From @masak

<TimToady> I think I've found a binding bug. http://wall.org/~larry/hamming.p6

#!/usr/local/bin/perl6

#hamming = 1 : map (2*) hamming `merge` map (3*) hamming `merge` map
(5*) hamming
# where merge (x​:xs) (y​:ys)
# | x < y = x : xs `merge` (y​:ys)
# | x > y = y : (x​:xs) `merge` ys
# | otherwise = x : xs `merge` ys

sub infix​:<merge> (@​x [$x, *@​xtail], @​y [$y,*@​ytail]) {
  if $x < $y { $x, (@​xtail merge @​y) }
  elsif $x > $y { $y, (@​x merge @​ytail) }
  else { $x, (@​xtail merge @​ytail) }
}

my @​hamming := (1, (@​hamming X* 2) merge (@​hamming X* 3) merge (@​hamming X* 5));

say ~@​hamming[^20];

<masak> ooh, the Hamming sequence!
<TimToady> I would guess that the *@​xtail is not successful in binding
to the conjectural part of the @​hamming array
<masak> TimToady​: any reason why it shouldn't bind?
<TimToady> rakudo​: sub foo (@​x [$xhead, *@​xtail]) { say ~@​xtail };
foo([1,2,3]) [21​:33]
<p6eval> rakudo 18189a​: OUTPUT«2 3␤»
<masak> \o/
<Tene> perl6​: my @​x = 1..5; sub foo(@​a [$a, *@​atail]) { say "head​:
$a\ntail​: {@​atail.perl}"; }; foo(@​x);
<p6eval> rakudo 18189a​: OUTPUT«head​: 1␤tail​: [2, 3, 4, 5]␤»
<TimToady> rakudo​: sub foo (@​x [$xhead, *@​xtail]) { say ~@​xtail };
foo([1, (2...3)])
<p6eval> rakudo 18189a​: OUTPUT«2 3␤»
<TimToady> rakudo​: sub foo (@​x [$xhead, *@​xtail]) { say ~@​xtail[^3] };
foo([1, 'x' xx *])
<p6eval> rakudo 18189a​: OUTPUT«(timeout)»
<TimToady> anyway, hamming is sort of an acid test for laziness, the
way man-or-boy is for scoping
<TimToady> and currently we flunk...
<pmichaud> file a bug report for hamming, please. I know enough of
the binding codenow that I think I might be able to fix it up.
<pmichaud> I'd like to see that one work.
* masak submits rakudobug for hamming

From @moritz

The code as-is will never work, because at some point it'll pass an
empty list to one side of the 'merge' operator, in which case the
subsignature binding fails.

Here is an updated version (see also https://gist.github.com/1704555 )

multi sub infix​:<merge> (@​ [], @​y) is default { @​y };
multi sub infix​:<merge> (@​x, @​ []) { @​x };
multi sub infix​:<merge> (@​x [$x, *@​xtail], @​y [$y,*@​ytail]) {
if $x < $y { $x, (@​xtail merge @​y) }
elsif $x > $y { $y, (@​x merge @​ytail) }
else { $x, (@​xtail merge @​ytail) }
}

my @​hamming := (1, (@​hamming X* 2) merge (@​hamming X* 3) merge (@​hamming
X* 5));

say ~@​hamming[^20];

output on current rakudo​: 1

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

From @coke

On Mon Jan 30 06​:13​:36 2012, moritz wrote​:

The code as-is will never work, because at some point it'll pass an
empty list to one side of the 'merge' operator, in which case the
subsignature binding fails.

Here is an updated version (see also https://gist.github.com/1704555 )

multi sub infix​:<merge> (@​ [], @​y) is default { @​y };
multi sub infix​:<merge> (@​x, @​ []) { @​x };
multi sub infix​:<merge> (@​x [$x, *@​xtail], @​y [$y,*@​ytail]) {
if $x < $y { $x, (@​xtail merge @​y) }
elsif $x > $y { $y, (@​x merge @​ytail) }
else { $x, (@​xtail merge @​ytail) }
}

my @​hamming := (1, (@​hamming X* 2) merge (@​hamming X* 3) merge (@​hamming
X* 5));

say ~@​hamming[^20];

output on current rakudo​: 1

11​:17 < [Coke]> moritz, TimToady​: what is the expected output of the last bit
  of code on https://rt-archive.perl.org/perl6/Ticket/Display.html?id=77474 ?
11​:18 < [Coke]> FYI, the current output is 1 0
11​:19 < TimToady> http://rosettacode.org/wiki/Hamming_numbers
11​:20 < TimToady> but we need the list refactor before that has a hope of
  working
11​:20 < [Coke]> so, "1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 25 27 30 32 36" is
  the expected output?
11​:21 < TimToady> yes, if Perl 6 were as good as Haskell at recursive
  definitions...
--
Will "Coke" Coleda

From @coke

On Tue Sep 02 08​:21​:59 2014, coke wrote​:

On Mon Jan 30 06​:13​:36 2012, moritz wrote​:

The code as-is will never work, because at some point it'll pass an
empty list to one side of the 'merge' operator, in which case the
subsignature binding fails.

Here is an updated version (see also https://gist.github.com/1704555
)

multi sub infix​:<merge> (@​ [], @​y) is default { @​y };
multi sub infix​:<merge> (@​x, @​ []) { @​x };
multi sub infix​:<merge> (@​x [$x, *@​xtail], @​y [$y,*@​ytail]) {
if $x < $y { $x, (@​xtail merge @​y) }
elsif $x > $y { $y, (@​x merge @​ytail) }
else { $x, (@​xtail merge @​ytail) }
}

my @​hamming := (1, (@​hamming X* 2) merge (@​hamming X* 3) merge
(@​hamming
X* 5));

say ~@​hamming[^20];

output on current rakudo​: 1

11​:17 < [Coke]> moritz, TimToady​: what is the expected output of the
last bit
of code on
https://rt-archive.perl.org/perl6/Ticket/Display.html?id=77474 ?
11​:18 < [Coke]> FYI, the current output is 1 0
11​:19 < TimToady> http://rosettacode.org/wiki/Hamming_numbers
11​:20 < TimToady> but we need the list refactor before that has a hope
of
working
11​:20 < [Coke]> so, "1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 25 27 30 32
36" is
the expected output?
11​:21 < TimToady> yes, if Perl 6 were as good as Haskell at recursive
definitions...

Both GLR & NOM now complain that you can't use @​hamming to declare @​hamming.
--
Will "Coke" Coleda