[REBOL] Re: Pre-REP on NONE! and SERIES! polymorphism
From: greggirwin:mindspring at: 10-Jun-2002 10:43
Hi Joel,
I've been a big fan of Design by Contract for a while, which leads you to be
very specific and assert everything that's important to ensure reliable
operation. With REBOL, I do things very differently and am still looking at
how that mindset fits with my (evolving) REBOL development style. Without
further digression, I'd vote for 3c.
3c) ...asking for FIND SELECT and FOREACH to be extended to
accept NONE as a first argument.
If returning NONE were always considered to be an error condition, that
would be a different story, but it isn't. From a DbC viewpoint, I could
argue that there is a clear distinction and that you shouldn't be trying to
FIND anything in a none! value but, as you pointed out, returning NONE is a
standard REBOL idiom. If you want to check for NONE values in certain cases,
there is nothing to prevent you from doing that, but that would be the
exception. Most code would benefit I think.
--Gregg
