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author | Richard M. Stallman <rms@gnu.org> | 1998-04-20 17:43:57 +0000 |
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committer | Richard M. Stallman <rms@gnu.org> | 1998-04-20 17:43:57 +0000 |
commit | 969fe9b5696c9d9d31f2faf1ca2e8af107013dcb (patch) | |
tree | 5d7d0399caf410b5c4849aa9d43352b18f68d4c9 /lispref/symbols.texi | |
parent | b933f645ac70a31659f364cabf7da730d27eb244 (diff) | |
download | emacs-969fe9b5696c9d9d31f2faf1ca2e8af107013dcb.tar.gz |
*** empty log message ***
Diffstat (limited to 'lispref/symbols.texi')
-rw-r--r-- | lispref/symbols.texi | 23 |
1 files changed, 13 insertions, 10 deletions
diff --git a/lispref/symbols.texi b/lispref/symbols.texi index 6472d0a40d2..9f52fc0e5be 100644 --- a/lispref/symbols.texi +++ b/lispref/symbols.texi @@ -145,7 +145,8 @@ variable. @code{defvar} and @code{defconst} are special forms that define a symbol as a global variable. They are documented in detail in -@ref{Defining Variables}. +@ref{Defining Variables}. For defining user option variables that can +be customized, use @code{defcustom} (@pxref{Customization}). @code{defun} defines a symbol as a function, creating a lambda expression and storing it in the function cell of the symbol. This @@ -229,11 +230,6 @@ valid way to create an obarray.} Prime numbers as lengths tend to result in good hashing; lengths one less than a power of two are also good. - It is possible for two different symbols to have the same name in -different obarrays; these symbols are not @code{eq} or @code{equal}. -However, this normally happens only as part of the abbrev mechanism -(@pxref{Abbrevs}). - @strong{Do not try to put symbols in an obarray yourself.} This does not work---only @code{intern} can enter a symbol in an obarray properly. @@ -440,10 +436,10 @@ an association list than to update a property. All properties for a symbol are stored in the same property list, so there is a possibility of a conflict between different uses of a property name. (For this reason, it is a good idea to choose property names that are probably -unique, such as by including the name of the library in the property -name.) An association list may be used like a stack where associations -are pushed on the front of the list and later discarded; this is not -possible with a property list. +unique, such as by beginning the property name with the program's usual +name-prefix for variables and functions.) An association list may be +used like a stack where associations are pushed on the front of the list +and later discarded; this is not possible with a property list. @node Symbol Plists @subsection Property List Functions for Symbols @@ -532,3 +528,10 @@ in the place where you got @var{plist}. For example, @end example @end defun + You could define @code{put} in terms of @code{plist-put} as follows: + +@example +(defun put (symbol prop value) + (setplist symbol + (plist-put (symbol-plist symbol) prop value))) +@end example |