I'm just wondering... since subroutines in Perl 6 are (like everything else) objects, whether state variables could be considered as public attributes, thus having an accessor, as in:

sub collect (Int *@nums) {
    state @data;
    @data.push(@nums);
}

# prepopulate it as late as possible:

&collect.data.push(get_some_values);

# ...
# use collect();

my @collected = &collect.data;

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Before anyone points it out: yes, I know that the example is trivial and there are OWTDI. Yet it's all about some syntactic sugar, and I don't know you, but I like it sweet. It also seems reliable enough to me but possibly for the clash with predefined methods, but there must an elegant and consistent way around...

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Re: [Perl 6] State variables as public attributes?
by moritz (Cardinal) on Aug 26, 2007 at 20:26 UTC
    You can just use a class for that. You can have a member variable @data that you can initialize, access and modify, and provide methods that do the modifications.

    I don't see why a sub should get the functionality of a class.

    Or is there a use case where the OO metapher doesn't hold?

    Perl 6 in German -- Difficult Sudoku

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      I don't see why a sub should get the functionality of a class.

      Why should I use a class when I don't need the full power of a class and the overhead of writing one? can you provide some minimal code that would do the same as my pseudo code is supposed to?

      Or is there a use case where the OO metapher doesn't hold?

      Because as $Larry himeself wrote, the realm of Perl lies in pragmatism, and there are cases in which you don't mind metaphors, but want to do something in a practical and neat way. Had I to write a class for everything, I would go Java, I presume...

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        class collector {
    has @.state;
    method collect(Int *@nums){
        self.state.push: @nums;
    }
}

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        In fact for the example you have given a simple array is enough, but I assume you want to do a bit more in collect.

        The idea of OO is to bundle data with the methods that work on it, now you suggest to bundle a "state" with the method that works on it - for me it sounds like that's the same, or at least that it can use the same abstraction - classes.

        And I don't quite see the overhead in writing classes - snytactically that's class, a name and two curly braces.

        (Updated: fixed missing brace)

        Perl 6 in German -- Difficult Sudoku

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