src/common/caldefn.c

#ifndef lint
static const char       RCSid[] = "$Id: caldefn.c,v 2.24 2010/03/05 17:28:46 greg Exp $";
#endif
/*
 *  Store variable definitions.
 *
 *  7/1/85  Greg Ward
 *
 *  11/11/85  Added conditional compiles (OUTCHAN) for control output.
 *
 *  4/2/86  Added conditional compiles for function definitions (FUNCTION).
 *
 *  1/15/88  Added clock for caching of variable values.
 *
 *  11/16/88  Added VARDEF structure for hard linking.
 *
 *  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 "copyright.h"

#include  <stdio.h>
#include  <string.h>
#include  <ctype.h>

#include  "rterror.h"
#include  "rtio.h"
#include  "rtmisc.h"
#include  "calcomp.h"

#ifndef  NHASH
#define  NHASH          521             /* hash size (a prime!) */
#endif

#define  hash(s)        (shash(s)%NHASH)

#define  newnode()      (EPNODE *)ecalloc(1, sizeof(EPNODE))

static double  dvalue(char  *name, EPNODE *d);

#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 */
static EPNODE  *ochpos;                 /* ...dnext */
static EPNODE  *outchan;

EPNODE  *curfunc = NULL;
#define  dname(ep)      ((ep)->v.kid->type == SYM ? \
                        (ep)->v.kid->v.name : \
                        (ep)->v.kid->v.kid->v.name)


void
fcompile(                       /* get definitions from a file */
        char  *fname
)
{
    FILE  *fp;

    if (fname == NULL)
        fp = stdin;
    else if ((fp = fopen(fname, "r")) == NULL) {
        eputs(fname);
        eputs(": cannot open\n");
        quit(1);
    }
    initfile(fp, fname, 0);
    while (nextc != EOF)
        getstatement();
    if (fname != NULL)
        fclose(fp);
}


void
scompile(               /* get definitions from a string */
        char  *str,
        char  *fn,
        int  ln
)
{
    initstr(str, fn, ln);
    while (nextc != EOF)
        getstatement();
}


double
varvalue(                       /* return a variable's value */
        char  *vname
)
{
    return(dvalue(vname, dlookup(vname)));
}


double
evariable(                      /* evaluate a variable */
        EPNODE  *ep
)
{
    VARDEF  *dp = ep->v.ln;

    return(dvalue(dp->name, dp->def));
}


void
varset(         /* set a variable's value */
        char  *vname,
        int  assign,
        double  val
)
{
    char  *qname;
    EPNODE  *ep1, *ep2;
                                        /* get qualified name */
    qname = qualname(vname, 0);
                                        /* check for quick set */
    if ((ep1 = dlookup(qname)) != NULL && ep1->v.kid->type == SYM &&
                (ep1->type == ':') <= (assign == ':')) {
        ep2 = ep1->v.kid->sibling;
        if (ep2->type == NUM) {
            ep2->v.num = val;
            ep1->type = assign;
            return;
        }
    }
                                        /* hand build definition */
    ep1 = newnode();
    ep1->type = assign;
    ep2 = newnode();
    ep2->type = SYM;
    ep2->v.name = savestr(vname);
    addekid(ep1, ep2);
    ep2 = newnode();
    ep2->type = NUM;
    ep2->v.num = val;
    addekid(ep1, ep2);
    if (assign == ':')
        dremove(qname);
    else
        dclear(qname);
    dpush(qname, ep1);
}


void
dclear(                 /* delete variable definitions of name */
        char  *name
)
{
    EPNODE  *ep;

    while ((ep = dpop(name)) != NULL) {
        if (ep->type == ':') {
            dpush(name, ep);            /* don't clear constants */
            return;
        }
        epfree(ep);
    }
}


void
dremove(                        /* delete all definitions of name */
        char  *name
)
{
    EPNODE  *ep;

    while ((ep = dpop(name)) != NULL)
        epfree(ep);
}


int
vardefined(     /* return non-zero if variable defined */
        char  *name
)
{
    EPNODE  *dp;

    return((dp = dlookup(name)) != NULL && dp->v.kid->type == SYM);
}


char *
setcontext(                     /* set a new context path */
        char  *ctx
)
{
    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];
    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 */
{
    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 */
        char  *nam,
        int  lvl
)
{
    static char  nambuf[RMAXWORD+1];
    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? */
        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)
)
{
    EPNODE  *ep;

    for (ep = outchan; ep != NULL; ep = ep->sibling)
        (*cs)(ep->v.kid->v.chan, evalue(ep->v.kid->sibling));

}


void
dcleanup(               /* clear definitions (0->vars,1->output,2->consts) */
        int  lvl
)
{
    int  i;
    VARDEF  *vp;
    EPNODE  *ep;
                                /* if context is global, clear all */
    for (i = 0; i < NHASH; i++)
        for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
            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;
    }
}


EPNODE *
dlookup(                        /* look up a definition */
        char  *name
)
{
    VARDEF  *vp;
    
    if ((vp = varlookup(name)) == NULL)
        return(NULL);
    return(vp->def);
}


VARDEF *
varlookup(                      /* look up a variable */
        char  *name
)
{
    int  lvl = 0;
    char  *qname;
    VARDEF  *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(                      /* get a link to a variable */
        char  *name
)
{
    VARDEF  *vp;
    int  hv;
    
    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->next = hashtbl[hv];
    hashtbl[hv] = vp;
    return(vp);
}


void
libupdate(                      /* update library links */
        char  *fn
)
{
    int  i;
    VARDEF  *vp;
                                        /* 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 */
        VARDEF   *ln
)
{
    VARDEF  *vp;
    int  hv;

    if (--ln->nlinks > 0)
        return;                         /* still active */

    hv = hash(ln->name);
    vp = hashtbl[hv];
    if (vp == ln)
        hashtbl[hv] = vp->next;
    else {
        while (vp->next != ln)          /* must be in list */
                vp = vp->next;
        vp->next = ln->next;
    }
    freestr(ln->name);
    efree((char *)ln);
}


EPNODE *
dfirst(void)                    /* return pointer to first definition */
{
    htndx = 0;
    htpos = NULL;
    ochpos = outchan;
    return(dnext());
}


EPNODE *
dnext(void)                             /* return pointer to next definition */
{
    EPNODE  *ep;
    char  *nm;

    while (htndx < NHASH) {
        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);
        }
    }
    if ((ep = ochpos) != NULL)
        ochpos = ep->sibling;
    return(ep);
}


EPNODE *
dpop(                   /* pop a definition */
        char  *name
)
{
    VARDEF  *vp;
    EPNODE  *dp;
    
    if ((vp = varlookup(name)) == NULL || vp->def == NULL)
        return(NULL);
    dp = vp->def;
    vp->def = dp->sibling;
    varfree(vp);
    return(dp);
}


void
dpush(                  /* push on a definition */
        char  *nm,
        EPNODE   *ep
)
{
    VARDEF  *vp;

    vp = varinsert(nm);
    ep->sibling = vp->def;
    vp->def = ep;
}


void
addchan(                        /* add an output channel assignment */
        EPNODE  *sp
)
{
    int  ch = sp->v.kid->v.chan;
    EPNODE  *ep, *epl;

    for (epl = NULL, ep = outchan; ep != NULL; epl = ep, ep = ep->sibling)
        if (ep->v.kid->v.chan >= ch) {
            if (epl != NULL)
                epl->sibling = sp;
            else
                outchan = sp;
            if (ep->v.kid->v.chan > ch)
                sp->sibling = ep;
            else {
                sp->sibling = ep->sibling;
                epfree(ep);
            }
            return;
        }
    if (epl != NULL)
        epl->sibling = sp;
    else
        outchan = sp;
    sp->sibling = NULL;

}


void
getstatement(void)                      /* get next statement */
{
    EPNODE  *ep;
    char  *qname;
    VARDEF  *vdef;

    if (nextc == ';') {         /* empty statement */
        scan();
        return;
    }
    if (esupport&E_OUTCHAN &&
                nextc == '$') {         /* channel assignment */
        ep = getchan();
        addchan(ep);
    } else {                            /* ordinary definition */
        ep = getdefn();
        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");
            }
        }
        if (ep->type == ':')
            dremove(qname);
        else
            dclear(qname);
        dpush(qname, ep);
    }
    if (nextc != EOF) {
        if (nextc != ';')
            syntax("';' expected");
        scan();
    }
}


EPNODE *
getdefn(void)
        /* A -> SYM = E1 */
        /*      SYM : E1 */
        /*      FUNC(SYM,..) = E1 */
        /*      FUNC(SYM,..) : E1 */
{
    EPNODE  *ep1, *ep2;

    if (!isalpha(nextc) && nextc != CNTXMARK)
        syntax("illegal variable name");

    ep1 = newnode();
    ep1->type = SYM;
    ep1->v.name = savestr(getname());

    if (esupport&E_FUNCTION && nextc == '(') {
        ep2 = newnode();
        ep2->type = FUNC;
        addekid(ep2, ep1);
        ep1 = ep2;
        do {
            scan();
            if (!isalpha(nextc))
                syntax("illegal parameter name");
            ep2 = newnode();
            ep2->type = SYM;
            ep2->v.name = savestr(getname());
            addekid(ep1, ep2);
        } while (nextc == ',');
        if (nextc != ')')
            syntax("')' expected");
        scan();
        curfunc = ep1;
    }

    if (nextc != '=' && nextc != ':')
        syntax("'=' or ':' expected");

    ep2 = newnode();
    ep2->type = nextc;
    scan();
    addekid(ep2, ep1);
    addekid(ep2, getE1());

    if (ep1->type == SYM && ep1->sibling->type != NUM) {
        ep1 = newnode();
        ep1->type = CLKT;
        ep1->v.tick = 0;
        addekid(ep2, ep1);
        ep1 = newnode();
        ep1->type = NUM;
        addekid(ep2, ep1);
    }
    curfunc = NULL;

    return(ep2);
}


EPNODE *
getchan(void)                   /* A -> $N = E1 */
{
    EPNODE  *ep1, *ep2;

    if (nextc != '$')
        syntax("missing '$'");
    scan();

    ep1 = newnode();
    ep1->type = CHAN;
    ep1->v.chan = getinum();

    if (nextc != '=')
        syntax("'=' expected");
    scan();

    ep2 = newnode();
    ep2->type = '=';
    addekid(ep2, ep1);
    addekid(ep2, getE1());

    return(ep2);
}


/*
 *  The following routines are for internal use only:
 */


static double                   /* evaluate a variable */
dvalue(char  *name, EPNODE      *d)
{
    EPNODE  *ep1, *ep2;
    
    if (d == NULL || d->v.kid->type != SYM) {
        eputs(name);
        eputs(": undefined variable\n");
        quit(1);
    }
    ep1 = d->v.kid->sibling;                    /* get expression */
    if (ep1->type == NUM)
        return(ep1->v.num);                     /* return if number */
    ep2 = ep1->sibling;                         /* check time */
    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);
}
Revision:	2.25
Committed:	Sun Jul 29 22:10:45 2012 UTC (11 years, 9 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.24:	+43 -39 lines
Log Message:	Made varset() behavior identical to loading definition
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.25	static const char RCSid[] = "$Id: caldefn.c,v 2.24 2010/03/05 17:28:46 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* Store variable definitions.
6			*
7			* 7/1/85 Greg Ward
8			*
9			* 11/11/85 Added conditional compiles (OUTCHAN) for control output.
10			*
11			* 4/2/86 Added conditional compiles for function definitions (FUNCTION).
12			*
13			* 1/15/88 Added clock for caching of variable values.
14			*
15			* 11/16/88 Added VARDEF structure for hard linking.
16	greg	1.2	*
17			* 5/31/90 Added conditional compile (REDEFW) for redefinition warning.
18	greg	1.8	*
19	greg	1.10	* 4/23/91 Added ':' assignment for constant expressions
20	greg	1.13	*
21			* 8/7/91 Added optional context path to append to variable names
22	greg	2.12	*
23			* 5/17/2001 Fixed clock counter wrapping behavior
24			*
25			* 2/19/03 Eliminated conditional compiles in favor of esupport extern.
26			*/
27
28	greg	2.13	#include "copyright.h"
29	greg	1.1
30			#include <stdio.h>
31	greg	2.12	#include <string.h>
32	greg	1.1	#include <ctype.h>
33
34	schorsch	2.18	#include "rterror.h"
35	schorsch	2.22	#include "rtio.h"
36	schorsch	2.21	#include "rtmisc.h"
37	greg	1.1	#include "calcomp.h"
38
39	greg	2.4	#ifndef NHASH
40			#define NHASH 521 /* hash size (a prime!) */
41	greg	1.1	#endif
42
43	greg	2.5	#define hash(s) (shash(s)%NHASH)
44
45	greg	2.4	#define newnode() (EPNODE *)ecalloc(1, sizeof(EPNODE))
46	greg	1.1
47	schorsch	2.18	static double dvalue(char name, EPNODE d);
48	greg	1.1
49	greg	2.12	#define MAXCLOCK (1L<<31) /* clock wrap value */
50	greg	1.1
51	greg	2.8	unsigned long eclock = 0; /* value storage timer */
52	greg	1.1
53	greg	2.11	#define MAXCNTX 1023 /* maximum context length */
54	greg	1.13
55	greg	2.11	static char context[MAXCNTX+1]; /* current context path */
56
57	greg	1.1	static VARDEF hashtbl[NHASH]; / definition list */
58			static int htndx; /* index for */
59			static VARDEF htpos; / ...dfirst() and */
60			static EPNODE ochpos; / ...dnext */
61			static EPNODE *outchan;
62
63	greg	2.10	EPNODE *curfunc = NULL;
64	greg	2.4	#define dname(ep) ((ep)->v.kid->type == SYM ? \
65	greg	1.1	(ep)->v.kid->v.name : \
66			(ep)->v.kid->v.kid->v.name)
67
68
69	greg	2.12	void
70	schorsch	2.16	fcompile( /* get definitions from a file */
71			char *fname
72			)
73	greg	1.1	{
74			FILE *fp;
75
76			if (fname == NULL)
77			fp = stdin;
78			else if ((fp = fopen(fname, "r")) == NULL) {
79			eputs(fname);
80			eputs(": cannot open\n");
81			quit(1);
82			}
83	greg	1.4	initfile(fp, fname, 0);
84	greg	1.1	while (nextc != EOF)
85	greg	1.13	getstatement();
86	greg	1.1	if (fname != NULL)
87			fclose(fp);
88			}
89
90
91	greg	2.12	void
92	schorsch	2.16	scompile( /* get definitions from a string */
93			char *str,
94			char *fn,
95			int ln
96			)
97	greg	1.1	{
98	greg	1.4	initstr(str, fn, ln);
99	greg	1.1	while (nextc != EOF)
100	greg	1.13	getstatement();
101	greg	1.1	}
102
103
104			double
105	schorsch	2.16	varvalue( /* return a variable's value */
106			char *vname
107			)
108	greg	1.1	{
109			return(dvalue(vname, dlookup(vname)));
110			}
111
112
113			double
114	schorsch	2.16	evariable( /* evaluate a variable */
115			EPNODE *ep
116			)
117	greg	1.1	{
118	greg	2.25	VARDEF *dp = ep->v.ln;
119	greg	1.1
120			return(dvalue(dp->name, dp->def));
121			}
122
123
124	greg	2.12	void
125	schorsch	2.16	varset( /* set a variable's value */
126			char *vname,
127			int assign,
128			double val
129			)
130	greg	1.1	{
131	greg	1.13	char *qname;
132	greg	2.25	EPNODE ep1, ep2;
133	greg	1.13	/* get qualified name */
134			qname = qualname(vname, 0);
135	greg	1.1	/* check for quick set */
136	greg	2.25	if ((ep1 = dlookup(qname)) != NULL && ep1->v.kid->type == SYM &&
137			(ep1->type == ':') <= (assign == ':')) {
138	greg	1.1	ep2 = ep1->v.kid->sibling;
139			if (ep2->type == NUM) {
140			ep2->v.num = val;
141	greg	1.8	ep1->type = assign;
142	greg	1.1	return;
143			}
144			}
145			/* hand build definition */
146			ep1 = newnode();
147	greg	1.8	ep1->type = assign;
148	greg	1.1	ep2 = newnode();
149			ep2->type = SYM;
150			ep2->v.name = savestr(vname);
151			addekid(ep1, ep2);
152			ep2 = newnode();
153			ep2->type = NUM;
154			ep2->v.num = val;
155			addekid(ep1, ep2);
156	greg	2.25	if (assign == ':')
157			dremove(qname);
158			else
159			dclear(qname);
160	greg	1.13	dpush(qname, ep1);
161	greg	1.1	}
162
163
164	greg	2.12	void
165	schorsch	2.16	dclear( /* delete variable definitions of name */
166			char *name
167			)
168	greg	1.1	{
169	greg	2.25	EPNODE *ep;
170	greg	1.1
171	greg	1.8	while ((ep = dpop(name)) != NULL) {
172			if (ep->type == ':') {
173	greg	1.13	dpush(name, ep); /* don't clear constants */
174	greg	1.8	return;
175			}
176			epfree(ep);
177			}
178			}
179
180
181	greg	2.12	void
182	schorsch	2.16	dremove( /* delete all definitions of name */
183			char *name
184			)
185	greg	1.8	{
186	greg	2.25	EPNODE *ep;
187	greg	1.8
188	greg	1.1	while ((ep = dpop(name)) != NULL)
189			epfree(ep);
190			}
191
192
193	greg	2.12	int
194	schorsch	2.16	vardefined( /* return non-zero if variable defined */
195			char *name
196			)
197	greg	1.1	{
198	greg	2.25	EPNODE *dp;
199	greg	1.1
200			return((dp = dlookup(name)) != NULL && dp->v.kid->type == SYM);
201			}
202
203
204	greg	1.13	char *
205	schorsch	2.16	setcontext( /* set a new context path */
206	greg	2.25	char *ctx
207	schorsch	2.16	)
208	greg	1.13	{
209	greg	2.25	char *cpp;
210	greg	1.13
211			if (ctx == NULL)
212			return(context); /* just asking */
213	greg	2.6	while (*ctx == CNTXMARK)
214			ctx++; /* skip past marks */
215	greg	1.13	if (!*ctx) {
216	greg	2.6	context[0] = '\0'; /* empty means clear context */
217	greg	1.13	return(context);
218			}
219	greg	2.6	cpp = context; /* start context with mark */
220			*cpp++ = CNTXMARK;
221			do { /* carefully copy new context */
222	greg	2.11	if (cpp >= context+MAXCNTX)
223	greg	1.18	break; /* just copy what we can */
224	greg	1.13	if (isid(*ctx))
225			cpp++ = ctx++;
226			else {
227			*cpp++ = '_'; ctx++;
228			}
229			} while (*ctx);
230	greg	2.6	while (cpp[-1] == CNTXMARK) /* cannot end in context mark */
231			cpp--;
232	greg	1.13	*cpp = '\0';
233	greg	2.6	return(context);
234			}
235
236
237			char *
238	schorsch	2.16	pushcontext( /* push on another context */
239			char *ctx
240			)
241	greg	2.6	{
242	greg	2.11	char oldcontext[MAXCNTX+1];
243	greg	2.25	int n;
244	greg	2.6
245			strcpy(oldcontext, context); /* save old context */
246			setcontext(ctx); /* set new context */
247			n = strlen(context); /* tack on old */
248	greg	2.11	if (n+strlen(oldcontext) > MAXCNTX) {
249			strncpy(context+n, oldcontext, MAXCNTX-n);
250			context[MAXCNTX] = '\0';
251	greg	2.6	} else
252			strcpy(context+n, oldcontext);
253			return(context);
254			}
255
256
257			char *
258	schorsch	2.16	popcontext(void) /* pop off top context */
259	greg	2.6	{
260	greg	2.25	char cp1, cp2;
261	greg	2.6
262			if (!context[0]) /* nothing left to pop */
263			return(context);
264			cp2 = context; /* find mark */
265			while (++cp2 && cp2 != CNTXMARK)
266			;
267			cp1 = context; /* copy tail to front */
268	schorsch	2.20	while ( (cp1++ = cp2++) )
269	greg	2.6	;
270	greg	1.13	return(context);
271			}
272
273
274			char *
275	schorsch	2.16	qualname( /* get qualified name */
276	greg	2.25	char *nam,
277	schorsch	2.16	int lvl
278			)
279	greg	1.13	{
280	schorsch	2.17	static char nambuf[RMAXWORD+1];
281	greg	2.25	char cp = nambuf, cpp;
282	greg	1.17	/* check for explicit local */
283	greg	1.15	if (*nam == CNTXMARK)
284	greg	1.17	if (lvl > 0) /* only action is to refuse search */
285			return(NULL);
286			else
287			nam++;
288			else if (nam == nambuf) /* check for repeat call */
289			return(lvl > 0 ? NULL : nam);
290	greg	1.13	/* copy name to static buffer */
291			while (*nam) {
292	schorsch	2.17	if (cp >= nambuf+RMAXWORD)
293	greg	1.13	goto toolong;
294	greg	1.17	cp++ = nam++;
295	greg	1.13	}
296	greg	1.17	/* check for explicit global */
297			if (cp > nambuf && cp[-1] == CNTXMARK) {
298	greg	1.13	if (lvl > 0)
299	greg	1.17	return(NULL);
300			*--cp = '\0';
301			return(nambuf); /* already qualified */
302			}
303			cpp = context; /* else skip the requested levels */
304			while (lvl-- > 0) {
305			if (!*cpp)
306			return(NULL); /* return NULL if past global level */
307			while (++cpp && cpp != CNTXMARK)
308			;
309			}
310	greg	1.13	while (cpp) { / copy context to static buffer */
311	schorsch	2.17	if (cp >= nambuf+RMAXWORD)
312	greg	1.13	goto toolong;
313			cp++ = cpp++;
314			}
315	greg	1.18	toolong:
316	greg	1.13	*cp = '\0';
317			return(nambuf); /* return qualified name */
318			}
319
320
321	greg	2.12	int
322	schorsch	2.16	incontext( /* is qualified name in current context? */
323	greg	2.25	char *qn
324	schorsch	2.16	)
325	greg	1.14	{
326	greg	2.9	if (!context[0]) /* global context accepts all */
327			return(1);
328	greg	1.14	while (qn && qn != CNTXMARK) /* find context mark */
329	greg	1.19	qn++;
330	greg	1.14	return(!strcmp(qn, context));
331			}
332
333
334	greg	2.12	void
335	schorsch	2.16	chanout( /* set output channels */
336			void (*cs)(int n, double v)
337			)
338	greg	1.1	{
339	greg	2.25	EPNODE *ep;
340	greg	1.1
341			for (ep = outchan; ep != NULL; ep = ep->sibling)
342	greg	1.6	(*cs)(ep->v.kid->v.chan, evalue(ep->v.kid->sibling));
343	greg	1.1
344			}
345
346
347	greg	2.12	void
348	schorsch	2.16	dcleanup( /* clear definitions (0->vars,1->output,2->consts) */
349			int lvl
350			)
351	greg	1.1	{
352	greg	2.25	int i;
353			VARDEF *vp;
354			EPNODE *ep;
355	greg	1.14	/* if context is global, clear all */
356	greg	1.1	for (i = 0; i < NHASH; i++)
357			for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
358	schorsch	2.19	if (incontext(vp->name)) {
359	greg	1.14	if (lvl >= 2)
360			dremove(vp->name);
361			else
362			dclear(vp->name);
363	schorsch	2.19	}
364	greg	1.12	if (lvl >= 1) {
365	greg	1.9	for (ep = outchan; ep != NULL; ep = ep->sibling)
366			epfree(ep);
367			outchan = NULL;
368			}
369	greg	1.1	}
370
371
372			EPNODE *
373	schorsch	2.16	dlookup( /* look up a definition */
374			char *name
375			)
376	greg	1.1	{
377	greg	2.25	VARDEF *vp;
378	greg	1.1
379			if ((vp = varlookup(name)) == NULL)
380	greg	2.4	return(NULL);
381	greg	1.1	return(vp->def);
382			}
383
384
385			VARDEF *
386	schorsch	2.16	varlookup( /* look up a variable */
387			char *name
388			)
389	greg	1.1	{
390	greg	2.4	int lvl = 0;
391	greg	2.25	char *qname;
392			VARDEF *vp;
393	greg	2.4	/* find most qualified match */
394	greg	1.13	while ((qname = qualname(name, lvl++)) != NULL)
395			for (vp = hashtbl[hash(qname)]; vp != NULL; vp = vp->next)
396			if (!strcmp(vp->name, qname))
397			return(vp);
398	greg	1.1	return(NULL);
399			}
400
401
402			VARDEF *
403	schorsch	2.16	varinsert( /* get a link to a variable */
404			char *name
405			)
406	greg	1.1	{
407	greg	2.25	VARDEF *vp;
408	greg	2.4	int hv;
409	greg	1.1
410	greg	1.13	if ((vp = varlookup(name)) != NULL) {
411			vp->nlinks++;
412			return(vp);
413			}
414	greg	2.3	vp = (VARDEF *)emalloc(sizeof(VARDEF));
415			vp->lib = liblookup(name);
416			if (vp->lib == NULL) /* if name not in library */
417	greg	1.16	name = qualname(name, 0); /* use fully qualified version */
418	greg	1.1	hv = hash(name);
419			vp->name = savestr(name);
420			vp->nlinks = 1;
421			vp->def = NULL;
422			vp->next = hashtbl[hv];
423			hashtbl[hv] = vp;
424			return(vp);
425			}
426	greg	2.2
427
428	greg	2.12	void
429	schorsch	2.16	libupdate( /* update library links */
430			char *fn
431			)
432	greg	2.2	{
433	greg	2.25	int i;
434			VARDEF *vp;
435	greg	2.2	/* if fn is NULL then relink all */
436			for (i = 0; i < NHASH; i++)
437			for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
438			if (vp->lib != NULL \|\| fn == NULL \|\| !strcmp(fn, vp->name))
439			vp->lib = liblookup(vp->name);
440			}
441	greg	1.1
442
443	greg	2.12	void
444	schorsch	2.16	varfree( /* release link to variable */
445	greg	2.25	VARDEF *ln
446	schorsch	2.16	)
447	greg	1.1	{
448	greg	2.25	VARDEF *vp;
449	greg	2.4	int hv;
450	greg	1.1
451			if (--ln->nlinks > 0)
452	greg	2.4	return; /* still active */
453	greg	1.1
454			hv = hash(ln->name);
455			vp = hashtbl[hv];
456			if (vp == ln)
457	greg	2.4	hashtbl[hv] = vp->next;
458	greg	1.1	else {
459	greg	2.4	while (vp->next != ln) /* must be in list */
460			vp = vp->next;
461			vp->next = ln->next;
462	greg	1.1	}
463			freestr(ln->name);
464			efree((char *)ln);
465			}
466
467
468			EPNODE *
469	schorsch	2.16	dfirst(void) /* return pointer to first definition */
470	greg	1.1	{
471			htndx = 0;
472			htpos = NULL;
473			ochpos = outchan;
474			return(dnext());
475			}
476
477
478			EPNODE *
479	schorsch	2.16	dnext(void) /* return pointer to next definition */
480	greg	1.1	{
481	greg	2.25	EPNODE *ep;
482			char *nm;
483	greg	1.1
484			while (htndx < NHASH) {
485	greg	2.4	if (htpos == NULL)
486			htpos = hashtbl[htndx++];
487			while (htpos != NULL) {
488			ep = htpos->def;
489	greg	1.19	nm = htpos->name;
490	greg	2.4	htpos = htpos->next;
491			if (ep != NULL && incontext(nm))
492			return(ep);
493			}
494	greg	1.1	}
495			if ((ep = ochpos) != NULL)
496	greg	2.4	ochpos = ep->sibling;
497	greg	1.1	return(ep);
498			}
499
500
501			EPNODE *
502	schorsch	2.16	dpop( /* pop a definition */
503			char *name
504			)
505	greg	1.1	{
506	greg	2.25	VARDEF *vp;
507			EPNODE *dp;
508	greg	1.1
509			if ((vp = varlookup(name)) == NULL \|\| vp->def == NULL)
510	greg	2.4	return(NULL);
511	greg	1.1	dp = vp->def;
512			vp->def = dp->sibling;
513			varfree(vp);
514			return(dp);
515			}
516
517
518	greg	2.12	void
519	schorsch	2.16	dpush( /* push on a definition */
520			char *nm,
521	greg	2.25	EPNODE *ep
522	schorsch	2.16	)
523	greg	1.1	{
524	greg	2.25	VARDEF *vp;
525	greg	1.1
526	greg	1.13	vp = varinsert(nm);
527	greg	1.1	ep->sibling = vp->def;
528			vp->def = ep;
529			}
530
531
532	greg	2.12	void
533	schorsch	2.16	addchan( /* add an output channel assignment */
534			EPNODE *sp
535			)
536	greg	1.1	{
537	greg	2.4	int ch = sp->v.kid->v.chan;
538	greg	2.25	EPNODE ep, epl;
539	greg	1.1
540			for (epl = NULL, ep = outchan; ep != NULL; epl = ep, ep = ep->sibling)
541			if (ep->v.kid->v.chan >= ch) {
542			if (epl != NULL)
543			epl->sibling = sp;
544			else
545			outchan = sp;
546			if (ep->v.kid->v.chan > ch)
547			sp->sibling = ep;
548			else {
549			sp->sibling = ep->sibling;
550			epfree(ep);
551			}
552			return;
553			}
554			if (epl != NULL)
555			epl->sibling = sp;
556			else
557			outchan = sp;
558			sp->sibling = NULL;
559
560			}
561
562
563	greg	2.12	void
564	schorsch	2.16	getstatement(void) /* get next statement */
565	greg	1.1	{
566	greg	2.25	EPNODE *ep;
567	greg	1.13	char *qname;
568	greg	2.25	VARDEF *vdef;
569	greg	1.1
570			if (nextc == ';') { /* empty statement */
571			scan();
572			return;
573			}
574	greg	2.12	if (esupport&E_OUTCHAN &&
575			nextc == '$') { /* channel assignment */
576	greg	1.1	ep = getchan();
577			addchan(ep);
578	greg	2.12	} else { /* ordinary definition */
579	greg	1.1	ep = getdefn();
580	greg	1.13	qname = qualname(dname(ep), 0);
581	schorsch	2.19	if (esupport&E_REDEFW && (vdef = varlookup(qname)) != NULL) {
582	greg	2.7	if (vdef->def != NULL && epcmp(ep, vdef->def)) {
583	greg	1.16	wputs(qname);
584			if (vdef->def->type == ':')
585			wputs(": redefined constant expression\n");
586			else
587			wputs(": redefined\n");
588	greg	2.12	} else if (ep->v.kid->type == FUNC && vdef->lib != NULL) {
589	greg	1.16	wputs(qname);
590			wputs(": definition hides library function\n");
591			}
592	schorsch	2.19	}
593	greg	1.10	if (ep->type == ':')
594	greg	1.13	dremove(qname);
595	greg	1.10	else
596	greg	1.13	dclear(qname);
597			dpush(qname, ep);
598	greg	1.1	}
599			if (nextc != EOF) {
600			if (nextc != ';')
601			syntax("';' expected");
602			scan();
603			}
604			}
605
606
607			EPNODE *
608	schorsch	2.16	getdefn(void)
609			/* A -> SYM = E1 */
610			/* SYM : E1 */
611			/* FUNC(SYM,..) = E1 */
612			/* FUNC(SYM,..) : E1 */
613	greg	1.1	{
614	greg	2.25	EPNODE ep1, ep2;
615	greg	1.1
616	greg	1.18	if (!isalpha(nextc) && nextc != CNTXMARK)
617	greg	1.1	syntax("illegal variable name");
618
619			ep1 = newnode();
620			ep1->type = SYM;
621			ep1->v.name = savestr(getname());
622
623	greg	2.12	if (esupport&E_FUNCTION && nextc == '(') {
624	greg	1.1	ep2 = newnode();
625			ep2->type = FUNC;
626			addekid(ep2, ep1);
627			ep1 = ep2;
628			do {
629			scan();
630			if (!isalpha(nextc))
631	greg	2.24	syntax("illegal parameter name");
632	greg	1.1	ep2 = newnode();
633			ep2->type = SYM;
634			ep2->v.name = savestr(getname());
635			addekid(ep1, ep2);
636			} while (nextc == ',');
637			if (nextc != ')')
638			syntax("')' expected");
639			scan();
640			curfunc = ep1;
641	greg	2.10	}
642	greg	1.1
643	greg	1.8	if (nextc != '=' && nextc != ':')
644			syntax("'=' or ':' expected");
645	greg	1.1
646			ep2 = newnode();
647	greg	1.8	ep2->type = nextc;
648			scan();
649	greg	1.1	addekid(ep2, ep1);
650			addekid(ep2, getE1());
651
652	greg	2.12	if (ep1->type == SYM && ep1->sibling->type != NUM) {
653	greg	1.1	ep1 = newnode();
654	greg	2.23	ep1->type = CLKT;
655	greg	2.8	ep1->v.tick = 0;
656	greg	1.1	addekid(ep2, ep1);
657			ep1 = newnode();
658			ep1->type = NUM;
659			addekid(ep2, ep1);
660			}
661	greg	2.10	curfunc = NULL;
662	greg	1.1
663			return(ep2);
664			}
665
666
667			EPNODE *
668	schorsch	2.16	getchan(void) /* A -> $N = E1 */
669	greg	1.1	{
670	greg	2.25	EPNODE ep1, ep2;
671	greg	1.1
672			if (nextc != '$')
673			syntax("missing '$'");
674			scan();
675
676			ep1 = newnode();
677			ep1->type = CHAN;
678			ep1->v.chan = getinum();
679
680			if (nextc != '=')
681			syntax("'=' expected");
682			scan();
683
684			ep2 = newnode();
685			ep2->type = '=';
686			addekid(ep2, ep1);
687			addekid(ep2, getE1());
688
689			return(ep2);
690			}
691
692
693
694			/*
695			* The following routines are for internal use only:
696			*/
697
698
699	schorsch	2.18	static double /* evaluate a variable */
700			dvalue(char name, EPNODE d)
701	greg	1.1	{
702	greg	2.25	EPNODE ep1, ep2;
703	greg	1.1
704			if (d == NULL \|\| d->v.kid->type != SYM) {
705			eputs(name);
706			eputs(": undefined variable\n");
707			quit(1);
708			}
709			ep1 = d->v.kid->sibling; /* get expression */
710	greg	1.5	if (ep1->type == NUM)
711			return(ep1->v.num); /* return if number */
712	greg	1.1	ep2 = ep1->sibling; /* check time */
713	greg	2.12	if (eclock >= MAXCLOCK)
714			eclock = 1; /* wrap clock counter */
715			if (ep2->v.tick < MAXCLOCK &&
716	schorsch	2.20	(ep2->v.tick == 0) \| (ep2->v.tick != eclock)) {
717	greg	2.12	ep2->v.tick = d->type == ':' ? MAXCLOCK : eclock;
718	greg	1.1	ep2 = ep2->sibling;
719	greg	1.5	ep2->v.num = evalue(ep1); /* needs new value */
720	greg	1.1	} else
721	greg	1.5	ep2 = ep2->sibling; /* else reuse old value */
722	greg	1.1
723			return(ep2->v.num);
724			}