1 |
#ifndef lint |
2 |
static const char RCSid[] = "$Id: calexpr.c,v 2.28 2003/11/14 17:22:06 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 |
* |
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* 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 "rtmisc.h" |
30 |
#include "rtio.h" |
31 |
#include "rterror.h" |
32 |
#include "calcomp.h" |
33 |
|
34 |
#define MAXLINE 256 /* maximum line length */ |
35 |
|
36 |
#define newnode() (EPNODE *)ecalloc(1, sizeof(EPNODE)) |
37 |
|
38 |
#define isdecimal(c) (isdigit(c) || (c) == '.') |
39 |
|
40 |
static double euminus(EPNODE *), eargument(EPNODE *), enumber(EPNODE *); |
41 |
static double echannel(EPNODE *); |
42 |
static double eadd(EPNODE *), esubtr(EPNODE *), |
43 |
emult(EPNODE *), edivi(EPNODE *), |
44 |
epow(EPNODE *); |
45 |
static double ebotch(EPNODE *); |
46 |
|
47 |
unsigned int esupport = /* what to support */ |
48 |
E_VARIABLE | E_FUNCTION ; |
49 |
|
50 |
int nextc; /* lookahead character */ |
51 |
|
52 |
double (*eoper[])(EPNODE *) = { /* expression operations */ |
53 |
ebotch, |
54 |
evariable, |
55 |
enumber, |
56 |
euminus, |
57 |
echannel, |
58 |
efunc, |
59 |
eargument, |
60 |
ebotch, |
61 |
ebotch, |
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
64 |
emult, |
65 |
eadd, |
66 |
0, |
67 |
esubtr, |
68 |
0, |
69 |
edivi, |
70 |
0,0,0,0,0,0,0,0,0,0, |
71 |
ebotch, |
72 |
0,0, |
73 |
ebotch, |
74 |
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
75 |
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
76 |
epow, |
77 |
}; |
78 |
|
79 |
static FILE *infp; /* input file pointer */ |
80 |
static char *linbuf; /* line buffer */ |
81 |
static char *infile; /* input file name */ |
82 |
static int lineno; /* input line number */ |
83 |
static int linepos; /* position in buffer */ |
84 |
|
85 |
|
86 |
EPNODE * |
87 |
eparse( /* parse an expression string */ |
88 |
char *expr |
89 |
) |
90 |
{ |
91 |
EPNODE *ep; |
92 |
|
93 |
initstr(expr, NULL, 0); |
94 |
curfunc = NULL; |
95 |
ep = getE1(); |
96 |
if (nextc != EOF) |
97 |
syntax("unexpected character"); |
98 |
return(ep); |
99 |
} |
100 |
|
101 |
|
102 |
double |
103 |
eval( /* evaluate an expression string */ |
104 |
char *expr |
105 |
) |
106 |
{ |
107 |
register EPNODE *ep; |
108 |
double rval; |
109 |
|
110 |
ep = eparse(expr); |
111 |
rval = evalue(ep); |
112 |
epfree(ep); |
113 |
return(rval); |
114 |
} |
115 |
|
116 |
|
117 |
int |
118 |
epcmp( /* compare two expressions for equivalence */ |
119 |
register EPNODE *ep1, |
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register EPNODE *ep2 |
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) |
122 |
{ |
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double d; |
124 |
|
125 |
if (ep1->type != ep2->type) |
126 |
return(1); |
127 |
|
128 |
switch (ep1->type) { |
129 |
|
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case VAR: |
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return(ep1->v.ln != ep2->v.ln); |
132 |
|
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case NUM: |
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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)); |
138 |
|
139 |
case CHAN: |
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case ARG: |
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return(ep1->v.chan != ep2->v.chan); |
142 |
|
143 |
case '=': |
144 |
case ':': |
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return(epcmp(ep1->v.kid->sibling, ep2->v.kid->sibling)); |
146 |
|
147 |
case TICK: |
148 |
case SYM: /* should never get this one */ |
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return(0); |
150 |
|
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default: |
152 |
ep1 = ep1->v.kid; |
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ep2 = ep2->v.kid; |
154 |
while (ep1 != NULL) { |
155 |
if (ep2 == NULL) |
156 |
return(1); |
157 |
if (epcmp(ep1, ep2)) |
158 |
return(1); |
159 |
ep1 = ep1->sibling; |
160 |
ep2 = ep2->sibling; |
161 |
} |
162 |
return(ep2 != NULL); |
163 |
} |
164 |
} |
165 |
|
166 |
|
167 |
void |
168 |
epfree( /* free a parse tree */ |
169 |
register EPNODE *epar |
170 |
) |
171 |
{ |
172 |
register EPNODE *ep; |
173 |
|
174 |
switch (epar->type) { |
175 |
|
176 |
case VAR: |
177 |
varfree(epar->v.ln); |
178 |
break; |
179 |
|
180 |
case SYM: |
181 |
freestr(epar->v.name); |
182 |
break; |
183 |
|
184 |
case NUM: |
185 |
case CHAN: |
186 |
case ARG: |
187 |
case TICK: |
188 |
break; |
189 |
|
190 |
default: |
191 |
while ((ep = epar->v.kid) != NULL) { |
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epar->v.kid = ep->sibling; |
193 |
epfree(ep); |
194 |
} |
195 |
break; |
196 |
|
197 |
} |
198 |
|
199 |
efree((char *)epar); |
200 |
} |
201 |
|
202 |
/* the following used to be a switch */ |
203 |
static double |
204 |
eargument( |
205 |
EPNODE *ep |
206 |
) |
207 |
{ |
208 |
return(argument(ep->v.chan)); |
209 |
} |
210 |
|
211 |
static double |
212 |
enumber( |
213 |
EPNODE *ep |
214 |
) |
215 |
{ |
216 |
return(ep->v.num); |
217 |
} |
218 |
|
219 |
static double |
220 |
euminus( |
221 |
EPNODE *ep |
222 |
) |
223 |
{ |
224 |
register EPNODE *ep1 = ep->v.kid; |
225 |
|
226 |
return(-evalue(ep1)); |
227 |
} |
228 |
|
229 |
static double |
230 |
echannel( |
231 |
EPNODE *ep |
232 |
) |
233 |
{ |
234 |
return(chanvalue(ep->v.chan)); |
235 |
} |
236 |
|
237 |
static double |
238 |
eadd( |
239 |
EPNODE *ep |
240 |
) |
241 |
{ |
242 |
register EPNODE *ep1 = ep->v.kid; |
243 |
|
244 |
return(evalue(ep1) + evalue(ep1->sibling)); |
245 |
} |
246 |
|
247 |
static double |
248 |
esubtr( |
249 |
EPNODE *ep |
250 |
) |
251 |
{ |
252 |
register EPNODE *ep1 = ep->v.kid; |
253 |
|
254 |
return(evalue(ep1) - evalue(ep1->sibling)); |
255 |
} |
256 |
|
257 |
static double |
258 |
emult( |
259 |
EPNODE *ep |
260 |
) |
261 |
{ |
262 |
register EPNODE *ep1 = ep->v.kid; |
263 |
|
264 |
return(evalue(ep1) * evalue(ep1->sibling)); |
265 |
} |
266 |
|
267 |
static double |
268 |
edivi( |
269 |
EPNODE *ep |
270 |
) |
271 |
{ |
272 |
register EPNODE *ep1 = ep->v.kid; |
273 |
double d; |
274 |
|
275 |
d = evalue(ep1->sibling); |
276 |
if (d == 0.0) { |
277 |
wputs("Division by zero\n"); |
278 |
errno = ERANGE; |
279 |
return(0.0); |
280 |
} |
281 |
return(evalue(ep1) / d); |
282 |
} |
283 |
|
284 |
static double |
285 |
epow( |
286 |
EPNODE *ep |
287 |
) |
288 |
{ |
289 |
register EPNODE *ep1 = ep->v.kid; |
290 |
double d; |
291 |
int lasterrno; |
292 |
|
293 |
lasterrno = errno; |
294 |
errno = 0; |
295 |
d = pow(evalue(ep1), evalue(ep1->sibling)); |
296 |
#ifdef IEEE |
297 |
if (!finite(d)) |
298 |
errno = EDOM; |
299 |
#endif |
300 |
if (errno == EDOM || errno == ERANGE) { |
301 |
wputs("Illegal power\n"); |
302 |
return(0.0); |
303 |
} |
304 |
errno = lasterrno; |
305 |
return(d); |
306 |
} |
307 |
|
308 |
static double |
309 |
ebotch( |
310 |
EPNODE *ep |
311 |
) |
312 |
{ |
313 |
eputs("Bad expression!\n"); |
314 |
quit(1); |
315 |
return 0.0; /* pro forma return */ |
316 |
} |
317 |
|
318 |
|
319 |
EPNODE * |
320 |
ekid( /* return pointer to a node's nth kid */ |
321 |
register EPNODE *ep, |
322 |
register int n |
323 |
) |
324 |
{ |
325 |
|
326 |
for (ep = ep->v.kid; ep != NULL; ep = ep->sibling) |
327 |
if (--n < 0) |
328 |
break; |
329 |
|
330 |
return(ep); |
331 |
} |
332 |
|
333 |
|
334 |
int |
335 |
nekids( /* return # of kids for node ep */ |
336 |
register EPNODE *ep |
337 |
) |
338 |
{ |
339 |
register int n = 0; |
340 |
|
341 |
for (ep = ep->v.kid; ep != NULL; ep = ep->sibling) |
342 |
n++; |
343 |
|
344 |
return(n); |
345 |
} |
346 |
|
347 |
|
348 |
void |
349 |
initfile( /* prepare input file */ |
350 |
FILE *fp, |
351 |
char *fn, |
352 |
int ln |
353 |
) |
354 |
{ |
355 |
static char inpbuf[MAXLINE]; |
356 |
|
357 |
infp = fp; |
358 |
linbuf = inpbuf; |
359 |
infile = fn; |
360 |
lineno = ln; |
361 |
linepos = 0; |
362 |
inpbuf[0] = '\0'; |
363 |
scan(); |
364 |
} |
365 |
|
366 |
|
367 |
void |
368 |
initstr( /* prepare input string */ |
369 |
char *s, |
370 |
char *fn, |
371 |
int ln |
372 |
) |
373 |
{ |
374 |
infp = NULL; |
375 |
infile = fn; |
376 |
lineno = ln; |
377 |
linbuf = s; |
378 |
linepos = 0; |
379 |
scan(); |
380 |
} |
381 |
|
382 |
|
383 |
void |
384 |
getscanpos( /* return current scan position */ |
385 |
char **fnp, |
386 |
int *lnp, |
387 |
char **spp, |
388 |
FILE **fpp |
389 |
) |
390 |
{ |
391 |
if (fnp != NULL) *fnp = infile; |
392 |
if (lnp != NULL) *lnp = lineno; |
393 |
if (spp != NULL) *spp = linbuf+linepos; |
394 |
if (fpp != NULL) *fpp = infp; |
395 |
} |
396 |
|
397 |
|
398 |
int |
399 |
scan(void) /* scan next character, return literal next */ |
400 |
{ |
401 |
register int lnext = 0; |
402 |
|
403 |
do { |
404 |
if (linbuf[linepos] == '\0') |
405 |
if (infp == NULL || fgets(linbuf, MAXLINE, infp) == NULL) |
406 |
nextc = EOF; |
407 |
else { |
408 |
nextc = linbuf[0]; |
409 |
lineno++; |
410 |
linepos = 1; |
411 |
} |
412 |
else |
413 |
nextc = linbuf[linepos++]; |
414 |
if (!lnext) |
415 |
lnext = nextc; |
416 |
if (nextc == '{') { |
417 |
scan(); |
418 |
while (nextc != '}') |
419 |
if (nextc == EOF) |
420 |
syntax("'}' expected"); |
421 |
else |
422 |
scan(); |
423 |
scan(); |
424 |
} |
425 |
} while (isspace(nextc)); |
426 |
return(lnext); |
427 |
} |
428 |
|
429 |
|
430 |
char * |
431 |
long2ascii( /* convert long to ascii */ |
432 |
long l |
433 |
) |
434 |
{ |
435 |
static char buf[16]; |
436 |
register char *cp; |
437 |
int neg = 0; |
438 |
|
439 |
if (l == 0) |
440 |
return("0"); |
441 |
if (l < 0) { |
442 |
l = -l; |
443 |
neg++; |
444 |
} |
445 |
cp = buf + sizeof(buf); |
446 |
*--cp = '\0'; |
447 |
while (l) { |
448 |
*--cp = l % 10 + '0'; |
449 |
l /= 10; |
450 |
} |
451 |
if (neg) |
452 |
*--cp = '-'; |
453 |
return(cp); |
454 |
} |
455 |
|
456 |
|
457 |
void |
458 |
syntax( /* report syntax error and quit */ |
459 |
char *err |
460 |
) |
461 |
{ |
462 |
register int i; |
463 |
|
464 |
if (infile != NULL || lineno != 0) { |
465 |
if (infile != NULL) eputs(infile); |
466 |
if (lineno != 0) { |
467 |
eputs(infile != NULL ? ", line " : "line "); |
468 |
eputs(long2ascii((long)lineno)); |
469 |
} |
470 |
eputs(":\n"); |
471 |
} |
472 |
eputs(linbuf); |
473 |
if (linbuf[strlen(linbuf)-1] != '\n') |
474 |
eputs("\n"); |
475 |
for (i = 0; i < linepos-1; i++) |
476 |
eputs(linbuf[i] == '\t' ? "\t" : " "); |
477 |
eputs("^ "); |
478 |
eputs(err); |
479 |
eputs("\n"); |
480 |
quit(1); |
481 |
} |
482 |
|
483 |
|
484 |
void |
485 |
addekid( /* add a child to ep */ |
486 |
register EPNODE *ep, |
487 |
EPNODE *ekid |
488 |
) |
489 |
{ |
490 |
if (ep->v.kid == NULL) |
491 |
ep->v.kid = ekid; |
492 |
else { |
493 |
for (ep = ep->v.kid; ep->sibling != NULL; ep = ep->sibling) |
494 |
; |
495 |
ep->sibling = ekid; |
496 |
} |
497 |
ekid->sibling = NULL; |
498 |
} |
499 |
|
500 |
|
501 |
char * |
502 |
getname(void) /* scan an identifier */ |
503 |
{ |
504 |
static char str[RMAXWORD+1]; |
505 |
register int i, lnext; |
506 |
|
507 |
lnext = nextc; |
508 |
for (i = 0; i < RMAXWORD && isid(lnext); i++, lnext = scan()) |
509 |
str[i] = lnext; |
510 |
str[i] = '\0'; |
511 |
while (isid(lnext)) /* skip rest of name */ |
512 |
lnext = scan(); |
513 |
|
514 |
return(str); |
515 |
} |
516 |
|
517 |
|
518 |
int |
519 |
getinum(void) /* scan a positive integer */ |
520 |
{ |
521 |
register int n, lnext; |
522 |
|
523 |
n = 0; |
524 |
lnext = nextc; |
525 |
while (isdigit(lnext)) { |
526 |
n = n * 10 + lnext - '0'; |
527 |
lnext = scan(); |
528 |
} |
529 |
return(n); |
530 |
} |
531 |
|
532 |
|
533 |
double |
534 |
getnum(void) /* scan a positive float */ |
535 |
{ |
536 |
register int i, lnext; |
537 |
char str[RMAXWORD+1]; |
538 |
|
539 |
i = 0; |
540 |
lnext = nextc; |
541 |
while (isdigit(lnext) && i < RMAXWORD) { |
542 |
str[i++] = lnext; |
543 |
lnext = scan(); |
544 |
} |
545 |
if (lnext == '.' && i < RMAXWORD) { |
546 |
str[i++] = lnext; |
547 |
lnext = scan(); |
548 |
if (i == 1 && !isdigit(lnext)) |
549 |
syntax("badly formed number"); |
550 |
while (isdigit(lnext) && i < RMAXWORD) { |
551 |
str[i++] = lnext; |
552 |
lnext = scan(); |
553 |
} |
554 |
} |
555 |
if ((lnext == 'e') | (lnext == 'E') && i < RMAXWORD) { |
556 |
str[i++] = lnext; |
557 |
lnext = scan(); |
558 |
if ((lnext == '-') | (lnext == '+') && i < RMAXWORD) { |
559 |
str[i++] = lnext; |
560 |
lnext = scan(); |
561 |
} |
562 |
if (!isdigit(lnext)) |
563 |
syntax("missing exponent"); |
564 |
while (isdigit(lnext) && i < RMAXWORD) { |
565 |
str[i++] = lnext; |
566 |
lnext = scan(); |
567 |
} |
568 |
} |
569 |
str[i] = '\0'; |
570 |
|
571 |
return(atof(str)); |
572 |
} |
573 |
|
574 |
|
575 |
EPNODE * |
576 |
getE1(void) /* E1 -> E1 ADDOP E2 */ |
577 |
/* E2 */ |
578 |
{ |
579 |
register EPNODE *ep1, *ep2; |
580 |
|
581 |
ep1 = getE2(); |
582 |
while (nextc == '+' || nextc == '-') { |
583 |
ep2 = newnode(); |
584 |
ep2->type = nextc; |
585 |
scan(); |
586 |
addekid(ep2, ep1); |
587 |
addekid(ep2, getE2()); |
588 |
if (esupport&E_RCONST && |
589 |
ep1->type == NUM && ep1->sibling->type == NUM) |
590 |
ep2 = rconst(ep2); |
591 |
ep1 = ep2; |
592 |
} |
593 |
return(ep1); |
594 |
} |
595 |
|
596 |
|
597 |
EPNODE * |
598 |
getE2(void) /* E2 -> E2 MULOP E3 */ |
599 |
/* E3 */ |
600 |
{ |
601 |
register EPNODE *ep1, *ep2; |
602 |
|
603 |
ep1 = getE3(); |
604 |
while (nextc == '*' || nextc == '/') { |
605 |
ep2 = newnode(); |
606 |
ep2->type = nextc; |
607 |
scan(); |
608 |
addekid(ep2, ep1); |
609 |
addekid(ep2, getE3()); |
610 |
if (esupport&E_RCONST && |
611 |
ep1->type == NUM && ep1->sibling->type == NUM) |
612 |
ep2 = rconst(ep2); |
613 |
ep1 = ep2; |
614 |
} |
615 |
return(ep1); |
616 |
} |
617 |
|
618 |
|
619 |
EPNODE * |
620 |
getE3(void) /* E3 -> E4 ^ E3 */ |
621 |
/* E4 */ |
622 |
{ |
623 |
register EPNODE *ep1, *ep2; |
624 |
|
625 |
ep1 = getE4(); |
626 |
if (nextc == '^') { |
627 |
ep2 = newnode(); |
628 |
ep2->type = nextc; |
629 |
scan(); |
630 |
addekid(ep2, ep1); |
631 |
addekid(ep2, getE3()); |
632 |
if (esupport&E_RCONST && |
633 |
ep1->type == NUM && ep1->sibling->type == NUM) |
634 |
ep2 = rconst(ep2); |
635 |
return(ep2); |
636 |
} |
637 |
return(ep1); |
638 |
} |
639 |
|
640 |
|
641 |
EPNODE * |
642 |
getE4(void) /* E4 -> ADDOP E5 */ |
643 |
/* E5 */ |
644 |
{ |
645 |
register EPNODE *ep1, *ep2; |
646 |
|
647 |
if (nextc == '-') { |
648 |
scan(); |
649 |
ep2 = getE5(); |
650 |
if (ep2->type == NUM) { |
651 |
ep2->v.num = -ep2->v.num; |
652 |
return(ep2); |
653 |
} |
654 |
if (ep2->type == UMINUS) { /* don't generate -(-E5) */ |
655 |
efree((char *)ep2); |
656 |
return(ep2->v.kid); |
657 |
} |
658 |
ep1 = newnode(); |
659 |
ep1->type = UMINUS; |
660 |
addekid(ep1, ep2); |
661 |
return(ep1); |
662 |
} |
663 |
if (nextc == '+') |
664 |
scan(); |
665 |
return(getE5()); |
666 |
} |
667 |
|
668 |
|
669 |
EPNODE * |
670 |
getE5(void) /* E5 -> (E1) */ |
671 |
/* VAR */ |
672 |
/* NUM */ |
673 |
/* $N */ |
674 |
/* FUNC(E1,..) */ |
675 |
/* ARG */ |
676 |
{ |
677 |
int i; |
678 |
char *nam; |
679 |
register EPNODE *ep1, *ep2; |
680 |
|
681 |
if (nextc == '(') { |
682 |
scan(); |
683 |
ep1 = getE1(); |
684 |
if (nextc != ')') |
685 |
syntax("')' expected"); |
686 |
scan(); |
687 |
return(ep1); |
688 |
} |
689 |
|
690 |
if (esupport&E_INCHAN && nextc == '$') { |
691 |
scan(); |
692 |
ep1 = newnode(); |
693 |
ep1->type = CHAN; |
694 |
ep1->v.chan = getinum(); |
695 |
return(ep1); |
696 |
} |
697 |
|
698 |
if (esupport&(E_VARIABLE|E_FUNCTION) && |
699 |
(isalpha(nextc) || nextc == CNTXMARK)) { |
700 |
nam = getname(); |
701 |
ep1 = NULL; |
702 |
if ((esupport&(E_VARIABLE|E_FUNCTION)) == (E_VARIABLE|E_FUNCTION) |
703 |
&& curfunc != NULL) |
704 |
for (i = 1, ep2 = curfunc->v.kid->sibling; |
705 |
ep2 != NULL; i++, ep2 = ep2->sibling) |
706 |
if (!strcmp(ep2->v.name, nam)) { |
707 |
ep1 = newnode(); |
708 |
ep1->type = ARG; |
709 |
ep1->v.chan = i; |
710 |
break; |
711 |
} |
712 |
if (ep1 == NULL) { |
713 |
ep1 = newnode(); |
714 |
ep1->type = VAR; |
715 |
ep1->v.ln = varinsert(nam); |
716 |
} |
717 |
if (esupport&E_FUNCTION && nextc == '(') { |
718 |
ep2 = newnode(); |
719 |
ep2->type = FUNC; |
720 |
addekid(ep2, ep1); |
721 |
ep1 = ep2; |
722 |
do { |
723 |
scan(); |
724 |
addekid(ep1, getE1()); |
725 |
} while (nextc == ','); |
726 |
if (nextc != ')') |
727 |
syntax("')' expected"); |
728 |
scan(); |
729 |
} else if (!(esupport&E_VARIABLE)) |
730 |
syntax("'(' expected"); |
731 |
if (esupport&E_RCONST && isconstvar(ep1)) |
732 |
ep1 = rconst(ep1); |
733 |
return(ep1); |
734 |
} |
735 |
|
736 |
if (isdecimal(nextc)) { |
737 |
ep1 = newnode(); |
738 |
ep1->type = NUM; |
739 |
ep1->v.num = getnum(); |
740 |
return(ep1); |
741 |
} |
742 |
syntax("unexpected character"); |
743 |
return NULL; /* pro forma return */ |
744 |
} |
745 |
|
746 |
|
747 |
EPNODE * |
748 |
rconst( /* reduce a constant expression */ |
749 |
register EPNODE *epar |
750 |
) |
751 |
{ |
752 |
register EPNODE *ep; |
753 |
|
754 |
ep = newnode(); |
755 |
ep->type = NUM; |
756 |
errno = 0; |
757 |
ep->v.num = evalue(epar); |
758 |
if (errno == EDOM || errno == ERANGE) |
759 |
syntax("bad constant expression"); |
760 |
epfree(epar); |
761 |
|
762 |
return(ep); |
763 |
} |
764 |
|
765 |
|
766 |
int |
767 |
isconstvar( /* is ep linked to a constant expression? */ |
768 |
register EPNODE *ep |
769 |
) |
770 |
{ |
771 |
register EPNODE *ep1; |
772 |
|
773 |
if (esupport&E_FUNCTION && ep->type == FUNC) { |
774 |
if (!isconstfun(ep->v.kid)) |
775 |
return(0); |
776 |
for (ep1 = ep->v.kid->sibling; ep1 != NULL; ep1 = ep1->sibling) |
777 |
if (ep1->type != NUM && !isconstfun(ep1)) |
778 |
return(0); |
779 |
return(1); |
780 |
} |
781 |
if (ep->type != VAR) |
782 |
return(0); |
783 |
ep1 = ep->v.ln->def; |
784 |
if (ep1 == NULL || ep1->type != ':') |
785 |
return(0); |
786 |
if (esupport&E_FUNCTION && ep1->v.kid->type != SYM) |
787 |
return(0); |
788 |
return(1); |
789 |
} |
790 |
|
791 |
|
792 |
int |
793 |
isconstfun( /* is ep linked to a constant function? */ |
794 |
register EPNODE *ep |
795 |
) |
796 |
{ |
797 |
register EPNODE *dp; |
798 |
register LIBR *lp; |
799 |
|
800 |
if (ep->type != VAR) |
801 |
return(0); |
802 |
if ((dp = ep->v.ln->def) != NULL) { |
803 |
if (dp->v.kid->type == FUNC) |
804 |
return(dp->type == ':'); |
805 |
else |
806 |
return(0); /* don't identify masked library functions */ |
807 |
} |
808 |
if ((lp = ep->v.ln->lib) != NULL) |
809 |
return(lp->atyp == ':'); |
810 |
return(0); |
811 |
} |