1 |
#ifndef lint |
2 |
static const char RCSid[] = "$Id: caldefn.c,v 2.40 2024/09/16 17:31:14 greg Exp $"; |
3 |
#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 |
* |
17 |
* 5/31/90 Added conditional compile (REDEFW) for redefinition warning. |
18 |
* |
19 |
* 4/23/91 Added ':' assignment for constant expressions |
20 |
* |
21 |
* 8/7/91 Added optional context path to append to variable names |
22 |
* |
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 |
#include "copyright.h" |
29 |
|
30 |
#include <ctype.h> |
31 |
|
32 |
#include "rterror.h" |
33 |
#include "rtio.h" |
34 |
#include "rtmisc.h" |
35 |
#include "calcomp.h" |
36 |
|
37 |
#ifndef NHASH |
38 |
#define NHASH 521 /* hash size (a prime!) */ |
39 |
#endif |
40 |
|
41 |
#define hash(s) (shash(s)%NHASH) |
42 |
|
43 |
#define newnode() (EPNODE *)ecalloc(1, sizeof(EPNODE)) |
44 |
|
45 |
static double dvalue(char *name, EPNODE *d); |
46 |
|
47 |
#define MAXCLOCK (1L<<31) /* clock wrap value */ |
48 |
|
49 |
unsigned long eclock = 0; /* value storage timer */ |
50 |
|
51 |
#define MAXCNTX 1023 /* maximum context length */ |
52 |
|
53 |
static char context[MAXCNTX+1]; /* current context path */ |
54 |
|
55 |
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 |
static int optimized = 0; /* are we optimized? */ |
62 |
|
63 |
EPNODE *ecurfunc = NULL; |
64 |
|
65 |
|
66 |
void |
67 |
fcompile( /* get definitions from a file */ |
68 |
char *fname |
69 |
) |
70 |
{ |
71 |
FILE *fp; |
72 |
|
73 |
if (fname == NULL) |
74 |
fp = stdin; |
75 |
else if ((fp = fopen(fname, "r")) == NULL) { |
76 |
eputs(fname); |
77 |
eputs(": cannot open\n"); |
78 |
quit(1); |
79 |
} |
80 |
#ifdef getc_unlocked /* avoid stupid semaphores */ |
81 |
flockfile(fp); |
82 |
#endif |
83 |
initfile(fp, fname, 0); |
84 |
while (nextc != EOF) |
85 |
egetstatement(); |
86 |
if (fname != NULL) |
87 |
fclose(fp); |
88 |
#ifdef getc_unlocked |
89 |
else |
90 |
funlockfile(fp); |
91 |
#endif |
92 |
} |
93 |
|
94 |
|
95 |
void |
96 |
scompile( /* get definitions from a string */ |
97 |
char *str, |
98 |
char *fn, |
99 |
int ln |
100 |
) |
101 |
{ |
102 |
initstr(str, fn, ln); |
103 |
while (nextc != EOF) |
104 |
egetstatement(); |
105 |
} |
106 |
|
107 |
|
108 |
double |
109 |
varvalue( /* return a variable's value */ |
110 |
char *vname |
111 |
) |
112 |
{ |
113 |
return(dvalue(vname, dlookup(vname))); |
114 |
} |
115 |
|
116 |
|
117 |
double |
118 |
evariable( /* evaluate a variable */ |
119 |
EPNODE *ep |
120 |
) |
121 |
{ |
122 |
VARDEF *dp = ep->v.ln; |
123 |
|
124 |
return(dvalue(dp->name, dp->def)); |
125 |
} |
126 |
|
127 |
|
128 |
void |
129 |
varset( /* set a variable's value */ |
130 |
char *vname, |
131 |
int assign, |
132 |
double val |
133 |
) |
134 |
{ |
135 |
char *qname; |
136 |
EPNODE *ep1, *ep2; |
137 |
/* get qualified name */ |
138 |
qname = qualname(vname, 0); |
139 |
/* check for quick set */ |
140 |
if ((ep1 = dlookup(qname)) != NULL && ep1->v.kid->type == SYM && |
141 |
(ep1->type == ':') <= (assign == ':')) { |
142 |
ep2 = ep1->v.kid->sibling; |
143 |
if (ep2->type == NUM) { |
144 |
ep2->v.num = val; |
145 |
ep1->type = assign; |
146 |
return; |
147 |
} |
148 |
} |
149 |
if (ep1 != NULL && esupport&E_REDEFW) { |
150 |
wputs(qname); |
151 |
if (ep1->type == ':') |
152 |
wputs(": reset constant expression\n"); |
153 |
else |
154 |
wputs(": reset expression\n"); |
155 |
} |
156 |
/* hand build definition */ |
157 |
ep1 = newnode(); |
158 |
ep1->type = assign; |
159 |
ep2 = newnode(); |
160 |
ep2->type = SYM; |
161 |
ep2->v.name = savestr(vname); |
162 |
addekid(ep1, ep2); |
163 |
ep2 = newnode(); |
164 |
ep2->type = NUM; |
165 |
ep2->v.num = val; |
166 |
addekid(ep1, ep2); |
167 |
if (assign == ':') |
168 |
dremove(qname); |
169 |
else |
170 |
dclear(qname); |
171 |
dpush(qname, ep1); |
172 |
} |
173 |
|
174 |
|
175 |
void |
176 |
dclear( /* delete variable definitions of name */ |
177 |
char *name |
178 |
) |
179 |
{ |
180 |
VARDEF *vp; |
181 |
EPNODE *dp; |
182 |
|
183 |
while ((vp = varlookup(name)) != NULL && |
184 |
(dp = vp->def) != NULL && dp->type == '=') { |
185 |
vp->def = dp->sibling; |
186 |
epfree(dp,1); |
187 |
varfree(vp); |
188 |
} |
189 |
} |
190 |
|
191 |
|
192 |
void |
193 |
dremove( /* delete all definitions of name */ |
194 |
char *name |
195 |
) |
196 |
{ |
197 |
EPNODE *ep; |
198 |
|
199 |
while ((ep = dpop(name)) != NULL) |
200 |
epfree(ep,1); |
201 |
} |
202 |
|
203 |
|
204 |
int |
205 |
vardefined( /* return '=' or ':' if variable/constant defined */ |
206 |
char *name |
207 |
) |
208 |
{ |
209 |
EPNODE *dp = dlookup(name); |
210 |
|
211 |
if (dp == NULL || dp->v.kid->type != SYM) |
212 |
return(0); |
213 |
|
214 |
return(dp->type); |
215 |
} |
216 |
|
217 |
|
218 |
char * |
219 |
calcontext( /* set a new context path */ |
220 |
char *ctx |
221 |
) |
222 |
{ |
223 |
char *cpp; |
224 |
|
225 |
if (ctx == NULL) |
226 |
return(context); /* just asking */ |
227 |
while (*ctx == CNTXMARK) |
228 |
ctx++; /* skip past marks */ |
229 |
if (!*ctx) { |
230 |
context[0] = '\0'; /* empty means clear context */ |
231 |
return(context); |
232 |
} |
233 |
cpp = context; /* start context with mark */ |
234 |
*cpp++ = CNTXMARK; |
235 |
do { /* carefully copy new context */ |
236 |
if (cpp >= context+MAXCNTX) |
237 |
break; /* just copy what we can */ |
238 |
if (isid(*ctx)) |
239 |
*cpp++ = *ctx++; |
240 |
else { |
241 |
*cpp++ = '_'; ctx++; |
242 |
} |
243 |
} while (*ctx); |
244 |
while (cpp[-1] == CNTXMARK) /* cannot end in context mark */ |
245 |
cpp--; |
246 |
*cpp = '\0'; |
247 |
return(context); |
248 |
} |
249 |
|
250 |
|
251 |
char * |
252 |
pushcontext( /* push on another context */ |
253 |
char *ctx |
254 |
) |
255 |
{ |
256 |
char oldcontext[MAXCNTX+1]; |
257 |
int n; |
258 |
|
259 |
strcpy(oldcontext, context); /* save old context */ |
260 |
calcontext(ctx); /* set new context */ |
261 |
n = strlen(context); /* tack on old */ |
262 |
if (n+strlen(oldcontext) > MAXCNTX) { |
263 |
strncpy(context+n, oldcontext, MAXCNTX-n); |
264 |
context[MAXCNTX] = '\0'; |
265 |
} else |
266 |
strcpy(context+n, oldcontext); |
267 |
return(context); |
268 |
} |
269 |
|
270 |
|
271 |
char * |
272 |
popcontext(void) /* pop off top context */ |
273 |
{ |
274 |
char *cp1, *cp2; |
275 |
|
276 |
if (!context[0]) /* nothing left to pop */ |
277 |
return(context); |
278 |
cp2 = context; /* find mark */ |
279 |
while (*++cp2 && *cp2 != CNTXMARK) |
280 |
; |
281 |
cp1 = context; /* copy tail to front */ |
282 |
while ( (*cp1++ = *cp2++) ) |
283 |
; |
284 |
return(context); |
285 |
} |
286 |
|
287 |
|
288 |
char * |
289 |
qualname( /* get qualified name */ |
290 |
char *nam, |
291 |
int lvl |
292 |
) |
293 |
{ |
294 |
static char nambuf[MAXCNTX+RMAXWORD+1]; |
295 |
char *cp = nambuf, *cpp; |
296 |
/* check for explicit local */ |
297 |
if (*nam == CNTXMARK) { |
298 |
if (lvl > 0) /* only action is to refuse search */ |
299 |
return(NULL); |
300 |
nam++; |
301 |
} else if (nam == nambuf) /* check for repeat call */ |
302 |
return(lvl > 0 ? NULL : nam); |
303 |
/* copy name to static buffer */ |
304 |
while (*nam) { |
305 |
if (cp >= nambuf+(MAXCNTX+RMAXWORD)) |
306 |
goto toolong; |
307 |
*cp++ = *nam++; |
308 |
} |
309 |
/* check for explicit global */ |
310 |
if (cp > nambuf && cp[-1] == CNTXMARK) { |
311 |
if (lvl > 0) |
312 |
return(NULL); |
313 |
*--cp = '\0'; |
314 |
return(nambuf); /* already qualified */ |
315 |
} |
316 |
cpp = context; /* else skip the requested levels */ |
317 |
while (lvl-- > 0) { |
318 |
if (!*cpp) |
319 |
return(NULL); /* return NULL if past global level */ |
320 |
while (*++cpp && *cpp != CNTXMARK) |
321 |
; |
322 |
} |
323 |
while (*cpp) { /* add remaining context to name */ |
324 |
if (cp >= nambuf+(MAXCNTX+RMAXWORD)) |
325 |
goto toolong; |
326 |
*cp++ = *cpp++; |
327 |
} |
328 |
toolong: |
329 |
*cp = '\0'; |
330 |
return(nambuf); /* return qualified name */ |
331 |
} |
332 |
|
333 |
|
334 |
int |
335 |
incontext( /* is qualified name in current context? */ |
336 |
char *qn |
337 |
) |
338 |
{ |
339 |
if (!context[0]) /* global context accepts all */ |
340 |
return(1); |
341 |
while (*qn && *qn != CNTXMARK) /* find context mark */ |
342 |
qn++; |
343 |
return(!strcmp(qn, context)); |
344 |
} |
345 |
|
346 |
|
347 |
void |
348 |
chanout( /* set output channels */ |
349 |
void (*cs)(int n, double v) |
350 |
) |
351 |
{ |
352 |
EPNODE *ep; |
353 |
|
354 |
for (ep = outchan; ep != NULL; ep = ep->sibling) |
355 |
(*cs)(ep->v.kid->v.chan, evalue(ep->v.kid->sibling)); |
356 |
|
357 |
} |
358 |
|
359 |
|
360 |
void |
361 |
doptimize(int activate) /* optimize current and future definitions? */ |
362 |
{ |
363 |
EPNODE *ep; |
364 |
|
365 |
if (activate && optimized) |
366 |
return; /* already going */ |
367 |
|
368 |
if (!(optimized = activate)) |
369 |
return; /* switching off */ |
370 |
|
371 |
for (ep = dfirst(); ep != NULL; ep = dnext()) |
372 |
epoptimize(ep); |
373 |
} |
374 |
|
375 |
|
376 |
void |
377 |
dcleanup( /* clear definitions (0->vars,1->output,2->consts) */ |
378 |
int lvl |
379 |
) |
380 |
{ |
381 |
int i; |
382 |
VARDEF *vp; |
383 |
EPNODE *ep; |
384 |
/* if context is global, clear all */ |
385 |
for (i = 0; i < NHASH; i++) |
386 |
for (vp = hashtbl[i]; vp != NULL; vp = vp->next) |
387 |
if (incontext(vp->name)) { |
388 |
if (lvl >= 2) |
389 |
dremove(vp->name); |
390 |
else |
391 |
dclear(vp->name); |
392 |
} |
393 |
if (lvl >= 1) |
394 |
while (outchan != NULL) { |
395 |
ep = outchan; |
396 |
outchan = ep->sibling; |
397 |
epfree(ep,1); |
398 |
} |
399 |
} |
400 |
|
401 |
|
402 |
EPNODE * |
403 |
dlookup( /* look up a definition */ |
404 |
char *name |
405 |
) |
406 |
{ |
407 |
VARDEF *vp; |
408 |
|
409 |
if ((vp = varlookup(name)) == NULL) |
410 |
return(NULL); |
411 |
return(vp->def); |
412 |
} |
413 |
|
414 |
|
415 |
VARDEF * |
416 |
varlookup( /* look up a variable */ |
417 |
char *name |
418 |
) |
419 |
{ |
420 |
int lvl = 0; |
421 |
char *qname; |
422 |
VARDEF *vp; |
423 |
/* find most qualified match */ |
424 |
while ((qname = qualname(name, lvl++)) != NULL) |
425 |
for (vp = hashtbl[hash(qname)]; vp != NULL; vp = vp->next) |
426 |
if (!strcmp(vp->name, qname)) |
427 |
return(vp); |
428 |
return(NULL); |
429 |
} |
430 |
|
431 |
|
432 |
VARDEF * |
433 |
varinsert( /* get a link to a variable */ |
434 |
char *name |
435 |
) |
436 |
{ |
437 |
VARDEF *vp; |
438 |
int hv; |
439 |
|
440 |
if ((vp = varlookup(name)) != NULL) { |
441 |
vp->nlinks++; |
442 |
return(vp); |
443 |
} |
444 |
vp = (VARDEF *)emalloc(sizeof(VARDEF)); |
445 |
vp->lib = eliblookup(name); |
446 |
if (vp->lib == NULL) /* if name not in library */ |
447 |
name = qualname(name, 0); /* use fully qualified version */ |
448 |
hv = hash(name); |
449 |
vp->name = savestr(name); |
450 |
vp->nlinks = 1; |
451 |
vp->def = NULL; |
452 |
vp->next = hashtbl[hv]; |
453 |
hashtbl[hv] = vp; |
454 |
return(vp); |
455 |
} |
456 |
|
457 |
|
458 |
void |
459 |
elibupdate( /* update library links */ |
460 |
char *fn |
461 |
) |
462 |
{ |
463 |
int i; |
464 |
VARDEF *vp; |
465 |
/* if fn is NULL then relink all */ |
466 |
for (i = 0; i < NHASH; i++) |
467 |
for (vp = hashtbl[i]; vp != NULL; vp = vp->next) |
468 |
if ((vp->lib != NULL) | (fn == NULL) || !strcmp(fn, vp->name)) |
469 |
vp->lib = eliblookup(vp->name); |
470 |
} |
471 |
|
472 |
|
473 |
void |
474 |
varfree( /* release link to variable */ |
475 |
VARDEF *ln |
476 |
) |
477 |
{ |
478 |
VARDEF *vp; |
479 |
int hv; |
480 |
|
481 |
if (--ln->nlinks > 0) |
482 |
return; /* still active */ |
483 |
|
484 |
hv = hash(ln->name); |
485 |
vp = hashtbl[hv]; |
486 |
if (vp == ln) |
487 |
hashtbl[hv] = vp->next; |
488 |
else { |
489 |
while (vp->next != ln) /* must be in list */ |
490 |
vp = vp->next; |
491 |
vp->next = ln->next; |
492 |
} |
493 |
freestr(ln->name); |
494 |
efree(ln); |
495 |
} |
496 |
|
497 |
|
498 |
EPNODE * |
499 |
dfirst(void) /* return pointer to first definition */ |
500 |
{ |
501 |
htndx = 0; |
502 |
htpos = NULL; |
503 |
ochpos = outchan; |
504 |
return(dnext()); |
505 |
} |
506 |
|
507 |
|
508 |
EPNODE * |
509 |
dnext(void) /* return pointer to next definition */ |
510 |
{ |
511 |
EPNODE *ep; |
512 |
char *nm; |
513 |
|
514 |
while (htndx < NHASH) { |
515 |
if (htpos == NULL) |
516 |
htpos = hashtbl[htndx++]; |
517 |
while (htpos != NULL) { |
518 |
ep = htpos->def; |
519 |
nm = htpos->name; |
520 |
htpos = htpos->next; |
521 |
if (ep != NULL && incontext(nm)) |
522 |
return(ep); |
523 |
} |
524 |
} |
525 |
if ((ep = ochpos) != NULL) |
526 |
ochpos = ep->sibling; |
527 |
return(ep); |
528 |
} |
529 |
|
530 |
|
531 |
EPNODE * |
532 |
dpop( /* pop a definition */ |
533 |
char *name |
534 |
) |
535 |
{ |
536 |
VARDEF *vp; |
537 |
EPNODE *dp; |
538 |
|
539 |
if ((vp = varlookup(name)) == NULL || vp->def == NULL) |
540 |
return(NULL); |
541 |
dp = vp->def; |
542 |
vp->def = dp->sibling; |
543 |
varfree(vp); |
544 |
return(dp); |
545 |
} |
546 |
|
547 |
|
548 |
void |
549 |
dpush( /* push on a definition */ |
550 |
char *nm, |
551 |
EPNODE *ep |
552 |
) |
553 |
{ |
554 |
VARDEF *vp; |
555 |
|
556 |
vp = varinsert(nm); |
557 |
ep->sibling = vp->def; |
558 |
vp->def = ep; |
559 |
} |
560 |
|
561 |
|
562 |
void |
563 |
eaddchan( /* add an output channel assignment */ |
564 |
EPNODE *sp |
565 |
) |
566 |
{ |
567 |
int ch = sp->v.kid->v.chan; |
568 |
EPNODE *ep, *epl; |
569 |
|
570 |
for (epl = NULL, ep = outchan; ep != NULL; epl = ep, ep = ep->sibling) |
571 |
if (ep->v.kid->v.chan >= ch) { |
572 |
if (epl != NULL) |
573 |
epl->sibling = sp; |
574 |
else |
575 |
outchan = sp; |
576 |
if (ep->v.kid->v.chan > ch) |
577 |
sp->sibling = ep; |
578 |
else { |
579 |
sp->sibling = ep->sibling; |
580 |
epfree(ep,1); |
581 |
} |
582 |
return; |
583 |
} |
584 |
if (epl != NULL) |
585 |
epl->sibling = sp; |
586 |
else |
587 |
outchan = sp; |
588 |
sp->sibling = NULL; |
589 |
|
590 |
} |
591 |
|
592 |
|
593 |
void |
594 |
egetstatement(void) /* get next statement */ |
595 |
{ |
596 |
EPNODE *ep; |
597 |
char *qname; |
598 |
VARDEF *vdef; |
599 |
|
600 |
if (nextc == ';') { /* empty statement */ |
601 |
escan(); |
602 |
return; |
603 |
} |
604 |
if (esupport&E_OUTCHAN && |
605 |
nextc == '$') { /* channel assignment */ |
606 |
ep = egetchan(); |
607 |
if (optimized) |
608 |
epoptimize(ep); /* optimize new chan expr */ |
609 |
eaddchan(ep); |
610 |
} else { /* ordinary definition */ |
611 |
ep = egetdefn(); |
612 |
if (optimized) |
613 |
epoptimize(ep); /* optimize new statement */ |
614 |
qname = qualname(dfn_name(ep), 0); |
615 |
if (esupport&E_REDEFW && (vdef = varlookup(qname)) != NULL) { |
616 |
if (vdef->def != NULL && epcmp(ep, vdef->def)) { |
617 |
wputs(qname); |
618 |
if (vdef->def->type == ':') |
619 |
wputs(": redefined constant expression\n"); |
620 |
else |
621 |
wputs(": redefined\n"); |
622 |
} else if (ep->v.kid->type == FUNC && vdef->lib != NULL) { |
623 |
wputs(qname); |
624 |
wputs(": definition hides library function\n"); |
625 |
} |
626 |
} |
627 |
if (ep->type == ':') |
628 |
dremove(qname); |
629 |
else |
630 |
dclear(qname); |
631 |
dpush(qname, ep); |
632 |
} |
633 |
if (nextc != EOF) { |
634 |
if (nextc != ';') |
635 |
esyntax("';' expected"); |
636 |
escan(); |
637 |
} |
638 |
} |
639 |
|
640 |
|
641 |
EPNODE * |
642 |
egetdefn(void) |
643 |
/* A -> SYM = E1 */ |
644 |
/* SYM : E1 */ |
645 |
/* FUNC(SYM,..) = E1 */ |
646 |
/* FUNC(SYM,..) : E1 */ |
647 |
{ |
648 |
EPNODE *ep1, *ep2; |
649 |
|
650 |
if (!isalpha(nextc) & (nextc != CNTXMARK)) |
651 |
esyntax("illegal variable name"); |
652 |
|
653 |
ep1 = newnode(); |
654 |
ep1->type = SYM; |
655 |
ep1->v.name = savestr(getname()); |
656 |
|
657 |
if (esupport&E_FUNCTION && nextc == '(') { |
658 |
ep2 = newnode(); |
659 |
ep2->type = FUNC; |
660 |
addekid(ep2, ep1); |
661 |
ep1 = ep2; |
662 |
do { |
663 |
escan(); |
664 |
if (!isalpha(nextc)) |
665 |
esyntax("illegal parameter name"); |
666 |
ep2 = newnode(); |
667 |
ep2->type = SYM; |
668 |
ep2->v.name = savestr(getname()); |
669 |
if (strchr(ep2->v.name, CNTXMARK) != NULL) |
670 |
esyntax("illegal parameter name"); |
671 |
addekid(ep1, ep2); |
672 |
} while (nextc == ','); |
673 |
if (nextc != ')') |
674 |
esyntax("')' expected"); |
675 |
escan(); |
676 |
ecurfunc = ep1; |
677 |
} |
678 |
|
679 |
if ((nextc != '=') & (nextc != ':')) |
680 |
esyntax("'=' or ':' expected"); |
681 |
|
682 |
ep2 = newnode(); |
683 |
ep2->type = nextc; |
684 |
escan(); |
685 |
addekid(ep2, ep1); |
686 |
addekid(ep2, getE1()); |
687 |
|
688 |
if (ep1->type == SYM && ep1->sibling->type != NUM) { |
689 |
ep1 = newnode(); |
690 |
ep1->type = CLKT; |
691 |
ep1->v.tick = 0; |
692 |
addekid(ep2, ep1); |
693 |
ep1 = newnode(); |
694 |
ep1->type = NUM; |
695 |
addekid(ep2, ep1); |
696 |
} |
697 |
ecurfunc = NULL; |
698 |
|
699 |
return(ep2); |
700 |
} |
701 |
|
702 |
|
703 |
EPNODE * |
704 |
egetchan(void) /* A -> $N = E1 */ |
705 |
{ |
706 |
EPNODE *ep1, *ep2; |
707 |
|
708 |
if (nextc != '$') |
709 |
esyntax("missing '$'"); |
710 |
escan(); |
711 |
|
712 |
ep1 = newnode(); |
713 |
ep1->type = CHAN; |
714 |
ep1->v.chan = getinum(); |
715 |
|
716 |
if (nextc != '=') |
717 |
esyntax("'=' expected"); |
718 |
escan(); |
719 |
|
720 |
ep2 = newnode(); |
721 |
ep2->type = '='; |
722 |
addekid(ep2, ep1); |
723 |
addekid(ep2, getE1()); |
724 |
|
725 |
return(ep2); |
726 |
} |
727 |
|
728 |
|
729 |
|
730 |
/* |
731 |
* The following routines are for internal use only: |
732 |
*/ |
733 |
|
734 |
|
735 |
static double /* evaluate a variable */ |
736 |
dvalue(char *name, EPNODE *d) |
737 |
{ |
738 |
EPNODE *ep1, *ep2; |
739 |
|
740 |
if (d == NULL || d->v.kid->type != SYM) { |
741 |
eputs(name); |
742 |
eputs(": undefined variable\n"); |
743 |
quit(1); |
744 |
} |
745 |
ep1 = d->v.kid->sibling; /* get expression */ |
746 |
if (ep1->type == NUM) |
747 |
return(ep1->v.num); /* return if number */ |
748 |
if (esupport&E_RCONST && d->type == ':') { |
749 |
wputs(name); |
750 |
wputs(": assigned non-constant value\n"); |
751 |
} |
752 |
ep2 = ep1->sibling; /* check time */ |
753 |
if (eclock >= MAXCLOCK) |
754 |
eclock = 1; /* wrap clock counter */ |
755 |
if (ep2->v.tick < MAXCLOCK && |
756 |
(ep2->v.tick == 0) | (ep2->v.tick != eclock)) { |
757 |
ep2->v.tick = d->type == ':' ? MAXCLOCK : eclock; |
758 |
ep2 = ep2->sibling; |
759 |
ep2->v.num = evalue(ep1); /* needs new value */ |
760 |
} else |
761 |
ep2 = ep2->sibling; /* else reuse old value */ |
762 |
|
763 |
return(ep2->v.num); |
764 |
} |