Path: utzoo!attcan!uunet!ficc!peter
From: peter@ficc.uu.net (Peter da Silva)
Newsgroups: comp.lang.misc
Subject: Re: Bondage and Discipline Languages
Message-ID: <2794@ficc.uu.net>
Date: 17 Jan 89 14:03:33 GMT
References: <4246@enea.se>
Organization: Xenix Support
Lines: 41

In article <4246@enea.se>, sommar@enea.se (Erland Sommarskog) writes:
> But to throw some new wood on the fire, consider the following: Assume
> you have routine you want to call but whose name you don't know until
> run-time, thus you have the name in a string. Now in which langauges
> can you easily do this? Interpreting langauges like Lisp and Basic,
> support this I guess. But compiled langauges?

I do this all the time in 'C', for one reason or another. Many of my
interactive programs have the equivalent of this in them. It's more
painful to implement this in a language without aggregate initialisation,
of course. I can't imagine doing without this capability. Chopping up a
line into argv/argc is an excersize left to the reader.

struct {
	char *fname;
	int (*fcode)();
} funtab[] = {
	"fname1", func1,
	"fname2", func2,
	"fname3", func3,
	...
};
int nfuns = sizeof funtab / sizeof *funtab;

int call(name, argc, argv)
char *name;
int argc;
char *argv;
{
	int i;

	for(i = 0; i < nfuns; i++)
		if(strcmp(name, funtab[i].fname) == 0)
			return (*funtab[i].func)(argc, argv);
	return 0;
}
-- 
Peter da Silva, Xenix Support, Ferranti International Controls Corporation.
Work: uunet.uu.net!ficc!peter, peter@ficc.uu.net, +1 713 274 5180.   `-_-'
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