Examining the result of #'length: `eql', not `=', it's better style & cheaper 2011-03-08 Aidan Kehoe <kehoea@parhasard.net> * buff-menu.el (list-buffers-noselect): * byte-optimize.el (byte-optimize-identity): * byte-optimize.el (byte-optimize-if): * byte-optimize.el (byte-optimize-nth): * byte-optimize.el (byte-optimize-nthcdr): * bytecomp.el (byte-compile-warn-wrong-args): * bytecomp.el (byte-compile-two-args-19->20): * bytecomp.el (byte-compile-list): * bytecomp.el (byte-compile-beginning-of-line): * bytecomp.el (byte-compile-set): * bytecomp.el (byte-compile-set-default): * bytecomp.el (byte-compile-values): * bytecomp.el (byte-compile-values-list): * bytecomp.el (byte-compile-integerp): * bytecomp.el (byte-compile-multiple-value-list-internal): * bytecomp.el (byte-compile-throw): * cl-macs.el (cl-do-arglist): * cl-macs.el (cl-parse-loop-clause): * cl-macs.el (multiple-value-bind): * cl-macs.el (multiple-value-setq): * cl-macs.el (get-setf-method): * cmdloop.el (command-error): * cmdloop.el (y-or-n-p-minibuf): * cmdloop.el (yes-or-no-p-minibuf): * coding.el (unencodable-char-position): * cus-edit.el (custom-face-prompt): * cus-edit.el (custom-buffer-create-internal): * cus-edit.el (widget-face-action): * cus-edit.el (custom-group-value-create): * descr-text.el (describe-char-unicode-data): * dialog-gtk.el (popup-builtin-question-dialog): * dragdrop.el (experimental-dragdrop-drop-log-function): * dragdrop.el (experimental-dragdrop-drop-mime-default): * easymenu.el (easy-menu-add): * easymenu.el (easy-menu-remove): * faces.el (read-face-name): * faces.el (set-face-stipple): * files.el (file-name-non-special): * font.el (font-combine-fonts): * font.el (font-set-face-font): * font.el (font-parse-rgb-components): * font.el (font-rgb-color-p): * font.el (font-color-rgb-components): * gnuserv.el (gnuserv-edit-files): * help.el (key-or-menu-binding): * help.el (function-documentation-1): * help.el (function-documentation): * info.el (info): * isearch-mode.el (isearch-exit): * isearch-mode.el (isearch-edit-string): * isearch-mode.el (isearch-*-char): * isearch-mode.el (isearch-complete1): * ldap.el (ldap-encode-country-string): * ldap.el (ldap-decode-string): * minibuf.el (read-file-name-internal-1): * minibuf.el (read-non-nil-coding-system): * minibuf.el (get-user-response): * mouse.el (drag-window-divider): * mule/ccl.el: * mule/ccl.el (ccl-compile-if): * mule/ccl.el (ccl-compile-break): * mule/ccl.el (ccl-compile-repeat): * mule/ccl.el (ccl-compile-write-repeat): * mule/ccl.el (ccl-compile-call): * mule/ccl.el (ccl-compile-end): * mule/ccl.el (ccl-compile-read-multibyte-character): * mule/ccl.el (ccl-compile-write-multibyte-character): * mule/ccl.el (ccl-compile-translate-character): * mule/ccl.el (ccl-compile-mule-to-unicode): * mule/ccl.el (ccl-compile-unicode-to-mule): * mule/ccl.el (ccl-compile-lookup-integer): * mule/ccl.el (ccl-compile-lookup-character): * mule/ccl.el (ccl-compile-map-multiple): * mule/ccl.el (ccl-compile-map-single): * mule/devan-util.el (devanagari-compose-to-one-glyph): * mule/devan-util.el (devanagari-composition-component): * mule/mule-cmds.el (finish-set-language-environment): * mule/viet-util.el: * mule/viet-util.el (viet-encode-viscii-char): * multicast.el (open-multicast-group): * newcomment.el (comment-quote-nested): * newcomment.el (comment-region): * newcomment.el (comment-dwim): * regexp-opt.el (regexp-opt-group): * replace.el (map-query-replace-regexp): * specifier.el (derive-device-type-from-tag-set): * subr.el (skip-chars-quote): * test-harness.el (test-harness-from-buffer): * test-harness.el (batch-test-emacs): * wid-edit.el (widget-choice-action): * wid-edit.el (widget-symbol-prompt-internal): * wid-edit.el (widget-color-action): * window-xemacs.el (push-window-configuration): * window-xemacs.el (pop-window-configuration): * window.el (quit-window): * x-compose.el (electric-diacritic): It's better style, and cheaper (often one assembler instruction vs. a C funcall in the byte code), to use `eql' instead of `=' when it's clear what numerical type a given result will be. Change much of our code to do this, with the help of a byte-compiler change (not comitted) that looked for calls to #'length (which always returns an integer) in its args.

--- a/lisp/bytecomp.el	Tue Mar 08 22:32:49 2011 +0000
+++ b/lisp/bytecomp.el	Tue Mar 08 23:41:52 2011 +0000
@@ -3220,7 +3220,7 @@
   (when (memq 'subr-callargs byte-compile-warnings)
     (byte-compile-warn "%s called with %d arg%s, but requires %s"
 		       (car form) (length (cdr form))
-		       (if (= 1 (length (cdr form))) "" "s") n)))
+		       (if (eql 1 (length (cdr form))) "" "s") n)))
 
 (defun byte-compile-subr-wrong-args (form n)
   (byte-compile-warn-wrong-args form n)
@@ -3345,7 +3345,7 @@
 ;; XEmacs: used for functions that have a different opcode in v19 than v20.
 ;; this includes `eq', `equal', and other old-ified functions.
 (defun byte-compile-two-args-19->20 (form)
-  (if (not (= (length form) 3))
+  (if (not (eql (length form) 3))
       (byte-compile-subr-wrong-args form 2)
     (byte-compile-form (car (cdr form)))  ;; Push the arguments
     (byte-compile-form (nth 2 form))
@@ -3446,7 +3446,7 @@
   (let* ((args (cdr form))
 	 (nargs (length args)))
     (cond
-     ((= nargs 0)
+     ((eql nargs 0)
       (byte-compile-constant nil))
      ((< nargs 5)
       (mapc 'byte-compile-form args)
@@ -3696,7 +3696,7 @@
   (let ((len (length form)))
     (cond ((> len 3)
 	   (byte-compile-subr-wrong-args form "0-2"))
-	  ((or (= len 3) (not (byte-compile-constp (nth 1 form))))
+	  ((or (eql len 3) (not (byte-compile-constp (nth 1 form))))
 	   (byte-compile-normal-call form))
 	  (t
 	   (byte-compile-form
@@ -3766,8 +3766,7 @@
   (let* ((args (cdr form))
 	 (nargs (length args))
 	 (var (car args)))
-    (when (and (= (safe-length var) 2)
-	       (eq (car var) 'quote))
+    (when (and (eql (safe-length var) 2) (eq (car var) 'quote))
       (let ((sym (nth 1 var)))
 	(cond
 	 ((not (symbolp sym))
@@ -3786,7 +3785,7 @@
 	 (t
 	  (byte-compile-warn "assignment to free variable %s" sym)
 	  (push sym byte-compile-free-assignments)))))
-    (if (= nargs 2)
+    (if (eql nargs 2)
 	;; now emit a normal call to set-default
 	(byte-compile-normal-call form)
       (byte-compile-subr-wrong-args form 2))))
@@ -3923,7 +3922,7 @@
   (byte-compile-body form t))
 
 (defun byte-compile-values (form)
-  (if (= 2 (length form))
+  (if (eql 2 (length form))
       (if (byte-compile-constp (second form))
 	  (byte-compile-form-do-effect (second form))
 	;; #'or compiles to bytecode, #'values doesn't:
@@ -3931,7 +3930,7 @@
     (byte-compile-normal-call form)))
 
 (defun byte-compile-values-list (form)
-  (if (and (= 2 (length form))
+  (if (and (eql 2 (length form))
            (or (null (second form))
                (and (consp (second form))
                     (eq (car (second form))
@@ -4110,7 +4109,7 @@
 ;; anyway).
 
 (defun byte-compile-integerp (form)
-  (if (/= 2 (length form))
+  (if (not (eql (length form) 2))
       (byte-compile-subr-wrong-args form 1)
     (let ((donetag (byte-compile-make-tag))
 	  (wintag (byte-compile-make-tag))
@@ -4338,7 +4337,7 @@
              :test #'equal)))
 
 (defun byte-compile-multiple-value-list-internal (form)
-  (if (/= 4 (length form))
+  (if (not (eql 4 (length form)))
       (progn
         (byte-compile-warn-wrong-args form 3)
         (byte-compile-normal-call
@@ -4360,7 +4359,7 @@
   ;; form, it provokes an invalid-function error instead (or at least it
   ;; should; there's a kludge around for the moment in eval.c that avoids
   ;; that, but this file should not assume that that will always be there).
-  (if (/= 2 (length (cdr form)))
+  (if (not (eql 2 (length (cdr form))))
       (progn
         (byte-compile-warn-wrong-args form 2)
         (byte-compile-normal-call