Re: [Chicken-hackers] extending define-values

[Alex Shinn]

On Tue, Apr 9, 2013 at 8:16 AM, Alex Shinn <address@hidden> wrote:

On Tue, Apr 9, 2013 at 6:49 AM, Felix <address@hidden> wrote:

>> "define-values" can not simply expand into a bunch of "defines".
>> To allow it to be intermixed with "define" in internal definitions,
>> it needs be special cased, due to the use of "call-with-values" (which
>> would "break" the sequence of definitions and treat all following
>> forms of the body as non-definitions). Or not?
>
> No, the call to call-with-values is wrapped in a definition too.
> It really is turtles all the way down.
>
>> BTW, where can I find the portable reference implementation you
>> mentioned?
>
> In Section 7.3 of the ninth draft, pp. 69-70.  Unfortunately,
> trac.sacrideo.us seems to be down, but it's normally at
> <http://trac.sacrideo.us/wg/raw-attachment/wiki/WikiStart/r7rs-draft-9.pdf>.
> There's a temporary copy at <http://www.ccil.org/~cowan/temp/r7rs-draft-9.pdf>.

Very clever, indeed. Thanks for the link. Rather inefficient,
but clever.

Sorry, what I described was a variation of the same theme.

If you do what I described instead of what I coded, and be

sure to pass a lambda with the same signature (in temp vars)

as the define-values to call-with-values then there is zero

overhead.

Note the following implementation from 2007 follows this approach:

http://permalink.gmane.org/gmane.lisp.scheme.gauche/1051

-- 

Alex