Path: utzoo!attcan!uunet!lll-winken!ames!pasteur!ucbvax!hplabs!otter!kers
From: kers@otter.hpl.hp.com (Christopher Dollin)
Newsgroups: comp.lang.misc
Subject: Re: What is B&D? (Re: Bondage and Discipline Languages)
Message-ID: <2400020@otter.hpl.hp.com>
Date: 18 Jan 89 09:24:45 GMT
References: <2670@ficc.uu.net>
Organization: Hewlett-Packard Laboratories, Bristol, UK.
Lines: 30

Erland Sommarskog said:

| 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?

It's not a matter of compiled vs interpreted; you can map strings to the
contents of the so-named variables in compiled Lisp. The question is: how much
information about the names of things is left lying around at run-time? In
Lisp, the symbols (and their values) are part of the language, and so can be
interrogated by the running code.

Of course it's likely to be *easier* in an interpreted language, since the
interpreter has to keep all that stuff around anyway.

Example compiled language that lets you call a routine known by a string:
Pop11. Code to do so:

    (the_string.consword.valof)( args )

or, if you prefer prefix notation rather than dotted suffixing:

    valof( consword( the_string ) )( args )

Caveats on request.

Regards, Kers.
"If anything anyone lacks, they'll find it all ready in stacks."