Re: What does `:_` and/or `:_:` signify?
[email protected] (William Michels via perl6-users)
| Newsgroups | perl.perl6.users |
|---|---|
| Message-ID | <[email protected]> |
Hi Marton, Thanks for the reply.
Below last example (in the REPL), does `dd` not work on Pairs?
Or is this Indirect Object Notation at work?
[3] > :_
_ => True
[4] > dd :_
:_
Nil
[5] > dd _
===SORRY!=== Error while compiling:
Undeclared name:
_ used at line 1
[5] > dd :_:
No such method 'dd' for invocant of type 'Pair'
in block <unit> at <unknown file> line 1
> On Sep 24, 2023, at 23:40, Polgár Márton <[email protected]> wrote:
>
> Hi Bill,
>
> :_ is a Pair with the colon syntax that stands for "_" => True. In the first case, it got passed as a named argument and say ignored it. The second case was a method call using the colon syntax - the syntax lizmat challenged not so long ago. https://github.com/Raku/problem-solving/issues/384 so, ultimately, it was (:_).say, a normal say method call on a Pair.
>
> Cheers
>
>
>
> A(z) Galaxy eszközömről küldve
>
>
>
> -------- Eredeti üzenet --------
> Feladó: William Michels <[email protected]>
> Dátum: 2023. 09. 25. 7:15 (GMT+01:00)
> Címzett: perl6-users <[email protected]>
> Tárgy: What does `:_` and/or `:_:` signify?
>
> Hello,
>
> While playing around in an attempt to define new operators, I stumbled upon some curious results.
>
> In the REPL, trying `say :_` returns a blank line.
>
> In the REPL, trying `say :_:` returns `_ => True`.
>
> What is the meaning of this?
>
> admin@mbp ~ % raku
> Welcome to Rakudo™ v2023.05.
> Implementing the Raku® Programming Language v6.d.
> Built on MoarVM version 2023.05.
>
> To exit type 'exit' or '^D'
> [0] > say _
> ===SORRY!=== Error while compiling:
> Undeclared name:
> _ used at line 1
>
> [0] > say :_
>
> [0] > say :_:
> _ => True
> [0] >