From: Daniel Colascione <dancol@dancol.org>
To: Emacs developers <emacs-devel@gnu.org>
Subject: Hash values of symbols: why look at the name?
Date: Mon, 15 Sep 2014 17:19:02 -0700 [thread overview]
Message-ID: <541781F6.7010600@dancol.org> (raw)
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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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next reply other threads:[~2014-09-16 0:19 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-16 0:19 Daniel Colascione [this message]
2014-09-16 3:00 ` Hash values of symbols: why look at the name? Stefan Monnier
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