From 7bbe1dea3b53faffed4683fd1f399e7be68e8162 Mon Sep 17 00:00:00 2001
From: "Richard M. Stallman" <rms@gnu.org>
Date: Mon, 19 Sep 1994 05:29:15 +0000
Subject: [PATCH] Handle ==, !=, + and -. (hif-tokenize): Handle ==, !=, + and
 -. (hif-token-regexp): Handle ==, !=, + and -. (hif-notequal, hif-plus,
 hif-minus, hif-mathify): New functions. (hif-math, hif-eq-expr): New
 functions. (hif-term): Call hif-eq-expr. (hide-ifdef-define): Pass 1 to
 hif-set-var.

---
 lisp/progmodes/hideif.el | 89 +++++++++++++++++++++++-----------------
 1 file changed, 51 insertions(+), 38 deletions(-)

diff --git a/lisp/progmodes/hideif.el b/lisp/progmodes/hideif.el
index 4cd538efcf..a285b98e49 100644
--- a/lisp/progmodes/hideif.el
+++ b/lisp/progmodes/hideif.el
@@ -107,38 +107,6 @@
 ;;; I will continue to upgrade hide-ifdef-mode
 ;;; with your contributions.
 
-;;; Change Log:
-;;;
-;;; Revision 1.7  88/02/16  03:12:58  liberte
-;;; Fixed comments and doc strings.
-;;; Added optional prefix arg for ifdef motion commands.
-;;; 
-;;; Revision 1.6  88/02/05  00:36:18  liberte
-;;; Bug fixes.
-;;; 1. A multi-line comment that starts on an #ifdef line
-;;;    now ends on that line.
-;;; 2. Fix bad function name: hide-hif-ifdef-toggle-read-only
-;;; 3. Make ifdef-block hiding work outside of ifdefs.
-;;; 
-;;; Revision 1.5  88/01/31  23:19:31  liberte
-;;; Major clean up.
-;;;   Prefix internal names with "hif-".
-;;; 
-;;; Revision 1.4  88/01/30  14:09:38  liberte
-;;; Add hide-ifdef-hiding and hide-ifdef-mode to minor-mode-alist.
-;;; 
-;;; Revision 1.3  88/01/29  00:38:19  liberte
-;;; Fix three bugs.
-;;; 1. Function "defined" is just like lookup.
-;;; 2. Skip to newline or cr in case text is hidden.
-;;; 3. Use car of token list if just one symbol.
-;;;
-;;; Revision 1.2  88/01/28  23:32:46  liberte
-;;; Use hide-ifdef-mode-prefix-key.
-;;; Copy current-local-map so other buffers do not get
-;;; hide-ifdef-mode bindings.
-;;;
-
 ;;; Code:
 
 (defvar hide-ifdef-mode-submap nil
@@ -372,7 +340,8 @@ that form should be displayed.")
   )
 
 ; pattern to match initial identifier, !, &&, ||, (, or ).
-(defconst hif-token-regexp "^\\(!\\|&&\\|||\\|[()]\\|\\w+\\)")
+; Added ==, + and -: garyo@avs.com 8/9/94
+(defconst hif-token-regexp "^\\(!\\|&&\\|||\\|[!=]=\\|[()+-]\\|\\w+\\)")
 (defconst hif-end-of-comment "\\*/")
 
 
@@ -418,13 +387,16 @@ that form should be displayed.")
 		       (cond
 			((string-equal token "||") 'or)
 			((string-equal token "&&") 'and)
+			((string-equal token "==") 'equal)
+			((string-equal token "!=") 'hif-notequal)
 			((string-equal token "!")  'not)
 			((string-equal token "defined") 'hif-defined)
 			((string-equal token "(") 'lparen)
 			((string-equal token ")") 'rparen)
+			((string-equal token "+") 'hif-plus)
+			((string-equal token "-") 'hif-minus)
 			(t (intern token)))
 		       token-list))))
-
 	     (t (error "Bad #if expression: %s" expr-string)))))
       (set-syntax-table current-syntax-table))
     (nreverse token-list)))
@@ -432,6 +404,7 @@ that form should be displayed.")
 ;;;-----------------------------------------------------------------
 ;;; Translate C preprocessor #if expressions using recursive descent.
 ;;; This parser is limited to the operators &&, ||, !, and "defined".
+;;; Added ==, !=, +, and -.  Gary Oberbrunner, garyo@avs.com, 8/9/94
 
 (defun hif-parse-if-exp (token-list)
   "Parse the TOKEN-LIST.  Return translated list in prefix form."
@@ -458,13 +431,35 @@ that form should be displayed.")
 
 (defun hif-term ()
   "Parse a term of the form
-       term : factor | term '&&' factor."
-  (let ((result (hif-factor)))
+       term : eq-expr | term '&&' eq-expr."
+  (let ((result (hif-eq-expr)))
     (while (eq token 'and)
       (hif-nexttoken)
-      (setq result (list 'and result (hif-factor))))
+      (setq result (list 'and result (hif-eq-expr))))
     result))
 
+(defun hif-eq-expr ()
+  "Parse a term of the form
+       eq-expr : math | eq-expr '=='|'!=' math."
+  (let ((result (hif-math))
+	(eq-token nil))
+    (while (or (eq token 'equal) (eq token 'hif-notequal))
+      (setq eq-token token)
+      (hif-nexttoken)
+      (setq result (list eq-token result (hif-math))))
+    result))
+
+(defun hif-math ()
+  "Parse an expression of the form
+       math : factor | math '+|-' factor."
+  (let ((result (hif-factor))
+	(math-op nil))
+    (while (or (eq  token 'hif-plus) (eq token 'hif-minus))
+      (setq math-op token)
+      (hif-nexttoken)
+      (setq result (list math-op result (hif-factor))))
+  result))
+  
 (defun hif-factor ()
   "Parse a factor of the form
        factor : '!' factor | '(' expr ')' | 'defined(' id ')' | id."
@@ -505,6 +500,24 @@ that form should be displayed.")
 	))
     ))
 
+(defun hif-mathify (val)
+  "Treat VAL as a number: if it's t or nil, use 1 or 0."
+  (cond ((eq val t)
+	 1)
+	((null val)
+	 0)
+	(t val)))
+
+(defun hif-plus (a b)
+  "Like ordinary plus but treat t and nil as 1 and 0."
+  (+ (hif-mathify a) (hif-mathify b)))
+(defun hif-minus (a b)
+  "Like ordinary minus but treat t and nil as 1 and 0."
+  (- (hif-mathify a) (hif-mathify b)))
+(defun hif-notequal (a b)
+  "Like (not (equal A B)) but as one symbol."
+  (not (equal a b)))
+
 ;;;----------- end of parser -----------------------
 
 
@@ -898,7 +911,7 @@ is first activated.")
 (defun hide-ifdef-define (var)
   "Define a VAR so that #ifdef VAR would be included."
   (interactive "SDefine what? ")
-  (hif-set-var var t)
+  (hif-set-var var 1)
   (if hide-ifdef-hiding (hide-ifdefs)))
 
 (defun hide-ifdef-undef (var)
-- 
2.20.1