2009/9/5 John Cowan <[email protected]>:
> (Almost. A continuation has to check how many arguments it expects
> at run time, because there's no way in Scheme to declare the number
> of values that a procedure returns. I argued for (lambda 2 (a b c)
> (values a b)), but Felix said it was too ugly.)
It would be a better expression than we have now, but it would still
inject bindings for return values a and b into the calling
environment, breaking lexical scope.
If lexical scope is to be preserved, then the call site rather than
the function has to bind the values to be recieved from the function
(as in the receive form). But if first-class functions are to be
preserved, then the number of returns is a property of the function
and not a property of the call site.
It's probably not a coincidence that 'parameters' and other forms
that break lexical scope come under consideration at roughly the
same moment in history as multiple returns.
Bear
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