Types::Const - Types that coerce references to read-only
version v0.5.0
use Moo; use Types::Const -types; use Types::Standard -types; ... has bar => ( is => 'ro', isa => Const[ArrayRef[Str]], coerce => 1, );
This is a type library that provides types to coerce read-only hash and array reference attributes to be deeply read-only.
See the known issues below for a discussion of side-effects.
Const[`a]
Any defined reference value that is read-only.
If parameterized, then the referred value must also pass the type constraint, for example Const[HashRef[Int]] must a a hash reference with integer values.
Const[HashRef[Int]]
It supports coercions to read-only.
This was added in v0.3.0.
A side-effect of read-only data structures is that an exception will be thrown if you attempt to fetch the value of a non-existent key:
Attempt to access disallowed key 'foo' in a restricted hash
The work around for this is to check that a key exists beforehand.
Validating that a complex data-structure is read-only can affect performance. If this is an issue, one workaround is to use Devel::StrictMode and only validate data structures during tests:
has bar => ( is => 'ro', isa => STRICT ? Const[ArrayRef[Str]] : ArrayRef, coerce => 1, );
Another means of improving performance is to only check the type once. (Since it is read-only, there is no need to re-check it.)
There may be an issue with regexp references. See RT#127635.
Since v0.5.0, the this module requires Perl v5.14 or later.
Future releases may only support Perl versions released in the last ten years.
If you need this module on Perl v5.10, please use one of the v0.4.x versions of this module. Significant bug or security fixes may be backported to those versions.
Const::Fast
Type::Tiny
Types::Standard
Types::ReadOnly
MooX::Const
Please report any bugs or feature requests on the bugtracker website https://github.com/robrwo/Types-Const/issues
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.
The development version is on github at https://github.com/robrwo/Types-Const and may be cloned from git://github.com/robrwo/Types-Const.git
Robert Rothenberg <rrwo@cpan.org>
Mohammad S Anwar <mohammad.anwar@yahoo.com>
This software is Copyright (c) 2018-2023 by Robert Rothenberg.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)
To install Types::Const, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Types::Const
CPAN shell
perl -MCPAN -e shell install Types::Const
For more information on module installation, please visit the detailed CPAN module installation guide.