[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

more srfi-12 rationale?



I have some questions with srfi-12, mainly dealing with conditions.

* Why do we need a new condition type, disjoint from other Scheme values,
with 5 new operations, some of which are quite non-trivial?  Why can't
we just use standard lists (perhaps association lists)?  It seems rather
non-Schemey (non-orthoginal) to me, to add a new data-stype, with new
operations, that is *similar* to existing data types, but which is
designed for one very specific applications (exceptions and handlers).

* What is the purpose of composite conditions?

I'm sure the authors, who have lots of experience as Scheme implementors,
have good reasons for this design.  I just don't see it in the srfi.

I also think the word "condition" is a bit of a mis-nomer.  I see
nothing conditional about them.

I will also for the record note that I think it is very desirable
that the exception system be implementable on Scheme systems that
do not support full continuations.  From my first reading, it
looks like the proposal *does* satisfy this goal.
-- 
	--Per Bothner
bothner@xxxxxxxxxxx  per@xxxxxxxxxxx   http://www.bothner.com/~per/