Re^2: [Perl 6] Object methods on the fly?

You're on the right track. You want something like:

    @array does role {
        method insert ($x) {
            @.push($x) unless any(self) eqv $x;
        }
    }
[download]

Arguably we could provide syntactic sugar to reduce that to:

    @array does method insert ($x) {
        @.push($x) unless any(self) eqv $x;
    }
[download]

Perhaps that use of does is redundant with but= and could be removed, but it does read better, I think. In any case, doing an operation like this on an object ends up creating an anonymous class that derives from the original class and adds in the extra method, so you don't clobber the original Array class.

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Re^3: [Perl 6] Object methods on the fly? by blazar (Canon) on Jul 19, 2007 at 20:29 UTC
`@array does role { method insert ($x) { @.push($x) unless any(self) eqv $x; } }` [download] Whoa! And it evens runs on Pugs: `pugs> my @array does role { ....> method insert ($x) { @.push($x) if none(self) eqv $x } ....> } () pugs> my @array=(1..5); pugs> @array.insert($_) for 1,2,6; pugs> say @array 123456 Bool::True` [download] BTW: Could I put the initialization in the definition too? I tried with `pugs> my @array does role { ....> method insert ($x) { @.push($x) if none(self) eqv $x } ....> } = (1..5); (1, 2, 3, 4, 5)` [download] and it works, but it doesn't with the assignment directly to the right of `@array`, OTOH I'm sure most people would find it to be more intuitive, while this way they would just say: "for clarity, initialize it in a separate statement." BTW: why doesn't the following work, instead? `pugs> my @array does role { ....> multi method insert ($x) { @.push($x) if none(self) eqv $x } ....> multi method insert (@x) { @.insert($_) for @x } ....> } = 1..5; (1, 2, 3, 4, 5) pugs> @array.insert(3..7); pugs> say @array 1234534567 Bool::True` [download] (If I use `@x`, pugs "hangs", instead.) BTW:* (the last, really!) what is `self` supposed to be? After all no suitable and short enough variable/pronoun was found? The following is all that pugs can tell me: `pugs> self macro {Prim ([Pugs.AST.Internals.Val] -> Pugs.AST.Eval.Eval Pugs.AST.I +nternals.Val)}` [download] Update: Two of the questions asked here were reposted in separate new threads in [Perl 6] Problem with multi methods [Perl 6] Initialization within complex declarations	[reply] [d/l] [select]
Re^4: [Perl 6] Object methods on the fly? by TimToady (Parson) on Jul 25, 2007 at 00:42 UTC
`self` is just a built-in function returning the invocant. If you want a different name for it, you can always declare it explicitly. Also, it's probably bogus to say `any(self)`. It should probably be a function that is not context sensitive, in which case we'd have to say `any(self[])` or some such to pull out the elements. Finally, I think the failure of the multi form is just hitting some things that aren't completely implemented in pugs yet.	[reply] [d/l] [select]