Re: defined class variable with Moose

G'day Hosen1989,

I suspect you may be mixing (and consequently, confusing) this type of Moose syntax:

has attribute => (
    default => sub { 0 },
);
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with normal Perl syntax for creating key-value pairs:

{
    default => 0,
}
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sub { 0 } is a code reference.

For your simpler cases, like

    description => sub{0}
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you could just use

    description => 0
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However, regardless of the complexity of the code within sub { ... }, what you really want is the return value when that code is executed. For that, use

sub { ... }->()
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Consider these three one-liners:

$ perl -wE 'my $x = { y => 0 }; say $x->{y}'
0
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$ perl -wE 'my $x = { y => sub { 0 } }; say $x->{y}'
CODE(0x7f8c34026a60)
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$ perl -wE 'my $x = { y => sub { 0 }->() }; say $x->{y}'
0
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-- Ken

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Re^2: defined class variable with Moose by Hosen1989 (Scribe) on Jun 26, 2015 at 20:02 UTC
Hi there, Thanks for you reply. I can see that my code hare are somewhat confusing, but I use `description => sub{0}` in-stand of `description => 0` to keep the consist with other item in my `@parserArray`, as i need them to be in the same format where i use each item in this array to read some part of my raw file. As my question here was not clear,let me ask again: but what i need to do is to define variable in my class that contain some predefined data (mix of array/hash/scalar/code). BR Hosen	[reply] [d/l] [select]
Re^3: defined class variable with Moose by kcott (Archbishop) on Jun 26, 2015 at 21:17 UTC
"but I use `description => sub{0}` in-stand of `description => 0` to keep the consist with other item in my `@parserArray`, ..." I only said "you could just use", not "you must* use". That was just a suggestion. By all means, keep them consistent. The main thrust of what I was pointing out, was that a value of '`sub { 0 }->()`', or just a plain old '`0`', will evaluate to `0`; however, the '`sub { 0 }`' that you showed evaluates to something like `CODE(0x7f8c34026a60)`. "... what i need to do is to define variable in my class that contain some predefined data"* Isn't `@parserArray_type_01` just such a variable with predefined data? I don't see a reason why you can't use something like `$parserArray_type_01[$index]{$key}` in your code (whether it uses `Moose` or not). Please post a short piece of code (10-20 lines) that demonstrates where such a variable is causing problems. -- Ken	[reply] [d/l] [select]