-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 You're right - my statement is inaccurate.
Implementation details aside, I am referring specifically to the statement "getChar ... has the type signature of a value". It clearly does not. Lennart Augustsson wrote: > Not it doesn't. getChar has the type signature IO Char. The IO > type is abstract. GHC happens to implement it by a state monad. > But in, e.g., hbc it is implemented in a totally different way, > more like a continuation monad. > > Peeking inside an implementation of IO can be illuminating, but one > must remember that IO is abstract. > > -- Lennart > > On Mon, Feb 9, 2009 at 10:26 AM, Tony Morris <tmor...@tmorris.net> > wrote: Gregg Reynolds wrote: >>>> The point being that the metalanguage commonly used to >>>> describe IO in Haskell contains a logical contradiction. A >>>> thing cannot be both a value and a function, but e,g, getChar >>>> behaves like a function and has the type signature of a >>>> value. > getChar has the signature RealWorld -> (RealWorld, Char) > >> _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe >> - -- Tony Morris http://tmorris.net/ S, K and I ought to be enough for anybody. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkmQAfkACgkQmnpgrYe6r61tmQCcCx42Cz1iunkD7JGubla/z2Pg uhAAoLk5rkjeHnrfc936IhYoBQYO/+0r =6xWk -----END PGP SIGNATURE----- _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
