--- ray/src/common/calexpr.c	1991/04/23 15:26:26	1.9
+++ ray/src/common/calexpr.c	2005/05/17 17:51:51	2.30
@@ -1,9 +1,6 @@
-/* Copyright (c) 1986 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: calexpr.c,v 2.30 2005/05/17 17:51:51 greg Exp $";
 #endif
-
 /*
  *  Compute data values using expression parser
  *
@@ -16,60 +13,53 @@ static char SCCSid[] = "$SunId$ LBL";
  *  1/29/87  Made variables conditional (VARIABLE)
  *
  *  5/19/88  Added constant subexpression elimination (RCONST)
+ *
+ *  2/19/03	Eliminated conditional compiles in favor of esupport extern.
  */
 
-#include  <stdio.h>
+#include "copyright.h"
 
+#include  <stdio.h>
+#include  <string.h>
 #include  <ctype.h>
-
 #include  <errno.h>
+#include  <math.h>
+#include  <stdlib.h>
 
+#include  "rtmisc.h"
+#include  "rtio.h"
+#include  "rterror.h"
 #include  "calcomp.h"
 
-#define  MAXLINE	256		/* maximum line length */
-#define  MAXWORD	64		/* maximum word length */
+#define	 MAXLINE	256		/* maximum line length */
 
-#define  newnode()	(EPNODE *)ecalloc(1, sizeof(EPNODE))
+#define	 newnode()	(EPNODE *)ecalloc(1, sizeof(EPNODE))
 
-#define  isid(c)	(isalnum(c) || (c) == '_' || (c) == '.')
+#define	 isdecimal(c)	(isdigit(c) || (c) == '.')
 
-#define  isdecimal(c)	(isdigit(c) || (c) == '.')
+static double  euminus(EPNODE *), eargument(EPNODE *), enumber(EPNODE *);
+static double  echannel(EPNODE *);
+static double  eadd(EPNODE *), esubtr(EPNODE *),
+               emult(EPNODE *), edivi(EPNODE *),
+               epow(EPNODE *);
+static double  ebotch(EPNODE *);
 
-extern double  atof(), pow();
-extern char  *fgets(), *savestr();
-extern char  *emalloc(), *ecalloc();
-extern EPNODE  *curfunc;
-extern double  efunc(), evariable();
-static double  euminus(), echannel(), eargument(), enumber();
-static double  eadd(), esubtr(), emult(), edivi(), epow();
-static double  ebotch();
-extern int  errno;
+unsigned int  esupport =		/* what to support */
+		E_VARIABLE | E_FUNCTION ;
 
+int  eofc = 0;				/* optional end-of-file character */
 int  nextc;				/* lookahead character */
 
-double  (*eoper[])() = {		/* expression operations */
+double	(*eoper[])(EPNODE *) = {	/* expression operations */
 	ebotch,
-#ifdef  VARIABLE
 	evariable,
-#else
-	ebotch,
-#endif
 	enumber,
 	euminus,
-#ifdef  INCHAN
 	echannel,
-#else
-	ebotch,
-#endif
-#ifdef  FUNCTION
 	efunc,
 	eargument,
-#else
 	ebotch,
 	ebotch,
-#endif
-	ebotch,
-	ebotch,
 	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
 	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
 	emult,
@@ -95,15 +85,14 @@ static int  linepos;			/* position in buffer */
 
 
 EPNODE *
-eparse(expr)			/* parse an expression string */
-char  *expr;
+eparse(			/* parse an expression string */
+    char  *expr
+)
 {
     EPNODE  *ep;
 
     initstr(expr, NULL, 0);
-#if  defined(VARIABLE) && defined(FUNCTION)
     curfunc = NULL;
-#endif
     ep = getE1();
     if (nextc != EOF)
 	syntax("unexpected character");
@@ -112,8 +101,9 @@ char  *expr;
 
 
 double
-eval(expr)			/* evaluate an expression string */
-char  *expr;
+eval(			/* evaluate an expression string */
+    char  *expr
+)
 {
     register EPNODE  *ep;
     double  rval;
@@ -125,18 +115,68 @@ char  *expr;
 }
 
 
-epfree(epar)			/* free a parse tree */
-register EPNODE  *epar;
+int
+epcmp(			/* compare two expressions for equivalence */
+    register EPNODE  *ep1,
+    register EPNODE  *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);
+	}
+}
+
+
+void
+epfree(			/* free a parse tree */
+    register EPNODE	 *epar
+)
+{
     register EPNODE  *ep;
 
     switch (epar->type) {
 
-#if  defined(VARIABLE) || defined(FUNCTION)
 	case VAR:
 	    varfree(epar->v.ln);
 	    break;
-#endif
 	    
 	case SYM:
 	    freestr(epar->v.name);
@@ -149,8 +189,10 @@ 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;
 
     }
@@ -159,43 +201,44 @@ register EPNODE  *epar;
 }
 
 				/* the following used to be a switch */
-#ifdef  FUNCTION
 static double
-eargument(ep)
-EPNODE  *ep;
+eargument(
+    EPNODE	*ep
+)
 {
     return(argument(ep->v.chan));
 }
-#endif
 
 static double
-enumber(ep)
-EPNODE  *ep;
+enumber(
+    EPNODE	*ep
+)
 {
     return(ep->v.num);
 }
 
 static double
-euminus(ep)
-EPNODE  *ep;
+euminus(
+    EPNODE	*ep
+)
 {
     register EPNODE  *ep1 = ep->v.kid;
 
     return(-evalue(ep1));
 }
 
-#ifdef  INCHAN
 static double
-echannel(ep)
-EPNODE  *ep;
+echannel(
+    EPNODE	*ep
+)
 {
     return(chanvalue(ep->v.chan));
 }
-#endif
 
 static double
-eadd(ep)
-EPNODE  *ep;
+eadd(
+    EPNODE	*ep
+)
 {
     register EPNODE  *ep1 = ep->v.kid;
 
@@ -203,8 +246,9 @@ EPNODE  *ep;
 }
 
 static double
-esubtr(ep)
-EPNODE  *ep;
+esubtr(
+    EPNODE	*ep
+)
 {
     register EPNODE  *ep1 = ep->v.kid;
 
@@ -212,8 +256,9 @@ EPNODE  *ep;
 }
 
 static double
-emult(ep)
-EPNODE  *ep;
+emult(
+    EPNODE	*ep
+)
 {
     register EPNODE  *ep1 = ep->v.kid;
 
@@ -221,8 +266,9 @@ EPNODE  *ep;
 }
 
 static double
-edivi(ep)
-EPNODE  *ep;
+edivi(
+    EPNODE	*ep
+)
 {
     register EPNODE  *ep1 = ep->v.kid;
     double  d;
@@ -237,21 +283,22 @@ EPNODE  *ep;
 }
 
 static double
-epow(ep)
-EPNODE  *ep;
+epow(
+    EPNODE	*ep
+)
 {
     register EPNODE  *ep1 = ep->v.kid;
     double  d;
-    int  lasterrno;
+    int	 lasterrno;
 
     lasterrno = errno;
     errno = 0;
     d = pow(evalue(ep1), evalue(ep1->sibling));
-#ifdef  IEEE
+#ifdef	IEEE
     if (!finite(d))
 	errno = EDOM;
 #endif
-    if (errno) {
+    if (errno == EDOM || errno == ERANGE) {
 	wputs("Illegal power\n");
 	return(0.0);
     }
@@ -260,18 +307,21 @@ EPNODE  *ep;
 }
 
 static double
-ebotch(ep)
-EPNODE  *ep;
+ebotch(
+    EPNODE	*ep
+)
 {
     eputs("Bad expression!\n");
     quit(1);
+	return 0.0; /* pro forma return */
 }
 
 
 EPNODE *
-ekid(ep, n)			/* return pointer to a node's nth kid */
-register EPNODE  *ep;
-register int  n;
+ekid(			/* return pointer to a node's nth kid */
+    register EPNODE	 *ep,
+    register int  n
+)
 {
 
     for (ep = ep->v.kid; ep != NULL; ep = ep->sibling)
@@ -283,8 +333,9 @@ register int  n;
 
 
 int
-nekids(ep)			/* return # of kids for node ep */
-register EPNODE  *ep;
+nekids(			/* return # of kids for node ep */
+    register EPNODE	 *ep
+)
 {
     register int  n = 0;
 
@@ -295,12 +346,14 @@ register EPNODE  *ep;
 }
 
 
-initfile(fp, fn, ln)		/* prepare input file */
-FILE  *fp;
-char  *fn;
-int  ln;
+void
+initfile(		/* prepare input file */
+    FILE  *fp,
+    char  *fn,
+    int  ln
+)
 {
-    static char  inpbuf[MAXLINE];
+    static char	 inpbuf[MAXLINE];
 
     infp = fp;
     linbuf = inpbuf;
@@ -312,10 +365,12 @@ int  ln;
 }
 
 
-initstr(s, fn, ln)		/* prepare input string */
-char  *s;
-char  *fn;
-int  ln;
+void
+initstr(		/* prepare input string */
+    char  *s,
+    char  *fn,
+    int  ln
+)
 {
     infp = NULL;
     infile = fn;
@@ -326,8 +381,26 @@ int  ln;
 }
 
 
-scan()				/* scan next character */
+void
+getscanpos(	/* return current scan position */
+    char  **fnp,
+    int  *lnp,
+    char  **spp,
+    FILE  **fpp
+)
 {
+    if (fnp != NULL) *fnp = infile;
+    if (lnp != NULL) *lnp = lineno;
+    if (spp != NULL) *spp = linbuf+linepos;
+    if (fpp != NULL) *fpp = infp;
+}
+
+
+int
+scan(void)		/* scan next character, return literal next */
+{
+    register int  lnext = 0;
+
     do {
 	if (linbuf[linepos] == '\0')
 	    if (infp == NULL || fgets(linbuf, MAXLINE, infp) == NULL)
@@ -339,6 +412,12 @@ scan()				/* scan next character */
 	    }
 	else
 	    nextc = linbuf[linepos++];
+	if (!lnext)
+		lnext = nextc;
+	if (nextc == eofc) {
+		nextc = EOF;
+		break;
+	}
 	if (nextc == '{') {
 	    scan();
 	    while (nextc != '}')
@@ -349,16 +428,18 @@ scan()				/* scan next character */
 	    scan();
 	}
     } while (isspace(nextc));
+    return(lnext);
 }
 
 
 char *
-ltoa(l)				/* convert long to ascii */
-long  l;
+long2ascii(			      /* convert long to ascii */
+    long  l
+)
 {
-    static char  buf[16];
+    static char	 buf[16];
     register char  *cp;
-    int  neg = 0;
+    int	 neg = 0;
 
     if (l == 0)
 	return("0");
@@ -378,8 +459,10 @@ long  l;
 }
 
 
-syntax(err)			/* report syntax error and quit */
-char  *err;
+void
+syntax(			/* report syntax error and quit */
+    char  *err
+)
 {
     register int  i;
 
@@ -387,9 +470,9 @@ 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')
@@ -403,9 +486,11 @@ char  *err;
 }
 
 
-addekid(ep, ekid)			/* add a child to ep */
-register EPNODE  *ep;
-EPNODE  *ekid;
+void
+addekid(			/* add a child to ep */
+    register EPNODE	 *ep,
+    EPNODE	*ekid
+)
 {
     if (ep->v.kid == NULL)
 	ep->v.kid = ekid;
@@ -419,62 +504,71 @@ EPNODE  *ekid;
 
 
 char *
-getname()			/* scan an identifier */
+getname(void)			/* scan an identifier */
 {
-    static char  str[MAXWORD+1];
-    register int  i;
+    static char	 str[RMAXWORD+1];
+    register int  i, lnext;
 
-    for (i = 0; i < MAXWORD && isid(nextc); i++, scan())
-	str[i] = nextc;
+    lnext = nextc;
+    for (i = 0; i < RMAXWORD && isid(lnext); i++, lnext = scan())
+	str[i] = lnext;
     str[i] = '\0';
+    while (isid(lnext))		/* skip rest of name */
+	lnext = scan();
 
     return(str);
 }
 
 
 int
-getinum()			/* scan a positive integer */
+getinum(void)			/* scan a positive integer */
 {
-    register int  n;
+    register int  n, lnext;
 
     n = 0;
-    while (isdigit(nextc)) {
-	n = n * 10 + nextc - '0';
-	scan();
+    lnext = nextc;
+    while (isdigit(lnext)) {
+	n = n * 10 + lnext - '0';
+	lnext = scan();
     }
     return(n);
 }
 
 
 double
-getnum()			/* scan a positive float */
+getnum(void)			/* scan a positive float */
 {
-    register int  i;
-    char  str[MAXWORD+1];
+    register int  i, lnext;
+    char  str[RMAXWORD+1];
 
     i = 0;
-    while (isdigit(nextc) && i < MAXWORD) {
-	str[i++] = nextc;
-	scan();
+    lnext = nextc;
+    while (isdigit(lnext) && i < RMAXWORD) {
+	str[i++] = lnext;
+	lnext = scan();
     }
-    if (nextc == '.' && i < MAXWORD) {
-    	str[i++] = nextc;
-    	scan();
-	while (isdigit(nextc) && i < MAXWORD) {
-	    str[i++] = nextc;
-	    scan();
+    if (lnext == '.' && i < RMAXWORD) {
+	str[i++] = lnext;
+	lnext = scan();
+	if (i == 1 && !isdigit(lnext))
+	    syntax("badly formed number");
+	while (isdigit(lnext) && i < RMAXWORD) {
+	    str[i++] = lnext;
+	    lnext = scan();
 	}
     }
-    if ((nextc == 'e' || nextc == 'E') && i < MAXWORD) {
-    	str[i++] = nextc;
-    	scan();
-	if ((nextc == '-' || nextc == '+') && i < MAXWORD) {
-	    str[i++] = nextc;
-	    scan();
+    if ((lnext == 'e') | (lnext == 'E') && i < RMAXWORD) {
+	str[i++] = lnext;
+	lnext = scan();
+	if ((lnext == '-') | (lnext == '+') && i < RMAXWORD) {
+	    str[i++] = lnext;
+	    lnext = scan();
 	}
-	while (isdigit(nextc) && i < MAXWORD) {
-	    str[i++] = nextc;
-	    scan();
+	if (!isdigit(lnext))
+	    syntax("missing exponent");
+	while (isdigit(lnext) && i < RMAXWORD) {
+	    str[i++] = lnext;
+	    lnext = scan();
 	}
     }
     str[i] = '\0';
@@ -484,8 +578,8 @@ getnum()			/* scan a positive float */
 
 
 EPNODE *
-getE1()				/* E1 -> E1 ADDOP E2 */
-				/*       E2 */
+getE1(void)				/* E1 -> E1 ADDOP E2 */
+				/*	 E2 */
 {
     register EPNODE  *ep1, *ep2;
 
@@ -496,10 +590,9 @@ getE1()				/* E1 -> E1 ADDOP E2 */
 	scan();
 	addekid(ep2, ep1);
 	addekid(ep2, getE2());
-#ifdef  RCONST
-	if (ep1->type == NUM && ep1->sibling->type == NUM)
+	if (esupport&E_RCONST &&
+			ep1->type == NUM && ep1->sibling->type == NUM)
 		ep2 = rconst(ep2);
-#endif
 	ep1 = ep2;
     }
     return(ep1);
@@ -507,8 +600,8 @@ getE1()				/* E1 -> E1 ADDOP E2 */
 
 
 EPNODE *
-getE2()				/* E2 -> E2 MULOP E3 */
-				/*       E3 */
+getE2(void)				/* E2 -> E2 MULOP E3 */
+				/*	 E3 */
 {
     register EPNODE  *ep1, *ep2;
 
@@ -519,10 +612,9 @@ getE2()				/* E2 -> E2 MULOP E3 */
 	scan();
 	addekid(ep2, ep1);
 	addekid(ep2, getE3());
-#ifdef  RCONST
-	if (ep1->type == NUM && ep1->sibling->type == NUM)
+	if (esupport&E_RCONST &&
+			ep1->type == NUM && ep1->sibling->type == NUM)
 		ep2 = rconst(ep2);
-#endif
 	ep1 = ep2;
     }
     return(ep1);
@@ -530,8 +622,8 @@ getE2()				/* E2 -> E2 MULOP E3 */
 
 
 EPNODE *
-getE3()				/* E3 -> E4 ^ E3 */
-				/*       E4 */
+getE3(void)				/* E3 -> E4 ^ E3 */
+				/*	 E4 */
 {
     register EPNODE  *ep1, *ep2;
 
@@ -542,10 +634,9 @@ getE3()				/* E3 -> E4 ^ E3 */
 	scan();
 	addekid(ep2, ep1);
 	addekid(ep2, getE3());
-#ifdef  RCONST
-	if (ep1->type == NUM && ep1->sibling->type == NUM)
+	if (esupport&E_RCONST &&
+			ep1->type == NUM && ep1->sibling->type == NUM)
 		ep2 = rconst(ep2);
-#endif
 	return(ep2);
     }
     return(ep1);
@@ -553,8 +644,8 @@ getE3()				/* E3 -> E4 ^ E3 */
 
 
 EPNODE *
-getE4()				/* E4 -> ADDOP E5 */
-				/*       E5 */
+getE4(void)				/* E4 -> ADDOP E5 */
+				/*	 E5 */
 {
     register EPNODE  *ep1, *ep2;
 
@@ -565,6 +656,10 @@ getE4()				/* E4 -> ADDOP E5 */
 		ep2->v.num = -ep2->v.num;
 		return(ep2);
 	}
+	if (ep2->type == UMINUS) {	/* don't generate -(-E5) */
+	    efree((char *)ep2);
+	    return(ep2->v.kid);
+	}
 	ep1 = newnode();
 	ep1->type = UMINUS;
 	addekid(ep1, ep2);
@@ -577,94 +672,87 @@ getE4()				/* E4 -> ADDOP E5 */
 
 
 EPNODE *
-getE5()				/* E5 -> (E1) */
-				/*       VAR */
-				/*       NUM */
-				/*       $N */
-				/*       FUNC(E1,..) */
-				/*       ARG */
+getE5(void)			/* E5 -> (E1) */
+				/*	 VAR */
+				/*	 NUM */
+				/*	 $N */
+				/*	 FUNC(E1,..) */
+				/*	 ARG */
 {
-    int  i;
-    register EPNODE  *ep1, *ep2;
+	int	 i;
+	char  *nam;
+	register EPNODE  *ep1, *ep2;
 
-    if (nextc == '(') {
-	scan();
-	ep1 = getE1();
-	if (nextc != ')')
-	    syntax("')' expected");
-	scan();
-	return(ep1);
-    }
+	if (nextc == '(') {
+		scan();
+		ep1 = getE1();
+		if (nextc != ')')
+			syntax("')' expected");
+		scan();
+		return(ep1);
+	}
 
-#ifdef  INCHAN
-    if (nextc == '$') {
-	scan();
-	ep1 = newnode();
-	ep1->type = CHAN;
-	ep1->v.chan = getinum();
-	return(ep1);
-    }
-#endif
+	if (esupport&E_INCHAN && nextc == '$') {
+		scan();
+		ep1 = newnode();
+		ep1->type = CHAN;
+		ep1->v.chan = getinum();
+		return(ep1);
+	}
 
-#if  defined(VARIABLE) || defined(FUNCTION)
-    if (isalpha(nextc)) {
-	ep1 = newnode();
-	ep1->type = VAR;
-	ep1->v.ln = varinsert(getname());
-
-#if  defined(VARIABLE) && defined(FUNCTION)
-	if (curfunc != NULL)
-	    for (i = 1, ep2 = curfunc->v.kid->sibling;
-	    			ep2 != NULL; i++, ep2 = ep2->sibling)
-		if (!strcmp(ep2->v.name, ep1->v.ln->name)) {
-		    epfree(ep1);
-		    ep1 = newnode();
-		    ep1->type = ARG;
-		    ep1->v.chan = i;
-		    break;
+	if (esupport&(E_VARIABLE|E_FUNCTION) &&
+			(isalpha(nextc) || nextc == CNTXMARK)) {
+		nam = getname();
+		ep1 = NULL;
+		if ((esupport&(E_VARIABLE|E_FUNCTION)) == (E_VARIABLE|E_FUNCTION)
+				&& curfunc != NULL)
+			for (i = 1, ep2 = curfunc->v.kid->sibling;
+					ep2 != NULL; i++, ep2 = ep2->sibling)
+				if (!strcmp(ep2->v.name, nam)) {
+					ep1 = newnode();
+					ep1->type = ARG;
+					ep1->v.chan = i;
+					break;
+				}
+		if (ep1 == NULL) {
+			ep1 = newnode();
+			ep1->type = VAR;
+			ep1->v.ln = varinsert(nam);
 		}
-#endif
-#ifdef  FUNCTION
-	if (nextc == '(') {
-	    ep2 = newnode();
-	    ep2->type = FUNC;
-	    addekid(ep2, ep1);
-	    ep1 = ep2;
-	    do {
-		scan();
-		addekid(ep1, getE1());
-	    } while (nextc == ',');
-	    if (nextc != ')')
-		syntax("')' expected");
-	    scan();
+		if (esupport&E_FUNCTION && nextc == '(') {
+			ep2 = newnode();
+			ep2->type = FUNC;
+			addekid(ep2, ep1);
+			ep1 = ep2;
+			do {
+				scan();
+				addekid(ep1, getE1());
+			} while (nextc == ',');
+			if (nextc != ')')
+				syntax("')' expected");
+			scan();
+		} else if (!(esupport&E_VARIABLE))
+			syntax("'(' expected");
+		if (esupport&E_RCONST && isconstvar(ep1))
+			ep1 = rconst(ep1);
+		return(ep1);
 	}
-#ifndef  VARIABLE
-	else
-	    syntax("'(' expected");
-#endif
-#endif
-#ifdef  RCONST
-	if (isconstvar(ep1))
-	    ep1 = rconst(ep1);
-#endif
-	return(ep1);
-    }
-#endif
 
-    if (isdecimal(nextc)) {
-	ep1 = newnode();
-	ep1->type = NUM;
-	ep1->v.num = getnum();
-	return(ep1);
-    }
-    syntax("unexpected character");
+	if (isdecimal(nextc)) {
+		ep1 = newnode();
+		ep1->type = NUM;
+		ep1->v.num = getnum();
+		return(ep1);
+	}
+	syntax("unexpected character");
+	return NULL; /* pro forma return */
 }
 
 
-#ifdef  RCONST
 EPNODE *
-rconst(epar)			/* reduce a constant expression */
-register EPNODE  *epar;
+rconst(			/* reduce a constant expression */
+    register EPNODE	 *epar
+)
 {
     register EPNODE  *ep;
 
@@ -672,48 +760,57 @@ register EPNODE  *epar;
     ep->type = NUM;
     errno = 0;
     ep->v.num = evalue(epar);
-    if (errno)
-    	syntax("bad constant expression");
+    if (errno == EDOM || errno == ERANGE)
+	syntax("bad constant expression");
     epfree(epar);
  
     return(ep);
 }
 
 
-isconstvar(ep)			/* is ep linked to a constant? */
-register EPNODE  *ep;
+int
+isconstvar(			/* is ep linked to a constant expression? */
+    register EPNODE	 *ep
+)
 {
-#ifdef  VARIABLE
     register EPNODE  *ep1;
-    
-#ifdef  FUNCTION
-    if (ep->type == FUNC) {
-	if (ep->v.kid->type != VAR)
-	    return(0);
-	ep1 = ep->v.kid->v.ln->def;
-	if (ep1 != NULL && ep1->type != ':')
-	    return(0);
-	if ((ep1 == NULL || ep1->v.kid->type != FUNC)
-		&& liblookup(ep->v.kid->v.ln->name) == NULL)
-	    return(0);
+
+    if (esupport&E_FUNCTION && ep->type == FUNC) {
+	if (!isconstfun(ep->v.kid))
+		return(0);
 	for (ep1 = ep->v.kid->sibling; ep1 != NULL; ep1 = ep1->sibling)
-	    if (ep1->type != NUM)
+	    if (ep1->type != NUM && !isconstfun(ep1))
 		return(0);
 	return(1);
     }
-#endif
     if (ep->type != VAR)
 	return(0);
     ep1 = ep->v.ln->def;
     if (ep1 == NULL || ep1->type != ':')
 	return(0);
-#ifdef  FUNCTION
-    if (ep1->v.kid->type != SYM)
+    if (esupport&E_FUNCTION && ep1->v.kid->type != SYM)
 	return(0);
-#endif
     return(1);
-#else
-    return(ep->type == FUNC);
-#endif
 }
-#endif
+
+
+int
+isconstfun(			/* is ep linked to a constant function? */
+    register EPNODE	 *ep
+)
+{
+    register EPNODE  *dp;
+    register LIBR  *lp;
+
+    if (ep->type != VAR)
+	return(0);
+    if ((dp = ep->v.ln->def) != NULL) {
+	if (dp->v.kid->type == FUNC)
+	    return(dp->type == ':');
+	else
+	    return(0);		/* don't identify masked library functions */
+    }
+    if ((lp = ep->v.ln->lib) != NULL)
+	return(lp->atyp == ':');
+    return(0);
+}