| JSON::Types(3pm) | User Contributed Perl Documentation | JSON::Types(3pm) |
JSON::Types - variable type utility for JSON encoding
# Export type functions by default
use JSON;
use JSON::Types;
print encode_json({
number => number "123",
string => string 123,
bool => bool "True value",
});
# => {"number":123,"string":"123","bool":true}
# Non export interface
use JSON::Types ();
print encode_json({
number => JSON::Types::number "123",
string => JSON::Types::string 123,
bool => JSON::Types::bool "True value",
});
The type mappings between JSON and Perl is annoying things. For example,
use JSON;
my $number = 123;
warn "[DEBUG] number:$number\n" if $ENV{DEBUG};
print encode_json([ $number ]);
Output of this code depends on whether DEBUG environment is set or not. If set, result is "[123]". If not to set, result is "["123"]". This is normal behaviour on Perl though, it sometimes causes unexpected JSON results.
There is a solution about this:
print encode_json([ $number + 0 ]);
This code always outputs "[123]". But the code is a bit ugly and not readable at all.
This module provides some functions to fix this variable types issue:
number $foo; # is always number
string $foo; # is always string
bool $foo; # is always bool
You can fix above code by using this module like this:
use JSON;
use JSON::Types;
my $number = 123;
warn "[DEBUG] number:$number\n" if $ENV{DEBUG};
print encode_json([ number $number ]);
There is three functions and all functions is exported by default.
If you don't want this exported functions, pass empty list to use line:
use JSON::Types ();
You should specify full function name when this case, like "JSON::Types::number $foo" or etc.
Passing undefined variable to string and number function is returns undef. If you doesn't prefer this, have to treat this like following:
number $undef_possible_value // 0
This code returns 0 if variable is undef.
Passing not numeric variable to number function is returns 0, but a warning will be occurred.
Daisuke Murase <typester@cpan.org>
Copyright (c) 2012 Daisuke Murase. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
The full text of the license can be found in the LICENSE file included with this module.
| 2022-10-13 | perl v5.34.0 |