Hi,
What sent me first into deep confusion is that I found all of {Text,GHC}.{Read,Show} first, and the Read classes marked as "nonportable GHC extensions". Quite disheartening :-( Well, then I found the Prelude definition (though it's entirely unclear how they relate to the Text and GHC versions).
The GHC versions are simply more efficient versions. Show and Read are completely portable.
Hmm... I can write out functions using the "Show (a -> b)" instance, but there's no matching "Read (a -> b)".
Show (a -> b) is a bogus instances -- you won't actually be able to use it for marshalling functions.
Or you could use the Binary class to get binary representations, but these (sometimes, depending on which implementation you use) have endianness issues if you're transmitting between different architectures.
I didn't find Binary in my GHC 6.0.1 distro. Is it a library that I have to install as an add-on?
I have a version on my web page: http://www.isi.edu/~hdaume/haskell/NewBinary/ you want Binary.hs from there, as well as FastMutInt.lhs. Unfortunately, these are GHC-specific, though they are a port of the Binary library from NHC. My version adds support for bit operations and is just an addition to the original port by Simon Marlow. Still can't do functions though -- you need internal compiler support for that.
In all, I'm finding it rather difficult to find my way in the documentation (just as a data point for the documentation folks). To make the critique helpful instead of just a critique, here are a few ideas of what might have helped me (YMMV):
I like going to google and searching for 'site:haskell.org haddock Show' or something like that. I find it's a reasonable way to find things, though of course not perfect.
2. Remove the split between "type/class index" and "function/constructor index" in the Haddockish doc-index.html file. For newbies like me, the
I agree :); or perhaps have the split as well as a big index without the split. - Hal -- Hal Daume III | hdaume@isi.edu "Arrest this man, he talks in maths." | www.isi.edu/~hdaume