1 |
#ifndef lint |
2 |
static const char RCSid[] = "$Id: calexpr.c,v 2.27 2003/08/04 19:20:26 greg 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[])(EPNODE *) = { /* 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( /* parse an expression string */ |
86 |
char *expr |
87 |
) |
88 |
{ |
89 |
EPNODE *ep; |
90 |
|
91 |
initstr(expr, NULL, 0); |
92 |
curfunc = NULL; |
93 |
ep = getE1(); |
94 |
if (nextc != EOF) |
95 |
syntax("unexpected character"); |
96 |
return(ep); |
97 |
} |
98 |
|
99 |
|
100 |
double |
101 |
eval( /* evaluate an expression string */ |
102 |
char *expr |
103 |
) |
104 |
{ |
105 |
register EPNODE *ep; |
106 |
double rval; |
107 |
|
108 |
ep = eparse(expr); |
109 |
rval = evalue(ep); |
110 |
epfree(ep); |
111 |
return(rval); |
112 |
} |
113 |
|
114 |
|
115 |
int |
116 |
epcmp( /* compare two expressions for equivalence */ |
117 |
register EPNODE *ep1, |
118 |
register EPNODE *ep2 |
119 |
) |
120 |
{ |
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double d; |
122 |
|
123 |
if (ep1->type != ep2->type) |
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return(1); |
125 |
|
126 |
switch (ep1->type) { |
127 |
|
128 |
case VAR: |
129 |
return(ep1->v.ln != ep2->v.ln); |
130 |
|
131 |
case NUM: |
132 |
if (ep2->v.num == 0) |
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return(ep1->v.num != 0); |
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d = ep1->v.num / ep2->v.num; |
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return((d > 1.000000000001) | (d < 0.999999999999)); |
136 |
|
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case CHAN: |
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case ARG: |
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return(ep1->v.chan != ep2->v.chan); |
140 |
|
141 |
case '=': |
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case ':': |
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return(epcmp(ep1->v.kid->sibling, ep2->v.kid->sibling)); |
144 |
|
145 |
case TICK: |
146 |
case SYM: /* should never get this one */ |
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return(0); |
148 |
|
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default: |
150 |
ep1 = ep1->v.kid; |
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ep2 = ep2->v.kid; |
152 |
while (ep1 != NULL) { |
153 |
if (ep2 == NULL) |
154 |
return(1); |
155 |
if (epcmp(ep1, ep2)) |
156 |
return(1); |
157 |
ep1 = ep1->sibling; |
158 |
ep2 = ep2->sibling; |
159 |
} |
160 |
return(ep2 != NULL); |
161 |
} |
162 |
} |
163 |
|
164 |
|
165 |
void |
166 |
epfree( /* free a parse tree */ |
167 |
register EPNODE *epar |
168 |
) |
169 |
{ |
170 |
register EPNODE *ep; |
171 |
|
172 |
switch (epar->type) { |
173 |
|
174 |
case VAR: |
175 |
varfree(epar->v.ln); |
176 |
break; |
177 |
|
178 |
case SYM: |
179 |
freestr(epar->v.name); |
180 |
break; |
181 |
|
182 |
case NUM: |
183 |
case CHAN: |
184 |
case ARG: |
185 |
case TICK: |
186 |
break; |
187 |
|
188 |
default: |
189 |
while ((ep = epar->v.kid) != NULL) { |
190 |
epar->v.kid = ep->sibling; |
191 |
epfree(ep); |
192 |
} |
193 |
break; |
194 |
|
195 |
} |
196 |
|
197 |
efree((char *)epar); |
198 |
} |
199 |
|
200 |
/* the following used to be a switch */ |
201 |
static double |
202 |
eargument( |
203 |
EPNODE *ep |
204 |
) |
205 |
{ |
206 |
return(argument(ep->v.chan)); |
207 |
} |
208 |
|
209 |
static double |
210 |
enumber( |
211 |
EPNODE *ep |
212 |
) |
213 |
{ |
214 |
return(ep->v.num); |
215 |
} |
216 |
|
217 |
static double |
218 |
euminus( |
219 |
EPNODE *ep |
220 |
) |
221 |
{ |
222 |
register EPNODE *ep1 = ep->v.kid; |
223 |
|
224 |
return(-evalue(ep1)); |
225 |
} |
226 |
|
227 |
static double |
228 |
echannel( |
229 |
EPNODE *ep |
230 |
) |
231 |
{ |
232 |
return(chanvalue(ep->v.chan)); |
233 |
} |
234 |
|
235 |
static double |
236 |
eadd( |
237 |
EPNODE *ep |
238 |
) |
239 |
{ |
240 |
register EPNODE *ep1 = ep->v.kid; |
241 |
|
242 |
return(evalue(ep1) + evalue(ep1->sibling)); |
243 |
} |
244 |
|
245 |
static double |
246 |
esubtr( |
247 |
EPNODE *ep |
248 |
) |
249 |
{ |
250 |
register EPNODE *ep1 = ep->v.kid; |
251 |
|
252 |
return(evalue(ep1) - evalue(ep1->sibling)); |
253 |
} |
254 |
|
255 |
static double |
256 |
emult( |
257 |
EPNODE *ep |
258 |
) |
259 |
{ |
260 |
register EPNODE *ep1 = ep->v.kid; |
261 |
|
262 |
return(evalue(ep1) * evalue(ep1->sibling)); |
263 |
} |
264 |
|
265 |
static double |
266 |
edivi( |
267 |
EPNODE *ep |
268 |
) |
269 |
{ |
270 |
register EPNODE *ep1 = ep->v.kid; |
271 |
double d; |
272 |
|
273 |
d = evalue(ep1->sibling); |
274 |
if (d == 0.0) { |
275 |
wputs("Division by zero\n"); |
276 |
errno = ERANGE; |
277 |
return(0.0); |
278 |
} |
279 |
return(evalue(ep1) / d); |
280 |
} |
281 |
|
282 |
static double |
283 |
epow( |
284 |
EPNODE *ep |
285 |
) |
286 |
{ |
287 |
register EPNODE *ep1 = ep->v.kid; |
288 |
double d; |
289 |
int lasterrno; |
290 |
|
291 |
lasterrno = errno; |
292 |
errno = 0; |
293 |
d = pow(evalue(ep1), evalue(ep1->sibling)); |
294 |
#ifdef IEEE |
295 |
if (!finite(d)) |
296 |
errno = EDOM; |
297 |
#endif |
298 |
if (errno == EDOM || errno == ERANGE) { |
299 |
wputs("Illegal power\n"); |
300 |
return(0.0); |
301 |
} |
302 |
errno = lasterrno; |
303 |
return(d); |
304 |
} |
305 |
|
306 |
static double |
307 |
ebotch( |
308 |
EPNODE *ep |
309 |
) |
310 |
{ |
311 |
eputs("Bad expression!\n"); |
312 |
quit(1); |
313 |
return 0.0; /* pro forma return */ |
314 |
} |
315 |
|
316 |
|
317 |
EPNODE * |
318 |
ekid( /* return pointer to a node's nth kid */ |
319 |
register EPNODE *ep, |
320 |
register int n |
321 |
) |
322 |
{ |
323 |
|
324 |
for (ep = ep->v.kid; ep != NULL; ep = ep->sibling) |
325 |
if (--n < 0) |
326 |
break; |
327 |
|
328 |
return(ep); |
329 |
} |
330 |
|
331 |
|
332 |
int |
333 |
nekids( /* return # of kids for node ep */ |
334 |
register EPNODE *ep |
335 |
) |
336 |
{ |
337 |
register int n = 0; |
338 |
|
339 |
for (ep = ep->v.kid; ep != NULL; ep = ep->sibling) |
340 |
n++; |
341 |
|
342 |
return(n); |
343 |
} |
344 |
|
345 |
|
346 |
void |
347 |
initfile( /* prepare input file */ |
348 |
FILE *fp, |
349 |
char *fn, |
350 |
int ln |
351 |
) |
352 |
{ |
353 |
static char inpbuf[MAXLINE]; |
354 |
|
355 |
infp = fp; |
356 |
linbuf = inpbuf; |
357 |
infile = fn; |
358 |
lineno = ln; |
359 |
linepos = 0; |
360 |
inpbuf[0] = '\0'; |
361 |
scan(); |
362 |
} |
363 |
|
364 |
|
365 |
void |
366 |
initstr( /* prepare input string */ |
367 |
char *s, |
368 |
char *fn, |
369 |
int ln |
370 |
) |
371 |
{ |
372 |
infp = NULL; |
373 |
infile = fn; |
374 |
lineno = ln; |
375 |
linbuf = s; |
376 |
linepos = 0; |
377 |
scan(); |
378 |
} |
379 |
|
380 |
|
381 |
void |
382 |
getscanpos( /* return current scan position */ |
383 |
char **fnp, |
384 |
int *lnp, |
385 |
char **spp, |
386 |
FILE **fpp |
387 |
) |
388 |
{ |
389 |
if (fnp != NULL) *fnp = infile; |
390 |
if (lnp != NULL) *lnp = lineno; |
391 |
if (spp != NULL) *spp = linbuf+linepos; |
392 |
if (fpp != NULL) *fpp = infp; |
393 |
} |
394 |
|
395 |
|
396 |
int |
397 |
scan(void) /* scan next character, return literal next */ |
398 |
{ |
399 |
register int lnext = 0; |
400 |
|
401 |
do { |
402 |
if (linbuf[linepos] == '\0') |
403 |
if (infp == NULL || fgets(linbuf, MAXLINE, infp) == NULL) |
404 |
nextc = EOF; |
405 |
else { |
406 |
nextc = linbuf[0]; |
407 |
lineno++; |
408 |
linepos = 1; |
409 |
} |
410 |
else |
411 |
nextc = linbuf[linepos++]; |
412 |
if (!lnext) |
413 |
lnext = nextc; |
414 |
if (nextc == '{') { |
415 |
scan(); |
416 |
while (nextc != '}') |
417 |
if (nextc == EOF) |
418 |
syntax("'}' expected"); |
419 |
else |
420 |
scan(); |
421 |
scan(); |
422 |
} |
423 |
} while (isspace(nextc)); |
424 |
return(lnext); |
425 |
} |
426 |
|
427 |
|
428 |
char * |
429 |
long2ascii( /* convert long to ascii */ |
430 |
long l |
431 |
) |
432 |
{ |
433 |
static char buf[16]; |
434 |
register char *cp; |
435 |
int neg = 0; |
436 |
|
437 |
if (l == 0) |
438 |
return("0"); |
439 |
if (l < 0) { |
440 |
l = -l; |
441 |
neg++; |
442 |
} |
443 |
cp = buf + sizeof(buf); |
444 |
*--cp = '\0'; |
445 |
while (l) { |
446 |
*--cp = l % 10 + '0'; |
447 |
l /= 10; |
448 |
} |
449 |
if (neg) |
450 |
*--cp = '-'; |
451 |
return(cp); |
452 |
} |
453 |
|
454 |
|
455 |
void |
456 |
syntax( /* report syntax error and quit */ |
457 |
char *err |
458 |
) |
459 |
{ |
460 |
register int i; |
461 |
|
462 |
if (infile != NULL || lineno != 0) { |
463 |
if (infile != NULL) eputs(infile); |
464 |
if (lineno != 0) { |
465 |
eputs(infile != NULL ? ", line " : "line "); |
466 |
eputs(long2ascii((long)lineno)); |
467 |
} |
468 |
eputs(":\n"); |
469 |
} |
470 |
eputs(linbuf); |
471 |
if (linbuf[strlen(linbuf)-1] != '\n') |
472 |
eputs("\n"); |
473 |
for (i = 0; i < linepos-1; i++) |
474 |
eputs(linbuf[i] == '\t' ? "\t" : " "); |
475 |
eputs("^ "); |
476 |
eputs(err); |
477 |
eputs("\n"); |
478 |
quit(1); |
479 |
} |
480 |
|
481 |
|
482 |
void |
483 |
addekid( /* add a child to ep */ |
484 |
register EPNODE *ep, |
485 |
EPNODE *ekid |
486 |
) |
487 |
{ |
488 |
if (ep->v.kid == NULL) |
489 |
ep->v.kid = ekid; |
490 |
else { |
491 |
for (ep = ep->v.kid; ep->sibling != NULL; ep = ep->sibling) |
492 |
; |
493 |
ep->sibling = ekid; |
494 |
} |
495 |
ekid->sibling = NULL; |
496 |
} |
497 |
|
498 |
|
499 |
char * |
500 |
getname(void) /* scan an identifier */ |
501 |
{ |
502 |
static char str[RMAXWORD+1]; |
503 |
register int i, lnext; |
504 |
|
505 |
lnext = nextc; |
506 |
for (i = 0; i < RMAXWORD && isid(lnext); i++, lnext = scan()) |
507 |
str[i] = lnext; |
508 |
str[i] = '\0'; |
509 |
while (isid(lnext)) /* skip rest of name */ |
510 |
lnext = scan(); |
511 |
|
512 |
return(str); |
513 |
} |
514 |
|
515 |
|
516 |
int |
517 |
getinum(void) /* scan a positive integer */ |
518 |
{ |
519 |
register int n, lnext; |
520 |
|
521 |
n = 0; |
522 |
lnext = nextc; |
523 |
while (isdigit(lnext)) { |
524 |
n = n * 10 + lnext - '0'; |
525 |
lnext = scan(); |
526 |
} |
527 |
return(n); |
528 |
} |
529 |
|
530 |
|
531 |
double |
532 |
getnum(void) /* scan a positive float */ |
533 |
{ |
534 |
register int i, lnext; |
535 |
char str[RMAXWORD+1]; |
536 |
|
537 |
i = 0; |
538 |
lnext = nextc; |
539 |
while (isdigit(lnext) && i < RMAXWORD) { |
540 |
str[i++] = lnext; |
541 |
lnext = scan(); |
542 |
} |
543 |
if (lnext == '.' && i < RMAXWORD) { |
544 |
str[i++] = lnext; |
545 |
lnext = scan(); |
546 |
if (i == 1 && !isdigit(lnext)) |
547 |
syntax("badly formed number"); |
548 |
while (isdigit(lnext) && i < RMAXWORD) { |
549 |
str[i++] = lnext; |
550 |
lnext = scan(); |
551 |
} |
552 |
} |
553 |
if ((lnext == 'e') | (lnext == 'E') && i < RMAXWORD) { |
554 |
str[i++] = lnext; |
555 |
lnext = scan(); |
556 |
if ((lnext == '-') | (lnext == '+') && i < RMAXWORD) { |
557 |
str[i++] = lnext; |
558 |
lnext = scan(); |
559 |
} |
560 |
if (!isdigit(lnext)) |
561 |
syntax("missing exponent"); |
562 |
while (isdigit(lnext) && i < RMAXWORD) { |
563 |
str[i++] = lnext; |
564 |
lnext = scan(); |
565 |
} |
566 |
} |
567 |
str[i] = '\0'; |
568 |
|
569 |
return(atof(str)); |
570 |
} |
571 |
|
572 |
|
573 |
EPNODE * |
574 |
getE1(void) /* E1 -> E1 ADDOP E2 */ |
575 |
/* E2 */ |
576 |
{ |
577 |
register EPNODE *ep1, *ep2; |
578 |
|
579 |
ep1 = getE2(); |
580 |
while (nextc == '+' || nextc == '-') { |
581 |
ep2 = newnode(); |
582 |
ep2->type = nextc; |
583 |
scan(); |
584 |
addekid(ep2, ep1); |
585 |
addekid(ep2, getE2()); |
586 |
if (esupport&E_RCONST && |
587 |
ep1->type == NUM && ep1->sibling->type == NUM) |
588 |
ep2 = rconst(ep2); |
589 |
ep1 = ep2; |
590 |
} |
591 |
return(ep1); |
592 |
} |
593 |
|
594 |
|
595 |
EPNODE * |
596 |
getE2(void) /* E2 -> E2 MULOP E3 */ |
597 |
/* E3 */ |
598 |
{ |
599 |
register EPNODE *ep1, *ep2; |
600 |
|
601 |
ep1 = getE3(); |
602 |
while (nextc == '*' || nextc == '/') { |
603 |
ep2 = newnode(); |
604 |
ep2->type = nextc; |
605 |
scan(); |
606 |
addekid(ep2, ep1); |
607 |
addekid(ep2, getE3()); |
608 |
if (esupport&E_RCONST && |
609 |
ep1->type == NUM && ep1->sibling->type == NUM) |
610 |
ep2 = rconst(ep2); |
611 |
ep1 = ep2; |
612 |
} |
613 |
return(ep1); |
614 |
} |
615 |
|
616 |
|
617 |
EPNODE * |
618 |
getE3(void) /* E3 -> E4 ^ E3 */ |
619 |
/* E4 */ |
620 |
{ |
621 |
register EPNODE *ep1, *ep2; |
622 |
|
623 |
ep1 = getE4(); |
624 |
if (nextc == '^') { |
625 |
ep2 = newnode(); |
626 |
ep2->type = nextc; |
627 |
scan(); |
628 |
addekid(ep2, ep1); |
629 |
addekid(ep2, getE3()); |
630 |
if (esupport&E_RCONST && |
631 |
ep1->type == NUM && ep1->sibling->type == NUM) |
632 |
ep2 = rconst(ep2); |
633 |
return(ep2); |
634 |
} |
635 |
return(ep1); |
636 |
} |
637 |
|
638 |
|
639 |
EPNODE * |
640 |
getE4(void) /* E4 -> ADDOP E5 */ |
641 |
/* E5 */ |
642 |
{ |
643 |
register EPNODE *ep1, *ep2; |
644 |
|
645 |
if (nextc == '-') { |
646 |
scan(); |
647 |
ep2 = getE5(); |
648 |
if (ep2->type == NUM) { |
649 |
ep2->v.num = -ep2->v.num; |
650 |
return(ep2); |
651 |
} |
652 |
if (ep2->type == UMINUS) { /* don't generate -(-E5) */ |
653 |
efree((char *)ep2); |
654 |
return(ep2->v.kid); |
655 |
} |
656 |
ep1 = newnode(); |
657 |
ep1->type = UMINUS; |
658 |
addekid(ep1, ep2); |
659 |
return(ep1); |
660 |
} |
661 |
if (nextc == '+') |
662 |
scan(); |
663 |
return(getE5()); |
664 |
} |
665 |
|
666 |
|
667 |
EPNODE * |
668 |
getE5(void) /* E5 -> (E1) */ |
669 |
/* VAR */ |
670 |
/* NUM */ |
671 |
/* $N */ |
672 |
/* FUNC(E1,..) */ |
673 |
/* ARG */ |
674 |
{ |
675 |
int i; |
676 |
char *nam; |
677 |
register EPNODE *ep1, *ep2; |
678 |
|
679 |
if (nextc == '(') { |
680 |
scan(); |
681 |
ep1 = getE1(); |
682 |
if (nextc != ')') |
683 |
syntax("')' expected"); |
684 |
scan(); |
685 |
return(ep1); |
686 |
} |
687 |
|
688 |
if (esupport&E_INCHAN && nextc == '$') { |
689 |
scan(); |
690 |
ep1 = newnode(); |
691 |
ep1->type = CHAN; |
692 |
ep1->v.chan = getinum(); |
693 |
return(ep1); |
694 |
} |
695 |
|
696 |
if (esupport&(E_VARIABLE|E_FUNCTION) && |
697 |
(isalpha(nextc) || nextc == CNTXMARK)) { |
698 |
nam = getname(); |
699 |
ep1 = NULL; |
700 |
if ((esupport&(E_VARIABLE|E_FUNCTION)) == (E_VARIABLE|E_FUNCTION) |
701 |
&& curfunc != NULL) |
702 |
for (i = 1, ep2 = curfunc->v.kid->sibling; |
703 |
ep2 != NULL; i++, ep2 = ep2->sibling) |
704 |
if (!strcmp(ep2->v.name, nam)) { |
705 |
ep1 = newnode(); |
706 |
ep1->type = ARG; |
707 |
ep1->v.chan = i; |
708 |
break; |
709 |
} |
710 |
if (ep1 == NULL) { |
711 |
ep1 = newnode(); |
712 |
ep1->type = VAR; |
713 |
ep1->v.ln = varinsert(nam); |
714 |
} |
715 |
if (esupport&E_FUNCTION && nextc == '(') { |
716 |
ep2 = newnode(); |
717 |
ep2->type = FUNC; |
718 |
addekid(ep2, ep1); |
719 |
ep1 = ep2; |
720 |
do { |
721 |
scan(); |
722 |
addekid(ep1, getE1()); |
723 |
} while (nextc == ','); |
724 |
if (nextc != ')') |
725 |
syntax("')' expected"); |
726 |
scan(); |
727 |
} else if (!(esupport&E_VARIABLE)) |
728 |
syntax("'(' expected"); |
729 |
if (esupport&E_RCONST && isconstvar(ep1)) |
730 |
ep1 = rconst(ep1); |
731 |
return(ep1); |
732 |
} |
733 |
|
734 |
if (isdecimal(nextc)) { |
735 |
ep1 = newnode(); |
736 |
ep1->type = NUM; |
737 |
ep1->v.num = getnum(); |
738 |
return(ep1); |
739 |
} |
740 |
syntax("unexpected character"); |
741 |
return NULL; /* pro forma return */ |
742 |
} |
743 |
|
744 |
|
745 |
EPNODE * |
746 |
rconst( /* reduce a constant expression */ |
747 |
register EPNODE *epar |
748 |
) |
749 |
{ |
750 |
register EPNODE *ep; |
751 |
|
752 |
ep = newnode(); |
753 |
ep->type = NUM; |
754 |
errno = 0; |
755 |
ep->v.num = evalue(epar); |
756 |
if (errno == EDOM || errno == ERANGE) |
757 |
syntax("bad constant expression"); |
758 |
epfree(epar); |
759 |
|
760 |
return(ep); |
761 |
} |
762 |
|
763 |
|
764 |
int |
765 |
isconstvar( /* is ep linked to a constant expression? */ |
766 |
register EPNODE *ep |
767 |
) |
768 |
{ |
769 |
register EPNODE *ep1; |
770 |
|
771 |
if (esupport&E_FUNCTION && ep->type == FUNC) { |
772 |
if (!isconstfun(ep->v.kid)) |
773 |
return(0); |
774 |
for (ep1 = ep->v.kid->sibling; ep1 != NULL; ep1 = ep1->sibling) |
775 |
if (ep1->type != NUM && !isconstfun(ep1)) |
776 |
return(0); |
777 |
return(1); |
778 |
} |
779 |
if (ep->type != VAR) |
780 |
return(0); |
781 |
ep1 = ep->v.ln->def; |
782 |
if (ep1 == NULL || ep1->type != ':') |
783 |
return(0); |
784 |
if (esupport&E_FUNCTION && ep1->v.kid->type != SYM) |
785 |
return(0); |
786 |
return(1); |
787 |
} |
788 |
|
789 |
|
790 |
int |
791 |
isconstfun( /* is ep linked to a constant function? */ |
792 |
register EPNODE *ep |
793 |
) |
794 |
{ |
795 |
register EPNODE *dp; |
796 |
register LIBR *lp; |
797 |
|
798 |
if (ep->type != VAR) |
799 |
return(0); |
800 |
if ((dp = ep->v.ln->def) != NULL) { |
801 |
if (dp->v.kid->type == FUNC) |
802 |
return(dp->type == ':'); |
803 |
else |
804 |
return(0); /* don't identify masked library functions */ |
805 |
} |
806 |
if ((lp = ep->v.ln->lib) != NULL) |
807 |
return(lp->atyp == ':'); |
808 |
return(0); |
809 |
} |