Kura Perl

kura - Unified Type Constraint Storage

kura provides a simple way to store and export type constraints from multiple libraries.

Core Usage

Basic Declaration

use Exporter 'import';
use Types::Common -types;

use kura Name => StrLength[1, 255];
use kura Age => Int & sub { $_ >= 0 };
use kura Email => sub { /@/ };  # Code ref auto-converted

Syntax: use kura NAME => CONSTRAINT;

Supported Constraints

• Type objects (Type::Tiny, Moose, Specio, Data::Checks)
• Code references (converted to Type::Tiny)
• Hash references with constraint and message

Practical Examples

Export Types

package MyTypes {
    use parent 'Exporter::Tiny';
    use Types::Common -types;

    use kura Name => StrLength[1, 255];
    use kura Email => Str & sub { /@/ };
}

use MyTypes qw(Name Email);
Name->check('John');  # true

Built-in Class (v5.40+)

class User {
    use Types::Common -types;
    use kura Name => StrLength[1, 255];

    field $name :param :reader;

    ADJUST {
        Name->assert_valid($name);
    }
}

my $user = User->new(name => '');  # Dies: validation error

Best Practices

1. Always load an exporter: use Exporter 'import';
2. Declare in order: Define child constraints before parent constraints

   use kura Child => Str;
   use kura Parent => Dict[ name => Child ];  # Correct order
   

3. Private constraints: Prefix with _ to prevent export

   use kura _Private => Str;  # Not exported
   

4. Package variables: @EXPORT_OK and @KURA are auto-populated