Re: MooseX::Declare and overload

You can see in the MooseX Declare documentation that it implicitly uses namespace::autoclean. This automatic cleaning of imported subs ends up removing the special subs installed by overload as well. There is a bug filed on namespace::autoclean to fix this issue. Another workaround aside from what ikegami posted would be to use the 'is dirty' modifier to avoid the automatic cleaning.

Test:

use MooseX::Declare;
class InDeclare {
    use overload '""' => \&to_string2;

    has val => is => 'rw';
    sub to_string2 { sprintf "(%s)", $_[0]->val }
};

class InDeclareDirty is dirty {
    use overload '""' => \&to_string2;

    has val => is => 'rw';
    sub to_string2 { sprintf "(%s)", $_[0]->val }
};


package main;
use strict;
use warnings;
use Test::More;

my $d = InDeclare->new(val=>666);
is $d,   "(666)", "mxd is ok";    # PASS: "(666)"
is "$d", "(666)", "mxd is ok (Q)"; # FAIL: "InDeclare=HASH(0x2166ab0)"

my $dd = InDeclareDirty->new(val=>6666);
is $dd,   "(6666)", "mxdd is ok";
is "$dd", "(6666)", "mxdd is ok (Q)";

done_testing;
[download]

Results:

ok 1 - mxd is ok
not ok 2 - mxd is ok (Q)
#   Failed test 'mxd is ok (Q)'
#   at test.pl line 24.
#          got: 'InDeclare=HASH(0x100e42bd0)'
#     expected: '(666)'
ok 3 - mxdd is ok
ok 4 - mxdd is ok (Q)
1..4
# Looks like you failed 1 test of 4.
[download]

Comment on Re: MooseX::Declare and overload Select or Download Code

Replies are listed 'Best First'.
Re^2: MooseX::Declare and overload by FunkyMonk (Chancellor) on Apr 01, 2010 at 10:17 UTC
Awesomer! Thanks Haarg++ This worked, but only when I declared to_string as a sub instead of a method, but I can live with that. And extra thanks for pointing out the bug in namespace::autoclean. That explained the problem clearly.	[reply]
Re^3: MooseX::Declare and overload by Haarg (Priest) on Apr 01, 2010 at 16:41 UTC
There is still a lot of black magic in MooseX::Declare interfering, but if you use `use overload '""' => 'to_string';` instead of referencing it symbolically, it should work if to_string is defined as either a sub or a method. It will also allow subclasses to override the stringification behavior.	[reply] [d/l]
Re^4: MooseX::Declare and overload by FunkyMonk (Chancellor) on Apr 01, 2010 at 17:41 UTC
You hit the nail on the head. `class InDeclareString is dirty { use overload '""' => 'to_string'; has val => (is => 'rw'); method to_string { sprintf "(%s)", $self->val } };` [download] works perfectly. Many thanks	[reply] [d/l]
Re^2: MooseX::Declare and overload by ikegami (Patriarch) on Apr 01, 2010 at 17:04 UTC
You can see in the MooseX Declare documentation that it implicitly uses namespace::autoclean. I noticed, but it says the "use namespace::autoclean;" occurs before the "use overload". Something's very buggy. And then there's the question as to why test 5 worked. Very weird.	[reply]
Re^3: MooseX::Declare and overload by Haarg (Priest) on Apr 01, 2010 at 17:21 UTC
namespace::autoclean, unlike namespace::clean, removes all imported functions regardless of if they were imported before or after it is used. I don't really know why test 5 worked, but Test::More does have special handling for overloaded objects. I'm assuming it is some odd interaction in there.	[reply]
Re^4: MooseX::Declare and overload by ikegami (Patriarch) on Apr 01, 2010 at 18:00 UTC
oh! I thought "namespace::autoclean" was "namespace::clean"! Thanks, that makes a lot more sense.	[reply]


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