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Re: proto and multi

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From:
yary
Date:
June 29, 2020 17:37
Subject:
Re: proto and multi
Message ID:
CAG2CFAa+xu-b2dn+jpK06P4-jc1jPauPUYug8_M66rnf9LZh=A@mail.gmail.com
It looks like you have spaces in the token { * } can you try it without,
using this {*} instead?

On Mon, Jun 29, 2020, 1:29 PM Richard Hainsworth <rnhainsworth@gmail.com>
wrote:

> I have several multi methods.
>
> All of them have the same first statement, then differ depending on the
> signature.
>
> proto seems to be a way to factor out the common statement, and there is a
> phrase in the Documentation that * can affect the dispatch, viz:
>
> "You can give the proto a function body, and place the {*} where you want
> the dispatch to be done. This can be useful when you have a "hole" in your
> routine that gives it different behavior depending on the arguments given:"
>
> The docs give and example proto, but unfortunately, not how this works
> with other multi's.
>
> So  I tried this:
>
> class NewClass {
>     has $.debug is rw = False;
>     has $.value is rw = 'Initial value';
>
>     proto method handle( |c ) {
>         note "value is $.value" if $.debug;
>         { * }    }
>     multi method handle(Str $s) {
>         $.value = $s;
>         say 'in string'    }
>     multi method handle(Positional @s) {
>         $.value = @s[0];
>         say 'in positional'    }
> }
> my NewClass $x .= new;
> $x.handle('hello world');$x.handle(<hello world>);$x.debug = True;$x.handle('hello world');$x.handle(<hello world>);
>
> #raku test.raku
> #value is Initial value
> #value is Initial value
>
> I am wondering how to use proto and {*}
>
>

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