Sidney Markowitz <sidney@sidney.com> wrote:
+
 XXJohan Bockgård wrote:
 > Actually, [in Emacs Lisp?] (/ 3 5) ==> 0

 CLtL 12.4 Arithmetic Operations
 / will produce a ratio if the mathematical
 quotient of two integers is not an exact integer.
+
Exactly. Which breaks the "equivalent semantics" rule of CLHS 1.7.
[So it's going to be hard to use Emac Lisp as the implementation
substrate of a conforming "CL subset".]
Whereas, if a purported "CL subset" gave a "don't do that!" error:
qdl> (/ 3 5)
/: Error: Division by 5 produced noninteger result!
qdl>
Then as long as you exclude programs that do that from the set of
"valid programs" for the purported subset, then that *wouldn't*
break the rule. [Bend real hard, maybe, but not break.] ;}
The question is whether such a subset would be considered "useful"...
Rob
p.s. If a fixnumonly subset included MOD and/or REM,
it would be a lot more useful than if it didn't. ;}

Rob Warnock <rpw3@rpw3.org>
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