changeset 4471:2d39535e1f9d

Say explicitly that eq is useful for chars; xref number comparison, lispref 2008-05-27 Aidan Kehoe <kehoea@parhasard.net> * lispref/objects.texi (Equality Predicates): Cross reference to the section on comparison of numbers when talking about using #'eq with integers; also mention that #'eq gives t when passed identical integers, and that #'char= is also available there.
author Aidan Kehoe <kehoea@parhasard.net>
date Tue, 27 May 2008 11:58:42 +0200
parents c76b1bc6bd28
children a99eb40f0b5b
files man/ChangeLog man/lispref/objects.texi
diffstat 2 files changed, 24 insertions(+), 11 deletions(-) [+]
line wrap: on
line diff
--- a/man/ChangeLog	Tue May 27 12:01:29 2008 +0200
+++ b/man/ChangeLog	Tue May 27 11:58:42 2008 +0200
@@ -1,3 +1,11 @@
+2008-05-27  Aidan Kehoe  <kehoea@parhasard.net>
+
+	* lispref/objects.texi (Equality Predicates): 
+	Cross reference to the section on comparison of numbers when
+	talking about using #'eq with integers; also mention that
+	#'eq gives t when passed identical integers, and that #'char= is
+	also available there.
+
 2008-05-21  Aidan Kehoe  <kehoea@parhasard.net>
 
 	* internals/internals.texi (Ben's README): 
--- a/man/lispref/objects.texi	Tue May 27 12:01:29 2008 +0200
+++ b/man/lispref/objects.texi	Tue May 27 11:58:42 2008 +0200
@@ -2246,12 +2246,17 @@
 change in one will be reflected by the same change in the other.
 
 @code{eq} returns @code{t} if @var{object1} and @var{object2} are
-integers with the same value.  Also, since symbol names are normally
-unique, if the arguments are symbols with the same name, they are
-@code{eq}.  For other types (e.g., lists, vectors, strings), two
-arguments with the same contents or elements are not necessarily
-@code{eq} to each other: they are @code{eq} only if they are the same
-object.
+integers with the same value.  It is preferable to use @code{=} or
+@code{eql} in many contexts for numeric comparison; @pxref{Comparison of
+Numbers}. @code{eq} also returns @code{t} if @var{object1} and
+@var{object2} are identical characters, though in this case you may
+prefer to use @code{char=}.
+
+Also, since symbol names are normally unique, if the arguments are
+symbols with the same name, they are @code{eq}.  For other types (e.g.,
+lists, vectors, strings), two arguments with the same contents or
+elements are not necessarily @code{eq} to each other: they are @code{eq}
+only if they are the same object.
 
 (The @code{make-symbol} function returns an uninterned symbol that is
 not interned in the standard @code{obarray}.  When uninterned symbols
@@ -2259,11 +2264,11 @@
 the same name are not @code{eq}.  @xref{Creating Symbols}.)
 
 NOTE: Under XEmacs 19, characters are really just integers, and thus
-characters and integers are @code{eq}.  Under XEmacs 20, it was
-necessary to preserve remnants of this in function such as @code{old-eq}
-in order to maintain byte-code compatibility.  Byte code compiled
-under any Emacs 19 will automatically have calls to @code{eq} mapped
-to @code{old-eq} when executed under XEmacs 20.
+characters and integers with the same numeric are @code{eq}.  Under
+XEmacs 20, it was necessary to preserve remnants of this in function
+such as @code{old-eq} in order to maintain byte-code compatibility.
+Byte code compiled under any Emacs 19 will automatically have calls to
+@code{eq} mapped to @code{old-eq} when executed under XEmacs 20.
 
 @example
 @group