1 |
#ifndef lint |
2 |
static const char RCSid[] = "$Id: calexpr.c,v 2.23 2003/07/03 22:41:44 schorsch Exp $"; |
3 |
#endif |
4 |
/* |
5 |
* Compute data values using expression parser |
6 |
* |
7 |
* 7/1/85 Greg Ward |
8 |
* |
9 |
* 11/11/85 Made channel input conditional with (INCHAN) compiles. |
10 |
* |
11 |
* 4/2/86 Added conditional compiles for function definitions (FUNCTION). |
12 |
* |
13 |
* 1/29/87 Made variables conditional (VARIABLE) |
14 |
* |
15 |
* 5/19/88 Added constant subexpression elimination (RCONST) |
16 |
* |
17 |
* 2/19/03 Eliminated conditional compiles in favor of esupport extern. |
18 |
*/ |
19 |
|
20 |
#include "copyright.h" |
21 |
|
22 |
#include <stdio.h> |
23 |
#include <string.h> |
24 |
#include <ctype.h> |
25 |
#include <errno.h> |
26 |
#include <math.h> |
27 |
#include <stdlib.h> |
28 |
|
29 |
#include "rterror.h" |
30 |
#include "calcomp.h" |
31 |
|
32 |
#define MAXLINE 256 /* maximum line length */ |
33 |
|
34 |
#define newnode() (EPNODE *)ecalloc(1, sizeof(EPNODE)) |
35 |
|
36 |
#define isdecimal(c) (isdigit(c) || (c) == '.') |
37 |
|
38 |
static double euminus(EPNODE *), eargument(EPNODE *), enumber(EPNODE *); |
39 |
static double echannel(EPNODE *); |
40 |
static double eadd(EPNODE *), esubtr(EPNODE *), |
41 |
emult(EPNODE *), edivi(EPNODE *), |
42 |
epow(EPNODE *); |
43 |
static double ebotch(EPNODE *); |
44 |
|
45 |
unsigned int esupport = /* what to support */ |
46 |
E_VARIABLE | E_FUNCTION ; |
47 |
|
48 |
int nextc; /* lookahead character */ |
49 |
|
50 |
double (*eoper[])() = { /* expression operations */ |
51 |
ebotch, |
52 |
evariable, |
53 |
enumber, |
54 |
euminus, |
55 |
echannel, |
56 |
efunc, |
57 |
eargument, |
58 |
ebotch, |
59 |
ebotch, |
60 |
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
61 |
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
62 |
emult, |
63 |
eadd, |
64 |
0, |
65 |
esubtr, |
66 |
0, |
67 |
edivi, |
68 |
0,0,0,0,0,0,0,0,0,0, |
69 |
ebotch, |
70 |
0,0, |
71 |
ebotch, |
72 |
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
73 |
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
74 |
epow, |
75 |
}; |
76 |
|
77 |
static FILE *infp; /* input file pointer */ |
78 |
static char *linbuf; /* line buffer */ |
79 |
static char *infile; /* input file name */ |
80 |
static int lineno; /* input line number */ |
81 |
static int linepos; /* position in buffer */ |
82 |
|
83 |
|
84 |
EPNODE * |
85 |
eparse(expr) /* parse an expression string */ |
86 |
char *expr; |
87 |
{ |
88 |
EPNODE *ep; |
89 |
|
90 |
initstr(expr, NULL, 0); |
91 |
curfunc = NULL; |
92 |
ep = getE1(); |
93 |
if (nextc != EOF) |
94 |
syntax("unexpected character"); |
95 |
return(ep); |
96 |
} |
97 |
|
98 |
|
99 |
double |
100 |
eval(expr) /* evaluate an expression string */ |
101 |
char *expr; |
102 |
{ |
103 |
register EPNODE *ep; |
104 |
double rval; |
105 |
|
106 |
ep = eparse(expr); |
107 |
rval = evalue(ep); |
108 |
epfree(ep); |
109 |
return(rval); |
110 |
} |
111 |
|
112 |
|
113 |
int |
114 |
epcmp(ep1, ep2) /* compare two expressions for equivalence */ |
115 |
register EPNODE *ep1, *ep2; |
116 |
{ |
117 |
double d; |
118 |
|
119 |
if (ep1->type != ep2->type) |
120 |
return(1); |
121 |
|
122 |
switch (ep1->type) { |
123 |
|
124 |
case VAR: |
125 |
return(ep1->v.ln != ep2->v.ln); |
126 |
|
127 |
case NUM: |
128 |
if (ep2->v.num == 0) |
129 |
return(ep1->v.num != 0); |
130 |
d = ep1->v.num / ep2->v.num; |
131 |
return(d > 1.000000000001 | d < 0.999999999999); |
132 |
|
133 |
case CHAN: |
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case ARG: |
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return(ep1->v.chan != ep2->v.chan); |
136 |
|
137 |
case '=': |
138 |
case ':': |
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return(epcmp(ep1->v.kid->sibling, ep2->v.kid->sibling)); |
140 |
|
141 |
case TICK: |
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case SYM: /* should never get this one */ |
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return(0); |
144 |
|
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default: |
146 |
ep1 = ep1->v.kid; |
147 |
ep2 = ep2->v.kid; |
148 |
while (ep1 != NULL) { |
149 |
if (ep2 == NULL) |
150 |
return(1); |
151 |
if (epcmp(ep1, ep2)) |
152 |
return(1); |
153 |
ep1 = ep1->sibling; |
154 |
ep2 = ep2->sibling; |
155 |
} |
156 |
return(ep2 != NULL); |
157 |
} |
158 |
} |
159 |
|
160 |
|
161 |
void |
162 |
epfree(epar) /* free a parse tree */ |
163 |
register EPNODE *epar; |
164 |
{ |
165 |
register EPNODE *ep; |
166 |
|
167 |
switch (epar->type) { |
168 |
|
169 |
case VAR: |
170 |
varfree(epar->v.ln); |
171 |
break; |
172 |
|
173 |
case SYM: |
174 |
freestr(epar->v.name); |
175 |
break; |
176 |
|
177 |
case NUM: |
178 |
case CHAN: |
179 |
case ARG: |
180 |
case TICK: |
181 |
break; |
182 |
|
183 |
default: |
184 |
while ((ep = epar->v.kid) != NULL) { |
185 |
epar->v.kid = ep->sibling; |
186 |
epfree(ep); |
187 |
} |
188 |
break; |
189 |
|
190 |
} |
191 |
|
192 |
efree((char *)epar); |
193 |
} |
194 |
|
195 |
/* the following used to be a switch */ |
196 |
static double |
197 |
eargument(ep) |
198 |
EPNODE *ep; |
199 |
{ |
200 |
return(argument(ep->v.chan)); |
201 |
} |
202 |
|
203 |
static double |
204 |
enumber(ep) |
205 |
EPNODE *ep; |
206 |
{ |
207 |
return(ep->v.num); |
208 |
} |
209 |
|
210 |
static double |
211 |
euminus(ep) |
212 |
EPNODE *ep; |
213 |
{ |
214 |
register EPNODE *ep1 = ep->v.kid; |
215 |
|
216 |
return(-evalue(ep1)); |
217 |
} |
218 |
|
219 |
static double |
220 |
echannel(ep) |
221 |
EPNODE *ep; |
222 |
{ |
223 |
return(chanvalue(ep->v.chan)); |
224 |
} |
225 |
|
226 |
static double |
227 |
eadd(ep) |
228 |
EPNODE *ep; |
229 |
{ |
230 |
register EPNODE *ep1 = ep->v.kid; |
231 |
|
232 |
return(evalue(ep1) + evalue(ep1->sibling)); |
233 |
} |
234 |
|
235 |
static double |
236 |
esubtr(ep) |
237 |
EPNODE *ep; |
238 |
{ |
239 |
register EPNODE *ep1 = ep->v.kid; |
240 |
|
241 |
return(evalue(ep1) - evalue(ep1->sibling)); |
242 |
} |
243 |
|
244 |
static double |
245 |
emult(ep) |
246 |
EPNODE *ep; |
247 |
{ |
248 |
register EPNODE *ep1 = ep->v.kid; |
249 |
|
250 |
return(evalue(ep1) * evalue(ep1->sibling)); |
251 |
} |
252 |
|
253 |
static double |
254 |
edivi(ep) |
255 |
EPNODE *ep; |
256 |
{ |
257 |
register EPNODE *ep1 = ep->v.kid; |
258 |
double d; |
259 |
|
260 |
d = evalue(ep1->sibling); |
261 |
if (d == 0.0) { |
262 |
wputs("Division by zero\n"); |
263 |
errno = ERANGE; |
264 |
return(0.0); |
265 |
} |
266 |
return(evalue(ep1) / d); |
267 |
} |
268 |
|
269 |
static double |
270 |
epow(ep) |
271 |
EPNODE *ep; |
272 |
{ |
273 |
register EPNODE *ep1 = ep->v.kid; |
274 |
double d; |
275 |
int lasterrno; |
276 |
|
277 |
lasterrno = errno; |
278 |
errno = 0; |
279 |
d = pow(evalue(ep1), evalue(ep1->sibling)); |
280 |
#ifdef IEEE |
281 |
if (!finite(d)) |
282 |
errno = EDOM; |
283 |
#endif |
284 |
if (errno == EDOM || errno == ERANGE) { |
285 |
wputs("Illegal power\n"); |
286 |
return(0.0); |
287 |
} |
288 |
errno = lasterrno; |
289 |
return(d); |
290 |
} |
291 |
|
292 |
static double |
293 |
ebotch(ep) |
294 |
EPNODE *ep; |
295 |
{ |
296 |
eputs("Bad expression!\n"); |
297 |
quit(1); |
298 |
return 0.0; /* pro forma return */ |
299 |
} |
300 |
|
301 |
|
302 |
EPNODE * |
303 |
ekid(ep, n) /* return pointer to a node's nth kid */ |
304 |
register EPNODE *ep; |
305 |
register int n; |
306 |
{ |
307 |
|
308 |
for (ep = ep->v.kid; ep != NULL; ep = ep->sibling) |
309 |
if (--n < 0) |
310 |
break; |
311 |
|
312 |
return(ep); |
313 |
} |
314 |
|
315 |
|
316 |
int |
317 |
nekids(ep) /* return # of kids for node ep */ |
318 |
register EPNODE *ep; |
319 |
{ |
320 |
register int n = 0; |
321 |
|
322 |
for (ep = ep->v.kid; ep != NULL; ep = ep->sibling) |
323 |
n++; |
324 |
|
325 |
return(n); |
326 |
} |
327 |
|
328 |
|
329 |
void |
330 |
initfile(fp, fn, ln) /* prepare input file */ |
331 |
FILE *fp; |
332 |
char *fn; |
333 |
int ln; |
334 |
{ |
335 |
static char inpbuf[MAXLINE]; |
336 |
|
337 |
infp = fp; |
338 |
linbuf = inpbuf; |
339 |
infile = fn; |
340 |
lineno = ln; |
341 |
linepos = 0; |
342 |
inpbuf[0] = '\0'; |
343 |
scan(); |
344 |
} |
345 |
|
346 |
|
347 |
void |
348 |
initstr(s, fn, ln) /* prepare input string */ |
349 |
char *s; |
350 |
char *fn; |
351 |
int ln; |
352 |
{ |
353 |
infp = NULL; |
354 |
infile = fn; |
355 |
lineno = ln; |
356 |
linbuf = s; |
357 |
linepos = 0; |
358 |
scan(); |
359 |
} |
360 |
|
361 |
|
362 |
void |
363 |
getscanpos(fnp, lnp, spp, fpp) /* return current scan position */ |
364 |
char **fnp; |
365 |
int *lnp; |
366 |
char **spp; |
367 |
FILE **fpp; |
368 |
{ |
369 |
if (fnp != NULL) *fnp = infile; |
370 |
if (lnp != NULL) *lnp = lineno; |
371 |
if (spp != NULL) *spp = linbuf+linepos; |
372 |
if (fpp != NULL) *fpp = infp; |
373 |
} |
374 |
|
375 |
|
376 |
int |
377 |
scan() /* scan next character, return literal next */ |
378 |
{ |
379 |
register int lnext = 0; |
380 |
|
381 |
do { |
382 |
if (linbuf[linepos] == '\0') |
383 |
if (infp == NULL || fgets(linbuf, MAXLINE, infp) == NULL) |
384 |
nextc = EOF; |
385 |
else { |
386 |
nextc = linbuf[0]; |
387 |
lineno++; |
388 |
linepos = 1; |
389 |
} |
390 |
else |
391 |
nextc = linbuf[linepos++]; |
392 |
if (!lnext) |
393 |
lnext = nextc; |
394 |
if (nextc == '{') { |
395 |
scan(); |
396 |
while (nextc != '}') |
397 |
if (nextc == EOF) |
398 |
syntax("'}' expected"); |
399 |
else |
400 |
scan(); |
401 |
scan(); |
402 |
} |
403 |
} while (isspace(nextc)); |
404 |
return(lnext); |
405 |
} |
406 |
|
407 |
|
408 |
char * |
409 |
long2ascii(l) /* convert long to ascii */ |
410 |
long l; |
411 |
{ |
412 |
static char buf[16]; |
413 |
register char *cp; |
414 |
int neg = 0; |
415 |
|
416 |
if (l == 0) |
417 |
return("0"); |
418 |
if (l < 0) { |
419 |
l = -l; |
420 |
neg++; |
421 |
} |
422 |
cp = buf + sizeof(buf); |
423 |
*--cp = '\0'; |
424 |
while (l) { |
425 |
*--cp = l % 10 + '0'; |
426 |
l /= 10; |
427 |
} |
428 |
if (neg) |
429 |
*--cp = '-'; |
430 |
return(cp); |
431 |
} |
432 |
|
433 |
|
434 |
void |
435 |
syntax(err) /* report syntax error and quit */ |
436 |
char *err; |
437 |
{ |
438 |
register int i; |
439 |
|
440 |
if (infile != NULL || lineno != 0) { |
441 |
if (infile != NULL) eputs(infile); |
442 |
if (lineno != 0) { |
443 |
eputs(infile != NULL ? ", line " : "line "); |
444 |
eputs(long2ascii((long)lineno)); |
445 |
} |
446 |
eputs(":\n"); |
447 |
} |
448 |
eputs(linbuf); |
449 |
if (linbuf[strlen(linbuf)-1] != '\n') |
450 |
eputs("\n"); |
451 |
for (i = 0; i < linepos-1; i++) |
452 |
eputs(linbuf[i] == '\t' ? "\t" : " "); |
453 |
eputs("^ "); |
454 |
eputs(err); |
455 |
eputs("\n"); |
456 |
quit(1); |
457 |
} |
458 |
|
459 |
|
460 |
void |
461 |
addekid(ep, ekid) /* add a child to ep */ |
462 |
register EPNODE *ep; |
463 |
EPNODE *ekid; |
464 |
{ |
465 |
if (ep->v.kid == NULL) |
466 |
ep->v.kid = ekid; |
467 |
else { |
468 |
for (ep = ep->v.kid; ep->sibling != NULL; ep = ep->sibling) |
469 |
; |
470 |
ep->sibling = ekid; |
471 |
} |
472 |
ekid->sibling = NULL; |
473 |
} |
474 |
|
475 |
|
476 |
char * |
477 |
getname() /* scan an identifier */ |
478 |
{ |
479 |
static char str[RMAXWORD+1]; |
480 |
register int i, lnext; |
481 |
|
482 |
lnext = nextc; |
483 |
for (i = 0; i < RMAXWORD && isid(lnext); i++, lnext = scan()) |
484 |
str[i] = lnext; |
485 |
str[i] = '\0'; |
486 |
while (isid(lnext)) /* skip rest of name */ |
487 |
lnext = scan(); |
488 |
|
489 |
return(str); |
490 |
} |
491 |
|
492 |
|
493 |
int |
494 |
getinum() /* scan a positive integer */ |
495 |
{ |
496 |
register int n, lnext; |
497 |
|
498 |
n = 0; |
499 |
lnext = nextc; |
500 |
while (isdigit(lnext)) { |
501 |
n = n * 10 + lnext - '0'; |
502 |
lnext = scan(); |
503 |
} |
504 |
return(n); |
505 |
} |
506 |
|
507 |
|
508 |
double |
509 |
getnum() /* scan a positive float */ |
510 |
{ |
511 |
register int i, lnext; |
512 |
char str[RMAXWORD+1]; |
513 |
|
514 |
i = 0; |
515 |
lnext = nextc; |
516 |
while (isdigit(lnext) && i < RMAXWORD) { |
517 |
str[i++] = lnext; |
518 |
lnext = scan(); |
519 |
} |
520 |
if (lnext == '.' && i < RMAXWORD) { |
521 |
str[i++] = lnext; |
522 |
lnext = scan(); |
523 |
if (i == 1 && !isdigit(lnext)) |
524 |
syntax("badly formed number"); |
525 |
while (isdigit(lnext) && i < RMAXWORD) { |
526 |
str[i++] = lnext; |
527 |
lnext = scan(); |
528 |
} |
529 |
} |
530 |
if ((lnext == 'e' | lnext == 'E') && i < RMAXWORD) { |
531 |
str[i++] = lnext; |
532 |
lnext = scan(); |
533 |
if ((lnext == '-' | lnext == '+') && i < RMAXWORD) { |
534 |
str[i++] = lnext; |
535 |
lnext = scan(); |
536 |
} |
537 |
if (!isdigit(lnext)) |
538 |
syntax("missing exponent"); |
539 |
while (isdigit(lnext) && i < RMAXWORD) { |
540 |
str[i++] = lnext; |
541 |
lnext = scan(); |
542 |
} |
543 |
} |
544 |
str[i] = '\0'; |
545 |
|
546 |
return(atof(str)); |
547 |
} |
548 |
|
549 |
|
550 |
EPNODE * |
551 |
getE1() /* E1 -> E1 ADDOP E2 */ |
552 |
/* E2 */ |
553 |
{ |
554 |
register EPNODE *ep1, *ep2; |
555 |
|
556 |
ep1 = getE2(); |
557 |
while (nextc == '+' || nextc == '-') { |
558 |
ep2 = newnode(); |
559 |
ep2->type = nextc; |
560 |
scan(); |
561 |
addekid(ep2, ep1); |
562 |
addekid(ep2, getE2()); |
563 |
if (esupport&E_RCONST && |
564 |
ep1->type == NUM && ep1->sibling->type == NUM) |
565 |
ep2 = rconst(ep2); |
566 |
ep1 = ep2; |
567 |
} |
568 |
return(ep1); |
569 |
} |
570 |
|
571 |
|
572 |
EPNODE * |
573 |
getE2() /* E2 -> E2 MULOP E3 */ |
574 |
/* E3 */ |
575 |
{ |
576 |
register EPNODE *ep1, *ep2; |
577 |
|
578 |
ep1 = getE3(); |
579 |
while (nextc == '*' || nextc == '/') { |
580 |
ep2 = newnode(); |
581 |
ep2->type = nextc; |
582 |
scan(); |
583 |
addekid(ep2, ep1); |
584 |
addekid(ep2, getE3()); |
585 |
if (esupport&E_RCONST && |
586 |
ep1->type == NUM && ep1->sibling->type == NUM) |
587 |
ep2 = rconst(ep2); |
588 |
ep1 = ep2; |
589 |
} |
590 |
return(ep1); |
591 |
} |
592 |
|
593 |
|
594 |
EPNODE * |
595 |
getE3() /* E3 -> E4 ^ E3 */ |
596 |
/* E4 */ |
597 |
{ |
598 |
register EPNODE *ep1, *ep2; |
599 |
|
600 |
ep1 = getE4(); |
601 |
if (nextc == '^') { |
602 |
ep2 = newnode(); |
603 |
ep2->type = nextc; |
604 |
scan(); |
605 |
addekid(ep2, ep1); |
606 |
addekid(ep2, getE3()); |
607 |
if (esupport&E_RCONST && |
608 |
ep1->type == NUM && ep1->sibling->type == NUM) |
609 |
ep2 = rconst(ep2); |
610 |
return(ep2); |
611 |
} |
612 |
return(ep1); |
613 |
} |
614 |
|
615 |
|
616 |
EPNODE * |
617 |
getE4() /* E4 -> ADDOP E5 */ |
618 |
/* E5 */ |
619 |
{ |
620 |
register EPNODE *ep1, *ep2; |
621 |
|
622 |
if (nextc == '-') { |
623 |
scan(); |
624 |
ep2 = getE5(); |
625 |
if (ep2->type == NUM) { |
626 |
ep2->v.num = -ep2->v.num; |
627 |
return(ep2); |
628 |
} |
629 |
if (ep2->type == UMINUS) { /* don't generate -(-E5) */ |
630 |
efree((char *)ep2); |
631 |
return(ep2->v.kid); |
632 |
} |
633 |
ep1 = newnode(); |
634 |
ep1->type = UMINUS; |
635 |
addekid(ep1, ep2); |
636 |
return(ep1); |
637 |
} |
638 |
if (nextc == '+') |
639 |
scan(); |
640 |
return(getE5()); |
641 |
} |
642 |
|
643 |
|
644 |
EPNODE * |
645 |
getE5() /* E5 -> (E1) */ |
646 |
/* VAR */ |
647 |
/* NUM */ |
648 |
/* $N */ |
649 |
/* FUNC(E1,..) */ |
650 |
/* ARG */ |
651 |
{ |
652 |
int i; |
653 |
char *nam; |
654 |
register EPNODE *ep1, *ep2; |
655 |
|
656 |
if (nextc == '(') { |
657 |
scan(); |
658 |
ep1 = getE1(); |
659 |
if (nextc != ')') |
660 |
syntax("')' expected"); |
661 |
scan(); |
662 |
return(ep1); |
663 |
} |
664 |
|
665 |
if (esupport&E_INCHAN && nextc == '$') { |
666 |
scan(); |
667 |
ep1 = newnode(); |
668 |
ep1->type = CHAN; |
669 |
ep1->v.chan = getinum(); |
670 |
return(ep1); |
671 |
} |
672 |
|
673 |
if (esupport&(E_VARIABLE|E_FUNCTION) && |
674 |
(isalpha(nextc) || nextc == CNTXMARK)) { |
675 |
nam = getname(); |
676 |
ep1 = NULL; |
677 |
if ((esupport&(E_VARIABLE|E_FUNCTION)) == (E_VARIABLE|E_FUNCTION) |
678 |
&& curfunc != NULL) |
679 |
for (i = 1, ep2 = curfunc->v.kid->sibling; |
680 |
ep2 != NULL; i++, ep2 = ep2->sibling) |
681 |
if (!strcmp(ep2->v.name, nam)) { |
682 |
ep1 = newnode(); |
683 |
ep1->type = ARG; |
684 |
ep1->v.chan = i; |
685 |
break; |
686 |
} |
687 |
if (ep1 == NULL) { |
688 |
ep1 = newnode(); |
689 |
ep1->type = VAR; |
690 |
ep1->v.ln = varinsert(nam); |
691 |
} |
692 |
if (esupport&E_FUNCTION && nextc == '(') { |
693 |
ep2 = newnode(); |
694 |
ep2->type = FUNC; |
695 |
addekid(ep2, ep1); |
696 |
ep1 = ep2; |
697 |
do { |
698 |
scan(); |
699 |
addekid(ep1, getE1()); |
700 |
} while (nextc == ','); |
701 |
if (nextc != ')') |
702 |
syntax("')' expected"); |
703 |
scan(); |
704 |
} else if (!(esupport&E_VARIABLE)) |
705 |
syntax("'(' expected"); |
706 |
if (esupport&E_RCONST && isconstvar(ep1)) |
707 |
ep1 = rconst(ep1); |
708 |
return(ep1); |
709 |
} |
710 |
|
711 |
if (isdecimal(nextc)) { |
712 |
ep1 = newnode(); |
713 |
ep1->type = NUM; |
714 |
ep1->v.num = getnum(); |
715 |
return(ep1); |
716 |
} |
717 |
syntax("unexpected character"); |
718 |
return NULL; /* pro forma return */ |
719 |
} |
720 |
|
721 |
|
722 |
EPNODE * |
723 |
rconst(epar) /* reduce a constant expression */ |
724 |
register EPNODE *epar; |
725 |
{ |
726 |
register EPNODE *ep; |
727 |
|
728 |
ep = newnode(); |
729 |
ep->type = NUM; |
730 |
errno = 0; |
731 |
ep->v.num = evalue(epar); |
732 |
if (errno == EDOM || errno == ERANGE) |
733 |
syntax("bad constant expression"); |
734 |
epfree(epar); |
735 |
|
736 |
return(ep); |
737 |
} |
738 |
|
739 |
|
740 |
int |
741 |
isconstvar(ep) /* is ep linked to a constant expression? */ |
742 |
register EPNODE *ep; |
743 |
{ |
744 |
register EPNODE *ep1; |
745 |
|
746 |
if (esupport&E_FUNCTION && ep->type == FUNC) { |
747 |
if (!isconstfun(ep->v.kid)) |
748 |
return(0); |
749 |
for (ep1 = ep->v.kid->sibling; ep1 != NULL; ep1 = ep1->sibling) |
750 |
if (ep1->type != NUM && !isconstfun(ep1)) |
751 |
return(0); |
752 |
return(1); |
753 |
} |
754 |
if (ep->type != VAR) |
755 |
return(0); |
756 |
ep1 = ep->v.ln->def; |
757 |
if (ep1 == NULL || ep1->type != ':') |
758 |
return(0); |
759 |
if (esupport&E_FUNCTION && ep1->v.kid->type != SYM) |
760 |
return(0); |
761 |
return(1); |
762 |
} |
763 |
|
764 |
|
765 |
int |
766 |
isconstfun(ep) /* is ep linked to a constant function? */ |
767 |
register EPNODE *ep; |
768 |
{ |
769 |
register EPNODE *dp; |
770 |
register LIBR *lp; |
771 |
|
772 |
if (ep->type != VAR) |
773 |
return(0); |
774 |
if ((dp = ep->v.ln->def) != NULL) |
775 |
if (dp->v.kid->type == FUNC) |
776 |
return(dp->type == ':'); |
777 |
else |
778 |
return(0); /* don't identify masked library functions */ |
779 |
if ((lp = ep->v.ln->lib) != NULL) |
780 |
return(lp->atyp == ':'); |
781 |
return(0); |
782 |
} |