From @bbkr

For sample class on Rakudo 2012.11

class A { method foo (Int) {} };

signature matches without problem when it is declared directly in code

say \(A, 1) ~~ A.^find_method("foo").signature;
True

but when signature is created from array it will not match

my @​t = 1; say \(A, @​t) ~~ A.^find_method("foo").signature;
False

Both signatures looks the same

say \(A, 1).perl
Capture.new( list => (A, 1).list, hash => EnumMap.new())
say \(A, @​t).perl
Capture.new( list => (A, 1).list, hash => EnumMap.new())

From @moritz

On Wed Dec 05 15​:00​:24 2012, pawel.pabian@​implix.com wrote​:

For sample class on Rakudo 2012.11

class A { method foo (Int) {} };

signature matches without problem when it is declared directly in code

say \(A, 1) ~~ A.^find_method("foo").signature;
True

but when signature is created from array it will not match

s/signature/capture/

my @​t = 1; say \(A, @​t) ~~ A.^find_method("foo").signature;
False

Both signatures looks the same

s/signatures/captures/

say \(A, 1).perl
Capture.new( list => (A, 1).list, hash => EnumMap.new())
say \(A, @​t).perl
Capture.new( list => (A, 1).list, hash => EnumMap.new())

That's a bug in Capture.perl, which flattens out the array @​t.

But Rakudo is correct to reject binding \(A, @​t) to (A, Int), because
Array !~~ Int.

If you do want to flatten out the @​t, write it as \(A, |@​t).

Cheers,
Moritz

The RT System itself - Status changed from 'new' to 'open'

From @bbkr

But Rakudo is correct to reject binding \(A, @​t) to (A, Int), because
Array !~~ Int.

If you do want to flatten out the @​t, write it as \(A, |@​t).

That was the first thing I've tried, but it produces syntax error​:

$ perl6 -e 'my @​t; \(|@​t)'
===SORRY!===
CHECK FAILED​:
Undefined routine '&prefix​:<|>' called (line 1)

From @bbkr

I've also tried

\(A, @​t.flat)

and it still won't match

From @usev6

There were two different problems here​:

1) It was not possible to flatten an array within \(...).

This has been fixed​:

$ perl6 -e 'my @​t = 1, 2; say \(|@​t)'
\(1, 2)

[BTW​: It was possible to do 'Capture(|@​t)' before, only with the unary backslash operator it didn't work.]

The smartmatch from the OP also works with |@​t (but it fails as expected without flattening the array).

$ perl6 -e 'class A { method foo (Int) {} }; my @​t = 1; say \(A, |@​t) ~~ A.^find_method("foo").signature;'
True

$ perl6 -e 'class A { method foo (Int) {} }; my @​t = 1; say \(A, @​t) ~~ A.^find_method("foo").signature;'
False

I added a test to S02-types/capture.t with commit Raku/roast@7c4672ced8

2) Capture.perl flattens elements.

This is still an issue, but there is a separate ticket​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=114100. I'll link to that ticket, but since the main issue 1) is solved, I'm going to close this ticket as 'resolved'.

@usev6 - Status changed from 'open' to 'resolved'