Re: [MIT-Scheme-devel] call-with-values requires thunk to use 'values'? Why?

[Taylor R Campbell]

   Date: Tue, 14 Dec 2010 08:09:33 -0800
   From: Joe Marshall <address@hidden>

   On Sun, Dec 12, 2010 at 8:25 PM, Daniel Katz <address@hidden> wrote:
   >
   > but when I look at R5RS, there doesn't seem to be anything in the
   > description of call-with-values that would require the use of 'values'
   > to return the values from the first argument to call-with-values.

   Unfortunately, the restriction is implied in two earlier sentences.
   Under the definition of call-with-current-continuation, it says
   ``The effect of passing no value or more than one value to
     continuations that were not created by call-with-values is
     unspecified.''

This precludes (list (values 1 2)), not (call-with-values (lambda ()
4) list).  That the former `works' in MIT Scheme is an accident.  That
the latter doesn't work in is a bug, and we don't need to try to
rationalize it.