[Ecls-list] unbound-variable handler

[Pierre THIERRY]

Scribit Dean O'Connor dies 25/06/2007 hora 16:48:
> Sure this has potential to cause difficult to debug problems depending
> on the application, but "grave bug" is a bit subjective.

Indeed. I like working from established specification and even try to
proove the correctness of algorithms. I'm a bit picky with bug
severities...

> Other scripting languages like Perl allow this by default.

That may prove my point. :-)

> the production Lisp engine (in-house based on elisp I think) allows
> NIL to be returned for references of vars that weren't declared

That's why portability is defined so narrowly in the CL spec. I'd
strongly suggest you to take the opportunity to make the code portable.
Having a portable code offers you the possibility to change the
underlying implementation quite freely.

> There are lots of client scripts out there (working fine), so we can't
> just change the handling now.

Obviously not.

Well, it all depends on how your DSL is implemented. It may not be hard
to change the evaluator or compiler to add a CL restart to return NIL
when a variable is unbound.

Curiously,
Pierre
-- 
nowhere.man at levallois.eu.org
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