all available keywords in all available dictionaries, use the following:

$loader->keywords( [ $loader->dicts ] );

set_default

If a requested phrase is not found in the named dictionary an attempt is made to find it in the default dictionary. Data::Phrasebook loaders normally use the first dictionary in the phrasebook as the default, but as mentioned in "DICTIONARY SUPPORT" this does not make sense because the dictionaries in JSON phrasebooks are not ordered.

To override the automatically selected default dictionary use this method, and pass it a default_dictionary_name. This value is only reset at phrasebook load time, so you'll probably need to trigger a reload:

$q->loader->set_default( $default_dictionary_name );
$q->loader->load( $file );

To reset the loader's behaviour to automatic default dictionary selection, pass this method an undefined value, and then reload.

DICTIONARY SUPPORT

This loader supports the use of dictionaries, as well as multiple dictionaries with a search order. If you are unfamiliar with these features, see Data::Phrasebook for more information.

Source data format for a single unnamed dictionary is a JSON stream that has as its root node an anonymous hash, like so:

{ 
  "first_key": "first_value", "second_key": "second_value"
}

In this case, specifying one or more named dictionaries will have no effect. The single dictionary that comprises the JSON file will take the place of your default dictionary, so will always be searched. To override this behaviour use the set_default object method.

Multiple dictionaries must be specified using a two-level hash system, where the root node of your JSON file is an anonymous hash containing dictionary names, and the values of those hash keys are further anonymous hashes containing the dictionary contents. Here is an example:

{ 
  "dict_one": { "first_key": "first_value", "second_key": "second_value" },
  "dict_two": { "first_key": "first_value", "second_key": "second_value" }
}

If you use any other structure for your JSON dictionary files, the result is uncertain, and this loader module is very likely to crash your program.

If a requested phrase is not found in the named dictionary an attempt is made to find it in the default dictionary. Data::Phrasebook loaders normally use the first dictionary in the phrasebook as the default, but this does not make sense because JSON phrasebook files contain an unordered hash of dictionaries.

This loader will therefore select the first dictionary from the list of lexically sorted dictionary names to be the default. To override this behaviour use the set_default object method. Alternatively, just include a dictionary that is guaranteed to be selected for the default (e.g. 0000default); it need not contain any keys.

ALTERNATIVES

This module was written to use JSON::XS. If you prefer to use JSON::Syck, I heartily recommend using Data::Phrasebook::Loader::JSON::Syck by Stevan Little. The only reason I didn't use his module is beacuse this was used in a project already using JSON::XS, and I didn't want to use two different JSON parsers.

SEE ALSO

Data::Phrasebook, Data::Phrasebook::Loader.

BUGS, PATCHES & FIXES

There are no known bugs at the time of this release. However, if you spot a bug or are experiencing difficulties, that is not explained within the POD documentation, please send an email to barbie@cpan.org or submit a bug to the RT system (http://rt.cpan.org/). However, it would help greatly if you are able to pinpoint problems or even supply a patch.

Fixes are dependent upon their severity and my availability. Should a fix not be forthcoming, please feel free to (politely) remind me.

AUTHOR

Barbie <barbie@cpan.org>
for Miss Barbell Productions <http://www.missbarbell.co.uk>.

COPYRIGHT AND LICENSE

Copyright (C) 2013-2014 Barbie for Miss Barbell Productions.

This distribution is free software; you can redistribute it and/or
modify it under the Artistic License 2.0.