Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!lavaca.uh.edu!menudo.uh.edu!sugar!ficc!peter
From: peter@ficc.ferranti.com (Peter da Silva)
Newsgroups: comp.lang.c
Subject: Re: function composition in C
Message-ID: <5SX9XUC@xds13.ferranti.com>
Date: 6 Mar 91 19:28:04 GMT
References: <6873@munnari.oz.au> <9754@uwm.edu> <1991Mar2.224617.2613@Neon.Stanford.EDU>
Reply-To: peter@ficc.ferranti.com (Peter da Silva)
Organization: Xenix Support, FICC
Lines: 12

See my recent article in comp.lang.misc. In general you can't compose normal
functions in any language that doesn't have an interpreter stage, such
as lisp or an object-oriented language like SmallTalk. But you can
implement objects in C: this is what C-preprocessors like CO2 and C++
do. They basically write a micro-interpreter for function calls using a
jump-table, and convert calls to these objects into calls to an application
function and an indirection through this jump-table. You can do the same
thing on a smaller scale to get the effect of first-class functions: but
these first-class functions are *not* C functions.
-- 
Peter da Silva.  `-_-'  peter@ferranti.com
+1 713 274 5180.  'U`  "Have you hugged your wolf today?"