Re: Special token names, or my mistake

[yary]

Thanks! Timo's explanation nailed it, the problem is with the action not
defining a method for "sum" so Any.sum becomes the action.

The parsing works in grammar B without actions; "sum" is fine as a token
name in that case.

grammar B {
  rule TOP {  }
  token sum { + % '+' }
  token int { \d+ }
}

say B.parse('5');  # OK

Re: Special token names, or my mistake

[Timo Paulssen]

The grammar will never by itself try to call a subroutine, it only looks
for methods in the action object. However, there is a "sum" method that
An-Action inherits from Any. You can find it here:
https://github.com/rakudo/rakudo/blob/master/src/core/Any.pm6#L440

It's probably a good idea to put an empty method of the same name that
accepts one argument (the match object) into the action class.

The same problem occurs with any of the other methods that already exist
on Any.

You can find them like this:

    perl6 -e 'Any.^methods(:all).>>.name.put'

Re: Special token names, or my mistake

[Laurent Rosenfeld via perl6-users]

Hi Yary,

I'm not sure whether this is really the reason, but sum is the name of a
built-in function (see https://docs.perl6.org/routine/sum). It seems that
the compiler interprets your token as a subroutine call of that builtin.

HTH,
Laurent.


2018-08-12 9:28 GMT+02:00 yary :

> If I call a token "sum", this example gives an error. If I call it
> "something-else", it doesn't. I didn't expect an error in either case.
> What's going on?
>
> ~~ actions-test.p6 ~~
> grammar A {
>   rule TOP {  }
>   token something-else { + % '+' }
>   token int { \d+ }
> }
>
> grammar B {
>   rule TOP {  }
>   token sum { + % '+' }
>   token int { \d+ }
> }
>
> class An-Action {
> }
>
> say A.parse('5',actions => An-Action.new); # OK
> say B.parse('5',actions => An-Action.new); # hopes, dashed
>
> __END__
>
> The B.parse says "Too many positionals passed; expected 1 argument but got
> 2
>   in regex sum at action-test.p6 line 9
>   in regex TOP at action-test.p6 line 8
>   in block  at action-test.p6 line 17"
>
> perl6 -v
> This is Rakudo Star version 2018.06 built on MoarVM version 2018.06
>
>
> -y
>

Special token names, or my mistake

[yary]

If I call a token "sum", this example gives an error. If I call it
"something-else", it doesn't. I didn't expect an error in either case.
What's going on?

~~ actions-test.p6 ~~
grammar A {
  rule TOP {  }
  token something-else { + % '+' }
  token int { \d+ }
}

grammar B {
  rule TOP {  }
  token sum { + % '+' }
  token int { \d+ }
}

class An-Action {
}

say A.parse('5',actions => An-Action.new); # OK
say B.parse('5',actions => An-Action.new); # hopes, dashed

__END__

The B.parse says "Too many positionals passed; expected 1 argument but got 2
  in regex sum at action-test.p6 line 9
  in regex TOP at action-test.p6 line 8
  in block  at action-test.p6 line 17"

perl6 -v
This is Rakudo Star version 2018.06 built on MoarVM version 2018.06


-y