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| author | Paul Eggert | 2018-04-02 12:19:00 -0700 |
|---|---|---|
| committer | Paul Eggert | 2018-04-02 12:19:34 -0700 |
| commit | dfa922dd844c7af966a42b949aee32248ce4e8a2 (patch) | |
| tree | 6498abf6cbf9585bd1b76cd4158b13a6c786854e /doc/lispref | |
| parent | e3525385a87c92fdca6b3cf929797a731c688a3f (diff) | |
| download | emacs-dfa922dd844c7af966a42b949aee32248ce4e8a2.tar.gz emacs-dfa922dd844c7af966a42b949aee32248ce4e8a2.zip | |
Clarify eq on floats
* doc/lispref/objects.texi (Equality Predicates):
Say that two floats with the same values might or might not be eq.
Diffstat (limited to 'doc/lispref')
| -rw-r--r-- | doc/lispref/objects.texi | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/doc/lispref/objects.texi b/doc/lispref/objects.texi index af740625adb..78a7dccc88d 100644 --- a/doc/lispref/objects.texi +++ b/doc/lispref/objects.texi | |||
| @@ -2083,6 +2083,10 @@ strings), two arguments with the same contents or elements are not | |||
| 2083 | necessarily @code{eq} to each other: they are @code{eq} only if they | 2083 | necessarily @code{eq} to each other: they are @code{eq} only if they |
| 2084 | are the same object, meaning that a change in the contents of one will | 2084 | are the same object, meaning that a change in the contents of one will |
| 2085 | be reflected by the same change in the contents of the other. | 2085 | be reflected by the same change in the contents of the other. |
| 2086 | For other types of objects whose contents cannot be changed (e.g., | ||
| 2087 | floats), two arguments with the same contents might or might not be | ||
| 2088 | the same object, and @code{eq} returns @code{t} or @code{nil} | ||
| 2089 | depending on whether the Lisp interpreter created one object or two. | ||
| 2086 | 2090 | ||
| 2087 | @example | 2091 | @example |
| 2088 | @group | 2092 | @group |
| @@ -2096,6 +2100,12 @@ be reflected by the same change in the contents of the other. | |||
| 2096 | @end group | 2100 | @end group |
| 2097 | 2101 | ||
| 2098 | @group | 2102 | @group |
| 2103 | (eq 3.0 3.0) | ||
| 2104 | @result{} t @r{or} nil | ||
| 2105 | ;; @r{The result is implementation-dependent.} | ||
| 2106 | @end group | ||
| 2107 | |||
| 2108 | @group | ||
| 2099 | (eq "asdf" "asdf") | 2109 | (eq "asdf" "asdf") |
| 2100 | @result{} nil | 2110 | @result{} nil |
| 2101 | @end group | 2111 | @end group |