package Specio::Constraint::Parameterizable;
use strict;
use warnings;
our $VERSION = '0.44';
use Carp qw( confess );
use Role::Tiny::With;
use Specio::Constraint::Parameterized;
use Specio::DeclaredAt;
use Specio::OO;
use Specio::TypeChecks qw( does_role isa_class );
use Specio::Constraint::Role::Interface;
with 'Specio::Constraint::Role::Interface';
{
## no critic (Subroutines::ProtectPrivateSubs)
my $role_attrs = Specio::Constraint::Role::Interface::_attrs();
## use critic
my $attrs = {
%{$role_attrs},
_parameterized_constraint_generator => {
isa => 'CodeRef',
init_arg => 'parameterized_constraint_generator',
predicate => '_has_parameterized_constraint_generator',
},
_parameterized_inline_generator => {
isa => 'CodeRef',
init_arg => 'parameterized_inline_generator',
predicate => '_has_parameterized_inline_generator',
},
};
## no critic (Subroutines::ProhibitUnusedPrivateSubroutines)
sub _attrs {
return $attrs;
}
}
sub BUILD {
my $self = shift;
if ( $self->_has_constraint ) {
die
'A parameterizable constraint with a constraint parameter must also have a parameterized_constraint_generator'
unless $self->_has_parameterized_constraint_generator;
}
if ( $self->_has_inline_generator ) {
die
'A parameterizable constraint with an inline_generator parameter must also have a parameterized_inline_generator'
unless $self->_has_parameterized_inline_generator;
}
return;
}
sub parameterize {
my $self = shift;
my %args = @_;
my ( $parameter, $declared_at ) = @args{qw( of declared_at )};
does_role( $parameter, 'Specio::Constraint::Role::Interface' )
or confess
'The "of" parameter passed to ->parameterize must be an object which does the Specio::Constraint::Role::Interface role';
if ($declared_at) {
isa_class( $declared_at, 'Specio::DeclaredAt' )
or confess
'The "declared_at" parameter passed to ->parameterize must be a Specio::DeclaredAt object';
}
$declared_at = Specio::DeclaredAt->new_from_caller(1)
unless defined $declared_at;
my %p = (
parent => $self,
parameter => $parameter,
declared_at => $declared_at,
);
if ( $self->_has_parameterized_constraint_generator ) {
$p{constraint}
= $self->_parameterized_constraint_generator->($parameter);
}
else {
confess
'The "of" parameter passed to ->parameterize must be an inlinable constraint if the parameterizable type has an inline_generator'
unless $parameter->can_be_inlined;
my $ig = $self->_parameterized_inline_generator;
$p{inline_generator} = sub { $ig->( shift, $parameter, @_ ) };
}
return Specio::Constraint::Parameterized->new(%p);
}
__PACKAGE__->_ooify;
1;
# ABSTRACT: A class which represents parameterizable constraints
__END__
=pod
=encoding UTF-8
=head1 NAME
Specio::Constraint::Parameterizable - A class which represents parameterizable constraints
=head1 VERSION
version 0.44
=head1 SYNOPSIS
my $arrayref = t('ArrayRef');
my $arrayref_of_int = $arrayref->parameterize( of => t('Int') );
=head1 DESCRIPTION
This class implements the API for parameterizable types like C<ArrayRef> and
C<Maybe>.
=for Pod::Coverage BUILD
=head1 API
This class implements the same API as L<Specio::Constraint::Simple>, with a few
additions.
=head2 Specio::Constraint::Parameterizable->new(...)
This class's constructor accepts two additional parameters:
=over 4
=item * parameterized_constraint_generator
This is a subroutine that generates a new constraint subroutine when the type
is parameterized.
It will be called as a method on the type and will be passed a single
argument, the type object for the type parameter.
This parameter is mutually exclusive with the
C<parameterized_inline_generator> parameter.
=item * parameterized_inline_generator
This is a subroutine that generates a new inline generator subroutine when the
type is parameterized.
It will be called as a method on the L<Specio::Constraint::Parameterized>
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.
This probably seems fairly confusing, so looking at the examples in the
L<Specio::Library::Builtins> code may be helpful.
This parameter is mutually exclusive with the
C<parameterized_constraint_generator> parameter.
=back
=head2 $type->parameterize(...)
This method takes two arguments. The C<of> argument should be an object which
does the L<Specio::Constraint::Role::Interface> role, and is required.
The other argument, C<declared_at>, is optional. If it is not given, then a
new L<Specio::DeclaredAt> object is creating using a call stack depth of 1.
This method returns a new L<Specio::Constraint::Parameterized> object.
=head1 SUPPORT
Bugs may be submitted at L<https://github.com/houseabsolute/Specio/issues>.
I am also usually active on IRC as 'autarch' on C<irc://irc.perl.org>.
=head1 SOURCE
The source code repository for Specio can be found at L<https://github.com/houseabsolute/Specio>.
=head1 AUTHOR
Dave Rolsky <autarch@urth.org>
=head1 COPYRIGHT AND LICENSE
This software is Copyright (c) 2012 - 2019 by Dave Rolsky.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)
The full text of the license can be found in the
F<LICENSE> file included with this distribution.
=cut