PEG Parsers - Hackdot

Re:PEG Parsers by mamcx on Wednesday July 24, 2019 @11:01AM (#20515924)

yeah, I get the purposed point of a "cut" but how I put one? Exist a basic sample? (ie: Using a peg parser how define what is a "cut"???)

    expr: expr '+' API_call_here? term | term

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Re:PEG Parsers by pacaro on Wednesday July 24, 2019 @01:00PM (#20517174)

Hmm, if you're using a peg parser that doesn't directly support this you can emulate it by choosing between the rhs of the cut and a production that will always match

  expr : atom (op <cut> expr)*

Would be replaced with

  expr : atom (op (expr / cut))*
  cut  : "XXX"?

or perhaps simpler

  expr : atom (op expr?)*

Either way when you process the expr rule there will be an empty match where the rhs should be, and an appropriate error can be generated

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