[r6rs-discuss] Compile-time detection of contract violations

From: William D Clinger <will>
Date: Wed Nov 1 02:11:14 2006

I am posting this as an individual member of the Scheme
community. I am not speaking for the R6RS editors.

Abdulaziz Ghuloum addressing Mike Sperber:
> Are you sure this program should return 1? From what I understand from
> this thread so far, the above is not a correct program and thus is
> meaningless (it may be rejected by some implementations, may return 1
> under others, and may return (1 . 2) under a third). If the above *is*
> a correct program that returns 1, then I need further explanation of
> its meaning when run under an "unsafe" declaration. I sure hope that
> declarations do not change the semantics of correct Scheme programs.

I suspect that Abdulaziz's understanding, stated above,
is based in part upon my analysis of language that appears
in the current draft of R6RS, section 9.22, page 56.

Mike's position, I believe, is that the language in section
9.22 of the current draft does not reflect the intent of
the editors, and should be repaired. I accept Mike's
analysis.

Speaking of blame assignment: I drafted section 9.22, so
you can blame me for this error.

Will
Received on Wed Nov 01 2006 - 02:11:08 UTC