On Fri, 2008-08-29 at 20:01 +0200, Johannes Waldmann wrote: > Donn Cave wrote: > > > ... I would implement the network service > > input data stream myself, with timeouts, encryption, whatever as required, > > and then apply the parser to available data as a simple, pure function > > that returns NNTP results and whatever data remains. So the parser would > > never see any streams or handles or anything, it would just get strings > > to parse. > > A likely problem with that is that your implementation of the "input > data stream" will still need to parse some information from it. > So you're going to replicate code from the parser. > > I think the following is analoguous. > > Imagine you're writing a parser for a simple programming language. > A program is a sequence of statements. > Fine, you do "readFile" (once) and then apply a pure Parsec parser. > > Then you decide to include "import" statements in your language. > Suddenly the parser needs to do IO. Assume the import statements > need not be the first statements of the program > (there may be headers, comments etc. before). > Then you really have to interweave the parsing and the IO. > > If anyone has a nice solution to this, please tell. - J.W.
Using parsec3 you can just do exactly what you said. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
