Just out of curiosity, has anyone done any work at benchmarking the various parsers? I use Parsec pretty exclusivly since it comes with ghc and is pretty straightforward and lightweight to use. I am wondering what I am giving up in terms of speed by going that route, rather than Happy or the compiler toolkit non-monadic but pure-haskell parser? hmm... John On Thu, May 10, 2001 at 03:42:00PM +0100, Simon Marlow wrote:
S. Alexander Jacobson writes:
I am not a parsing expert, but given the recent discussion on macros, I have to ask: why use happy rather than monadic parsing? Monadic parsing allows you to avoid a whole additional language/compilation step and work in Hugs (where you don't have a makefile). What does Happy buy you here?
It buys you (a) speed, (b) confidence that your grammar is non-ambiguous, and (c) familiar BNF notation. On the down side, as you point out, you lose Haskell's abstraction facilities.
I'd be willing to sacrifice (c) in order to write parsers in Haskell, but I don't think there's a combinator library that matches Happy in terms of speed (disclaimer: I haven't exhaustively tested them all, but given the tricks Happy does I'd be surprised). AFAIK none of the combinator libraries gives you (b).
-- -------------------------------------------------------------- John Meacham http://www.ugcs.caltech.edu/~john/ California Institute of Technology, Alum. john@foo.net --------------------------------------------------------------