Re: [Scheme-reports] About the behavior of continuation in top-level begin form

[John Cowan <cowan@x>]

張書瀚 scripsit:

> But the problem of begin, as I said before, is still there.  I don't
> think it's good to deliberately leave that behavior unspecified
> in the standard, so I post it here (for me, it creates unnecessary
> misunderstandings).

It's a hard problem.  Suppose you are using a Scheme system like Chicken
or Gambit, that compiles Scheme code to stand-alone executables.  What do
you expect this to do?

(call/cc (lambda (x) (x)))

There just isn't any good answer, because the captured continuation is
outside Scheme.  Likewise, if you run something like this from a REPL,
you are capturing a continuation in the REPL's own code, which may or
may not be in Scheme.

Such issues are inherently outside the scope of any Scheme standard.

-- 
John Cowan   cowan@x    http://ccil.org/~cowan
You cannot enter here.  Go back to the abyss prepared for you!  Go back!
Fall into the nothingness that awaits you and your Master.  Go! --Gandalf

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