Path: utzoo!censor!geac!torsqnt!lethe!yunexus!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!cs.utexas.edu!rice!bbc From: bbc@rice.edu (Benjamin Chase) Newsgroups: comp.lang.misc Subject: Re: On whether C has first-class composable functions Message-ID: Date: 12 Jan 91 22:02:09 GMT References: <442@data.UUCP> <4408:Jan421:44:3391@kramden.acf.nyu.edu> <1991Jan5.182428.615@mathrt0.math.chalmers.se> <4762@pkmab.se> Sender: news@rice.edu (News) Reply-To: Benjamin Chase Followup-To: comp.lang.misc Organization: Center for Research on Parallel Computations Lines: 23 In-Reply-To: ske@pkmab.se's message of 12 Jan 91 06:47:02 GMT There is an unfortunate limitation of Kristoffer Eriksson's code, and of other purported+ implementations of a composition function for C functions. These implementations of function composition have not been for C functions, but rather for monadic C functions that map "int"s to "int"s. +("purported" is perhaps too strong a word; they didn't claim, but seemed to have merely overlooked) Can a (reasonably efficient and portable) compose function for (all) C functions be written in C?* I'm still waiting for that existence proof... :-) I believe that it cannot be done. Actually, I'm not really waiting for the existence proof. I don't really care to see such code. (Note that "reasonably efficient" is an important and subjective restriction here. I will let Dan Bernstein be the arbiter for "reasonably efficient and portable.") *(Note that this is not the same question as: "Does C have composable functions?") -- Ben Chase , Rice University, Houston, Texas