From sirrobert@gmail.com

A snippet from IRC...

16​:18 < sirrobert> On the error that says, "Cannot call 'whatever'; none of
these signature match​: " it would be great
  if we could add the signature we tried to call it with
16​:18 < masak> yeah.
16​:18 < masak> do we have an RT ticket for that?
16​:18 * masak checks
16​:20 < masak> doesn't seem we do.
16​:20 < masak> sirrobert​: if you have time, please put together a nice
concrete example where having this would help,
  and submit to rakudobug@​perl.org. thank you.
16​:20 < sirrobert> sure thing

As requested, here's a snippet that demonstrates the utility of this
request​:

class A {
  has Hash %!h;

  multi method f (Pair $p) {
  return $p.WHAT;
  }

};

my $n = (a => b => 'c');
my $m = a => b => 'c';

say $n.WHAT;
say $m.WHAT;

say A.new.f(a => b => 'c');

The output of this file is​:

Pair()
Pair()
Cannot call 'f'; none of these signatures match​:
:(A , Pair $p, Mu *%_)

  in method f at src/gen/CORE.setting​:310
  in block <anon> at ./test.p6​:20

It is not obvious to me how to change the signature of the method to make
the last call work. I *think* in the context of a function call the nested
pair is counted as a hash or something... still working on it. In the
meantime, it would be helpful to know what signature I was (apparently)
trying to call with.

Thanks!

-Sir

From @Mouq

On Thu Jul 19 13​:54​:31 2012, sirrobert@​gmail.com wrote​:

A snippet from IRC...

16​:18 < sirrobert> On the error that says, "Cannot call 'whatever'; none of
these signature match​: " it would be great
if we could add the signature we tried to call it with
16​:18 < masak> yeah.
16​:18 < masak> do we have an RT ticket for that?
16​:18 * masak checks
16​:20 < masak> doesn't seem we do.
16​:20 < masak> sirrobert​: if you have time, please put together a nice
concrete example where having this would help,
and submit to rakudobug@​perl.org. thank you.
16​:20 < sirrobert> sure thing

As requested, here's a snippet that demonstrates the utility of this
request​:

class A {
has Hash %!h;

multi method f (Pair $p) {
return $p.WHAT;
}

};

my $n = (a => b => 'c');
my $m = a => b => 'c';

say $n.WHAT;
say $m.WHAT;

say A.new.f(a => b => 'c');

The output of this file is​:

Pair()
Pair()
Cannot call 'f'; none of these signatures match​:
:(A , Pair $p, Mu *%_)

in method f at src/gen/CORE.setting​:310
in block <anon> at ./test.p6​:20

It is not obvious to me how to change the signature of the method to make
the last call work. I *think* in the context of a function call the nested
pair is counted as a hash or something... still working on it. In the
meantime, it would be helpful to know what signature I was (apparently)
trying to call with.

Thanks!

-Sir

Current output​:

07​:08 <Mouq> m​: class A { multi method f (Pair $p) {return $p.WHAT;}}; say A.new.f("a" => b => "c");
07​:08 <camelia> rakudo-moar dfad9c​: OUTPUT«(Pair)␤»
07​:08 <Mouq> m​: class A { multi method f (Pair $p) {return $p.WHAT;}}; say A.new.f(a => b => "c");
07​:08 <camelia> rakudo-moar dfad9c​: OUTPUT«Cannot call f(A​: :a(Pair)); none of these signatures match​:␤ (A​: Pair $p, *%_)␤ in block
  <unit> at /tmp/tV96UsCt6B​:1␤␤»

The erroneous call now lists "f(A​: :a(Pair))". Tests for this already exist in Roast in the file S06-signature/errors.t.

Closing this ticket as resolved :)

~Mouq

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

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