X* Methods

[Cecil Phillip]

What's the difference between the X* methods and the non X* methods? For instance XMany vs Many?

[nblum...@nblumhardt.com]

Hi Cecil - IIRC the X indicates eXclusive: if the parser starts parsing an element (or an option in the case of XOr) and succeeds, it will not backtrack to try alternatives on failure. This improves error message quality.

E.g. if I have a grammar AB | C, the using XOr to parse broken input "AD" will give an error on the D, stating that B was expected, instead of backtracking to try C and then failing with the error message that A was found but C was expected.

HTH!

Nick