The code tried to do the same with `dd` as with `say`. There are two
differences:
* `dd`, as a kind of debug tool, doesn't assign any special meaning to
named arguments so it's more than willing to give a Pair back with a
colon syntax representation even if was understood as a named argument.
* there is no `dd` method. I think nowhere in the core but at least
not in the interface of a Pair.
By the way, I don't think the underscore has any special significance in
these examples. It would be all the same with `:foobar`, `dd :foobar`,
`dd foobar`, `dd :foobar:`
Hope this helps ^^
On 2023. 09. 26. 23:02, William Michels wrote:
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
<polgar.mar...@windowslive.com> 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 <w...@caa.columbia.edu>
Dátum: 2023. 09. 25. 7:15 (GMT+01:00)
Címzett: perl6-users <perl6-us...@perl.org>
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] >
