How to debug an invalid ParseKit Grammar?
问题 I am trying to write a grammar for ParseKit so that it matches basic propositional logic sentences in an iphone app. Can someone please tell me where im going wrong. @start = wff; wff = disjunction (implies disjunction)?; disjunction = conjuction (or conjuction)*; conjunction = notExpression (and notExpression)*; notExpression = (not | not primaryExpression); primaryExpression = variable | lbracket wff rbracket; variable = p | q | r; p = 'P'; q = 'Q'; r = 'R'; implies = '→'; and = '∧'; or = '