Can't fix this failure.

[enjoysmath]

Can't fix this failure.

[veelo]

Hi, for situations like this I wrote the tracing capability of Pegged, see https://github.com/PhilippeSigaud/Pegged/wiki/Grammar-Debugging.

But let me try to parse your input with your grammar manually:

• Typed tries to parse a+b:A, invokes List.
  • List tries to parse a+b:A, invokes Template.
    • Template tries to parse a+b:A, invokes TemplatePart.
      • TemplatePart tries to parse a+b:A, invokes Variable.
        • Variable tries to parse a+b:A, invokes identifier.
          • identifier tries to parse a+b:A, matches a. Remaining input: +b:A
      • TemplatePart matches a. Remaining input: +b:A
    • Template tries to parse +b:A, invokes another TemplatePart.
      • TemplatePart tries to parse +b:A, invokes Variable.
        • Variable tries to parse +b:A, invokes identifier.
          • identifier tries to parse +b:A, fails.
      • TemplatePart tries to parse +b:A, invokes Number.
        • Number tries to parse +b:A, fails.
      • TemplatePart tries to parse +b:A, invokes Text.
        • Text tries to parse +b:A. Text cannot match anything but the empty string because it only contains a negative lookahead, repeated 0 or more times. It succeeds on the empty string. Remaining input: +b:A.
    • Template has not advanced the input, gives up on trying another TemplatePart.
  • List succeeds with a. Remaining input: +b:A.
• Typed expects literal ":" after List, but the remaining input is +b:A, and fails.

I assume you expect "+" to be matched by Text, and it looks like you just forgot the "match anything parser" . in

Text           < (!(Variable / Number / ":" / ",") . )*

Hope this helps,
Bastiaan.

[enjoysmath]

Hi, for situations like this I wrote the tracing capability of Pegged, see https://github.com/PhilippeSigaud/Pegged/wiki/Grammar-Debugging.

But let me try to parse your input with your grammar manually:

• Typed tries to parse a+b:A, invokes List.

  • List tries to parse a+b:A, invokes Template.

    • Template tries to parse a+b:A, invokes TemplatePart.

      • TemplatePart tries to parse a+b:A, invokes Variable.

        • Variable tries to parse a+b:A, invokes identifier.

          • identifier tries to parse a+b:A, matches a. Remaining input: +b:A

      • TemplatePart matches a. Remaining input: +b:A

    • Template tries to parse +b:A, invokes another TemplatePart.

      • TemplatePart tries to parse +b:A, invokes Variable.

        • Variable tries to parse +b:A, invokes identifier.

          • identifier tries to parse +b:A, fails.

      • TemplatePart tries to parse +b:A, invokes Number.

        • Number tries to parse +b:A, fails.

      • TemplatePart tries to parse +b:A, invokes Text.

        • Text tries to parse +b:A. Text cannot match anything but the empty string because it only contains a negative lookahead, repeated 0 or more times. It succeeds on the empty string. Remaining input: +b:A.

    • Template has not advanced the input, gives up on trying another TemplatePart.

  • List succeeds with a. Remaining input: +b:A.

• Typed expects literal ":" after List, but the remaining input is +b:A, and fails.

I assume you expect "+" to be matched by Text, and it looks like you just forgot the "match anything parser" . in

Text           < (!(Variable / Number / ":" / ",") . )*

Hope this helps,
Bastiaan.

@veelo Yes, that fixed it! :)