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/regexp-opt.el	Tue Mar 08 22:32:49 2011 +0000
+++ b/lisp/regexp-opt.el	Tue Mar 08 23:41:52 2011 +0000
@@ -175,23 +175,23 @@
     (cond
      ;;
      ;; If there are no strings, just return the empty string.
-     ((= (length strings) 0)
+     ((eql (length strings) 0)
       "")
      ;;
      ;; If there is only one string, just return it.
-     ((= (length strings) 1)
-      (if (= (length (car strings)) 1)
+     ((eql (length strings) 1)
+      (if (eql (length (car strings)) 1)
 	  (concat open-charset (regexp-quote (car strings)) close-charset)
 	(concat open-group (regexp-quote (car strings)) close-group)))
      ;;
      ;; If there is an empty string, remove it and recurse on the rest.
-     ((= (length (car strings)) 0)
+     ((eql (length (car strings)) 0)
       (concat open-charset
 	      (regexp-opt-group (cdr strings) t t) "?"
 	      close-charset))
      ;;
      ;; If all are one-character strings, just return a character set.
-     ((= (length strings) (apply '+ (mapcar 'length strings)))
+     ((eql (length strings) (apply '+ (mapcar 'length strings)))
       (concat open-charset
 	      (regexp-opt-charset strings)
 	      close-charset))