NAME
MooX::Const - Syntactic sugar for constant and write-once Moo attributes
VERSION
version v0.6.2
SYNOPSIS
use Moo;
use MooX::Const;
use Types::Standard -types;
has thing => (
is => 'const',
isa => ArrayRef[HashRef],
);DESCRIPTION
This is syntactic sugar for using Types::Const with Moo. The SYNOPSIS above is equivalent to:
use Types::Const -types;
has thing => (
is => 'ro',
isa => Const[ArrayRef[HashRef]],
coerce => 1,
);It modifies the has function to support "const" attributes. These are read-only ("ro") attributes for references, where the underlying data structure has been set as read-only.
This will return an error if there is no "isa", the "isa" is not a Type::Tiny type, if it is not a reference, or if it is blessed object.
Simple value types such as Int or Str are silently converted to read-only attributes.
As of v0.5.0, it also supports write-once ("once") attributes for references:
has setting => (
is => 'once',
isa => HashRef,
);This allows you to set the attribute once. The value is coerced into a constant, and cannot be changed again.
Note that "wo" is a removed synonym for "once". It no longer works in v0.6.0, since "wo" is used for "write-only" in some Moose-like extensions.
As of v0.4.0, this now supports the strict setting:
has thing => (
is => 'const',
isa => ArrayRef[HashRef],
strict => 0,
);When this is set to a false value, then the read-only constraint will only be applied when running in strict mode, see Devel::StrictMode.
If omitted, strict is assumed to be true.
KNOWN ISSUES
Accessing non-existent keys for hash references will throw an error. This is a feature, not a bug, of read-only hash references, and it can be used to catch mistakes in code that refer to non-existent keys.
Unfortunately, this behaviour is not replicated with array references.
See Types::Const for other known issues related to the Const type.
Using with Moose and Mouse
This module appears to work with Moose, and there is now a small test suite.
It does not work with Mouse. Pull requests are welcome.
SUPPORT FOR OLDER PERL VERSIONS
Since v0.6.0, 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 v0.5.x versions of this module. Significant bug or security fixes may be backported to those versions.
SEE ALSO
SOURCE
The development version is on github at https://github.com/robrwo/MooX-Const and may be cloned from git://github.com/robrwo/MooX-Const.git
BUGS
Please report any bugs or feature requests on the bugtracker website https://github.com/robrwo/MooX-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.
AUTHOR
Robert Rothenberg <rrwo@cpan.org>
This module was inspired by suggestions from Kang-min Liu 劉康民 <gugod@gugod.org> in a blog post.
CONTRIBUTOR
Kang-min Liu 劉康民 <gugod@gugod.org>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2018-2023 by Robert Rothenberg.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)