Re: [Haskell-cafe] Re: Abstraction leak

Jon Fairbairn wrote:

Andrew Coppin writes:

...

While we're on the subject... am I the first person to notice that Haskell doesn't appear to have much support for fiddling with streams of bits?

No. Presumably the author of Data.Bits noticed some lack. (Note that Integer is an instance of Num and hence Bits)

Right. But (for instance) there is no library function anywhere to convert a Word16 into a [Bool] (never mind handling endian issues), or back again. There is no standard construct for reading from a [Word8] as if it's a [Bool], or for writing to a [Bool] and ending up with a [Word8]... ...Then again, there is no library function for reading from a file and getting a [Word8]. The only way I have found to do this is to open a file, put the handle into "binary mode", use hGetContents to read a [Char] from it, and then do a map (fromIntegral . fromEnum) on that. Writing binary data back to a file requires opening a handle, putting it into binary mode, taking your [Word8] and doing a map (toEnum . fromIntegral) over it, and then using putStr. All of which works because, apparently, in binary mode the file is interpreted as 8-bit ASCII. God forbit that Haskell ever decides to transparently support other encodings... I haven't actually tried, but presumably a TCP connection is represented in the same way as a file, and so has the same problems. Basically doing binary I/O seems to be one of those things that in Haskell falls into the class of "it's possibly but annoyingly messy"...