Sah::Schema::date::month_num - Month number, coercible from English month names (Dec/DECEMBER)


This document describes version 0.017 of Sah::Schema::date::month_num (from Perl distribution Sah-Schemas-Date), released on 2021-08-04.


Sample data and validation results against this schema

 ""  # INVALID (Empty string)

 0  # INVALID (Not between 1-12)

 1  # valid

 "JUN"  # valid, becomes 6

 12  # valid

 13  # INVALID (Not between 1-12)

Using with Data::Sah

To check data against this schema (requires Data::Sah):

 use Data::Sah qw(gen_validator);
 my $validator = gen_validator("date::month_num*");
 say $validator->($data) ? "valid" : "INVALID!";

The above schema returns a boolean value (true if data is valid, false if otherwise). To return an error message string instead (empty string if data is valid, a non-empty error message otherwise):

 my $validator = gen_validator("date::month_num", {return_type=>'str_errmsg'});
 my $errmsg = $validator->($data);
 # a sample valid data
 $data = 1;
 my $errmsg = $validator->($data); # => ""
 # a sample invalid data
 $data = 13;
 my $errmsg = $validator->($data); # => "Must be at most 12"

Often a schema has coercion rule or default value, so after validation the validated value is different. To return the validated (set-as-default, coerced, prefiltered) value:

 my $validator = gen_validator("date::month_num", {return_type=>'str_errmsg+val'});
 my $res = $validator->($data); # [$errmsg, $validated_val]
 # a sample valid data
 $data = 1;
 my $res = $validator->($data); # => ["",1]
 # a sample invalid data
 $data = 13;
 my $res = $validator->($data); # => ["Must be at most 12",13]

Data::Sah can also create validator that returns a hash of detaild error message. Data::Sah can even create validator that targets other language, like JavaScript, from the same schema. Other things Data::Sah can do: show source code for validator, generate a validator code with debug comments and/or log statements, generate human text from schema. See its documentation for more details.

Using with Params::Sah

To validate function parameters against this schema (requires Params::Sah):

 use Params::Sah qw(gen_validator);

 sub myfunc {
     my @args = @_;
     state $validator = gen_validator("date::month_num*");

Using with Perinci::CmdLine::Lite

To specify schema in Rinci function metadata and use the metadata with Perinci::CmdLine (Perinci::CmdLine::Lite) to create a CLI:

 # in lib/
 our %SPEC;
 $SPEC{myfunc} = {
     v => 1.1,
     summary => 'Routine to do blah ...',
     args => {
         arg1 => {
             summary => 'The blah blah argument',
             schema => ['date::month_num*'],
 sub myfunc {
     my %args = @_;

 # in
 use Perinci::CmdLine::Any;

 # in command-line
 % ./ --help
 myapp - Routine to do blah ...

 % ./ --version

 % ./ --arg1 ...


See also related schemas that coerce from other locales, e.g. Sah::Schema::date::month_num::id (Indonesian), Sah::Schema::date::month_num::en_or_id (English/Indonesian), etc.


Please visit the project's homepage at


Source repository is at


Please report any bugs or feature requests on the bugtracker website

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.


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