On 8 April 2012 19:17, Myles C. Maxfield
It's a JPEG parser. ....
Ahem, I'm a bit of of my depth then, but one thing you should consider is that writing your own parser monad is trivial, especially for well defined binary formats. Well defined binary formats should be deterministic and don't need backtracking, hence you won't need to worry about defining Alternative / MonadPlus instances which is where the complication lies. As you should be able to live without backtracking for JPEG it shouldn't be hard to make the parser efficient if you stick closely to the API of the Vector or Array library you are using - e.g. you might want to move a cursor forward through the Array rather than "unconsing" [*] at the head which would create work for the garbage collector. This should still be amenable to streaming - you just work at a larger chunk size. Presumably you've seen Jeroen Fokker's paper on JPEG decoding with Gofer? (Gofer is ~= Haskell). [*] Parsec etc. work by unconsing the head of the input stream.