On 1 November 2010 22:18, Andrew Coppin <andrewcop...@btinternet.com> wrote:
> I vaguely recall somebody mentioning a parser library on Hackage where > "try" is the default behaviour and you turn it off explicitly, rather than > turning it on explicitly. Apparently this is much more intuitive. But > unfortunately I can't remember what the hell the library was... polyparse, is it? from http://code.haskell.org/~malcolm/polyparse/docs/index.html#what > If you have only ever used the parsec combinators before, then you might be pleasantly surprised by polyparse: all of the same functionality is > available, but it removes the confusion that all too commonly arises from a failure to use parsec's try combinator correctly. Ambiguous grammars often fail to be compositional in parsec, and it can be a black art guessing where to > introduce a try to fix it. In contrast, polyparsers are by default fully > compositional. It is possible to improve their efficiency (and the accuracy of error messages) by inserting commits (which are the dual of try), but it is not necessary for writing a correct parser, and furthermore, it is usually > obvious where it can be beneficial to add a commit. Ozgur
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