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Postings from September 2009
Mike Diehl pondered: > Well, I've continued to think about this and I've got some more questions. > > I did read up on the <defer: directive. I don't think that will help me. If > I'm missing something, please let me know. No, it won't help. The problem is that you want to *parse* every command, but not *execute* every command (only the ones in the correct branches of the if). > So, I've come up with two different ways to handle this situation: > > 1. Pass in a boolean areguement to each production, and if that arguement > is "true" process the action, otherwise, simply return the TEXT of the > matched expression. > > This way, my if statement passes [1] and [0] to the two clauses. This > introduces substantial logic into my grammar, though. > > 2. The other way is to build the "parse tree" inside the grammar and > then "walk" the tree. This would entail almost completely rewriting my > grammar actions. But this way would also, potentially?, allow me to compile > my language and forgo the parser step alltogether. > > Which method would you recommend? Definitely, the second approach. There's a good reason that people usually separate compilation and execution: namely that mixing them is both vastly more complex and considerably more error-prone. DamianThread Previous | Thread Next