* Jason Dusek
I'm having some trouble with memory usage in rebuilding a ByteString with some sequences escaped. I thought I'd try vectors. However, it seems that even a relatively simple function, one that places all the bytes of a ByteString in to a vector, uses a great deal of memory.
Should I be annotating my functions with strictness, for the vector reference, for example? Should I be using STUArrays, instead?
Hi Jason, I think what's happening here is ByteString's "strictness" makes things actually lazy on your side. Namely, unpack function produces its result "strictly", whole list at once. As a result, the resulting list cannot be consumed one-by-one, so it takes memory. You see ST thunks because mapM_ f as = sequence_ (map f as) and that map probably gets fused with unpack. I guess the proper solution here is to use lazy bytestring and make sure the chunks are not very big. -- Roman I. Cheplyaka :: http://ro-che.info/