--- ray/src/common/calexpr.c	1992/09/21 12:01:54	2.6
+++ ray/src/common/calexpr.c	1995/02/16 09:49:29	2.16
@@ -24,6 +24,8 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include  <errno.h>
 
+#include  <math.h>
+
 #include  "calcomp.h"
 
 #define	 MAXLINE	256		/* maximum line length */
@@ -32,18 +34,21 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #define	 isdecimal(c)	(isdigit(c) || (c) == '.')
 
-#ifndef atof
-extern double  atof();
-#endif
-extern double  pow();
-extern char  *fgets(), *savestr();
+extern char  *savestr();
 extern char  *emalloc(), *ecalloc();
 extern EPNODE  *curfunc;
 extern double  efunc(), evariable();
-static double  euminus(), echannel(), eargument(), enumber();
+static double  euminus(), eargument(), enumber();
+#ifdef  INCHAN
+static double  echannel();
+#endif
 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 */
@@ -124,6 +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;
 {
@@ -148,8 +200,10 @@ register EPNODE	 *epar;
 	    break;
 
 	default:
-	    for (ep = epar->v.kid; ep != NULL; ep = ep->sibling)
+	    while ((ep = epar->v.kid) != NULL) {
+		epar->v.kid = ep->sibling;
 		epfree(ep);
+	    }
 	    break;
 
     }
@@ -371,7 +425,7 @@ scan()				/* scan next character, return literal next 
 
 
 char *
-ltoa(l)				/* convert long to ascii */
+long2ascii(l)			      /* convert long to ascii */
 long  l;
 {
     static char	 buf[16];
@@ -405,9 +459,9 @@ char  *err;
 	if (infile != NULL) eputs(infile);
 	if (lineno != 0) {
 	    eputs(infile != NULL ? ", line " : "line ");
-	    eputs(ltoa((long)lineno));
+	    eputs(long2ascii((long)lineno));
 	}
-	eputs(": syntax error:\n");
+	eputs(":\n");
     }
     eputs(linbuf);
     if (linbuf[strlen(linbuf)-1] != '\n')