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eqv?: incorrect behavior with uninterned symbols #709

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Zipheir opened this issue Jan 29, 2025 · 0 comments · May be fixed by #710
Open

eqv?: incorrect behavior with uninterned symbols #709

Zipheir opened this issue Jan 29, 2025 · 0 comments · May be fixed by #710

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@Zipheir
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Zipheir commented Jan 29, 2025

When invoked on one or more uninterned symbols, eqv? gives a different answer from symbol=?:

(define usym (string->uninterned-symbol "x"))

(eqv? usym 'x) => #t

(symbol=? usym 'x) => #f

In general, eqv? returns #t for uninterned symbols with the same name:

(eqv? (string->uninterned-symbol "x") (string->uninterned-symbol "x"))
  => #t
jpellegrini added a commit to jpellegrini/STklos that referenced this issue Jan 29, 2025
@jpellegrini
Make eqv? and symbol=? agree. Currently, if one of the symbols is
f0187af 
uninterned, `eqv?` may consider both to be the same. With this
patch, `eqv?` won't deal with uninterned symbols, rteating them
always as "different from whatever else".

This is the same behavior as Chez, Chicken, Gambit, Gauche, MIT.
(Bigloo, Kawa, Chibi do not have string->uninterned-symbol).

The change is:

1. In `eqv?`, check for hard equality (with `==`) so if one of the
   symbols is uninterned, the result is `#f`
2. Since we're at it, rewrite `symbol=?` so it will not accept
   non-symbol arguments (so its behavior will be the same as
   `string=?`

So now:
(eqv? (string->uninterned-symbol "x")
      (string->uninterned-symbol "x"))       => #f

This should fix egallesio#709
jpellegrini added a commit to jpellegrini/STklos that referenced this issue Jan 29, 2025
@jpellegrini
Make eqv? and symbol=? agree.
5ef2a22 
Currently, if one of the symbols is uninterned, `eqv?` may consider
both to be the same. With this patch, `eqv?` won't deal with
uninterned symbols, rteating them always as "different from whatever
else".

This is the same behavior as Chez, Chicken, Gambit, Gauche, MIT.
(Bigloo, Kawa, Chibi do not have string->uninterned-symbol).

The change is:

1. In `eqv?`, check for hard equality (with `==`) so if one of the
   symbols is uninterned, the result is `#f`
2. Since we're at it, rewrite `symbol=?` so it will not accept
   non-symbol arguments (so its behavior will be the same as
   `string=?`

So now:
(eqv? (string->uninterned-symbol "x")
      (string->uninterned-symbol "x"))       => #f

This should fix egallesio#709
@jpellegrini jpellegrini linked a pull request Jan 29, 2025 that will close this issue
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Make eqv? and symbol=? agree. jpellegrini/STklos
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@Zipheir