Date: Thu, 12 Nov 1998 22:05:54 -0800 (PST)
From: Ned Freed <Ned(_dot_)Freed(_at_)innosoft(_dot_)com>
My personal take is that short-circuit evaluation is useful enough to
warrant a MUST. But I'd rather have a statement saying scripts MUST
NOT take advantage of short-circuit evaluation than one saying
implementations MAY do it.
Okay, scripts can't currently take advantage of short-circuit
evaluation.
If an extension exists that makes it possible to use short-circuit
evaluation, could we have that extension change this assumption?
I suppose so in theory, but I really don't much care for the idea.
I'm sorry, but if short circuit evaluation is useful then it should be a
requirement, and if not it should not even be an extension. I don't buy the
argument that this is problematic because some languages don't support
short-circuit evaluation. Just because you don't have short-circuit in some
language doesn't mean that you cannot write a sieve interpreter in that
language that does have short circuit characteristics. The two are largely
unrelated unless you're using a direct translation approach, in which case
other constraints are likely to be a lot more onerous.
Indeed, my sieve implementation is a case in point -- it does short circuit
evaluation and it is written in a language that doesn't itself support the
concept. And my using a language with this concept would not have altered the
implementation task in any significant way.
Ned