* Hash values of symbols: why look at the name?
@ 2014-09-16 0:19 Daniel Colascione
2014-09-16 3:00 ` Stefan Monnier
0 siblings, 1 reply; 2+ messages in thread
From: Daniel Colascione @ 2014-09-16 0:19 UTC (permalink / raw)
To: Emacs developers
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Right now, this form always evaluates to t:
(eql (sxhash (make-symbol "a")) (sxhash (make-symbol "a")))
This form always evaluates to nil:
(equal (make-symbol "a") (make-symbol "a"))
The hash of a symbol is the hash of its namel; that seems silly, since
symbol equality is based on identity. We should be able to just use the
symbol address instead, right?
=== modified file 'src/fns.c'
--- src/fns.c 2014-09-15 05:09:44 +0000
+++ src/fns.c 2014-09-16 00:14:52 +0000
@@ -4482,13 +4482,10 @@
break;
case Lisp_Misc:
+ case Lisp_Symbol:
hash = XHASH (obj);
break;
- case Lisp_Symbol:
- obj = SYMBOL_NAME (obj);
- /* Fall through. */
-
case Lisp_String:
hash = sxhash_string (SSDATA (obj), SBYTES (obj));
break;
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Hash values of symbols: why look at the name?
2014-09-16 0:19 Hash values of symbols: why look at the name? Daniel Colascione
@ 2014-09-16 3:00 ` Stefan Monnier
0 siblings, 0 replies; 2+ messages in thread
From: Stefan Monnier @ 2014-09-16 3:00 UTC (permalink / raw)
To: Daniel Colascione; +Cc: Emacs developers
> The hash of a symbol is the hash of its namel; that seems silly, since
> symbol equality is based on identity. We should be able to just use the
> symbol address instead, right?
Sounds right,
Stefan
^ permalink raw reply [flat|nested] 2+ messages in thread
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2014-09-16 0:19 Hash values of symbols: why look at the name? Daniel Colascione
2014-09-16 3:00 ` Stefan Monnier
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