Re: Playing with protos and phasers
While {*} is only useful in a proto, the compiler detects it no matter
where you write it.
> my $block = {*};
===SORRY!=== Error while compiling:
{*} may only appear in proto
at line 2
--> ⏏
On Thu, Jun 25, 2020 at 3:48 PM Fernando Santagata <
nando.santag...@gmail.com> wrote:
> On Thu, Jun 25, 2020 at 8:10 PM Brad Gilbert wrote:
>
>> {*} is specially handled by the compiler as a term.
>>
>
> Thank you!
>
> I guess that handling is peculiar to proto, and maybe it's worth
> documenting it.
>
> --
> Fernando Santagata
>
Re: Playing with protos and phasers
On Thu, Jun 25, 2020 at 8:10 PM Brad Gilbert wrote:
> {*} is specially handled by the compiler as a term.
>
Thank you!
I guess that handling is peculiar to proto, and maybe it's worth
documenting it.
--
Fernando Santagata
Re: Playing with protos and phasers
{*} is specially handled by the compiler as a term.
Let's say you have a class named Foo:
class Foo {…}
You wouldn't expect to be able to use it like this:
F o o.new()
It is the same thing with {*}.
The only difference is that {*} is meant to look like a Block { } combined
with a Whatever *.
It was meant to be both visually distinctive, and visually similar to how
you might think about it.
---
If you were allowed to add spaces to the {*} term, it would be annoying if
you wanted to create a lambda that returned a Whatever.
my $block = { * };
say $block.() ~~ Whatever; # True.
On Thu, Jun 25, 2020 at 2:47 AM Fernando Santagata <
nando.santag...@gmail.com> wrote:
> Hi *,
> I was trying to see if one can delegate phasers to a proto, like this:
>
> proto sub foo(|) {
> ENTER { say 'In' }
> LEAVE { say 'Out' }
> {*}
> }
> multi sub foo(Int $a) {
> $a
> }
> multi sub foo(Str $a) {
> $a
> }
>
> say foo(1);
> say foo('hello');
>
> Yes indeed, it outputs:
>
> In
> Out
> 1
> In
> Out
> hello
>
> But at first it didn't work, because I added a space on both sides of the
> '*':
>
> proto sub foo(|) {
> ENTER { say 'In' }
> LEAVE { say 'Out' }
> { * }
> }
>
> It outputs:
>
> In
> Out
> *
> In
> Out
> *
>
> If I add a return:
>
> proto sub foo(|) {
> ENTER { say 'In' }
> LEAVE { say 'Out' }
> return { * }
> }
>
> it outputs:
>
> In
> Out
> -> ;; $_? is raw = OUTER::<$_> { #`(Block|94038346387904) ... }
> In
> Out
> -> ;; $_? is raw = OUTER::<$_> { #`(Block|94038346388120) ... }
>
> Why are spaces significant in this case?
>
> If this behavior is intentional, can this be a trap worth being documented?
>
> --
> Fernando Santagata
>
Playing with protos and phasers
Hi *,
I was trying to see if one can delegate phasers to a proto, like this:
proto sub foo(|) {
ENTER { say 'In' }
LEAVE { say 'Out' }
{*}
}
multi sub foo(Int $a) {
$a
}
multi sub foo(Str $a) {
$a
}
say foo(1);
say foo('hello');
Yes indeed, it outputs:
In
Out
1
In
Out
hello
But at first it didn't work, because I added a space on both sides of the
'*':
proto sub foo(|) {
ENTER { say 'In' }
LEAVE { say 'Out' }
{ * }
}
It outputs:
In
Out
*
In
Out
*
If I add a return:
proto sub foo(|) {
ENTER { say 'In' }
LEAVE { say 'Out' }
return { * }
}
it outputs:
In
Out
-> ;; $_? is raw = OUTER::<$_> { #`(Block|94038346387904) ... }
In
Out
-> ;; $_? is raw = OUTER::<$_> { #`(Block|94038346388120) ... }
Why are spaces significant in this case?
If this behavior is intentional, can this be a trap worth being documented?
--
Fernando Santagata
