Support full Common Lisp multiple values in C. lisp/ChangeLog 2009-08-11 Aidan Kehoe <kehoea@parhasard.net> * bytecomp.el : Update this file to support full C-level multiple values. This involves: -- Four new bytecodes, and special compiler functions to compile multiple-value-call, multiple-value-list-internal, values, values-list, and, since it now needs to pass back multiple values and is a special form, throw. -- There's a new compiler variable, byte-compile-checks-on-load, which is a list of forms that are evaluated at the very start of a file, with an error thrown if any of them give nil. -- The header is now inserted *after* compilation, giving a chance for the compilation process to influence what those checks are. There is still a check done before compilation for non-ASCII characters, to try to turn off dynamic docstrings if appopriate, in `byte-compile-maybe-reset-coding'. Space is reserved for checks; comments describing the version of the byte compiler generating the file are inserted if space remains for them. * bytecomp.el (byte-compile-version): Update this, we're a newer version of the byte compiler. * byte-optimize.el (byte-optimize-funcall): Correct a comment. * bytecomp.el (byte-compile-lapcode): Discard the arg with byte-multiple-value-call. * bytecomp.el (byte-compile-checks-and-comments-space): New variable, describe how many octets to reserve for checks at the start of byte-compiled files. * cl-compat.el: Remove the fake multiple-value implementation. Have the functions that use it use the real multiple-value implementation instead. * cl-macs.el (cl-block-wrapper, cl-block-throw): Revise the byte-compile properties of these symbols to work now we've made throw into a special form; keep the byte-compile properties as anonymous lambdas, since we don't have docstrings for them. * cl-macs.el (multiple-value-bind, multiple-value-setq) (multiple-value-list, nth-value): Update these functions to work with the C support for multiple values. * cl-macs.el (values): Modify the setf handler for this to call #'multiple-value-list-internal appropriately. * cl-macs.el (cl-setf-do-store): If the store form is a cons, treat it specially as wrapping the store value. * cl.el (cl-block-wrapper): Make this an alias of #'and, not #'identity, since it needs to pass back multiple values. * cl.el (multiple-value-apply): We no longer support this, mark it obsolete. * lisp-mode.el (eval-interactive-verbose): Remove a useless space in the docstring. * lisp-mode.el (eval-interactive): Update this function and its docstring. It now passes back a list, basically wrapping any eval calls with multiple-value-list. This allows multiple values to be printed by default in *scratch*. * lisp-mode.el (prin1-list-as-multiple-values): New function, printing a list as multiple values in the manner of Bruno Haible's clisp, separating each entry with " ;\n". * lisp-mode.el (eval-last-sexp): Call #'prin1-list-as-multiple-values on the return value of #'eval-interactive. * lisp-mode.el (eval-defun): Call #'prin1-list-as-multiple-values on the return value of #'eval-interactive. * mouse.el (mouse-eval-sexp): Deal with lists corresponding to multiple values from #'eval-interactive. Call #'cl-prettyprint, which is always available, instead of sometimes calling #'pprint and sometimes falling back to prin1. * obsolete.el (obsolete-throw): New function, called from eval.c when #'funcall encounters an attempt to call #'throw (now a special form) as a function. Only needed for compatibility with 21.4 byte-code. man/ChangeLog addition: 2009-08-11 Aidan Kehoe <kehoea@parhasard.net> * cl.texi (Organization): Remove references to the obsolete multiple-value emulating code. src/ChangeLog addition: 2009-08-11 Aidan Kehoe <kehoea@parhasard.net> * bytecode.c (enum Opcode /* Byte codes */): Add four new bytecodes, to deal with multiple values. (POP_WITH_MULTIPLE_VALUES): New macro. (POP): Modify this macro to ignore multiple values. (DISCARD_PRESERVING_MULTIPLE_VALUES): New macro. (DISCARD): Modify this macro to ignore multiple values. (TOP_WITH_MULTIPLE_VALUES): New macro. (TOP_ADDRESS): New macro. (TOP): Modify this macro to ignore multiple values. (TOP_LVALUE): New macro. (Bcall): Ignore multiple values where appropriate. (Breturn): Pass back multiple values. (Bdup): Preserve multiple values. Use TOP_LVALUE with most bytecodes that assign anything to anything. (Bbind_multiple_value_limits, Bmultiple_value_call, Bmultiple_value_list_internal, Bthrow): Implement the new bytecodes. (Bgotoifnilelsepop, Bgotoifnonnilelsepop, BRgotoifnilelsepop, BRgotoifnonnilelsepop): Discard any multiple values. * callint.c (Fcall_interactively): Ignore multiple values when calling #'eval, in two places. * device-x.c (x_IO_error_handler): * macros.c (pop_kbd_macro_event): * eval.c (Fsignal): * eval.c (flagged_a_squirmer): Call throw_or_bomb_out, not Fthrow, now that the latter is a special form. * eval.c: Make Qthrow, Qobsolete_throw available as symbols. Provide multiple_value_current_limit, multiple-values-limit (the latter as specified by Common Lisp. * eval.c (For): Ignore multiple values when comparing with Qnil, but pass any multiple values back for the last arg. * eval.c (Fand): Ditto. * eval.c (Fif): Ignore multiple values when examining the result of the condition. * eval.c (Fcond): Ignore multiple values when comparing what the clauses give, but pass them back if a clause gave non-nil. * eval.c (Fprog2): Never pass back multiple values. * eval.c (FletX, Flet): Ignore multiple when evaluating what exactly symbols should be bound to. * eval.c (Fwhile): Ignore multiple values when evaluating the test. * eval.c (Fsetq, Fdefvar, Fdefconst): Ignore multiple values. * eval.c (Fthrow): Declare this as a special form; ignore multiple values for TAG, preserve them for VALUE. * eval.c (throw_or_bomb_out): Make this available to other files, now Fthrow is a special form. * eval.c (Feval): Ignore multiple values when calling a compiled function, a non-special-form subr, or a lambda expression. * eval.c (Ffuncall): If we attempt to call #'throw (now a special form) as a function, don't error, call #'obsolete-throw instead. * eval.c (make_multiple_value, multiple_value_aset) (multiple_value_aref, print_multiple_value, mark_multiple_value) (size_multiple_value): Implement the multiple_value type. Add a long comment describing our implementation. * eval.c (bind_multiple_value_limits): New function, used by the bytecode and by #'multiple-value-call, #'multiple-value-list-internal. * eval.c (multiple_value_call): New function, used by the bytecode and #'multiple-value-call. * eval.c (Fmultiple_value_call): New special form. * eval.c (multiple_value_list_internal): New function, used by the byte code and #'multiple-value-list-internal. * eval.c (Fmultiple_value_list_internal, Fmultiple_value_prog1): New special forms. * eval.c (Fvalues, Fvalues_list): New Lisp functions. * eval.c (values2): New function, for C code returning multiple values. * eval.c (syms_of_eval): Make our new Lisp functions and symbols available. * eval.c (multiple-values-limit): Make this available to Lisp. * event-msw.c (dde_eval_string): * event-stream.c (execute_help_form): * glade.c (connector): * glyphs-widget.c (glyph_instantiator_to_glyph): * glyphs.c (evaluate_xpm_color_symbols): * gui-x.c (wv_set_evalable_slot, button_item_to_widget_value): * gui.c (gui_item_value, gui_item_display_flush_left): * lread.c (check_if_suppressed): * menubar-gtk.c (menu_convert, menu_descriptor_to_widget_1): * menubar-msw.c (populate_menu_add_item): * print.c (Fwith_output_to_temp_buffer): * symbols.c (Fsetq_default): Ignore multiple values when calling Feval. * symeval.h: Add the header declarations necessary for the multiple-values implementation. * inline.c: #include symeval.h, now that it has some inline functions. * lisp.h: Update Fthrow's declaration. Make throw_or_bomb_out available to all files. * lrecord.h (enum lrecord_type): Add the multiple_value type here.

--- a/lisp/cl-macs.el	Sun Aug 16 14:58:57 2009 +0100
+++ b/lisp/cl-macs.el	Sun Aug 16 20:55:49 2009 +0100
@@ -715,24 +715,30 @@
 
 (defvar cl-active-block-names nil)
 
-(put 'cl-block-wrapper 'byte-compile 'cl-byte-compile-block)
-(defun cl-byte-compile-block (cl-form)
-  (if (fboundp 'byte-compile-form-do-effect)  ; Check for optimizing compiler
-      (progn
-	(let* ((cl-entry (cons (nth 1 (nth 1 (nth 1 cl-form))) nil))
-	       (cl-active-block-names (cons cl-entry cl-active-block-names))
-	       (cl-body (byte-compile-top-level
-			 (cons 'progn (cddr (nth 1 cl-form))))))
-	  (if (cdr cl-entry)
-	      (byte-compile-form (list 'catch (nth 1 (nth 1 cl-form)) cl-body))
-	    (byte-compile-form cl-body))))
-    (byte-compile-form (nth 1 cl-form))))
-
-(put 'cl-block-throw 'byte-compile 'cl-byte-compile-throw)
-(defun cl-byte-compile-throw (cl-form)
-  (let ((cl-found (assq (nth 1 (nth 1 cl-form)) cl-active-block-names)))
-    (if cl-found (setcdr cl-found t)))
-  (byte-compile-normal-call (cons 'throw (cdr cl-form))))
+(put 'cl-block-wrapper 'byte-compile
+     #'(lambda (cl-form)
+         (if (/= (length cl-form) 2)
+             (byte-compile-warn-wrong-args cl-form 1))
+
+         (if (fboundp 'byte-compile-form-do-effect)  ; Check for optimizing
+						     ; compiler
+             (progn
+               (let* ((cl-entry (cons (nth 1 (nth 1 (nth 1 cl-form))) nil))
+                      (cl-active-block-names (cons cl-entry
+                                                   cl-active-block-names))
+                      (cl-body (byte-compile-top-level
+                                (cons 'progn (cddr (nth 1 cl-form))))))
+                 (if (cdr cl-entry)
+                     (byte-compile-form (list 'catch (nth 1 (nth 1 cl-form))
+                                              cl-body))
+                   (byte-compile-form cl-body))))
+           (byte-compile-form (nth 1 cl-form)))))
+
+(put 'cl-block-throw 'byte-compile
+     #'(lambda (cl-form)
+         (let ((cl-found (assq (nth 1 (nth 1 cl-form)) cl-active-block-names)))
+           (if cl-found (setcdr cl-found t)))
+         (byte-compile-throw (cons 'throw (cdr cl-form)))))
 
 ;;;###autoload
 (defmacro return (&optional result)
@@ -1841,47 +1847,70 @@
 	      (list 'function (cons 'lambda rest)))
 	(list 'quote func)))
 
-
-;;; Multiple values.
+;;; Multiple values. We support full Common Lisp conventions here.
 
 ;;;###autoload
-(defmacro multiple-value-bind (vars form &rest body)
-  "(multiple-value-bind (SYM SYM...) FORM BODY): collect multiple return values.
-FORM must return a list; the BODY is then executed with the first N elements
-of this list bound (`let'-style) to each of the symbols SYM in turn.  This
-is analogous to the Common Lisp `multiple-value-bind' macro, using lists to
-simulate true multiple return values.  For compatibility, (values A B C) is
-a synonym for (list A B C)."
-  (let ((temp (gensym)) (n -1))
-    (list* 'let* (cons (list temp form)
-		       (mapcar #'(lambda (v)
-				   (list v (list 'nth (setq n (1+ n)) temp)))
-			       vars))
-	   body)))
+(defmacro multiple-value-bind (syms form &rest body)
+  "Collect and bind multiple return values.
+
+If FORM returns multiple values, each symbol in SYMS is bound to one of
+them, in order, and BODY is executed.  If FORM returns fewer multiple values
+than there are SYMS, remaining SYMS are bound to nil.  If FORM does
+not return multiple values, it is treated as returning one multiple value.
+
+Returns the value given by the last element of BODY."
+  (if (null syms)
+      `(progn ,form ,@body)
+    (if (= 1 (length syms))
+        ;; Code written to deal with other "implementations" of multiple
+        ;; values may have a one-element SYMS.
+        `(let ((,(car syms) ,form))
+          ,@body)
+      (let ((temp (gensym)))
+        `(let* ((,temp (multiple-value-list-internal 0 ,(length syms) ,form))
+                ,@(loop 
+                    for var in syms
+                    collect `(,var (prog1 (car ,temp)
+                                     (setq ,temp (cdr ,temp))))))
+          ,@body)))))
 
 ;;;###autoload
-(defmacro multiple-value-setq (vars form)
-  "(multiple-value-setq (SYM SYM...) FORM): collect multiple return values.
-FORM must return a list; the first N elements of this list are stored in
-each of the symbols SYM in turn.  This is analogous to the Common Lisp
-`multiple-value-setq' macro, using lists to simulate true multiple return
-values.  For compatibility, (values A B C) is a synonym for (list A B C)."
-  (cond ((null vars) (list 'progn form nil))
-	((null (cdr vars)) (list 'setq (car vars) (list 'car form)))
-	(t
-	 (let* ((temp (gensym)) (n 0))
-	   (list 'let (list (list temp form))
-		 (list 'prog1 (list 'setq (pop vars) (list 'car temp))
-		       (cons 'setq
-			     (apply 'nconc
-				    (mapcar
-				     #'(lambda (v)
-					 (list v (list
-						  'nth
-						  (setq n (1+ n))
-						  temp)))
-					    vars)))))))))
-
+(defmacro multiple-value-setq (syms form)
+  "Collect and set multiple values.
+
+FORM should normally return multiple values; the first N values are stored
+in the symbols in SYMS in turn.  If FORM returns fewer than N values, the
+remaining symbols have their values set to nil.  FORM not returning multiple
+values is treated as FORM returning one multiple value, with other elements
+of SYMS initialized to nil.
+
+Returns the first of the multiple values given by FORM."
+  (if (null syms)
+      ;; Never return multiple values from multiple-value-setq:
+      (and form `(values ,form))
+    (if (= 1 (length syms))
+        `(setq ,(car syms) ,form)
+      (let ((temp (gensym)))
+        `(let* ((,temp (multiple-value-list-internal 0 ,(length syms) ,form)))
+           (setq ,@(loop
+                     for sym in syms
+                     nconc `(,sym (car-safe ,temp)
+                             ,temp (cdr-safe ,temp))))
+           ,(car syms))))))
+
+;;;###autoload
+(defmacro multiple-value-list (form)
+  "Evaluate FORM and return a list of the multiple values it returned."
+  `(multiple-value-list-internal 0 multiple-values-limit ,form))
+
+;;;###autoload
+(defmacro nth-value (n form)
+  "Evaluate FORM and return the Nth multiple value it returned."
+  (if (integerp n)
+      `(car (multiple-value-list-internal ,n ,(1+ n) ,form))
+    (let ((temp (gensym)))
+      `(let ((,temp ,n))
+        (car (multiple-value-list-internal ,temp (1+ ,temp) ,form))))))
 
 ;;; Declarations.
 
@@ -2346,8 +2375,9 @@
 	(store-temp (gensym "--values-store--")))
     (list (apply 'append (mapcar 'first methods))
 	  (apply 'append (mapcar 'second methods))
-	  (list store-temp)
-	  (cons 'list
+	  `((,store-temp
+	     (multiple-value-list-internal 0 ,(if args (length args) 1))))
+	  (cons 'values
 		(mapcar #'(lambda (m)
 			    (cl-setf-do-store (cons (car (third m)) (fourth m))
 					      (list 'pop store-temp)))
@@ -2410,11 +2440,25 @@
 (defun cl-setf-do-store (spec val)
   (let ((sym (car spec))
 	(form (cdr spec)))
-    (if (or (cl-const-expr-p val)
-	    (and (cl-simple-expr-p val) (eq (cl-expr-contains form sym) 1))
-	    (cl-setf-simple-store-p sym form))
-	(subst val sym form)
-      (list 'let (list (list sym val)) form))))
+    (if (consp sym)
+	;; XEmacs change, only used for implementing #'values at the moment.
+	(let* ((orig (copy-list sym))
+	       (intermediate (last orig))
+	       (circular-limit 32))
+	  (while (consp (car intermediate))
+	    (when (zerop circular-limit)
+	      (error 'circular-list "Form seems to contain loops"))
+	    (setq intermediate (last (car intermediate))
+		  circular-limit (1- circular-limit)))
+	  (setcdr intermediate (list val))
+	  `(let (,orig)
+	    ,form))
+      (if (or (cl-const-expr-p val)
+	      (and (cl-simple-expr-p val)
+		   (eq (cl-expr-contains form sym) 1))
+	      (cl-setf-simple-store-p sym form))
+	  (subst val sym form)
+	(list 'let (list (list sym val)) form)))))
 
 (defun cl-setf-simple-store-p (sym form)
   (and (consp form) (eq (cl-expr-contains form sym) 1)