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

Re: [Scheme-reports] Draft 3 Comments: Chapter 4

Am 27.07.2011 19:21, schrieb Andre van Tonder:
> On Wed, 27 Jul 2011, Denis Washington wrote:
>> Thinking about it, leaving this unspecified makes sense as one couldn't
>> use "when" and "unless" to return a value from a procedure anyway
>> without risking an unspecified return value (if the test evaluates to #f
>> or #t, respectively).
>> On the other hand, "begin" in an expression context also a sole
>> side-effect construct (otherwise, all expressions except the last in a
>> "begin" form would be useless) and still returns the last expression's
>> result. Given that "when" and "unless" are very similar, I find it to be
>> pretty intuitive if they have the same behavior. I'm undecided.
> The difference is that BEGIN in an expression context always has a last
> expression. On the other hand, WHEN with a #f test is more like an empty
> Could you maybe come up with a use case illustrating the usefulness of
> your proposed change? I can't think of anything myself.

I realized that my proposal wouldn't really add anything useful for the 
reason you stated. So feel free to ignore it. :)


Scheme-reports mailing list