src/common/caldefn.c

#ifndef lint
static const char       RCSid[] = "$Id: caldefn.c,v 2.30 2022/03/12 15:50:13 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  <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;
        }
    }
    if (ep1 != NULL && esupport&E_REDEFW) {
        wputs(qname);
        if (ep1->type == ':')
            wputs(": reset constant expression\n");
        else
            wputs(": reset expression\n");
    }
                                        /* 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 '=' or ':' if variable/constant defined */
        char  *name
)
{
    EPNODE  *dp = dlookup(name);

    if (dp == NULL || dp->v.kid->type != SYM)
        return(0);

    return(dp->type);
}


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());
            if (strchr(ep2->v.name, CNTXMARK) != NULL)
                syntax("illegal parameter name");
            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 */
    if (esupport&E_RCONST && d->type == ':') {
        wputs(name);
        wputs(": assigned non-constant value\n");
    }
    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:	2.31
Committed:	Sat Mar 12 17:21:10 2022 UTC (2 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.30:	+4 -3 lines
Log Message:	style: Minor code cleanup
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.31	static const char RCSid[] = "$Id: caldefn.c,v 2.30 2022/03/12 15:50:13 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 <ctype.h>
31
32	schorsch	2.18	#include "rterror.h"
33	schorsch	2.22	#include "rtio.h"
34	schorsch	2.21	#include "rtmisc.h"
35	greg	1.1	#include "calcomp.h"
36
37	greg	2.4	#ifndef NHASH
38			#define NHASH 521 /* hash size (a prime!) */
39	greg	1.1	#endif
40
41	greg	2.5	#define hash(s) (shash(s)%NHASH)
42
43	greg	2.4	#define newnode() (EPNODE *)ecalloc(1, sizeof(EPNODE))
44	greg	1.1
45	schorsch	2.18	static double dvalue(char name, EPNODE d);
46	greg	1.1
47	greg	2.12	#define MAXCLOCK (1L<<31) /* clock wrap value */
48	greg	1.1
49	greg	2.8	unsigned long eclock = 0; /* value storage timer */
50	greg	1.1
51	greg	2.11	#define MAXCNTX 1023 /* maximum context length */
52	greg	1.13
53	greg	2.11	static char context[MAXCNTX+1]; /* current context path */
54
55	greg	1.1	static VARDEF hashtbl[NHASH]; / definition list */
56			static int htndx; /* index for */
57			static VARDEF htpos; / ...dfirst() and */
58			static EPNODE ochpos; / ...dnext */
59			static EPNODE *outchan;
60
61	greg	2.10	EPNODE *curfunc = NULL;
62	greg	2.4	#define dname(ep) ((ep)->v.kid->type == SYM ? \
63	greg	1.1	(ep)->v.kid->v.name : \
64			(ep)->v.kid->v.kid->v.name)
65
66
67	greg	2.12	void
68	schorsch	2.16	fcompile( /* get definitions from a file */
69			char *fname
70			)
71	greg	1.1	{
72			FILE *fp;
73
74			if (fname == NULL)
75			fp = stdin;
76			else if ((fp = fopen(fname, "r")) == NULL) {
77			eputs(fname);
78			eputs(": cannot open\n");
79			quit(1);
80			}
81	greg	1.4	initfile(fp, fname, 0);
82	greg	1.1	while (nextc != EOF)
83	greg	1.13	getstatement();
84	greg	1.1	if (fname != NULL)
85			fclose(fp);
86			}
87
88
89	greg	2.12	void
90	schorsch	2.16	scompile( /* get definitions from a string */
91			char *str,
92			char *fn,
93			int ln
94			)
95	greg	1.1	{
96	greg	1.4	initstr(str, fn, ln);
97	greg	1.1	while (nextc != EOF)
98	greg	1.13	getstatement();
99	greg	1.1	}
100
101
102			double
103	schorsch	2.16	varvalue( /* return a variable's value */
104			char *vname
105			)
106	greg	1.1	{
107			return(dvalue(vname, dlookup(vname)));
108			}
109
110
111			double
112	schorsch	2.16	evariable( /* evaluate a variable */
113			EPNODE *ep
114			)
115	greg	1.1	{
116	greg	2.25	VARDEF *dp = ep->v.ln;
117	greg	1.1
118			return(dvalue(dp->name, dp->def));
119			}
120
121
122	greg	2.12	void
123	schorsch	2.16	varset( /* set a variable's value */
124			char *vname,
125			int assign,
126			double val
127			)
128	greg	1.1	{
129	greg	1.13	char *qname;
130	greg	2.25	EPNODE ep1, ep2;
131	greg	1.13	/* get qualified name */
132			qname = qualname(vname, 0);
133	greg	1.1	/* check for quick set */
134	greg	2.25	if ((ep1 = dlookup(qname)) != NULL && ep1->v.kid->type == SYM &&
135			(ep1->type == ':') <= (assign == ':')) {
136	greg	1.1	ep2 = ep1->v.kid->sibling;
137			if (ep2->type == NUM) {
138			ep2->v.num = val;
139	greg	1.8	ep1->type = assign;
140	greg	1.1	return;
141			}
142			}
143	greg	2.26	if (ep1 != NULL && esupport&E_REDEFW) {
144			wputs(qname);
145			if (ep1->type == ':')
146			wputs(": reset constant expression\n");
147			else
148			wputs(": reset expression\n");
149			}
150	greg	1.1	/* hand build definition */
151			ep1 = newnode();
152	greg	1.8	ep1->type = assign;
153	greg	1.1	ep2 = newnode();
154			ep2->type = SYM;
155			ep2->v.name = savestr(vname);
156			addekid(ep1, ep2);
157			ep2 = newnode();
158			ep2->type = NUM;
159			ep2->v.num = val;
160			addekid(ep1, ep2);
161	greg	2.25	if (assign == ':')
162			dremove(qname);
163			else
164			dclear(qname);
165	greg	1.13	dpush(qname, ep1);
166	greg	1.1	}
167
168
169	greg	2.12	void
170	schorsch	2.16	dclear( /* delete variable definitions of name */
171			char *name
172			)
173	greg	1.1	{
174	greg	2.25	EPNODE *ep;
175	greg	1.1
176	greg	1.8	while ((ep = dpop(name)) != NULL) {
177			if (ep->type == ':') {
178	greg	1.13	dpush(name, ep); /* don't clear constants */
179	greg	1.8	return;
180			}
181			epfree(ep);
182			}
183			}
184
185
186	greg	2.12	void
187	schorsch	2.16	dremove( /* delete all definitions of name */
188			char *name
189			)
190	greg	1.8	{
191	greg	2.25	EPNODE *ep;
192	greg	1.8
193	greg	1.1	while ((ep = dpop(name)) != NULL)
194			epfree(ep);
195			}
196
197
198	greg	2.12	int
199	greg	2.30	vardefined( /* return '=' or ':' if variable/constant defined */
200	schorsch	2.16	char *name
201			)
202	greg	1.1	{
203	greg	2.31	EPNODE *dp = dlookup(name);
204	greg	1.1
205	greg	2.31	if (dp == NULL \|\| dp->v.kid->type != SYM)
206	greg	2.30	return(0);
207	greg	2.31
208	greg	2.30	return(dp->type);
209	greg	1.1	}
210
211
212	greg	1.13	char *
213	schorsch	2.16	setcontext( /* set a new context path */
214	greg	2.25	char *ctx
215	schorsch	2.16	)
216	greg	1.13	{
217	greg	2.25	char *cpp;
218	greg	1.13
219			if (ctx == NULL)
220			return(context); /* just asking */
221	greg	2.6	while (*ctx == CNTXMARK)
222			ctx++; /* skip past marks */
223	greg	1.13	if (!*ctx) {
224	greg	2.6	context[0] = '\0'; /* empty means clear context */
225	greg	1.13	return(context);
226			}
227	greg	2.6	cpp = context; /* start context with mark */
228			*cpp++ = CNTXMARK;
229			do { /* carefully copy new context */
230	greg	2.11	if (cpp >= context+MAXCNTX)
231	greg	1.18	break; /* just copy what we can */
232	greg	1.13	if (isid(*ctx))
233			cpp++ = ctx++;
234			else {
235			*cpp++ = '_'; ctx++;
236			}
237			} while (*ctx);
238	greg	2.6	while (cpp[-1] == CNTXMARK) /* cannot end in context mark */
239			cpp--;
240	greg	1.13	*cpp = '\0';
241	greg	2.6	return(context);
242			}
243
244
245			char *
246	schorsch	2.16	pushcontext( /* push on another context */
247			char *ctx
248			)
249	greg	2.6	{
250	greg	2.11	char oldcontext[MAXCNTX+1];
251	greg	2.25	int n;
252	greg	2.6
253			strcpy(oldcontext, context); /* save old context */
254			setcontext(ctx); /* set new context */
255			n = strlen(context); /* tack on old */
256	greg	2.11	if (n+strlen(oldcontext) > MAXCNTX) {
257			strncpy(context+n, oldcontext, MAXCNTX-n);
258			context[MAXCNTX] = '\0';
259	greg	2.6	} else
260			strcpy(context+n, oldcontext);
261			return(context);
262			}
263
264
265			char *
266	schorsch	2.16	popcontext(void) /* pop off top context */
267	greg	2.6	{
268	greg	2.25	char cp1, cp2;
269	greg	2.6
270			if (!context[0]) /* nothing left to pop */
271			return(context);
272			cp2 = context; /* find mark */
273			while (++cp2 && cp2 != CNTXMARK)
274			;
275			cp1 = context; /* copy tail to front */
276	schorsch	2.20	while ( (cp1++ = cp2++) )
277	greg	2.6	;
278	greg	1.13	return(context);
279			}
280
281
282			char *
283	schorsch	2.16	qualname( /* get qualified name */
284	greg	2.25	char *nam,
285	schorsch	2.16	int lvl
286			)
287	greg	1.13	{
288	schorsch	2.17	static char nambuf[RMAXWORD+1];
289	greg	2.25	char cp = nambuf, cpp;
290	greg	1.17	/* check for explicit local */
291	greg	1.15	if (*nam == CNTXMARK)
292	greg	1.17	if (lvl > 0) /* only action is to refuse search */
293			return(NULL);
294			else
295			nam++;
296			else if (nam == nambuf) /* check for repeat call */
297			return(lvl > 0 ? NULL : nam);
298	greg	1.13	/* copy name to static buffer */
299			while (*nam) {
300	schorsch	2.17	if (cp >= nambuf+RMAXWORD)
301	greg	1.13	goto toolong;
302	greg	1.17	cp++ = nam++;
303	greg	1.13	}
304	greg	1.17	/* check for explicit global */
305			if (cp > nambuf && cp[-1] == CNTXMARK) {
306	greg	1.13	if (lvl > 0)
307	greg	1.17	return(NULL);
308			*--cp = '\0';
309			return(nambuf); /* already qualified */
310			}
311			cpp = context; /* else skip the requested levels */
312			while (lvl-- > 0) {
313			if (!*cpp)
314			return(NULL); /* return NULL if past global level */
315			while (++cpp && cpp != CNTXMARK)
316			;
317			}
318	greg	1.13	while (cpp) { / copy context to static buffer */
319	schorsch	2.17	if (cp >= nambuf+RMAXWORD)
320	greg	1.13	goto toolong;
321			cp++ = cpp++;
322			}
323	greg	1.18	toolong:
324	greg	1.13	*cp = '\0';
325			return(nambuf); /* return qualified name */
326			}
327
328
329	greg	2.12	int
330	schorsch	2.16	incontext( /* is qualified name in current context? */
331	greg	2.25	char *qn
332	schorsch	2.16	)
333	greg	1.14	{
334	greg	2.9	if (!context[0]) /* global context accepts all */
335			return(1);
336	greg	1.14	while (qn && qn != CNTXMARK) /* find context mark */
337	greg	1.19	qn++;
338	greg	1.14	return(!strcmp(qn, context));
339			}
340
341
342	greg	2.12	void
343	schorsch	2.16	chanout( /* set output channels */
344			void (*cs)(int n, double v)
345			)
346	greg	1.1	{
347	greg	2.25	EPNODE *ep;
348	greg	1.1
349			for (ep = outchan; ep != NULL; ep = ep->sibling)
350	greg	1.6	(*cs)(ep->v.kid->v.chan, evalue(ep->v.kid->sibling));
351	greg	1.1
352			}
353
354
355	greg	2.12	void
356	schorsch	2.16	dcleanup( /* clear definitions (0->vars,1->output,2->consts) */
357			int lvl
358			)
359	greg	1.1	{
360	greg	2.25	int i;
361			VARDEF *vp;
362			EPNODE *ep;
363	greg	1.14	/* if context is global, clear all */
364	greg	1.1	for (i = 0; i < NHASH; i++)
365			for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
366	schorsch	2.19	if (incontext(vp->name)) {
367	greg	1.14	if (lvl >= 2)
368			dremove(vp->name);
369			else
370			dclear(vp->name);
371	schorsch	2.19	}
372	greg	1.12	if (lvl >= 1) {
373	greg	1.9	for (ep = outchan; ep != NULL; ep = ep->sibling)
374			epfree(ep);
375			outchan = NULL;
376			}
377	greg	1.1	}
378
379
380			EPNODE *
381	schorsch	2.16	dlookup( /* look up a definition */
382			char *name
383			)
384	greg	1.1	{
385	greg	2.25	VARDEF *vp;
386	greg	1.1
387			if ((vp = varlookup(name)) == NULL)
388	greg	2.4	return(NULL);
389	greg	1.1	return(vp->def);
390			}
391
392
393			VARDEF *
394	schorsch	2.16	varlookup( /* look up a variable */
395			char *name
396			)
397	greg	1.1	{
398	greg	2.4	int lvl = 0;
399	greg	2.25	char *qname;
400			VARDEF *vp;
401	greg	2.4	/* find most qualified match */
402	greg	1.13	while ((qname = qualname(name, lvl++)) != NULL)
403			for (vp = hashtbl[hash(qname)]; vp != NULL; vp = vp->next)
404			if (!strcmp(vp->name, qname))
405			return(vp);
406	greg	1.1	return(NULL);
407			}
408
409
410			VARDEF *
411	schorsch	2.16	varinsert( /* get a link to a variable */
412			char *name
413			)
414	greg	1.1	{
415	greg	2.25	VARDEF *vp;
416	greg	2.4	int hv;
417	greg	1.1
418	greg	1.13	if ((vp = varlookup(name)) != NULL) {
419			vp->nlinks++;
420			return(vp);
421			}
422	greg	2.3	vp = (VARDEF *)emalloc(sizeof(VARDEF));
423			vp->lib = liblookup(name);
424			if (vp->lib == NULL) /* if name not in library */
425	greg	1.16	name = qualname(name, 0); /* use fully qualified version */
426	greg	1.1	hv = hash(name);
427			vp->name = savestr(name);
428			vp->nlinks = 1;
429			vp->def = NULL;
430			vp->next = hashtbl[hv];
431			hashtbl[hv] = vp;
432			return(vp);
433			}
434	greg	2.2
435
436	greg	2.12	void
437	schorsch	2.16	libupdate( /* update library links */
438			char *fn
439			)
440	greg	2.2	{
441	greg	2.25	int i;
442			VARDEF *vp;
443	greg	2.2	/* if fn is NULL then relink all */
444			for (i = 0; i < NHASH; i++)
445			for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
446			if (vp->lib != NULL \|\| fn == NULL \|\| !strcmp(fn, vp->name))
447			vp->lib = liblookup(vp->name);
448			}
449	greg	1.1
450
451	greg	2.12	void
452	schorsch	2.16	varfree( /* release link to variable */
453	greg	2.25	VARDEF *ln
454	schorsch	2.16	)
455	greg	1.1	{
456	greg	2.25	VARDEF *vp;
457	greg	2.4	int hv;
458	greg	1.1
459			if (--ln->nlinks > 0)
460	greg	2.4	return; /* still active */
461	greg	1.1
462			hv = hash(ln->name);
463			vp = hashtbl[hv];
464			if (vp == ln)
465	greg	2.4	hashtbl[hv] = vp->next;
466	greg	1.1	else {
467	greg	2.4	while (vp->next != ln) /* must be in list */
468			vp = vp->next;
469			vp->next = ln->next;
470	greg	1.1	}
471			freestr(ln->name);
472			efree((char *)ln);
473			}
474
475
476			EPNODE *
477	schorsch	2.16	dfirst(void) /* return pointer to first definition */
478	greg	1.1	{
479			htndx = 0;
480			htpos = NULL;
481			ochpos = outchan;
482			return(dnext());
483			}
484
485
486			EPNODE *
487	schorsch	2.16	dnext(void) /* return pointer to next definition */
488	greg	1.1	{
489	greg	2.25	EPNODE *ep;
490			char *nm;
491	greg	1.1
492			while (htndx < NHASH) {
493	greg	2.4	if (htpos == NULL)
494			htpos = hashtbl[htndx++];
495			while (htpos != NULL) {
496			ep = htpos->def;
497	greg	1.19	nm = htpos->name;
498	greg	2.4	htpos = htpos->next;
499			if (ep != NULL && incontext(nm))
500			return(ep);
501			}
502	greg	1.1	}
503			if ((ep = ochpos) != NULL)
504	greg	2.4	ochpos = ep->sibling;
505	greg	1.1	return(ep);
506			}
507
508
509			EPNODE *
510	schorsch	2.16	dpop( /* pop a definition */
511			char *name
512			)
513	greg	1.1	{
514	greg	2.25	VARDEF *vp;
515			EPNODE *dp;
516	greg	1.1
517			if ((vp = varlookup(name)) == NULL \|\| vp->def == NULL)
518	greg	2.4	return(NULL);
519	greg	1.1	dp = vp->def;
520			vp->def = dp->sibling;
521			varfree(vp);
522			return(dp);
523			}
524
525
526	greg	2.12	void
527	schorsch	2.16	dpush( /* push on a definition */
528			char *nm,
529	greg	2.25	EPNODE *ep
530	schorsch	2.16	)
531	greg	1.1	{
532	greg	2.25	VARDEF *vp;
533	greg	1.1
534	greg	1.13	vp = varinsert(nm);
535	greg	1.1	ep->sibling = vp->def;
536			vp->def = ep;
537			}
538
539
540	greg	2.12	void
541	schorsch	2.16	addchan( /* add an output channel assignment */
542			EPNODE *sp
543			)
544	greg	1.1	{
545	greg	2.4	int ch = sp->v.kid->v.chan;
546	greg	2.25	EPNODE ep, epl;
547	greg	1.1
548			for (epl = NULL, ep = outchan; ep != NULL; epl = ep, ep = ep->sibling)
549			if (ep->v.kid->v.chan >= ch) {
550			if (epl != NULL)
551			epl->sibling = sp;
552			else
553			outchan = sp;
554			if (ep->v.kid->v.chan > ch)
555			sp->sibling = ep;
556			else {
557			sp->sibling = ep->sibling;
558			epfree(ep);
559			}
560			return;
561			}
562			if (epl != NULL)
563			epl->sibling = sp;
564			else
565			outchan = sp;
566			sp->sibling = NULL;
567
568			}
569
570
571	greg	2.12	void
572	schorsch	2.16	getstatement(void) /* get next statement */
573	greg	1.1	{
574	greg	2.25	EPNODE *ep;
575	greg	1.13	char *qname;
576	greg	2.25	VARDEF *vdef;
577	greg	1.1
578			if (nextc == ';') { /* empty statement */
579			scan();
580			return;
581			}
582	greg	2.12	if (esupport&E_OUTCHAN &&
583			nextc == '$') { /* channel assignment */
584	greg	1.1	ep = getchan();
585			addchan(ep);
586	greg	2.12	} else { /* ordinary definition */
587	greg	1.1	ep = getdefn();
588	greg	1.13	qname = qualname(dname(ep), 0);
589	schorsch	2.19	if (esupport&E_REDEFW && (vdef = varlookup(qname)) != NULL) {
590	greg	2.7	if (vdef->def != NULL && epcmp(ep, vdef->def)) {
591	greg	1.16	wputs(qname);
592			if (vdef->def->type == ':')
593			wputs(": redefined constant expression\n");
594			else
595			wputs(": redefined\n");
596	greg	2.12	} else if (ep->v.kid->type == FUNC && vdef->lib != NULL) {
597	greg	1.16	wputs(qname);
598			wputs(": definition hides library function\n");
599			}
600	schorsch	2.19	}
601	greg	1.10	if (ep->type == ':')
602	greg	1.13	dremove(qname);
603	greg	1.10	else
604	greg	1.13	dclear(qname);
605			dpush(qname, ep);
606	greg	1.1	}
607			if (nextc != EOF) {
608			if (nextc != ';')
609			syntax("';' expected");
610			scan();
611			}
612			}
613
614
615			EPNODE *
616	schorsch	2.16	getdefn(void)
617			/* A -> SYM = E1 */
618			/* SYM : E1 */
619			/* FUNC(SYM,..) = E1 */
620			/* FUNC(SYM,..) : E1 */
621	greg	1.1	{
622	greg	2.25	EPNODE ep1, ep2;
623	greg	1.1
624	greg	1.18	if (!isalpha(nextc) && nextc != CNTXMARK)
625	greg	1.1	syntax("illegal variable name");
626
627			ep1 = newnode();
628			ep1->type = SYM;
629			ep1->v.name = savestr(getname());
630
631	greg	2.12	if (esupport&E_FUNCTION && nextc == '(') {
632	greg	1.1	ep2 = newnode();
633			ep2->type = FUNC;
634			addekid(ep2, ep1);
635			ep1 = ep2;
636			do {
637			scan();
638			if (!isalpha(nextc))
639	greg	2.24	syntax("illegal parameter name");
640	greg	1.1	ep2 = newnode();
641			ep2->type = SYM;
642			ep2->v.name = savestr(getname());
643	greg	2.29	if (strchr(ep2->v.name, CNTXMARK) != NULL)
644			syntax("illegal parameter name");
645	greg	1.1	addekid(ep1, ep2);
646			} while (nextc == ',');
647			if (nextc != ')')
648			syntax("')' expected");
649			scan();
650			curfunc = ep1;
651	greg	2.10	}
652	greg	1.1
653	greg	1.8	if (nextc != '=' && nextc != ':')
654			syntax("'=' or ':' expected");
655	greg	1.1
656			ep2 = newnode();
657	greg	1.8	ep2->type = nextc;
658			scan();
659	greg	1.1	addekid(ep2, ep1);
660			addekid(ep2, getE1());
661
662	greg	2.12	if (ep1->type == SYM && ep1->sibling->type != NUM) {
663	greg	1.1	ep1 = newnode();
664	greg	2.23	ep1->type = CLKT;
665	greg	2.8	ep1->v.tick = 0;
666	greg	1.1	addekid(ep2, ep1);
667			ep1 = newnode();
668			ep1->type = NUM;
669			addekid(ep2, ep1);
670			}
671	greg	2.10	curfunc = NULL;
672	greg	1.1
673			return(ep2);
674			}
675
676
677			EPNODE *
678	schorsch	2.16	getchan(void) /* A -> $N = E1 */
679	greg	1.1	{
680	greg	2.25	EPNODE ep1, ep2;
681	greg	1.1
682			if (nextc != '$')
683			syntax("missing '$'");
684			scan();
685
686			ep1 = newnode();
687			ep1->type = CHAN;
688			ep1->v.chan = getinum();
689
690			if (nextc != '=')
691			syntax("'=' expected");
692			scan();
693
694			ep2 = newnode();
695			ep2->type = '=';
696			addekid(ep2, ep1);
697			addekid(ep2, getE1());
698
699			return(ep2);
700			}
701
702
703
704			/*
705			* The following routines are for internal use only:
706			*/
707
708
709	schorsch	2.18	static double /* evaluate a variable */
710	greg	2.28	dvalue(char name, EPNODE d)
711	greg	1.1	{
712	greg	2.25	EPNODE ep1, ep2;
713	greg	1.1
714			if (d == NULL \|\| d->v.kid->type != SYM) {
715			eputs(name);
716			eputs(": undefined variable\n");
717			quit(1);
718			}
719			ep1 = d->v.kid->sibling; /* get expression */
720	greg	1.5	if (ep1->type == NUM)
721			return(ep1->v.num); /* return if number */
722	greg	2.28	if (esupport&E_RCONST && d->type == ':') {
723			wputs(name);
724			wputs(": assigned non-constant value\n");
725			}
726	greg	1.1	ep2 = ep1->sibling; /* check time */
727	greg	2.12	if (eclock >= MAXCLOCK)
728			eclock = 1; /* wrap clock counter */
729			if (ep2->v.tick < MAXCLOCK &&
730	schorsch	2.20	(ep2->v.tick == 0) \| (ep2->v.tick != eclock)) {
731	greg	2.12	ep2->v.tick = d->type == ':' ? MAXCLOCK : eclock;
732	greg	1.1	ep2 = ep2->sibling;
733	greg	1.5	ep2->v.num = evalue(ep1); /* needs new value */
734	greg	1.1	} else
735	greg	1.5	ep2 = ep2->sibling; /* else reuse old value */
736	greg	1.1
737			return(ep2->v.num);
738			}