Is there an alternative to MKS Yacc that supports “selection preference syntax” or something very similar? [closed]
问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 years ago . MKS Yacc supports a notation which their web site calls "selection preference syntax". It isn't illustrated, but it consists of a token in square brackets, optionally with a caret, and it indicates that a particular token is required to follow, or is required not to follow, the rest of the rules: non_terminal: