Re: build failure with net-utils

On Mon, 26 Aug 2002 11:41:20 +0900, "Stephen J. Turnbull" said: The problem I've seen is the following: 1) Author A produces Package A that allows better handling of Elvish. 2) Author B produces an add-on B that allows tagging of Early, Middle, and Late Elvish - this of course does a (require 'A) for the obvious reasons. 3) Author A then adds hooks for B in his package. He does a (require 'B) to get the stuff loaded in. Can somebody tell me the *right* XEmacs Lisp idiom for this, that will Do The Right Thing when run *or* byte-compiled either with or without B: (if (available-feature 'B-elvish) (add-elvish-hook 'early-elvish)) (In other words, if it's available use it - but if it's not available so "early-elvish" isn't a known symbol, don't throw a complaint either. I'd be willing to bet a lot of the "circular" requires are actually 'conditional requires' that the programmer can't understand how to get it to not throw errors (I freely admit I looked at the docs for 'require' and the byte compiler for about 45 minutes last night, and came away totally unenlightened on how to do this....) -- Valdis Kletnieks Computer Systems Senior Engineer Virginia Tech