--- ray/src/common/calexpr.c	1993/06/04 14:27:58	2.13
+++ ray/src/common/calexpr.c	1998/08/17 17:57:30	2.17
@@ -1,7 +1,7 @@
-/* Copyright (c) 1992 Regents of the University of California */
+/* Copyright (c) 1998 Silicon Graphics, Inc. */
 
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static char SCCSid[] = "$SunId$ SGI";
 #endif
 
 /*
@@ -34,7 +34,7 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #define	 isdecimal(c)	(isdigit(c) || (c) == '.')
 
-extern char  *fgets(), *savestr();
+extern char  *savestr();
 extern char  *emalloc(), *ecalloc();
 extern EPNODE  *curfunc;
 extern double  efunc(), evariable();
@@ -45,6 +45,10 @@ static double  echannel();
 static double  eadd(), esubtr(), emult(), edivi(), epow();
 static double  ebotch();
 
+#ifdef  DCL_ATOF
+extern double  atof();
+#endif
+
 int  nextc;				/* lookahead character */
 
 double	(*eoper[])() = {		/* expression operations */
@@ -125,6 +129,53 @@ char  *expr;
 }
 
 
+epcmp(ep1, ep2)			/* compare two expressions for equivalence */
+register EPNODE  *ep1, *ep2;
+{
+	double  d;
+
+	if (ep1->type != ep2->type)
+		return(1);
+
+	switch (ep1->type) {
+
+	case VAR:
+		return(ep1->v.ln != ep2->v.ln);
+
+	case NUM:
+		if (ep2->v.num == 0)
+			return(ep1->v.num != 0);
+		d = ep1->v.num / ep2->v.num;
+		return(d > 1.000000000001 | d < 0.999999999999);
+
+	case CHAN:
+	case ARG:
+		return(ep1->v.chan != ep2->v.chan);
+
+	case '=':
+	case ':':
+		return(epcmp(ep1->v.kid->sibling, ep2->v.kid->sibling));
+
+	case TICK:
+	case SYM:			/* should never get this one */
+		return(0);
+
+	default:
+		ep1 = ep1->v.kid;
+		ep2 = ep2->v.kid;
+		while (ep1 != NULL) {
+			if (ep2 == NULL)
+				return(1);
+			if (epcmp(ep1, ep2))
+				return(1);
+			ep1 = ep1->sibling;
+			ep2 = ep2->sibling;
+		}
+		return(ep2 != NULL);
+	}
+}
+
+
 epfree(epar)			/* free a parse tree */
 register EPNODE	 *epar;
 {
@@ -488,18 +539,22 @@ getnum()			/* scan a positive float */
     if (lnext == '.' && i < MAXWORD) {
 	str[i++] = lnext;
 	lnext = scan();
+	if (i == 1 && !isdigit(lnext))
+	    syntax("badly formed number");
 	while (isdigit(lnext) && i < MAXWORD) {
 	    str[i++] = lnext;
 	    lnext = scan();
 	}
     }
-    if ((lnext == 'e' || lnext == 'E') && i < MAXWORD) {
+    if ((lnext == 'e' | lnext == 'E') && i < MAXWORD) {
 	str[i++] = lnext;
 	lnext = scan();
-	if ((lnext == '-' || lnext == '+') && i < MAXWORD) {
+	if ((lnext == '-' | lnext == '+') && i < MAXWORD) {
 	    str[i++] = lnext;
 	    lnext = scan();
 	}
+	if (!isdigit(lnext))
+	    syntax("missing exponent");
 	while (isdigit(lnext) && i < MAXWORD) {
 	    str[i++] = lnext;
 	    lnext = scan();