Specio::Constraint::Structurable

Section: User Contributed Perl Documentation (3)
Updated: 2021-01-31
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NAME

Specio::Constraint::Structurable - A class which represents structurable constraints

VERSION

version 0.47

SYNOPSIS

    my $tuple = t('Tuple');

    my $tuple_of_str_int = $tuple->parameterize( of => [ t('Str'), t('Int') ] );

DESCRIPTION

This class implements the API for structurable types like "Dict", "Map"< and "Tuple".

API

This class implements the same API as Specio::Constraint::Simple, with a few additions.

Specio::Constraint::Structurable->new(...)

This class's constructor accepts two additional parameters:

•

parameterization_args_builder

This is a subroutine that takes the values passed to "of" and returns a hash of named arguments. These arguments will then be passed into the "structured_constraint_generator" or "structured_inline_generator".

This should also do argument checking to make sure that the argument passed are valid. For example, the "Tuple" type turns the arrayref passed to "of" into a hash, along the way checking that the caller did not do things like interleave optional and required elements or mix optional and slurpy together in the definition.

This parameter is required.

•

name_builder

This is a subroutine that is called to generate a name for the structured type when it is created. This will be called as a method on the "Specio::Constraint::Structurable" object. It will be passed the hash of arguments returned by the "parameterization_args_builder".

This parameter is required.

•

structured_constraint_generator

This is a subroutine that generates a new constraint subroutine when the type is structured.

It will be called as a method on the type and will be passed the hash of arguments returned by the "parameterization_args_builder".

This parameter is mutually exclusive with the "structured_inline_generator" parameter.

This parameter or the "structured_inline_generator" parameter is required.

•

structured_inline_generator

This is a subroutine that generates a new inline generator subroutine when the type is structured.

It will be called as a method on the Specio::Constraint::Structured object when that object needs to generate an inline constraint. It will receive the type parameter as the first argument and the variable name as a string as the second.

The remaining arguments will be the parameter hash returned by the "parameterization_args_builder".

This probably seems fairly confusing, so looking at the examples in the Specio::Library::Structured::* code may be helpful.

This parameter is mutually exclusive with the "structured_constraint_generator" parameter.

This parameter or the "structured_constraint_generator" parameter is required.

$type->parameterize(...)

This method takes two arguments. The "of" argument should be an object which does the Specio::Constraint::Role::Interface role, and is required.

The other argument, "declared_at", is optional. If it is not given, then a new Specio::DeclaredAt object is creating using a call stack depth of 1.

This method returns a new Specio::Constraint::Structured object.

SUPPORT

Bugs may be submitted at <https://github.com/houseabsolute/Specio/issues>.

I am also usually active on IRC as 'autarch' on "irc://irc.perl.org".

SOURCE

The source code repository for Specio can be found at <https://github.com/houseabsolute/Specio>.

AUTHOR

Dave Rolsky <autarch@urth.org>

COPYRIGHT AND LICENSE

This is free software, licensed under:

  The Artistic License 2.0 (GPL Compatible)

The full text of the license can be found in the LICENSE file included with this distribution.