Parse::RecDescent::FAQ 5.02

Parse::RecDescent::FAQ is the official, authorized FAQ for Parse::RecDescent. OVERVIEW-TYPE QUESTIONS Is Parse::RecDescent LL(1)? LL(N)? LR(1)? LR(N)? Answer by Yves Orton: I have a data structure which is a hash of entries where an entry is a list/array of sets I have also a grammar that can parse the syntax of the text files that contain the data I want to fill this structure with. Until here everything is ok. Problem: I cannot figure out how to actually FILL the parsed data into the structure. I can only decide if a string is grammatically correct or not. Also see the "Left-recursion" section under "PARSER BEHAVIOR" DEBUGGING Flags you can set Paraphrased from Yves Orton: To understand more about why your parser is not behaving as it should take advantage of the follow variables: $::RD_ERRORS # unless undefined, report fatal errors $::RD_WARN # unless undefined, also report non-fatal problems $::RD_HINT # if defined, also suggestion remedies $::RD_TRACE # if defined, also trace parsers behaviour Making warning line numbers correspond to your grammar How do I match the line numbers with the actual contents of my script? At present, you cant (but thats on the ToDo list). Setting $::RD_TRACE can be useful though: Once youve run with $RD_TRACE, do this: perl -w RD_TRACE Then go and examine the actual line numbers given for the error in the file RD_TRACE. That will show you the actual generated code thats the problem. That code will, in turn, give you a hint where the problem is in the grammar (e.g. find out which subroutine its in, which will tell you the name of the offending rule)..

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