* bug#13345: 24.2.91; Wrong assumption in a hash table example + fix
@ 2013-01-03 12:01 Ari Roponen
2013-01-03 18:41 ` Glenn Morris
0 siblings, 1 reply; 2+ messages in thread
From: Ari Roponen @ 2013-01-03 12:01 UTC (permalink / raw
To: 13345
In file doc/lispref/hash.texi, there is an example:
@example
(defun case-fold-string= (a b)
(compare-strings a nil nil b nil nil t))
(defun case-fold-string-hash (a)
(sxhash (upcase a)))
(define-hash-table-test 'case-fold
'case-fold-string= 'case-fold-string-hash)
(make-hash-table :test 'case-fold)
@end example
The documentation of `define-hash-table-test' says:
The function @var{test-fn} should accept two arguments, two keys, and
return non-@code{nil} if they are considered ``the same''.
In the above example, the test function returns always non-nil, because
it assumes `compare-strings' returns nil for differing strings. The
patch below fixes this wrong assumption.
2013-01-03 Ari Roponen <ari.roponen@gmail.com> (tiny change)
* hash.texi (Defining Hash): Fix example.
=== modified file 'doc/lispref/hash.texi'
--- doc/lispref/hash.texi 2013-01-01 09:11:05 +0000
+++ doc/lispref/hash.texi 2013-01-03 10:50:19 +0000
@@ -293,7 +293,7 @@
@example
(defun case-fold-string= (a b)
- (compare-strings a nil nil b nil nil t))
+ (eq t (compare-strings a nil nil b nil nil t)))
(defun case-fold-string-hash (a)
(sxhash (upcase a)))
In GNU Emacs 24.2.91.9 (x86_64-unknown-linux-gnu, GTK+ Version 3.7.2)
of 2013-01-03 on arirop
Bzr revision: 111125 rgm@gnu.org-20130103063325-sx99hs1usiuqlxvb
Windowing system distributor `Fedora Project', version 11.0.11300000
System Description: Fedora release 18 (Spherical Cow)
--
Ari Roponen
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2013-01-03 12:01 bug#13345: 24.2.91; Wrong assumption in a hash table example + fix Ari Roponen
2013-01-03 18:41 ` Glenn Morris
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