--- ray/src/common/caldefn.c	1991/07/16 10:37:45	1.11
+++ ray/src/common/caldefn.c	2003/07/21 22:30:17	2.19
@@ -1,9 +1,6 @@
-/* Copyright (c) 1991 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: caldefn.c,v 2.19 2003/07/21 22:30:17 schorsch Exp $";
 #endif
-
 /*
  *  Store variable definitions.
  *
@@ -20,46 +17,57 @@ static char SCCSid[] = "$SunId$ LBL";
  *  5/31/90  Added conditional compile (REDEFW) for redefinition warning.
  *
  *  4/23/91  Added ':' assignment for constant expressions
+ *
+ *  8/7/91  Added optional context path to append to variable names
+ *
+ *  5/17/2001  Fixed clock counter wrapping behavior
+ *
+ *  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  "rterror.h"
 #include  "calcomp.h"
 
-#ifndef  NHASH
-#define  NHASH		521		/* hash size (a prime!) */
+#ifndef	 NHASH
+#define	 NHASH		521		/* hash size (a prime!) */
 #endif
 
-#define  newnode()	(EPNODE *)ecalloc(1, sizeof(EPNODE))
+#define  hash(s)	(shash(s)%NHASH)
 
-extern char  *ecalloc(), *savestr();
+#define	 newnode()	(EPNODE *)ecalloc(1, sizeof(EPNODE))
 
-static double  dvalue();
+static double  dvalue(char  *name, EPNODE *d);
 
-long  eclock = -1;			/* value storage timer */
+#define  MAXCLOCK	(1L<<31)	/* clock wrap value */
 
+unsigned long  eclock = 0;		/* value storage timer */
+
+#define  MAXCNTX	1023		/* maximum context length */
+
+static char  context[MAXCNTX+1];	/* current context path */
+
 static VARDEF  *hashtbl[NHASH];		/* definition list */
 static int  htndx;			/* index for */		
 static VARDEF  *htpos;			/* ...dfirst() and */
-#ifdef  OUTCHAN
 static EPNODE  *ochpos;			/* ...dnext */
 static EPNODE  *outchan;
-#endif
 
-#ifdef  FUNCTION
-EPNODE  *curfunc;
-#define  dname(ep)	((ep)->v.kid->type == SYM ? \
+EPNODE	*curfunc = NULL;
+#define	 dname(ep)	((ep)->v.kid->type == SYM ? \
 			(ep)->v.kid->v.name : \
 			(ep)->v.kid->v.kid->v.name)
-#else
-#define  dname(ep)	((ep)->v.kid->v.name)
-#endif
 
 
-fcompile(fname)			/* get definitions from a file */
-char  *fname;
+void
+fcompile(			/* get definitions from a file */
+	char  *fname
+)
 {
     FILE  *fp;
 
@@ -72,34 +80,38 @@ char  *fname;
     }
     initfile(fp, fname, 0);
     while (nextc != EOF)
-	loaddefn();
+	getstatement();
     if (fname != NULL)
 	fclose(fp);
 }
 
 
-scompile(str, fn, ln)		/* get definitions from a string */
-char  *str;
-char  *fn;
-int  ln;
+void
+scompile(		/* get definitions from a string */
+	char  *str,
+	char  *fn,
+	int  ln
+)
 {
     initstr(str, fn, ln);
     while (nextc != EOF)
-	loaddefn();
+	getstatement();
 }
 
 
 double
-varvalue(vname)			/* return a variable's value */
-char  *vname;
+varvalue(			/* return a variable's value */
+	char  *vname
+)
 {
     return(dvalue(vname, dlookup(vname)));
 }
 
 
 double
-evariable(ep)			/* evaluate a variable */
-EPNODE  *ep;
+evariable(			/* evaluate a variable */
+	EPNODE	*ep
+)
 {
     register VARDEF  *dp = ep->v.ln;
 
@@ -107,14 +119,19 @@ EPNODE  *ep;
 }
 
 
-varset(vname, assign, val)	/* set a variable's value */
-char  *vname;
-int  assign;
-double  val;
+void
+varset(		/* set a variable's value */
+	char  *vname,
+	int  assign,
+	double	val
+)
 {
+    char  *qname;
     register EPNODE  *ep1, *ep2;
+					/* get qualified name */
+    qname = qualname(vname, 0);
 					/* check for quick set */
-    if ((ep1 = dlookup(vname)) != NULL && ep1->v.kid->type == SYM) {
+    if ((ep1 = dlookup(qname)) != NULL && ep1->v.kid->type == SYM) {
 	ep2 = ep1->v.kid->sibling;
 	if (ep2->type == NUM) {
 	    ep2->v.num = val;
@@ -133,19 +150,21 @@ double  val;
     ep2->type = NUM;
     ep2->v.num = val;
     addekid(ep1, ep2);
-    dremove(vname);
-    dpush(ep1);
+    dremove(qname);
+    dpush(qname, ep1);
 }
 
 
-dclear(name)			/* delete variable definitions of name */
-char  *name;
+void
+dclear(			/* delete variable definitions of name */
+	char  *name
+)
 {
     register EPNODE  *ep;
 
     while ((ep = dpop(name)) != NULL) {
 	if (ep->type == ':') {
-	    dpush(ep);		/* don't clear constants */
+	    dpush(name, ep);		/* don't clear constants */
 	    return;
 	}
 	epfree(ep);
@@ -153,8 +172,10 @@ char  *name;
 }
 
 
-dremove(name)			/* delete all definitions of name */
-char  *name;
+void
+dremove(			/* delete all definitions of name */
+	char  *name
+)
 {
     register EPNODE  *ep;
 
@@ -163,8 +184,10 @@ char  *name;
 }
 
 
-vardefined(name)	/* return non-zero if variable defined */
-char  *name;
+int
+vardefined(	/* return non-zero if variable defined */
+	char  *name
+)
 {
     register EPNODE  *dp;
 
@@ -172,108 +195,264 @@ char  *name;
 }
 
 
-#ifdef  OUTCHAN
-chanout(cs)			/* set output channels */
-int  (*cs)();
+char *
+setcontext(			/* set a new context path */
+	register char  *ctx
+)
 {
+    register char  *cpp;
+
+    if (ctx == NULL)
+	return(context);		/* just asking */
+    while (*ctx == CNTXMARK)
+	ctx++;				/* skip past marks */
+    if (!*ctx) {
+	context[0] = '\0';		/* empty means clear context */
+	return(context);
+    }
+    cpp = context;			/* start context with mark */
+    *cpp++ = CNTXMARK;
+    do {				/* carefully copy new context */
+	if (cpp >= context+MAXCNTX)
+	    break;			/* just copy what we can */
+	if (isid(*ctx))
+	    *cpp++ = *ctx++;
+	else {
+	    *cpp++ = '_'; ctx++;
+	}
+    } while (*ctx);
+    while (cpp[-1] == CNTXMARK)		/* cannot end in context mark */
+	cpp--;
+    *cpp = '\0';
+    return(context);
+}
+
+
+char *
+pushcontext(		/* push on another context */
+	char  *ctx
+)
+{
+    char  oldcontext[MAXCNTX+1];
+    register int  n;
+
+    strcpy(oldcontext, context);	/* save old context */
+    setcontext(ctx);			/* set new context */
+    n = strlen(context);		/* tack on old */
+    if (n+strlen(oldcontext) > MAXCNTX) {
+	strncpy(context+n, oldcontext, MAXCNTX-n);
+	context[MAXCNTX] = '\0';
+    } else
+	strcpy(context+n, oldcontext);
+    return(context);
+}
+
+
+char *
+popcontext(void)			/* pop off top context */
+{
+    register char  *cp1, *cp2;
+
+    if (!context[0])			/* nothing left to pop */
+	return(context);
+    cp2 = context;			/* find mark */
+    while (*++cp2 && *cp2 != CNTXMARK)
+	;
+    cp1 = context;			/* copy tail to front */
+    while (*cp1++ = *cp2++)
+	;
+    return(context);
+}
+
+
+char *
+qualname(		/* get qualified name */
+	register char  *nam,
+	int  lvl
+)
+{
+    static char	 nambuf[RMAXWORD+1];
+    register char  *cp = nambuf, *cpp;
+				/* check for explicit local */
+    if (*nam == CNTXMARK)
+	if (lvl > 0)		/* only action is to refuse search */
+	    return(NULL);
+	else
+	    nam++;
+    else if (nam == nambuf)	/* check for repeat call */
+	return(lvl > 0 ? NULL : nam);
+				/* copy name to static buffer */
+    while (*nam) {
+	if (cp >= nambuf+RMAXWORD)
+		goto toolong;
+	*cp++ = *nam++;
+    }
+				/* check for explicit global */
+    if (cp > nambuf && cp[-1] == CNTXMARK) {
+	if (lvl > 0)
+	    return(NULL);
+	*--cp = '\0';
+	return(nambuf);		/* already qualified */
+    }
+    cpp = context;		/* else skip the requested levels */
+    while (lvl-- > 0) {
+	if (!*cpp)
+	    return(NULL);	/* return NULL if past global level */
+	while (*++cpp && *cpp != CNTXMARK)
+	    ;
+    }
+    while (*cpp) {		/* copy context to static buffer */
+	if (cp >= nambuf+RMAXWORD)
+	    goto toolong;
+	*cp++ = *cpp++;
+    }
+toolong:
+    *cp = '\0';
+    return(nambuf);		/* return qualified name */
+}
+
+
+int
+incontext(			/* is qualified name in current context? */
+	register char  *qn
+)
+{
+    if (!context[0])			/* global context accepts all */
+	return(1);
+    while (*qn && *qn != CNTXMARK)	/* find context mark */
+	qn++;
+    return(!strcmp(qn, context));
+}
+
+
+void
+chanout(			/* set output channels */
+	void  (*cs)(int n, double v)
+)
+{
     register EPNODE  *ep;
 
     for (ep = outchan; ep != NULL; ep = ep->sibling)
 	(*cs)(ep->v.kid->v.chan, evalue(ep->v.kid->sibling));
 
 }
-#endif
 
 
-dcleanup(lvl)			/* clear definitions (0->vars,1->consts,2->output) */
-int  lvl;
+void
+dcleanup(		/* clear definitions (0->vars,1->output,2->consts) */
+	int  lvl
+)
 {
     register int  i;
     register VARDEF  *vp;
     register EPNODE  *ep;
-
+				/* if context is global, clear all */
     for (i = 0; i < NHASH; i++)
 	for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
-	    if (lvl >= 1)
-		dremove(vp->name);
-	    else
-		dclear(vp->name);
-#ifdef  OUTCHAN
-    if (lvl >= 2) {
+	    if (incontext(vp->name)) {
+		if (lvl >= 2)
+		    dremove(vp->name);
+		else
+		    dclear(vp->name);
+	    }
+    if (lvl >= 1) {
 	for (ep = outchan; ep != NULL; ep = ep->sibling)
 	    epfree(ep);
 	outchan = NULL;
     }
-#endif
 }
 
 
 EPNODE *
-dlookup(name)			/* look up a definition */
-char  *name;
+dlookup(			/* look up a definition */
+	char  *name
+)
 {
     register VARDEF  *vp;
     
     if ((vp = varlookup(name)) == NULL)
-    	return(NULL);
+	return(NULL);
     return(vp->def);
 }
 
 
 VARDEF *
-varlookup(name)			/* look up a variable */
-char  *name;
+varlookup(			/* look up a variable */
+	char  *name
+)
 {
+    int	 lvl = 0;
+    register char  *qname;
     register VARDEF  *vp;
-    
-    for (vp = hashtbl[hash(name)]; vp != NULL; vp = vp->next)
-    	if (!strcmp(vp->name, name))
-    	    return(vp);
+				/* find most qualified match */
+    while ((qname = qualname(name, lvl++)) != NULL)
+	for (vp = hashtbl[hash(qname)]; vp != NULL; vp = vp->next)
+	    if (!strcmp(vp->name, qname))
+		return(vp);
     return(NULL);
 }
 
 
 VARDEF *
-varinsert(name)			/* get a link to a variable */
-char  *name;
+varinsert(			/* get a link to a variable */
+	char  *name
+)
 {
     register VARDEF  *vp;
-    int  hv;
+    int	 hv;
     
-    hv = hash(name);
-    for (vp = hashtbl[hv]; vp != NULL; vp = vp->next)
-    	if (!strcmp(vp->name, name)) {
-    	    vp->nlinks++;
-    	    return(vp);
-    	}
+    if ((vp = varlookup(name)) != NULL) {
+	vp->nlinks++;
+	return(vp);
+    }
     vp = (VARDEF *)emalloc(sizeof(VARDEF));
+    vp->lib = liblookup(name);
+    if (vp->lib == NULL)		/* if name not in library */
+	name = qualname(name, 0);	/* use fully qualified version */
+    hv = hash(name);
     vp->name = savestr(name);
     vp->nlinks = 1;
     vp->def = NULL;
-    vp->lib = NULL;
     vp->next = hashtbl[hv];
     hashtbl[hv] = vp;
     return(vp);
 }
 
 
-varfree(ln)				/* release link to variable */
-register VARDEF  *ln;
+void
+libupdate(			/* update library links */
+	char  *fn
+)
 {
+    register int  i;
     register VARDEF  *vp;
-    int  hv;
+					/* if fn is NULL then relink all */
+    for (i = 0; i < NHASH; i++)
+	for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
+	    if (vp->lib != NULL || fn == NULL || !strcmp(fn, vp->name))
+		vp->lib = liblookup(vp->name);
+}
 
+
+void
+varfree(				/* release link to variable */
+	register VARDEF	 *ln
+)
+{
+    register VARDEF  *vp;
+    int	 hv;
+
     if (--ln->nlinks > 0)
-    	return;				/* still active */
+	return;				/* still active */
 
     hv = hash(ln->name);
     vp = hashtbl[hv];
     if (vp == ln)
-    	hashtbl[hv] = vp->next;
+	hashtbl[hv] = vp->next;
     else {
-    	while (vp->next != ln)		/* must be in list */
-    		vp = vp->next;
-    	vp->next = ln->next;
+	while (vp->next != ln)		/* must be in list */
+		vp = vp->next;
+	vp->next = ln->next;
     }
     freestr(ln->name);
     efree((char *)ln);
@@ -281,51 +460,48 @@ register VARDEF  *ln;
 
 
 EPNODE *
-dfirst()			/* return pointer to first definition */
+dfirst(void)			/* return pointer to first definition */
 {
     htndx = 0;
     htpos = NULL;
-#ifdef  OUTCHAN
     ochpos = outchan;
-#endif
     return(dnext());
 }
 
 
 EPNODE *
-dnext()				/* return pointer to next definition */
+dnext(void)				/* return pointer to next definition */
 {
     register EPNODE  *ep;
+    register char  *nm;
 
     while (htndx < NHASH) {
-    	if (htpos == NULL)
-    		htpos = hashtbl[htndx++];
-    	while (htpos != NULL) {
-    	    ep = htpos->def;
-    	    htpos = htpos->next;
-    	    if (ep != NULL)
-    	    	return(ep);
-    	}
+	if (htpos == NULL)
+		htpos = hashtbl[htndx++];
+	while (htpos != NULL) {
+	    ep = htpos->def;
+	    nm = htpos->name;
+	    htpos = htpos->next;
+	    if (ep != NULL && incontext(nm))
+		return(ep);
+	}
     }
-#ifdef  OUTCHAN
     if ((ep = ochpos) != NULL)
-    	ochpos = ep->sibling;
+	ochpos = ep->sibling;
     return(ep);
-#else
-    return(NULL);
-#endif
 }
 
 
 EPNODE *
-dpop(name)			/* pop a definition */
-char  *name;
+dpop(			/* pop a definition */
+	char  *name
+)
 {
     register VARDEF  *vp;
     register EPNODE  *dp;
     
     if ((vp = varlookup(name)) == NULL || vp->def == NULL)
-    	return(NULL);
+	return(NULL);
     dp = vp->def;
     vp->def = dp->sibling;
     varfree(vp);
@@ -333,22 +509,26 @@ char  *name;
 }
 
 
-dpush(ep)			/* push on a definition */
-register EPNODE  *ep;
+void
+dpush(			/* push on a definition */
+	char  *nm,
+	register EPNODE	 *ep
+)
 {
     register VARDEF  *vp;
 
-    vp = varinsert(dname(ep));
+    vp = varinsert(nm);
     ep->sibling = vp->def;
     vp->def = ep;
 }
 
 
-#ifdef  OUTCHAN
-addchan(sp)			/* add an output channel assignment */
-EPNODE  *sp;
+void
+addchan(			/* add an output channel assignment */
+	EPNODE	*sp
+)
 {
-    int  ch = sp->v.kid->v.chan;
+    int	 ch = sp->v.kid->v.chan;
     register EPNODE  *ep, *epl;
 
     for (epl = NULL, ep = outchan; ep != NULL; epl = ep, ep = ep->sibling)
@@ -372,47 +552,43 @@ EPNODE  *sp;
     sp->sibling = NULL;
 
 }
-#endif
 
 
-loaddefn()			/* load next definition */
+void
+getstatement(void)			/* get next statement */
 {
     register EPNODE  *ep;
-    EPNODE  *lastdef;
+    char  *qname;
+    register VARDEF  *vdef;
 
     if (nextc == ';') {		/* empty statement */
 	scan();
 	return;
     }
-#ifdef  OUTCHAN
-    if (nextc == '$') {		/* channel assignment */
+    if (esupport&E_OUTCHAN &&
+		nextc == '$') {		/* channel assignment */
 	ep = getchan();
 	addchan(ep);
-    } else
-#endif
-    {				/* ordinary definition */
+    } else {				/* ordinary definition */
 	ep = getdefn();
-#ifdef  REDEFW
-	if ((lastdef = dlookup(dname(ep))) != NULL) {
-	    wputs(dname(ep));
-	    if (lastdef->type == ':')
-		wputs(": redefined constant expression\n");
-	    else
-		wputs(": redefined\n");
+	qname = qualname(dname(ep), 0);
+	if (esupport&E_REDEFW && (vdef = varlookup(qname)) != NULL) {
+	    if (vdef->def != NULL && epcmp(ep, vdef->def)) {
+		wputs(qname);
+		if (vdef->def->type == ':')
+		    wputs(": redefined constant expression\n");
+		else
+		    wputs(": redefined\n");
+	    } else if (ep->v.kid->type == FUNC && vdef->lib != NULL) {
+		wputs(qname);
+		wputs(": definition hides library function\n");
+	    }
 	}
-#ifdef  FUNCTION
-	else if (ep->v.kid->type == FUNC &&
-			liblookup(ep->v.kid->v.kid->v.name) != NULL) {
-	    wputs(ep->v.kid->v.kid->v.name);
-	    wputs(": definition hides library function\n");
-	}
-#endif
-#endif
 	if (ep->type == ':')
-	    dremove(dname(ep));
+	    dremove(qname);
 	else
-	    dclear(dname(ep));
-	dpush(ep);
+	    dclear(qname);
+	dpush(qname, ep);
     }
     if (nextc != EOF) {
 	if (nextc != ';')
@@ -423,22 +599,22 @@ loaddefn()			/* load next definition */
 
 
 EPNODE *
-getdefn()			/* A -> SYM = E1 */
-				/*	SYM : E1 */
-				/*      FUNC(SYM,..) = E1 */
-				/*	FUNC(SYM,..) : E1 */
+getdefn(void)
+	/* A -> SYM = E1 */
+	/*	SYM : E1 */
+	/*	FUNC(SYM,..) = E1 */
+	/*	FUNC(SYM,..) : E1 */
 {
     register EPNODE  *ep1, *ep2;
 
-    if (!isalpha(nextc))
+    if (!isalpha(nextc) && nextc != CNTXMARK)
 	syntax("illegal variable name");
 
     ep1 = newnode();
     ep1->type = SYM;
     ep1->v.name = savestr(getname());
 
-#ifdef  FUNCTION
-    if (nextc == '(') {
+    if (esupport&E_FUNCTION && nextc == '(') {
 	ep2 = newnode();
 	ep2->type = FUNC;
 	addekid(ep2, ep1);
@@ -456,9 +632,7 @@ getdefn()			/* A -> SYM = E1 */
 	    syntax("')' expected");
 	scan();
 	curfunc = ep1;
-    } else
-	curfunc = NULL;
-#endif
+    }
 
     if (nextc != '=' && nextc != ':')
 	syntax("'=' or ':' expected");
@@ -469,27 +643,23 @@ getdefn()			/* A -> SYM = E1 */
     addekid(ep2, ep1);
     addekid(ep2, getE1());
 
-    if (
-#ifdef  FUNCTION
-    	    ep1->type == SYM &&
-#endif
-	    ep1->sibling->type != NUM) {
+    if (ep1->type == SYM && ep1->sibling->type != NUM) {
 	ep1 = newnode();
 	ep1->type = TICK;
-	ep1->v.tick = -1;
+	ep1->v.tick = 0;
 	addekid(ep2, ep1);
 	ep1 = newnode();
 	ep1->type = NUM;
 	addekid(ep2, ep1);
     }
+    curfunc = NULL;
 
     return(ep2);
 }
 
 
-#ifdef  OUTCHAN
 EPNODE *
-getchan()			/* A -> $N = E1 */
+getchan(void)			/* A -> $N = E1 */
 {
     register EPNODE  *ep1, *ep2;
 
@@ -512,7 +682,6 @@ getchan()			/* A -> $N = E1 */
 
     return(ep2);
 }
-#endif
 
 
 
@@ -521,10 +690,8 @@ getchan()			/* A -> $N = E1 */
  */
 
 
-static double
-dvalue(name, d)			/* evaluate a variable */
-char  *name;
-EPNODE  *d;
+static double			/* evaluate a variable */
+dvalue(char  *name, EPNODE	*d)
 {
     register EPNODE  *ep1, *ep2;
     
@@ -537,25 +704,15 @@ EPNODE  *d;
     if (ep1->type == NUM)
 	return(ep1->v.num);			/* return if number */
     ep2 = ep1->sibling;				/* check time */
-    if (ep2->v.tick < 0 || ep2->v.tick < eclock) {
-	ep2->v.tick = d->type == ':' ? 1L<<30 : eclock;
+    if (eclock >= MAXCLOCK)
+	eclock = 1;				/* wrap clock counter */
+    if (ep2->v.tick < MAXCLOCK &&
+		ep2->v.tick == 0 | ep2->v.tick != eclock) {
+	ep2->v.tick = d->type == ':' ? MAXCLOCK : eclock;
 	ep2 = ep2->sibling;
 	ep2->v.num = evalue(ep1);		/* needs new value */
     } else
 	ep2 = ep2->sibling;			/* else reuse old value */
 
     return(ep2->v.num);
-}
-
-
-static int
-hash(s)				/* hash a string */
-register char  *s;
-{
-    register int  rval = 0;
-
-    while (*s)
-	rval += *s++;
-    
-    return(rval % NHASH);
 }