1MooX::StrictConstructorU(s3e)r Contributed Perl DocumentaMtoiooXn::StrictConstructor(3)
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NAME

6       MooX::StrictConstructor - Make your Moo-based object constructors blow
7       up on unknown attributes.
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VERSION

10       version 0.010
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SYNOPSIS

13           package My::Class;
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15           use Moo;
16           use MooX::StrictConstructor;
17
18           has 'size' => ( is => 'rw');
19
20           # then somewhere else, when constructing a new instance
21           # of My::Class ...
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23           # this blows up because color is not a known attribute
24           My::Class->new( size => 5, color => 'blue' );
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DESCRIPTION

27       Simply loading this module makes your constructors "strict". If your
28       constructor is called with an attribute init argument that your class
29       does not declare, then it dies. This is a great way to catch small
30       typos.
31
32   STANDING ON THE SHOULDERS OF ...
33       Most of this package was lifted from MooX::InsideOut and most of the
34       Role that implements the strictness was lifted from
35       MooseX::StrictConstructor.
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37   SUBVERTING STRICTNESS
38       MooseX::StrictConstructor documents two tricks for subverting
39       strictness and avoid having problematic arguments cause an exception:
40       handling them in BUILD or handle them in BUILDARGS.
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42       In MooX::StrictConstructor you can use a BUILDARGS function to handle
43       them, e.g. this will allow you to pass in a parameter called "spy"
44       without raising an exception.  Useful?  Only you can tell.
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46          sub BUILDARGS {
47              my ($self, %params) = @_;
48              my $spy delete $params{spy};
49              # do something useful with the spy param
50              return \%params;
51          }
52
53       Because "BUILD" methods are run after an object has been constructed
54       and this code runs before the object is constructed the "BUILD" trick
55       will not work.
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BUGS/ODDITIES

58   Inheritance
59       A class that uses MooX::StrictConstructor but extends another class
60       that does not will not be handled properly.  This code hooks into the
61       constructor as it is being strung up (literally) and that happens in
62       the parent class, not the one using strict.
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64       A class that inherits from a Moose based class will discover that the
65       Moose class's attributes are disallowed.  Given sufficient Moose meta
66       knowledge it might be possible to work around this.  I'd appreciate
67       pull requests and or an outline of a solution.
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69   Subverting strictness
70       MooseX::StrictConstructor documents a trick for subverting strictness
71       using BUILD.  This does not work here because strictness is enforced in
72       the early stage of object construction but the BUILD subs are run after
73       the objects has been built.
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75   Interactions with namespace::clean
76       MooX::StrictConstructor creates a "new" method that namespace::clean
77       will over-zealously clean.  Workarounds include using
78       MooX::StrictConstructor after namespace::autoclean or telling
79       namespace::clean to ignore "new" with something like:
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81         use namespace::clean -except => ['new','meta'];
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SEE ALSO

84       ·   MooX::InsideOut
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86       ·   MooseX::StrictConstructor
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AUTHOR

89       George Hartzell <hartzell@cpan.org>
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92       This software is copyright (c) 2018 by George Hartzell.
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94       This is free software; you can redistribute it and/or modify it under
95       the same terms as the Perl 5 programming language system itself.
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99perl v5.30.0                      2019-07-26        MooX::StrictConstructor(3)
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