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 BEGIN. Could you maybe come up with a use case illustrating the usefulness of your proposed change? I can't think of anything myself. _______________________________________________ Scheme-reports mailing list [email protected] http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports
