Make #'substring an alias of #'subseq; give the latter the byte code. src/ChangeLog addition: 2010-03-03 Aidan Kehoe <kehoea@parhasard.net> * fns.c (Fsubstring): Removed. * search.c (Freplace_match): * minibuf.c (Ftry_completion): * lisp.h: * keymap.c (ensure_meta_prefix_char_keymapp): * dired.c (user_name_completion, file_name_completion): * console-x.c (x_canonicalize_console_connection): * bytecode.c (Bsubseq): * bytecode-ops.h (subseq): Move #'substring to Lisp, as an alias for #'subseq; change all C Fsubstring() calls to Fsubseq(), change the Bsubstring bytecode to Bsubseq. Motivation; not accepting vectors in #'substring is incompatible with GNU, and Common Lisp prefers #'subseq, it has no #'substring. lisp/ChangeLog addition: 2010-03-03 Aidan Kehoe <kehoea@parhasard.net> Move byte code #o117 to #'subseq, not #'substring. Make #'substring available as an alias for #'subseq in Lisp. * bytecomp.el (79, subseq, substring): * bytecomp.el (byte-compile-subseq): New. * update-elc.el (update-elc-chop-extension): Use #'subseq, not #'substring, the latter is not yet available. * subr.el (substring): New alias, to #'subseq. man/ChangeLog addition: 2010-03-03 Aidan Kehoe <kehoea@parhasard.net> * lispref/tips.texi (Comment Tips): * lispref/text.texi (Text Properties): * lispref/strings.texi (Creating Strings): * lispref/processes.texi (Input to Processes): * lispref/functions.texi (Argument List): * lispref/extents.texi (Duplicable Extents): Move examples that used substring to using subseq; in strings.texi, do not change the examples, but document that in this XEmacs, it is an alias for subseq, and that there may be some incompatibilities if you depend on that.

--- a/lisp/bytecomp.el	Tue Mar 02 13:42:37 2010 -0700
+++ b/lisp/bytecomp.el	Wed Mar 03 18:40:12 2010 +0000
@@ -609,7 +609,7 @@
 (byte-defop  76 -1 byte-set)
 (byte-defop  77 -1 byte-fset) ; this was commented out
 (byte-defop  78 -1 byte-get)
-(byte-defop  79 -2 byte-substring)
+(byte-defop  79 -2 byte-subseq)
 (byte-defop  80 -1 byte-concat2)
 (byte-defop  81 -2 byte-concat3)
 (byte-defop  82 -3 byte-concat4)
@@ -3111,7 +3111,8 @@
 (byte-defop-compiler aref		2)
 (byte-defop-compiler get		2+1)
 (byte-defop-compiler nth		2)
-(byte-defop-compiler substring		2-3)
+(byte-defop-compiler subseq byte-compile-subseq)
+(byte-defop-compiler (substring byte-subseq) 2-3)
 (byte-defop-compiler (move-marker byte-set-marker) 2-3)
 (byte-defop-compiler set-marker		2-3)
 (byte-defop-compiler match-beginning	1)
@@ -3524,6 +3525,12 @@
      the syntax (function (lambda (...) ...)) instead."))))
   (byte-compile-two-args form))
 
+(defun byte-compile-subseq (form)
+  (byte-compile-two-or-three-args form)
+  ;; Check that XEmacs supports the substring-subseq equivalence.
+  (pushnew '(eq 'subseq (symbol-function 'substring))
+           byte-compile-checks-on-load :test #'equal))
+
 (defmacro byte-compile-funarg-n (&rest n)
   `#'(lambda (form)
        ,@(loop