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[Emacs-diffs] Changes to emacs/src/fns.c
From: |
Kim F . Storm |
Subject: |
[Emacs-diffs] Changes to emacs/src/fns.c |
Date: |
Mon, 15 Nov 2004 10:35:18 -0500 |
Index: emacs/src/fns.c
diff -c emacs/src/fns.c:1.375 emacs/src/fns.c:1.376
*** emacs/src/fns.c:1.375 Sat Nov 6 17:01:27 2004
--- emacs/src/fns.c Mon Nov 15 15:21:14 2004
***************
*** 1997,2002 ****
--- 1997,2031 ----
return Qnil;
}
+ DEFUN ("safe-plist-get", Fsafe_plist_get, Ssafe_plist_get, 2, 2, 0,
+ doc: /* Extract a value from a property list.
+ PLIST is a property list, which is a list of the form
+ \(PROP1 VALUE1 PROP2 VALUE2...). This function returns the value
+ corresponding to the given PROP, or nil if PROP is not
+ one of the properties on the list.
+ This function never signals an error. */)
+ (plist, prop)
+ Lisp_Object plist;
+ Lisp_Object prop;
+ {
+ Lisp_Object tail, halftail;
+
+ /* halftail is used to detect circular lists. */
+ tail = halftail = plist;
+ while (CONSP (tail) && CONSP (XCDR (tail)))
+ {
+ if (EQ (prop, XCAR (tail)))
+ return XCAR (XCDR (tail));
+
+ tail = XCDR (XCDR (tail));
+ halftail = XCDR (halftail);
+ if (EQ (tail, halftail))
+ break;
+ }
+
+ return Qnil;
+ }
+
DEFUN ("get", Fget, Sget, 2, 2, 0,
doc: /* Return the value of SYMBOL's PROPNAME property.
This is the last value stored with `(put SYMBOL PROPNAME VALUE)'. */)
***************
*** 5734,5739 ****
--- 5763,5769 ----
defsubr (&Sreverse);
defsubr (&Ssort);
defsubr (&Splist_get);
+ defsubr (&Ssafe_plist_get);
defsubr (&Sget);
defsubr (&Splist_put);
defsubr (&Sput);