| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: calexpr.c,v 2.38 2019/12/07 16:38:08 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 <ctype.h> |
| 23 |
#include <errno.h> |
| 24 |
#include <math.h> |
| 25 |
#include <stdlib.h> |
| 26 |
|
| 27 |
#include "rtmisc.h" |
| 28 |
#include "rtio.h" |
| 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 eofc = 0; /* optional end-of-file character */ |
| 49 |
int nextc; /* lookahead character */ |
| 50 |
|
| 51 |
double (*eoper[])(EPNODE *) = { /* expression operations */ |
| 52 |
ebotch, |
| 53 |
evariable, |
| 54 |
enumber, |
| 55 |
euminus, |
| 56 |
echannel, |
| 57 |
efunc, |
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eargument, |
| 59 |
ebotch, |
| 60 |
ebotch, |
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
| 62 |
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
| 63 |
emult, |
| 64 |
eadd, |
| 65 |
0, |
| 66 |
esubtr, |
| 67 |
0, |
| 68 |
edivi, |
| 69 |
0,0,0,0,0,0,0,0,0,0, |
| 70 |
ebotch, |
| 71 |
0,0, |
| 72 |
ebotch, |
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
| 74 |
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, |
| 75 |
epow, |
| 76 |
}; |
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|
| 78 |
static FILE *infp; /* input file pointer */ |
| 79 |
static char *linbuf; /* line buffer */ |
| 80 |
static char *infile; /* input file name */ |
| 81 |
static int lineno; /* input line number */ |
| 82 |
static int linepos; /* position in buffer */ |
| 83 |
|
| 84 |
|
| 85 |
EPNODE * |
| 86 |
eparse( /* parse an expression string */ |
| 87 |
char *expr |
| 88 |
) |
| 89 |
{ |
| 90 |
EPNODE *ep; |
| 91 |
|
| 92 |
initstr(expr, NULL, 0); |
| 93 |
curfunc = NULL; |
| 94 |
ep = getE1(); |
| 95 |
if (nextc != EOF) |
| 96 |
syntax("unexpected character"); |
| 97 |
return(ep); |
| 98 |
} |
| 99 |
|
| 100 |
|
| 101 |
double |
| 102 |
eval( /* evaluate an expression string */ |
| 103 |
char *expr |
| 104 |
) |
| 105 |
{ |
| 106 |
int prev_support = esupport; |
| 107 |
EPNODE *ep; |
| 108 |
double rval; |
| 109 |
|
| 110 |
esupport &= ~E_RCONST; /* don't bother reducing constant expr */ |
| 111 |
ep = eparse(expr); |
| 112 |
esupport = prev_support; /* as you were */ |
| 113 |
rval = evalue(ep); |
| 114 |
epfree(ep); |
| 115 |
return(rval); |
| 116 |
} |
| 117 |
|
| 118 |
|
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int |
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epcmp( /* compare two expressions for equivalence */ |
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EPNODE *ep1, |
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EPNODE *ep2 |
| 123 |
) |
| 124 |
{ |
| 125 |
double d; |
| 126 |
|
| 127 |
if (ep1->type != ep2->type) |
| 128 |
return(1); |
| 129 |
|
| 130 |
switch (ep1->type) { |
| 131 |
|
| 132 |
case VAR: |
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return(ep1->v.ln != ep2->v.ln); |
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|
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case NUM: |
| 136 |
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)); |
| 140 |
|
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case CHAN: |
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case ARG: |
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return(ep1->v.chan != ep2->v.chan); |
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|
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case '=': |
| 146 |
case ':': |
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return(epcmp(ep1->v.kid->sibling, ep2->v.kid->sibling)); |
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|
| 149 |
case CLKT: |
| 150 |
case SYM: /* should never get this one */ |
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return(0); |
| 152 |
|
| 153 |
default: |
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ep1 = ep1->v.kid; |
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ep2 = ep2->v.kid; |
| 156 |
while (ep1 != NULL) { |
| 157 |
if (ep2 == NULL) |
| 158 |
return(1); |
| 159 |
if (epcmp(ep1, ep2)) |
| 160 |
return(1); |
| 161 |
ep1 = ep1->sibling; |
| 162 |
ep2 = ep2->sibling; |
| 163 |
} |
| 164 |
return(ep2 != NULL); |
| 165 |
} |
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} |
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|
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|
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void |
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epfree( /* free a parse tree */ |
| 171 |
EPNODE *epar |
| 172 |
) |
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{ |
| 174 |
EPNODE *ep; |
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|
| 176 |
switch (epar->type) { |
| 177 |
|
| 178 |
case VAR: |
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varfree(epar->v.ln); |
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break; |
| 181 |
|
| 182 |
case SYM: |
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freestr(epar->v.name); |
| 184 |
break; |
| 185 |
|
| 186 |
case NUM: |
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case CHAN: |
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case ARG: |
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case CLKT: |
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break; |
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|
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default: |
| 193 |
while ((ep = epar->v.kid) != NULL) { |
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epar->v.kid = ep->sibling; |
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epfree(ep); |
| 196 |
} |
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break; |
| 198 |
|
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} |
| 200 |
|
| 201 |
efree((char *)epar); |
| 202 |
} |
| 203 |
|
| 204 |
/* the following used to be a switch */ |
| 205 |
static double |
| 206 |
eargument( |
| 207 |
EPNODE *ep |
| 208 |
) |
| 209 |
{ |
| 210 |
return(argument(ep->v.chan)); |
| 211 |
} |
| 212 |
|
| 213 |
static double |
| 214 |
enumber( |
| 215 |
EPNODE *ep |
| 216 |
) |
| 217 |
{ |
| 218 |
return(ep->v.num); |
| 219 |
} |
| 220 |
|
| 221 |
static double |
| 222 |
euminus( |
| 223 |
EPNODE *ep |
| 224 |
) |
| 225 |
{ |
| 226 |
EPNODE *ep1 = ep->v.kid; |
| 227 |
|
| 228 |
return(-evalue(ep1)); |
| 229 |
} |
| 230 |
|
| 231 |
static double |
| 232 |
echannel( |
| 233 |
EPNODE *ep |
| 234 |
) |
| 235 |
{ |
| 236 |
return(chanvalue(ep->v.chan)); |
| 237 |
} |
| 238 |
|
| 239 |
static double |
| 240 |
eadd( |
| 241 |
EPNODE *ep |
| 242 |
) |
| 243 |
{ |
| 244 |
EPNODE *ep1 = ep->v.kid; |
| 245 |
|
| 246 |
return(evalue(ep1) + evalue(ep1->sibling)); |
| 247 |
} |
| 248 |
|
| 249 |
static double |
| 250 |
esubtr( |
| 251 |
EPNODE *ep |
| 252 |
) |
| 253 |
{ |
| 254 |
EPNODE *ep1 = ep->v.kid; |
| 255 |
|
| 256 |
return(evalue(ep1) - evalue(ep1->sibling)); |
| 257 |
} |
| 258 |
|
| 259 |
static double |
| 260 |
emult( |
| 261 |
EPNODE *ep |
| 262 |
) |
| 263 |
{ |
| 264 |
EPNODE *ep1 = ep->v.kid; |
| 265 |
|
| 266 |
return(evalue(ep1) * evalue(ep1->sibling)); |
| 267 |
} |
| 268 |
|
| 269 |
static double |
| 270 |
edivi( |
| 271 |
EPNODE *ep |
| 272 |
) |
| 273 |
{ |
| 274 |
EPNODE *ep1 = ep->v.kid; |
| 275 |
double d; |
| 276 |
|
| 277 |
d = evalue(ep1->sibling); |
| 278 |
if (d == 0.0) { |
| 279 |
wputs("Division by zero\n"); |
| 280 |
errno = ERANGE; |
| 281 |
return(0.0); |
| 282 |
} |
| 283 |
return(evalue(ep1) / d); |
| 284 |
} |
| 285 |
|
| 286 |
static double |
| 287 |
epow( |
| 288 |
EPNODE *ep |
| 289 |
) |
| 290 |
{ |
| 291 |
EPNODE *ep1 = ep->v.kid; |
| 292 |
double d; |
| 293 |
int lasterrno; |
| 294 |
|
| 295 |
lasterrno = errno; |
| 296 |
errno = 0; |
| 297 |
d = pow(evalue(ep1), evalue(ep1->sibling)); |
| 298 |
#ifdef isnan |
| 299 |
if (errno == 0) { |
| 300 |
if (isnan(d)) |
| 301 |
errno = EDOM; |
| 302 |
else if (isinf(d)) |
| 303 |
errno = ERANGE; |
| 304 |
} |
| 305 |
#endif |
| 306 |
if (errno == EDOM || errno == ERANGE) { |
| 307 |
wputs("Illegal power\n"); |
| 308 |
return(0.0); |
| 309 |
} |
| 310 |
errno = lasterrno; |
| 311 |
return(d); |
| 312 |
} |
| 313 |
|
| 314 |
static double |
| 315 |
ebotch( |
| 316 |
EPNODE *ep |
| 317 |
) |
| 318 |
{ |
| 319 |
eputs("Bad expression!\n"); |
| 320 |
quit(1); |
| 321 |
return 0.0; /* pro forma return */ |
| 322 |
} |
| 323 |
|
| 324 |
|
| 325 |
EPNODE * |
| 326 |
ekid( /* return pointer to a node's nth kid */ |
| 327 |
EPNODE *ep, |
| 328 |
int n |
| 329 |
) |
| 330 |
{ |
| 331 |
|
| 332 |
for (ep = ep->v.kid; ep != NULL; ep = ep->sibling) |
| 333 |
if (--n < 0) |
| 334 |
break; |
| 335 |
|
| 336 |
return(ep); |
| 337 |
} |
| 338 |
|
| 339 |
|
| 340 |
int |
| 341 |
nekids( /* return # of kids for node ep */ |
| 342 |
EPNODE *ep |
| 343 |
) |
| 344 |
{ |
| 345 |
int n = 0; |
| 346 |
|
| 347 |
for (ep = ep->v.kid; ep != NULL; ep = ep->sibling) |
| 348 |
n++; |
| 349 |
|
| 350 |
return(n); |
| 351 |
} |
| 352 |
|
| 353 |
|
| 354 |
void |
| 355 |
initfile( /* prepare input file */ |
| 356 |
FILE *fp, |
| 357 |
char *fn, |
| 358 |
int ln |
| 359 |
) |
| 360 |
{ |
| 361 |
static char inpbuf[MAXLINE]; |
| 362 |
|
| 363 |
infp = fp; |
| 364 |
linbuf = inpbuf; |
| 365 |
infile = fn; |
| 366 |
lineno = ln; |
| 367 |
linepos = 0; |
| 368 |
inpbuf[0] = '\0'; |
| 369 |
scan(); |
| 370 |
} |
| 371 |
|
| 372 |
|
| 373 |
void |
| 374 |
initstr( /* prepare input string */ |
| 375 |
char *s, |
| 376 |
char *fn, |
| 377 |
int ln |
| 378 |
) |
| 379 |
{ |
| 380 |
infp = NULL; |
| 381 |
infile = fn; |
| 382 |
lineno = ln; |
| 383 |
linbuf = s; |
| 384 |
linepos = 0; |
| 385 |
scan(); |
| 386 |
} |
| 387 |
|
| 388 |
|
| 389 |
void |
| 390 |
getscanpos( /* return current scan position */ |
| 391 |
char **fnp, |
| 392 |
int *lnp, |
| 393 |
char **spp, |
| 394 |
FILE **fpp |
| 395 |
) |
| 396 |
{ |
| 397 |
if (fnp != NULL) *fnp = infile; |
| 398 |
if (lnp != NULL) *lnp = lineno; |
| 399 |
if (spp != NULL) *spp = linbuf+linepos; |
| 400 |
if (fpp != NULL) *fpp = infp; |
| 401 |
} |
| 402 |
|
| 403 |
|
| 404 |
int |
| 405 |
scan(void) /* scan next character, return literal next */ |
| 406 |
{ |
| 407 |
int lnext = 0; |
| 408 |
|
| 409 |
do { |
| 410 |
if (linbuf[linepos] == '\0') |
| 411 |
if (infp == NULL || fgets(linbuf, MAXLINE, infp) == NULL) |
| 412 |
nextc = EOF; |
| 413 |
else { |
| 414 |
nextc = linbuf[0]; |
| 415 |
lineno++; |
| 416 |
linepos = 1; |
| 417 |
} |
| 418 |
else |
| 419 |
nextc = linbuf[linepos++]; |
| 420 |
if (!lnext) |
| 421 |
lnext = nextc; |
| 422 |
if (nextc == eofc) { |
| 423 |
nextc = EOF; |
| 424 |
break; |
| 425 |
} |
| 426 |
if (nextc == '{') { |
| 427 |
scan(); |
| 428 |
while (nextc != '}') |
| 429 |
if (nextc == EOF) |
| 430 |
syntax("'}' expected"); |
| 431 |
else |
| 432 |
scan(); |
| 433 |
scan(); |
| 434 |
} |
| 435 |
} while (isspace(nextc)); |
| 436 |
return(lnext); |
| 437 |
} |
| 438 |
|
| 439 |
|
| 440 |
char * |
| 441 |
long2ascii( /* convert long to ascii */ |
| 442 |
long l |
| 443 |
) |
| 444 |
{ |
| 445 |
static char buf[16]; |
| 446 |
char *cp; |
| 447 |
int neg = 0; |
| 448 |
|
| 449 |
if (l == 0) |
| 450 |
return("0"); |
| 451 |
if (l < 0) { |
| 452 |
l = -l; |
| 453 |
neg++; |
| 454 |
} |
| 455 |
cp = buf + sizeof(buf); |
| 456 |
*--cp = '\0'; |
| 457 |
while (l) { |
| 458 |
*--cp = l % 10 + '0'; |
| 459 |
l /= 10; |
| 460 |
} |
| 461 |
if (neg) |
| 462 |
*--cp = '-'; |
| 463 |
return(cp); |
| 464 |
} |
| 465 |
|
| 466 |
|
| 467 |
void |
| 468 |
syntax( /* report syntax error and quit */ |
| 469 |
char *err |
| 470 |
) |
| 471 |
{ |
| 472 |
int i; |
| 473 |
|
| 474 |
if (infile != NULL || lineno != 0) { |
| 475 |
if (infile != NULL) eputs(infile); |
| 476 |
if (lineno != 0) { |
| 477 |
eputs(infile != NULL ? ", line " : "line "); |
| 478 |
eputs(long2ascii((long)lineno)); |
| 479 |
} |
| 480 |
eputs(":\n"); |
| 481 |
} |
| 482 |
eputs(linbuf); |
| 483 |
if (linbuf[strlen(linbuf)-1] != '\n') |
| 484 |
eputs("\n"); |
| 485 |
for (i = 0; i < linepos-1; i++) |
| 486 |
eputs(linbuf[i] == '\t' ? "\t" : " "); |
| 487 |
eputs("^ "); |
| 488 |
eputs(err); |
| 489 |
eputs("\n"); |
| 490 |
quit(1); |
| 491 |
} |
| 492 |
|
| 493 |
|
| 494 |
void |
| 495 |
addekid( /* add a child to ep */ |
| 496 |
EPNODE *ep, |
| 497 |
EPNODE *ekid |
| 498 |
) |
| 499 |
{ |
| 500 |
if (ep->v.kid == NULL) |
| 501 |
ep->v.kid = ekid; |
| 502 |
else { |
| 503 |
for (ep = ep->v.kid; ep->sibling != NULL; ep = ep->sibling) |
| 504 |
; |
| 505 |
ep->sibling = ekid; |
| 506 |
} |
| 507 |
ekid->sibling = NULL; |
| 508 |
} |
| 509 |
|
| 510 |
|
| 511 |
char * |
| 512 |
getname(void) /* scan an identifier */ |
| 513 |
{ |
| 514 |
static char str[RMAXWORD+1]; |
| 515 |
int i, lnext; |
| 516 |
|
| 517 |
lnext = nextc; |
| 518 |
for (i = 0; i < RMAXWORD && isid(lnext); i++, lnext = scan()) |
| 519 |
str[i] = lnext; |
| 520 |
str[i] = '\0'; |
| 521 |
while (isid(lnext)) /* skip rest of name */ |
| 522 |
lnext = scan(); |
| 523 |
|
| 524 |
return(str); |
| 525 |
} |
| 526 |
|
| 527 |
|
| 528 |
int |
| 529 |
getinum(void) /* scan a positive integer */ |
| 530 |
{ |
| 531 |
int n, lnext; |
| 532 |
|
| 533 |
n = 0; |
| 534 |
lnext = nextc; |
| 535 |
while (isdigit(lnext)) { |
| 536 |
n = n * 10 + lnext - '0'; |
| 537 |
lnext = scan(); |
| 538 |
} |
| 539 |
return(n); |
| 540 |
} |
| 541 |
|
| 542 |
|
| 543 |
double |
| 544 |
getnum(void) /* scan a positive float */ |
| 545 |
{ |
| 546 |
int i, lnext; |
| 547 |
char str[RMAXWORD+1]; |
| 548 |
|
| 549 |
i = 0; |
| 550 |
lnext = nextc; |
| 551 |
while (isdigit(lnext) && i < RMAXWORD) { |
| 552 |
str[i++] = lnext; |
| 553 |
lnext = scan(); |
| 554 |
} |
| 555 |
if (lnext == '.' && i < RMAXWORD) { |
| 556 |
str[i++] = lnext; |
| 557 |
lnext = scan(); |
| 558 |
if (i == 1 && !isdigit(lnext)) |
| 559 |
syntax("badly formed number"); |
| 560 |
while (isdigit(lnext) && i < RMAXWORD) { |
| 561 |
str[i++] = lnext; |
| 562 |
lnext = scan(); |
| 563 |
} |
| 564 |
} |
| 565 |
if ((lnext == 'e') | (lnext == 'E') && i < RMAXWORD) { |
| 566 |
str[i++] = lnext; |
| 567 |
lnext = scan(); |
| 568 |
if ((lnext == '-') | (lnext == '+') && i < RMAXWORD) { |
| 569 |
str[i++] = lnext; |
| 570 |
lnext = scan(); |
| 571 |
} |
| 572 |
if (!isdigit(lnext)) |
| 573 |
syntax("missing exponent"); |
| 574 |
while (isdigit(lnext) && i < RMAXWORD) { |
| 575 |
str[i++] = lnext; |
| 576 |
lnext = scan(); |
| 577 |
} |
| 578 |
} |
| 579 |
str[i] = '\0'; |
| 580 |
|
| 581 |
return(atof(str)); |
| 582 |
} |
| 583 |
|
| 584 |
|
| 585 |
EPNODE * |
| 586 |
getE1(void) /* E1 -> E1 ADDOP E2 */ |
| 587 |
/* E2 */ |
| 588 |
{ |
| 589 |
EPNODE *ep1, *ep2; |
| 590 |
|
| 591 |
ep1 = getE2(); |
| 592 |
while (nextc == '+' || nextc == '-') { |
| 593 |
ep2 = newnode(); |
| 594 |
ep2->type = nextc; |
| 595 |
scan(); |
| 596 |
addekid(ep2, ep1); |
| 597 |
addekid(ep2, getE2()); |
| 598 |
if (esupport&E_RCONST && |
| 599 |
ep1->type == NUM && ep1->sibling->type == NUM) |
| 600 |
ep2 = rconst(ep2); |
| 601 |
ep1 = ep2; |
| 602 |
} |
| 603 |
return(ep1); |
| 604 |
} |
| 605 |
|
| 606 |
|
| 607 |
EPNODE * |
| 608 |
getE2(void) /* E2 -> E2 MULOP E3 */ |
| 609 |
/* E3 */ |
| 610 |
{ |
| 611 |
EPNODE *ep1, *ep2; |
| 612 |
|
| 613 |
ep1 = getE3(); |
| 614 |
while (nextc == '*' || nextc == '/') { |
| 615 |
ep2 = newnode(); |
| 616 |
ep2->type = nextc; |
| 617 |
scan(); |
| 618 |
addekid(ep2, ep1); |
| 619 |
addekid(ep2, getE3()); |
| 620 |
if (esupport&E_RCONST) { |
| 621 |
EPNODE *ep3 = ep1->sibling; |
| 622 |
if (ep1->type == NUM && ep3->type == NUM) { |
| 623 |
ep2 = rconst(ep2); |
| 624 |
} else if (ep3->type == NUM) { |
| 625 |
if (ep2->type == '/') { |
| 626 |
if (ep3->v.num == 0) |
| 627 |
syntax("divide by zero constant"); |
| 628 |
ep2->type = '*'; /* for speed */ |
| 629 |
ep3->v.num = 1./ep3->v.num; |
| 630 |
} else if (ep3->v.num == 0) { |
| 631 |
ep1->sibling = NULL; /* (E2 * 0) */ |
| 632 |
epfree(ep2); |
| 633 |
ep2 = ep3; |
| 634 |
} |
| 635 |
} else if (ep1->type == NUM && ep1->v.num == 0) { |
| 636 |
epfree(ep3); /* (0 * E3) or (0 / E3) */ |
| 637 |
ep1->sibling = NULL; |
| 638 |
efree((char *)ep2); |
| 639 |
ep2 = ep1; |
| 640 |
} |
| 641 |
} |
| 642 |
ep1 = ep2; |
| 643 |
} |
| 644 |
return(ep1); |
| 645 |
} |
| 646 |
|
| 647 |
|
| 648 |
EPNODE * |
| 649 |
getE3(void) /* E3 -> E4 ^ E3 */ |
| 650 |
/* E4 */ |
| 651 |
{ |
| 652 |
EPNODE *ep1, *ep2; |
| 653 |
|
| 654 |
ep1 = getE4(); |
| 655 |
if (nextc != '^') |
| 656 |
return(ep1); |
| 657 |
ep2 = newnode(); |
| 658 |
ep2->type = nextc; |
| 659 |
scan(); |
| 660 |
addekid(ep2, ep1); |
| 661 |
addekid(ep2, getE3()); |
| 662 |
if (esupport&E_RCONST) { |
| 663 |
EPNODE *ep3 = ep1->sibling; |
| 664 |
if (ep1->type == NUM && ep3->type == NUM) { |
| 665 |
ep2 = rconst(ep2); |
| 666 |
} else if (ep1->type == NUM && ep1->v.num == 0) { |
| 667 |
epfree(ep3); /* (0 ^ E3) */ |
| 668 |
ep1->sibling = NULL; |
| 669 |
efree((char *)ep2); |
| 670 |
ep2 = ep1; |
| 671 |
} else if ((ep3->type == NUM && ep3->v.num == 0) || |
| 672 |
(ep1->type == NUM && ep1->v.num == 1)) { |
| 673 |
epfree(ep2); /* (E4 ^ 0) or (1 ^ E3) */ |
| 674 |
ep2 = newnode(); |
| 675 |
ep2->type = NUM; |
| 676 |
ep2->v.num = 1; |
| 677 |
} |
| 678 |
} |
| 679 |
return(ep2); |
| 680 |
} |
| 681 |
|
| 682 |
|
| 683 |
EPNODE * |
| 684 |
getE4(void) /* E4 -> ADDOP E5 */ |
| 685 |
/* E5 */ |
| 686 |
{ |
| 687 |
EPNODE *ep1, *ep2; |
| 688 |
|
| 689 |
if (nextc == '-') { |
| 690 |
scan(); |
| 691 |
ep2 = getE5(); |
| 692 |
if (ep2->type == NUM) { |
| 693 |
ep2->v.num = -ep2->v.num; |
| 694 |
return(ep2); |
| 695 |
} |
| 696 |
if (ep2->type == UMINUS) { /* don't generate -(-E5) */ |
| 697 |
ep1 = ep2->v.kid; |
| 698 |
efree((char *)ep2); |
| 699 |
return(ep1); |
| 700 |
} |
| 701 |
ep1 = newnode(); |
| 702 |
ep1->type = UMINUS; |
| 703 |
addekid(ep1, ep2); |
| 704 |
return(ep1); |
| 705 |
} |
| 706 |
if (nextc == '+') |
| 707 |
scan(); |
| 708 |
return(getE5()); |
| 709 |
} |
| 710 |
|
| 711 |
|
| 712 |
EPNODE * |
| 713 |
getE5(void) /* E5 -> (E1) */ |
| 714 |
/* VAR */ |
| 715 |
/* NUM */ |
| 716 |
/* $N */ |
| 717 |
/* FUNC(E1,..) */ |
| 718 |
/* ARG */ |
| 719 |
{ |
| 720 |
int i; |
| 721 |
char *nam; |
| 722 |
EPNODE *ep1, *ep2; |
| 723 |
|
| 724 |
if (nextc == '(') { |
| 725 |
scan(); |
| 726 |
ep1 = getE1(); |
| 727 |
if (nextc != ')') |
| 728 |
syntax("')' expected"); |
| 729 |
scan(); |
| 730 |
return(ep1); |
| 731 |
} |
| 732 |
|
| 733 |
if (esupport&E_INCHAN && nextc == '$') { |
| 734 |
scan(); |
| 735 |
ep1 = newnode(); |
| 736 |
ep1->type = CHAN; |
| 737 |
ep1->v.chan = getinum(); |
| 738 |
return(ep1); |
| 739 |
} |
| 740 |
|
| 741 |
if (esupport&(E_VARIABLE|E_FUNCTION) && |
| 742 |
(isalpha(nextc) || nextc == CNTXMARK)) { |
| 743 |
nam = getname(); |
| 744 |
ep1 = NULL; |
| 745 |
if ((esupport&(E_VARIABLE|E_FUNCTION)) == (E_VARIABLE|E_FUNCTION) |
| 746 |
&& curfunc != NULL) |
| 747 |
for (i = 1, ep2 = curfunc->v.kid->sibling; |
| 748 |
ep2 != NULL; i++, ep2 = ep2->sibling) |
| 749 |
if (!strcmp(ep2->v.name, nam)) { |
| 750 |
ep1 = newnode(); |
| 751 |
ep1->type = ARG; |
| 752 |
ep1->v.chan = i; |
| 753 |
break; |
| 754 |
} |
| 755 |
if (ep1 == NULL) { |
| 756 |
ep1 = newnode(); |
| 757 |
ep1->type = VAR; |
| 758 |
ep1->v.ln = varinsert(nam); |
| 759 |
} |
| 760 |
if (esupport&E_FUNCTION && nextc == '(') { |
| 761 |
ep2 = newnode(); |
| 762 |
ep2->type = FUNC; |
| 763 |
addekid(ep2, ep1); |
| 764 |
ep1 = ep2; |
| 765 |
do { |
| 766 |
scan(); |
| 767 |
addekid(ep1, getE1()); |
| 768 |
} while (nextc == ','); |
| 769 |
if (nextc != ')') |
| 770 |
syntax("')' expected"); |
| 771 |
scan(); |
| 772 |
} else if (!(esupport&E_VARIABLE)) |
| 773 |
syntax("'(' expected"); |
| 774 |
if (esupport&E_RCONST && isconstvar(ep1)) |
| 775 |
ep1 = rconst(ep1); |
| 776 |
return(ep1); |
| 777 |
} |
| 778 |
|
| 779 |
if (isdecimal(nextc)) { |
| 780 |
ep1 = newnode(); |
| 781 |
ep1->type = NUM; |
| 782 |
ep1->v.num = getnum(); |
| 783 |
return(ep1); |
| 784 |
} |
| 785 |
syntax("unexpected character"); |
| 786 |
return NULL; /* pro forma return */ |
| 787 |
} |
| 788 |
|
| 789 |
|
| 790 |
EPNODE * |
| 791 |
rconst( /* reduce a constant expression */ |
| 792 |
EPNODE *epar |
| 793 |
) |
| 794 |
{ |
| 795 |
EPNODE *ep; |
| 796 |
|
| 797 |
ep = newnode(); |
| 798 |
ep->type = NUM; |
| 799 |
errno = 0; |
| 800 |
ep->v.num = evalue(epar); |
| 801 |
if (errno == EDOM || errno == ERANGE) |
| 802 |
syntax("bad constant expression"); |
| 803 |
epfree(epar); |
| 804 |
|
| 805 |
return(ep); |
| 806 |
} |
| 807 |
|
| 808 |
|
| 809 |
int |
| 810 |
isconstvar( /* is ep linked to a constant expression? */ |
| 811 |
EPNODE *ep |
| 812 |
) |
| 813 |
{ |
| 814 |
EPNODE *ep1; |
| 815 |
|
| 816 |
if (esupport&E_FUNCTION && ep->type == FUNC) { |
| 817 |
if (!isconstfun(ep->v.kid)) |
| 818 |
return(0); |
| 819 |
for (ep1 = ep->v.kid->sibling; ep1 != NULL; ep1 = ep1->sibling) |
| 820 |
if (ep1->type != NUM && !isconstfun(ep1)) |
| 821 |
return(0); |
| 822 |
return(1); |
| 823 |
} |
| 824 |
if (ep->type != VAR) |
| 825 |
return(0); |
| 826 |
ep1 = ep->v.ln->def; |
| 827 |
if (ep1 == NULL || ep1->type != ':') |
| 828 |
return(0); |
| 829 |
if (esupport&E_FUNCTION && ep1->v.kid->type != SYM) |
| 830 |
return(0); |
| 831 |
return(1); |
| 832 |
} |
| 833 |
|
| 834 |
|
| 835 |
int |
| 836 |
isconstfun( /* is ep linked to a constant function? */ |
| 837 |
EPNODE *ep |
| 838 |
) |
| 839 |
{ |
| 840 |
EPNODE *dp; |
| 841 |
LIBR *lp; |
| 842 |
|
| 843 |
if (ep->type != VAR) |
| 844 |
return(0); |
| 845 |
if ((dp = ep->v.ln->def) != NULL) { |
| 846 |
if (dp->v.kid->type == FUNC) |
| 847 |
return(dp->type == ':'); |
| 848 |
else |
| 849 |
return(0); /* don't identify masked library functions */ |
| 850 |
} |
| 851 |
if ((lp = ep->v.ln->lib) != NULL) |
| 852 |
return(lp->atyp == ':'); |
| 853 |
return(0); |
| 854 |
} |
