From @lizmat

[23​:19​:47] <lizmat> m​: sub a { .Int with $^a }; a(Str).perl.say # somehow I expect this to say Str instead of ()
[23​:19​:48] <+camelia> rakudo-moar 0d47a4​: OUTPUT«()␤»
[23​:21​:29] <vendethiel> m​: say Str.Int.perl
[23​:21​:29] <+camelia> rakudo-moar 0d47a4​: OUTPUT«Invocant requires an instance of type Str, but a type object was passed. Did you forget a .new?␤ in block <unit> at /tmp/yFKn3e0pMl​:1␤␤»
[23​:22​:10] <vendethiel> lizmat​: the "with" is not traversed, that's correct, right? I don't think it should return its operand in the other case
[23​:23​:37] <lizmat> vendethiel​: I was thinking about this​:
[23​:23​:41] <lizmat> .lines(​:close, |c) with self.open(|c)
[23​:23​:59] <lizmat> if the open fails, I would like to see it returned
[23​:23​:59] <vendethiel> lizmat​: wouldn't .given be more useful there?
[23​:24​:11] <lizmat> .given ???
[23​:24​:20] <vendethiel> uhm. I mean given{} :P
[23​:24​:31] <vendethiel> well, I guess you could invent a .given...
[23​:25​:20] <lizmat> given self.open(|c) { .... and then ?
[23​:27​:20] <vendethiel> lizmat​: you can "cling onto" the result with it (and just end the block with $_ I guess). But I was actually thinking of some closing mechanism (python-like "with"), so disregard my comment
[23​:28​:43] <lizmat> I think .method with $a returning the value of $a if not defined, would be a useful idiom
[23​:29​:08] <vendethiel> lizmat​: seems a bit like andthen, in some way, maybe?
[23​:29​:35] <vendethiel> m​: say Str andthen .Int
[23​:29​:36] <+camelia> rakudo-moar 655a45​: OUTPUT«(Str)␤»
[23​:29​:41] <vendethiel> m​: say "3" andthen .Int
[23​:29​:42] <+camelia> rakudo-moar 655a45​: OUTPUT«3␤»
[23​:31​:09] <lizmat> vendethiel++
[23​:32​:23] <lizmat> m​: sub a { $^a andthen .Int }; a(Str).perl.say; a(42).perl.say # still not quite what I want :-(
[23​:32​:24] <+camelia> rakudo-moar 655a45​: OUTPUT«()␤42␤»
[23​:32​:43] vendethiel wats
[23​:33​:03] <vendethiel> m​: sub a { say $^a.perl; $^a }; a(Str).perl.say
[23​:33​:03] <+camelia> rakudo-moar 655a45​: OUTPUT«Str␤Str␤»
[23​:33​:14] <vendethiel> m​: sub a { say $^a.perl; $^a andthen 1 }; a(Str).perl.say
[23​:33​:15] <+camelia> rakudo-moar 655a45​: OUTPUT«Str␤()␤»
[23​:33​:32] <lizmat> bug?
[23​:33​:38] <vendethiel> m​: sub a { say $^a.perl; say $^a andthen 1 }; a(Str).perl
[23​:33​:38] <+camelia> rakudo-moar 655a45​: OUTPUT«Str␤(Str)␤»
[23​:33​:47] <vendethiel> lizmat​: ...looks like a part of it isn't returned? idk
[23​:33​:53] <vendethiel> m​: sub a { say $^a.perl; return $^a andthen 1 }; a(Str).perl.say
[23​:33​:53] <+camelia> rakudo-moar 655a45​: OUTPUT«Str␤Str␤»
[23​:33​:56] <vendethiel> lizmat​: ^
[23​:33​:58] <vendethiel> seems like a bug
[23​:34​:17] <lizmat> m​: sub a { return $^a andthen .Int }; a(Str).perl.say; a(42).perl.say
[23​:34​:18] <+camelia> rakudo-moar 655a45​: OUTPUT«Str␤42␤»
[23​:34​:20] <lizmat> aha...
[23​:34​:22] <lizmat> bug indeed
[23​:34​:36] <vendethiel> lizmat++ # golfing

From @jnthn

On Sun Sep 13 14​:39​:28 2015, elizabeth wrote​:

[23​:19​:47] <lizmat> m​: sub a { .Int with $^a }; a(Str).perl.say #
somehow I expect this to say Str instead of ()
[23​:19​:48] <+camelia> rakudo-moar 0d47a4​: OUTPUT«()␤»
[23​:21​:29] <vendethiel> m​: say Str.Int.perl
[23​:21​:29] <+camelia> rakudo-moar 0d47a4​: OUTPUT«Invocant requires
an instance of type Str, but a type object was passed. Did you forget
a .new?␤ in block <unit> at /tmp/yFKn3e0pMl​:1␤␤»
[23​:22​:10] <vendethiel> lizmat​: the "with" is not traversed,
that's correct, right? I don't think it should return its operand in
the other case
[23​:23​:37] <lizmat> vendethiel​: I was thinking about this​:
[23​:23​:41] <lizmat> .lines(​:close, |c) with self.open(|c)
[23​:23​:59] <lizmat> if the open fails, I would like to see it
returned
[23​:23​:59] <vendethiel> lizmat​: wouldn't .given be more useful
there?
[23​:24​:11] <lizmat> .given ???
[23​:24​:20] <vendethiel> uhm. I mean given{} :P
[23​:24​:31] <vendethiel> well, I guess you could invent a
.given...
[23​:25​:20] <lizmat> given self.open(|c) { .... and then ?
[23​:27​:20] <vendethiel> lizmat​: you can "cling onto" the
result with it (and just end the block with $_ I guess). But I was
actually thinking of some closing mechanism (python-like "with"), so
disregard my comment
[23​:28​:43] <lizmat> I think .method with $a returning the value of
$a if not defined, would be a useful idiom
[23​:29​:08] <vendethiel> lizmat​: seems a bit like andthen, in
some way, maybe?
[23​:29​:35] <vendethiel> m​: say Str andthen .Int
[23​:29​:36] <+camelia> rakudo-moar 655a45​: OUTPUT«(Str)␤»
[23​:29​:41] <vendethiel> m​: say "3" andthen .Int
[23​:29​:42] <+camelia> rakudo-moar 655a45​: OUTPUT«3␤»
[23​:31​:09] <lizmat> vendethiel++
[23​:32​:23] <lizmat> m​: sub a { $^a andthen .Int };
a(Str).perl.say; a(42).perl.say # still not quite what I want :-(
[23​:32​:24] <+camelia> rakudo-moar 655a45​: OUTPUT«()␤42␤»
[23​:32​:43] vendethiel wats
[23​:33​:03] <vendethiel> m​: sub a { say $^a.perl; $^a };
a(Str).perl.say
[23​:33​:03] <+camelia> rakudo-moar 655a45​: OUTPUT«Str␤Str␤»
[23​:33​:14] <vendethiel> m​: sub a { say $^a.perl; $^a andthen 1
}; a(Str).perl.say
[23​:33​:15] <+camelia> rakudo-moar 655a45​: OUTPUT«Str␤()␤»
[23​:33​:32] <lizmat> bug?
[23​:33​:38] <vendethiel> m​: sub a { say $^a.perl; say $^a
andthen 1 }; a(Str).perl
[23​:33​:38] <+camelia> rakudo-moar 655a45​: OUTPUT«Str␤(Str)␤»
[23​:33​:47] <vendethiel> lizmat​: ...looks like a part of it
isn't returned? idk
[23​:33​:53] <vendethiel> m​: sub a { say $^a.perl; return $^a
andthen 1 }; a(Str).perl.say
[23​:33​:53] <+camelia> rakudo-moar 655a45​: OUTPUT«Str␤Str␤»
[23​:33​:56] <vendethiel> lizmat​: ^
[23​:33​:58] <vendethiel> seems like a bug
[23​:34​:17] <lizmat> m​: sub a { return $^a andthen .Int };
a(Str).perl.say; a(42).perl.say
[23​:34​:18] <+camelia> rakudo-moar 655a45​: OUTPUT«Str␤42␤»
[23​:34​:20] <lizmat> aha...
[23​:34​:22] <lizmat> bug indeed
[23​:34​:36] <vendethiel> lizmat++ # golfing

Not a bug, just a misremembering that andthen has very loose precedence.

09​:34 < jnthn> m​: sub a { return $^a andthen .Int }; a(Str).perl.say;
  a(42).perl.say
09​:34 <+camelia> rakudo-moar 1bd727​: OUTPUT«Str␤42␤»
09​:34 < jnthn> m​: sub a { return ($^a andthen .Int) }; a(Str).perl.say;
  a(42).perl.say
09​:34 <+camelia> rakudo-moar 1bd727​: OUTPUT«()␤42␤»
09​:34 * jnthn rejects RT #​126050 with a reminder about precedence :)

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

@jnthn - Status changed from 'open' to 'rejected'