From @MadcapJake

From IRC​:
9​:22 PM <MadcapJake> if I pass a : at the beginning of a string argument to MAIN, it fails to match any signatures and triggers the Usage message
9​:25 PM <ZoffixWin> MadcapJake, can't reproduce. What's the sig for MAIN you're using and what's the way you're calling the script with?
9​:25 PM <MadcapJake> ./bin/rabble -e -d "​: addone 1 + ; 1 addone ."
9​:26 PM <ZoffixWin> MadcapJake, but the usage message tells you to use -d="..." doesn't it? You're missing the equals sign
9​:26 PM <MadcapJake> no, those are Bools
9​:27 PM <MadcapJake> ~/github/rabble/bin/rabble --expression|-e [--debug|-d] <expr>
9​:27 PM <MadcapJake> ~/github/rabble/bin/rabble [--debug|-d] <file>
9​:28 PM <ZoffixWin> MadcapJake, confirmed on my box. You should rakudobug this​: perl6 -e 'sub MAIN ($x) {}' "​: 42" <-- triggers usage... perl6 -e 'sub MAIN ($x) {}' "42" <-- no usage
9​:28 PM <MadcapJake> :(Str $expr, Bool :expression(​:$e)!, Bool :debug(​:$d)) is the signature I'm trying to match
9​:29 PM <ZoffixWin> The bug seems to exist with a single positional as well. A "​:" as the first char in the positional breaks something
9​:33 PM <ZoffixWin> MadcapJake, are you rakudobugging it? I found this works​: to set $y to 45​: perl6 -e 'sub MAIN ($x, :$y) { say $y }' "​:y=45" 42
9​:34 PM <ZoffixWin> In addition it's also impossible to pass "-y=45" to a positional argument, because it gets interpreted as a named arg, it seems
9​:35 PM <teatime> ZoffixWin​: even if you do -- first ?
9​:35 PM <ZoffixWin> teatime, was about to say.... the -- is the way.
9​:35 PM <ZoffixWin> This is more about the shell than Perl 6, but :y should still be parsed as normal string and not a named arg IMO
9​:36 PM <ZoffixWin> perl6 -e 'sub MAIN ($x) { say $x }' -- "​:y=45" works fine
9​:36 PM <ZoffixWin> Unless there are some shells where : instead of - on args is used that I'm unaware of.

From @peschwa

On Fri Apr 08 19​:39​:49 2016, madcap.russo+p6@​gmail.com wrote​:

From IRC​:
9​:22 PM <MadcapJake> if I pass a : at the beginning of a string
argument to MAIN, it fails to match any signatures and triggers the
Usage message
9​:25 PM <ZoffixWin> MadcapJake, can't reproduce. What's the sig for
MAIN you're using and what's the way you're calling the script with?
9​:25 PM <MadcapJake> ./bin/rabble -e -d "​: addone 1 + ; 1 addone ."
9​:26 PM <ZoffixWin> MadcapJake, but the usage message tells you to use
-d="..." doesn't it? You're missing the equals sign
9​:26 PM <MadcapJake> no, those are Bools
9​:27 PM <MadcapJake> ~/github/rabble/bin/rabble --expression|-e [--
debug|-d] <expr>
9​:27 PM <MadcapJake> ~/github/rabble/bin/rabble [--debug|-d] <file>
9​:28 PM <ZoffixWin> MadcapJake, confirmed on my box. You should
rakudobug this​: perl6 -e 'sub MAIN ($x) {}' "​: 42" <-- triggers
usage... perl6 -e 'sub MAIN ($x) {}' "42" <-- no usage
9​:28 PM <MadcapJake> :(Str $expr, Bool :expression(​:$e)!, Bool
:debug(​:$d)) is the signature I'm trying to match
9​:29 PM <ZoffixWin> The bug seems to exist with a single positional as
well. A "​:" as the first char in the positional breaks something
9​:33 PM <ZoffixWin> MadcapJake, are you rakudobugging it? I found this
works​: to set $y to 45​: perl6 -e 'sub MAIN ($x, :$y) { say $y }'
"​:y=45" 42
9​:34 PM <ZoffixWin> In addition it's also impossible to pass "-y=45"
to a positional argument, because it gets interpreted as a named arg,
it seems
9​:35 PM <teatime> ZoffixWin​: even if you do -- first ?
9​:35 PM <ZoffixWin> teatime, was about to say.... the -- is the way.
9​:35 PM <ZoffixWin> This is more about the shell than Perl 6, but :y
should still be parsed as normal string and not a named arg IMO
9​:36 PM <ZoffixWin> perl6 -e 'sub MAIN ($x) { say $x }' -- "​:y=45"
works fine
9​:36 PM <ZoffixWin> Unless there are some shells where : instead of -
on args is used that I'm unaware of.

S19 specifies

  Options must begin with one of the following symbols​: --, -, or :.

So this is not up to the shell, but the interpreter.

Of course, that doesn't change that there's something weird. Consider the following examples​:

$ ./perl6-m --version
This is Rakudo version 2016.03-106-gd847011 built on MoarVM version 2016.03-104-g10d3971
implementing Perl 6.c.
$ ./perl6-m "--version"
This is Rakudo version 2016.03-106-gd847011 built on MoarVM version 2016.03-104-g10d3971
implementing Perl 6.c.
$ ./perl6-m -e'multi MAIN($a) { say "pos" }; multi MAIN(​:$a) { say "named" }' "​:a"
named
$ ./perl6-m -e'multi MAIN($a) { say "pos" }; multi MAIN(​:$a) { say "named" }' -- "​:a"
named
$ ./perl6-m -e'multi MAIN($a) { say "pos" }; multi MAIN(​:$a) { say "named" }' -- "--a"
named
$ ./perl6-m -e'multi MAIN($a) { say "pos" }; multi MAIN(​:$a) { say "named" }' "--a"
Illegal option --a
[rest of < perl6 --help > here]

The last case is probably the most interesting one... :)

In any case, what actually seems to be wrong is that the interpreter can't distinguish between quoted arguments that look like switches and non-quoted switches, and -- as "only arguments from here on" doesn't seem to work completely reliably either.

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

From @peschwa

S19 specifies

s/specifies/speculated/ ... :)

From paul@littlebluetech.com

There is also discussion / description here​:

https://design.perl6.org/S06.html#Declaring_a_MAIN_subroutine