NAME
MooX::Const - Syntactic sugar for constant and write-once Moo attributes
VERSION
version v0.4.4
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 v0.2.0, it also supports write-once ("wo") attributes for references:
has setting => (
is => 'wo',
isa => HashRef,
);This allows you to set the attribute once. The value is coerced into a constant, and cannot be changed again.
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.
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) 2018-2020 by Robert Rothenberg.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)