Daniel Hartwig <mand...@gmail.com> skribis:
> scheme@(guile-user)> (define x 1/2)
> scheme@(guile-user)> (eq? x 2/4)
> $7 = #f
> scheme@(guile-user)> ,optimize (eq? x 2/4)
> $8 = (eq? x 1/2)
> scheme@(guile-user)> (define y 2/4)
> scheme@(guile-user)> (eq? x y)
> $9 = #f
> scheme@(guile-user)> ,optimize (define y 2/4)
> $10 = (define y 1/2)
Quoth R5RS:
`Eq?''s behavior on numbers and characters is
implementation-dependent, but it will always return either true or
false, and will return true only when `eqv?' would also return
true. `Eq?' may also behave differently from `eqv?' on empty
vectors and empty strings.
What we may get wrong is that it looks as if it doesn’t always return
either true or false, because the behavior depends on whether one of the
operands is a literal.
However, it’s fundamentally wrong to rely on eq? to compare numbers. So
the test case you mention seems buggy, to start with.
WDYT?
Ludo’.
