parser.c

   1 #include <malloc.h>
   2 #include <math.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6
   7 #include "debug.h"
   8
   9 #include "parser.h"
  10
  11 /* global variables */
  12
  13 double answer = 0;
  14
  15 #define DEFAULT_STORAGE_SIZE 10
  16 int storage_size = -1;
  17
  18 double *storage = NULL;
  19
  20 #define DEFAULT_FORMAT "=> %.6g\n"
  21 char *format = NULL;
  22 char *minform = NULL;
  23
  24 /* compare codes */
  25
  26 int codecmp (char *ref, char *str)
  27 {
  28     int sig;
  29
  30     while (*ref != '\0') {
  31         if (*ref == '\t') {
  32              sig = (*str == '.') ? -1 : ((*str >= '0') && (*str <= '9'));
  33         } else {
  34             sig = *str - *ref;
  35         }
  36         if (sig != 0) {
  37             return (sig > 0) ? 1 : -1;
  38         }
  39         str++;
  40         ref++;
  41     }
  42
  43     return 0;
  44 }
  45
  46 /* allocate new element */
  47
  48 element_t *newelement (func_t function, int nbops, int prio)
  49 {
  50     element_t *new = (element_t *) calloc (1, sizeof (element_t));
  51     if (new == NULL) {
  52         VERBOSE (ERROR, fprintf (stderr, "can't allocate memory\n"));
  53         exit (1);
  54     }
  55     if (nbops) {
  56         new->ops = (element_t **) calloc (nbops, sizeof (element_t *));
  57         if (new->ops == NULL) {
  58             VERBOSE (ERROR, fprintf (stderr, "can't allocate memory\n"));
  59             exit (1);
  60         }
  61     }
  62     new->func = function;
  63     new->nbops = nbops;
  64     new->prio = prio;
  65
  66     return new;
  67 }
  68
  69 /* desallocate element */
  70
  71 void delelement (element_t *root)
  72 {
  73     if ((root != NULL) && (root != ERROR_OP)) {
  74         int i;
  75         for (i = 0; i < root->nbops; i++) {
  76             if ((root->ops[i] != NULL) && (root->ops[i] != ERROR_OP)) {
  77                 delelement (root->ops[i]);
  78             }
  79         }
  80         if (root->nbops) {
  81             free (root->ops);
  82         }
  83         free (root);
  84     }
  85 }
  86
  87 /* duplicate element */
  88
  89 element_t *dupelement (element_t *root)
  90 {
  91     element_t *tmp = NULL;
  92     int i;
  93
  94     if ((root == NULL) || (root == ERROR_OP)) {
  95         return root;
  96     }
  97     tmp = newelement (root->func, root->nbops, root->prio);
  98     tmp->value = root->value;
  99     for (i = 0; i < root->nbops; i++) {
 100         tmp->ops[i] = dupelement (root->ops[i]);
 101     }
 102     return tmp;
 103 }
 104
 105 /* functions */
 106
 107 #define NB_OPERATORS 14
 108 keyword_t operators[NB_OPERATORS] = {
 109     { "+\t", Add, 2, 1, 1},
 110     { "-\t", Sub, 2, 1, 1},
 111     { "*",   Mul, 2, 1, 2},
 112     { "/",   Div, 2, 1, 2},
 113     { "%",   Mod, 2, 1, 3},
 114     { "^",   Pow, 2, 1, 4},
 115     { "==",  Equal, 2, 2, -1},
 116     { "!=",  Diff, 2, 2, -1},
 117     { ">=",  Ge, 2, 2, -1},
 118     { "<=",  Le, 2, 2, -1},
 119     { ">",   Gt, 2, 1, -1},
 120     { "<",   Lt, 2, 1, -1},
 121     { "&",   And, 2, 1, -2},
 122     { "|",   Or, 2, 1, -2}
 123 };
 124
 125 #define NB_FUNCTIONS 25
 126 keyword_t functions[NB_FUNCTIONS] = {
 127     { "sqrt", Sqr, 1, 4, 5},
 128     { "pow",  Pow, 2, 3, 5},
 129     { "cos",  Cos, 1, 3, 5},
 130     { "sin",  Sin, 1, 3, 5},
 131     { "tan",  Tan, 1, 3, 5},
 132     { "acos", Acos, 1, 4, 5},
 133     { "asin", Asin, 1, 4, 5},
 134     { "atan", Atan, 1, 4, 5},
 135     { "log",  Log, 1, 3, 5},
 136     { "exp",  Exp, 1, 3, 5},
 137     { "abs",  Abs, 1, 3, 5},
 138     { "floor", Floor, 1, 5, 5},
 139     { "ceil", Ceil, 1, 4, 5},
 140     { "sto",  Store, 2, 3, 5},
 141     { "rcl",  Recall, 1, 3, 5},
 142     { "inc",  Inc, 1, 3, 5},
 143     { "dec",  Dec, 1, 3, 5},
 144     { "disp", Disp, 0, 4, 9},
 145     { "mem",  Mem, 1, 3, 9},
 146     { "quit", Quit, 0, 4, 9},
 147     { "help", Help, 0, 4, 9},
 148     { "!",    Not, 1, 1, 6},
 149     { "cond", Cond, 3, 4, 5},
 150     { "while", While, 2, 5, 5},
 151     { "print", Print, 1, 5, 5}
 152 };
 153
 154 #define NB_CONSTANTS 3
 155 keyword_t constants[NB_CONSTANTS] = {
 156     { "ans", Ans, 0, 3, 5},
 157     { "e",   E, 0, 1, 5},
 158     { "pi",  Pi, 0, 2, 5}
 159 };
 160
 161 #define NB_SYMBOLS 4
 162 char *symbols[NB_SYMBOLS] = {
 163     "(", ")", "{", "}"
 164 };
 165
 166 /* subparser function */
 167
 168 element_t *subparser (element_t **proot, char **pstr, func_t func, int nbops, int prio)
 169 {
 170     element_t *new = newelement (func, nbops, prio);
 171     new->ops[0] = *proot;
 172     new->ops[1] = parser (*pstr, pstr, new->prio);
 173     if ((new->ops[1] == NULL) || ((new->ops[1] != ERROR_OP) && (new->ops[1]->prio == 9))) {
 174         delelement (new->ops[1]);
 175         new->ops[1] = ERROR_OP;
 176     }
 177     if (new->ops[1] == ERROR_OP) {
 178         delelement (new);
 179         *proot = NULL;
 180         return ERROR_OP;
 181     }
 182     *proot = newelement (Val, 1, 5);
 183     (*proot)->ops[0] = new;
 184
 185     return *proot;
 186 }
 187
 188 /* parser function */
 189
 190 element_t *parser (char *str, char **next, int prio)
 191 {
 192     element_t *root = NULL;
 193     int i;
 194
 195     VERBOSE (DEBUG, fprintf (stdout, "Starting parsing\n"));
 196
 197     /* main loop */
 198     while (*str != '\0') {
 199         int found = 0;
 200         element_t *new = NULL;
 201         VERBOSE (INFO, fprintf (stdout, "Processing: %s\n", str));
 202
 203         /* end without printing */
 204
 205         if (*str == ';') {
 206             if (root) {
 207                 root->hidden = 1;
 208             }
 209             break;
 210         }
 211
 212         /* skip spaces and tabs */
 213
 214         if ((*str == ' ') || (*str == '\t')) {
 215             str++;
 216             continue;
 217         }
 218
 219         /* check for open brace */
 220
 221         if (*str == '{') {
 222             VERBOSE (DEBUG, fprintf (stdout, "start processing brace\n"));
 223             if (root != NULL) {
 224                 delelement (root);
 225                 return ERROR_OP;
 226             }
 227             element_t **prog = NULL;
 228             new = newelement (Prog, 0, 5);
 229             root = new;
 230             prog = &root;
 231
 232             do {
 233                 new = parser (str + 1, &str, 0);
 234                 if ((new == NULL) || ((new != ERROR_OP) && (new->prio == 9))) {
 235                     delelement (new);
 236                     new = ERROR_OP;
 237                 }
 238                 if (new == ERROR_OP) {
 239                     delelement (root);
 240                     return ERROR_OP;
 241                 }
 242                 element_t *newprog = newelement (Prog, (*prog)->nbops + 1, 5);
 243                 for (i = 0; i < (*prog)->nbops; i++) {
 244                     newprog->ops[i] = (*prog)->ops[i];
 245                     (*prog)->ops[i] = NULL;
 246                 }
 247                 newprog->ops[(*prog)->nbops] = new;
 248                 delelement (*prog);
 249                 (*prog) = newprog;
 250             } while (*str == ',');
 251
 252             if (*str != '}') {
 253                 delelement (root);
 254                 return ERROR_OP;
 255             }
 256             str++;
 257             VERBOSE (DEBUG, fprintf (stdout, "stop processing brace\n"));
 258             continue;
 259         }
 260
 261         /* check for open bracket */
 262
 263         if (*str == '(') {
 264             VERBOSE (DEBUG, fprintf (stdout, "start processing bracket\n"));
 265             if (root) {
 266                 do {
 267                     found = 0;
 268                     new = parser (str + 1, &str, 0);
 269                     if ((new == NULL) || ((new != ERROR_OP) && (new->prio == 9))) {
 270                         delelement (new);
 271                         new = ERROR_OP;
 272                     }
 273                     if ((new == NULL) || (new == ERROR_OP)) {
 274                         delelement (root);
 275                         return ERROR_OP;
 276                     }
 277                     for (i = 0; i < root->nbops; i++) {
 278                         if (root->ops[i] == NULL) {
 279                             root->ops[i] = new;
 280                             found = 1;
 281                             break;
 282                         }
 283                     }
 284                     if (!found) {
 285                         delelement (new);
 286                         delelement (root);
 287                         return ERROR_OP;
 288                     }
 289                 } while (*str == ',');
 290             } else {
 291                 root = newelement (Val, 1, 5);
 292                 new = parser (str + 1, &str, 0);
 293                 if ((new == NULL) || ((new != ERROR_OP) && (new->prio == 9))) {
 294                     delelement (new);
 295                     new = ERROR_OP;
 296                 }
 297                 if ((new == NULL) || (new == ERROR_OP) || (*str == ',')) {
 298                     delelement (new);
 299                     delelement (root);
 300                     return ERROR_OP;
 301                 }
 302                 root->ops[0] = new;
 303             }
 304             if (*str != ')') {
 305                 delelement (root);
 306                 return ERROR_OP;
 307             }
 308             str++;
 309             VERBOSE (DEBUG, fprintf (stdout, "stop processing bracket\n"));
 310             continue;
 311         }
 312
 313         /* check for closing bracket, closing brace or koma */
 314
 315         if ((*str == ')') || (*str == '}') || (*str == ',')) {
 316             if (prio == -9) {
 317                 delelement (root);
 318                 return ERROR_OP;
 319             }
 320             if (next != NULL) {
 321                 *next = str;
 322             }
 323             return root;
 324         }
 325
 326         /* look for operators */
 327
 328         for (i = 0; i < NB_OPERATORS; i++) {
 329             keyword_t *operator = operators + i;
 330             if (codecmp (operator->keyword, str) == 0) {
 331                 VERBOSE (DEBUG, fprintf (stdout, "start processing operator\n"));
 332                 if (root) {
 333                     if ((prio) && (prio > operator->prio)) {
 334                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 335                         *next = str;
 336                         return root;
 337                     }
 338                     str += operator->offset;
 339                     VERBOSE (INFO, fprintf (stdout, "Oper: %d\n", operator->func));
 340                     if (subparser (&root, &str, operator->func, operator->nbops, operator->prio) == ERROR_OP) {
 341                         delelement (root);
 342                         return ERROR_OP;
 343                     }
 344                 } else if (*str == '-') {
 345                     root = newelement (Sig, 1, 9);
 346                 } else {
 347                     return ERROR_OP;
 348                 }
 349                 found = 1;
 350                 VERBOSE (DEBUG, fprintf (stdout, "stop processing operator\n"));
 351                 break;
 352             }
 353         }
 354         if (found) {
 355             continue;
 356         }
 357
 358         /* look for functions */
 359
 360         for (i = 0; i < NB_FUNCTIONS; i++) {
 361             keyword_t *function = functions + i;
 362             if (codecmp (function->keyword, str) == 0) {
 363                 VERBOSE (DEBUG, fprintf (stdout, "start processing function\n"));
 364                 if (root == NULL) {
 365                     VERBOSE (INFO, fprintf (stdout, "Func: %d\n", function->func));
 366                     root = newelement (function->func, function->nbops, function->prio);
 367                 } else {
 368                     delelement (root);
 369                     return ERROR_OP;
 370                 }
 371                 str += function->offset;
 372                 found = 1;
 373                 VERBOSE (DEBUG, fprintf (stdout, "stop processing function\n"));
 374                 break;
 375             }
 376         }
 377         if (found) {
 378             continue;
 379         }
 380
 381         /* look for constant */
 382
 383         for (i = 0; i < NB_CONSTANTS; i++) {
 384             keyword_t *constant = constants + i;
 385             if (codecmp (constant->keyword, str) == 0) {
 386                 VERBOSE (DEBUG, fprintf (stdout, "start processing constant\n"));
 387                 if (root == NULL) {
 388                     VERBOSE (INFO, fprintf (stdout, "Const: %d\n", constant->func));
 389                     root = newelement (constant->func, constant->nbops, constant->prio);
 390                 } else {
 391                     delelement (root);
 392                     return ERROR_OP;
 393                 }
 394                 str += constant->offset;
 395                 found = 1;
 396                 VERBOSE (DEBUG, fprintf (stdout, "stop processing constant\n"));
 397                 break;
 398             }
 399         }
 400         if (found) {
 401             continue;
 402         }
 403
 404         /* look for number */
 405
 406         if (((*str >= '0') && (*str <= '9')) ||
 407             (*str == '.') || (*str == '+') || (*str == '-')) {
 408             VERBOSE (DEBUG, fprintf (stdout, "start processing value\n"));
 409             char *pt;
 410             double value = strtod (str, &pt);
 411             VERBOSE (INFO, fprintf (stdout, "Value: %f\n", value));
 412             if (str != pt) {
 413                 if ((root == NULL) || (root->prio == 6)) {
 414                     new = newelement (Val, 1, 5);
 415                     new->value = value;
 416                     if (root == NULL) {
 417                         root = new;
 418                     } else {
 419                         for (i = 0; i < root->nbops; i++) {
 420                             if (root->ops[i] == NULL) {
 421                                 root->ops[i] = new;
 422                                 found = 1;
 423                                 break;
 424                             }
 425                         }
 426                         if (!found) {
 427                             delelement (new);
 428                             delelement (root);
 429                             return ERROR_OP;
 430                         }
 431                     }
 432                     str = pt;
 433                 } else if ((*str == '+') || (*str == '-')) {
 434                     if ((prio) && (prio > 1)) {
 435                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 436                         *next = str;
 437                         return root;
 438                     }
 439                     if (subparser (&root, &str, Add, 2, 1) == ERROR_OP) {
 440                         delelement (root);
 441                         return ERROR_OP;
 442                     }
 443                 } else {
 444                     delelement (root);
 445                     return ERROR_OP;
 446                 }
 447                 found = 1;
 448             }
 449             VERBOSE (DEBUG, fprintf (stdout, "stop processing value\n"));
 450         }
 451
 452         /* error */
 453
 454         if (!found) {
 455             delelement (root);
 456             return ERROR_OP;
 457         }
 458
 459     }
 460
 461     if (next != NULL) {
 462         *next = str;
 463     }
 464
 465     return root;
 466 }
 467
 468 /* print element tree */
 469
 470 void print_element (element_t *root, int level)
 471 {
 472     char *func = NULL;
 473     int i;
 474
 475     if ((root == NULL) || (root == ERROR_OP)) {
 476         return;
 477     }
 478
 479     for (i = 0; i < level; i++) {
 480         fprintf (stdout, " ");
 481     }
 482
 483     switch (root->func) {
 484     case Val: func = "Value"; break;
 485     case Sig: func = "Sign"; break;
 486     case Add: func = "Addition"; break;
 487     case Sub: func = "Subtraction"; break;
 488     case Mul: func = "Multiplication"; break;
 489     case Div: func = "Division"; break;
 490     case Mod: func = "Modulo"; break;
 491     case Pow: func = "Power"; break;
 492     case Sqr: func = "Square Root"; break;
 493     case Cos: func = "Cosine"; break;
 494     case Sin: func = "Sine"; break;
 495     case Tan: func = "Tangent"; break;
 496     case Acos: func = "Arc Cosine"; break;
 497     case Asin: func = "Arc Sine"; break;
 498     case Atan: func = "Arc Tangent"; break;
 499     case Log: func = "Logarithm"; break;
 500     case Exp: func = "Exponantial"; break;
 501     case Abs: func = "Absolute value"; break;
 502     case Ceil: func = "Ceil value"; break;
 503     case Floor: func = "Floor value"; break;
 504     case Store: func = "Store"; break;
 505     case Recall: func = "Recall"; break;
 506     case Inc: func = "Increase"; break;
 507     case Dec: func = "Decrease"; break;
 508     case Disp: func = "Display"; break;
 509     case Mem: func = "Memory"; break;
 510     case Quit: func = "Quit"; break;
 511     case Help: func = "Help"; break;
 512     case Ans: func = "Ans"; break;
 513     case Pi: func = "Pi"; break;
 514     case E: func = "E"; break;
 515     case Equal: func = "Equal"; break;
 516     case Diff: func = "Different"; break;
 517     case Ge: func = "Greater or equal"; break;
 518     case Le: func = "Lesser or equal"; break;
 519     case Gt: func = "Greater"; break;
 520     case Lt: func = "Lesser"; break;
 521     case And: func = "And"; break;
 522     case Or: func = "Or"; break;
 523     case Not: func = "Not"; break;
 524     case Cond: func = "Condition"; break;
 525     case While: func = "While"; break;
 526     case Prog: func = "Program"; break;
 527     case Print: func = "Print"; break;
 528     }
 529
 530     fprintf (stdout, "Function: %s\n", func);
 531
 532     if ((root->func == Val) && (root->ops[0] == NULL)) {
 533         for (i = 0; i < level; i++) {
 534             fprintf (stdout, " ");
 535         }
 536         fprintf (stdout, "value: %f\n", root->value);
 537     } else {
 538         for (i = 0; i < root->nbops; i++) {
 539             print_element (root->ops[i], level + 1);
 540         }
 541     }
 542 }
 543
 544 /* storage functions */
 545
 546 void memory (int nb)
 547 {
 548     int i, l;
 549     double *tmp = NULL;
 550     if (nb != storage_size) {
 551         l = (nb < storage_size) ? nb : storage_size;
 552         tmp = (double *) calloc (nb, sizeof (double));
 553         if (tmp == NULL) {
 554             VERBOSE (ERROR, fprintf (stderr, "can't allocate memory\n"));
 555             exit (1);
 556         }
 557         for (i = 0; i < l; i++) {
 558             tmp[i] = storage[i];
 559         }
 560         if (storage != NULL) {
 561             free (storage);
 562         }
 563         storage = tmp;
 564         storage_size = nb;
 565     }
 566 }
 567
 568 double store (int index, double value)
 569 {
 570     if (storage_size == -1) {
 571         memory (DEFAULT_STORAGE_SIZE);
 572     }
 573     if ((index > 0) && (index <= storage_size)) {
 574         storage[index - 1] = value;
 575     } else {
 576         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [%d, %d]\n", index, (storage_size) ? 1 : 0, storage_size));
 577     }
 578     return value;
 579 }
 580
 581 double recall (int index)
 582 {
 583     if (storage_size == -1) {
 584         memory (DEFAULT_STORAGE_SIZE);
 585     }
 586     if ((index > 0) && (index <= storage_size)) {
 587         return storage[index - 1];
 588     } else {
 589         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [%d, %d]\n", index, (storage_size) ? 1 : 0, storage_size));
 590     }
 591     return 0;
 592 }
 593
 594 double increase (int index)
 595 {
 596     if (storage_size == -1) {
 597         memory (DEFAULT_STORAGE_SIZE);
 598     }
 599     if ((index > 0) && (index <= storage_size)) {
 600         return storage[index - 1]++;
 601     } else {
 602         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [%d, %d]\n", index, (storage_size) ? 1 : 0, storage_size));
 603     }
 604     return 0;
 605 }
 606
 607 double decrease (int index)
 608 {
 609     if (storage_size == -1) {
 610         memory (DEFAULT_STORAGE_SIZE);
 611     }
 612     if ((index > 0) && (index <= storage_size)) {
 613         return storage[index - 1]--;
 614     } else {
 615         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [%d, %d]\n", index, (storage_size) ? 1 : 0, storage_size));
 616     }
 617     return 0;
 618 }
 619
 620 void display (void)
 621 {
 622     int i;
 623     if (storage_size == -1) {
 624         memory (DEFAULT_STORAGE_SIZE);
 625     }
 626     fprintf (stdout, "storage:");
 627     for (i = 0; i < storage_size; i++) {
 628         fprintf (stdout, " ");
 629         fprintf (stdout, minform, storage[i]);
 630     }
 631     fprintf (stdout, "\n");
 632 }
 633
 634 /* While do function */
 635
 636 double while_do (element_t *cond, element_t *action)
 637 {
 638     double ret = 0;
 639     element_t *temp = NULL;
 640
 641     VERBOSE (DEBUG, fprintf (stdout, "starting while loop\n"));
 642     while (1) {
 643         VERBOSE (DEBUG, fprintf (stdout, "loop...\n"));
 644
 645         temp = dupelement (cond);
 646         if (!evaluate_element (temp, 0)) {
 647             break;
 648         }
 649         if (action) {
 650             temp = dupelement (action);
 651             ret = evaluate_element (temp, 0);
 652         }
 653     }
 654
 655     VERBOSE (DEBUG, fprintf (stdout, "ending while loop\n"));
 656
 657     return ret;
 658 }
 659
 660 /* program function */
 661
 662 double program_do (element_t **prog, int nbcalls)
 663 {
 664     double ret = 0;
 665     int i;
 666     for (i = 0; i < nbcalls; i++) {
 667         ret = evaluate_element (prog[i], 0);
 668         prog[i] = NULL;
 669     }
 670     return ret;
 671 }
 672
 673 /* print function */
 674
 675 void set_format (char *prompt, int precision)
 676 {
 677     char buffer[128] = {0};
 678     free_format ();
 679     sprintf (buffer, "%s%%.%dg\n", prompt, precision);
 680     format = strdup (buffer);
 681     sprintf (buffer, "%%.%dg", precision);
 682     minform = strdup (buffer);
 683 }
 684
 685 void free_format ()
 686 {
 687     if (format) {
 688         free (format);
 689         format = NULL;
 690     }
 691     if (minform) {
 692         free (minform);
 693         minform = NULL;
 694     }
 695 }
 696
 697 double print (double value)
 698 {
 699     fprintf (stdout, format ? format : DEFAULT_FORMAT, value);
 700     fflush (stdout);
 701     return value;
 702 }
 703
 704 /* quit function */
 705
 706 void quit (void)
 707 {
 708     fprintf (stdout, "bye\n");
 709     exit (0);
 710 }
 711
 712 /* help message */
 713
 714 void help (void)
 715 {
 716     fprintf (stdout, "calc is a simple calculator\n\n");
 717     fprintf (stdout, "supported operators:");
 718     fprintf (stdout, " + - * / %% ^\n");
 719     fprintf (stdout, "camparison operators:");
 720     fprintf (stdout, " == != >= <= > <\n");
 721     fprintf (stdout, "logical operators:");
 722     fprintf (stdout, " & | !\n");
 723     fprintf (stdout, "mathematic functions:");
 724     fprintf (stdout, " pow sqrt log exp\n");
 725     fprintf (stdout, "trig. func.:");
 726     fprintf (stdout, " cos sin tan acos asin atan\n");
 727     fprintf (stdout, "supported functions:");
 728     fprintf (stdout, " abs ceil floor\n");
 729     fprintf (stdout, "storage functions:");
 730     fprintf (stdout, " mem sto rcl inc dec disp\n");
 731     fprintf (stdout, "prog. functions:");
 732     fprintf (stdout, " cond while print {} ;\n");
 733     fprintf (stdout, "misc. functions:");
 734     fprintf (stdout, " quit help\n");
 735     fprintf (stdout, "supported constants:");
 736     fprintf (stdout, " e pi\n");
 737 }
 738
 739 /* evaluate element tree */
 740
 741 #define MASK_SUB 0x1
 742 #define MASK_DIV 0x2
 743
 744 double evaluate_element (element_t *root, char mask)
 745 {
 746     double op0 = 0, op1 = 0;
 747     char nextmask = mask;
 748
 749     if ((root == NULL) || (root == ERROR_OP)) {
 750         VERBOSE (WARNING, fprintf (stdout, "error while evaluating\n"));
 751         return 0;
 752     }
 753
 754     /* mask to manage sub operator sub and div */
 755     switch (root->func) {
 756     case Add:
 757         nextmask &= ~MASK_SUB;
 758         nextmask &= ~MASK_DIV;
 759         break;
 760     case Sub:
 761         nextmask |= MASK_SUB;
 762         nextmask &= ~MASK_DIV;
 763         break;
 764     case Mul:
 765         nextmask &= ~MASK_DIV;
 766         break;
 767     case Div:
 768         nextmask |= MASK_DIV;
 769         break;
 770     default:
 771         nextmask = mask;
 772     }
 773
 774     switch (root->func) {
 775     case Val:
 776     case Sig:
 777         op0 = (root->ops[0]) ? evaluate_element (root->ops[0], nextmask) : root->value;
 778         break;
 779     case Add:
 780     case Sub:
 781     case Mul:
 782     case Div:
 783     case Mod:
 784     case Pow:
 785     case Store:
 786     case Equal:
 787     case Diff:
 788     case Ge:
 789     case Le:
 790     case Gt:
 791     case Lt:
 792     case And:
 793     case Or:
 794         if (root->ops[1]) {
 795             op1 = evaluate_element (root->ops[1], nextmask);
 796         } else if (root->func != Store) {
 797             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[1])\n"));
 798             return 0;
 799         }
 800         /* fallthrough */
 801     case Sqr:
 802     case Cos:
 803     case Sin:
 804     case Tan:
 805     case Acos:
 806     case Asin:
 807     case Atan:
 808     case Log:
 809     case Exp:
 810     case Abs:
 811     case Ceil:
 812     case Floor:
 813     case Recall:
 814     case Inc:
 815     case Dec:
 816     case Not:
 817     case Mem:
 818     case Cond:
 819         if (root->ops[0]) {
 820             op0 = evaluate_element (root->ops[0], 0);
 821         } else {
 822             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[0])\n"));
 823             return 0;
 824         }
 825         break;
 826     case Disp:
 827     case Quit:
 828     case Help:
 829     case Ans:
 830     case Pi:
 831     case E:
 832     case Prog:
 833         break;
 834     case While:
 835         if (root->ops[0] == NULL) {
 836             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[0])\n"));
 837             return 0;
 838         }
 839         break;
 840     case Print:
 841         op0 = (root->ops[0]) ? evaluate_element (root->ops[0], 0) : answer;
 842         break;
 843     }
 844
 845     switch (root->func) {
 846     case Val: return op0;
 847     case Sig: return -op0;
 848     case Add: return ((mask & MASK_SUB) == 0) ? op0 + op1 : op0 - op1;
 849     case Sub: return ((mask & MASK_SUB) == 0) ? op0 - op1 : op0 + op1;
 850     case Mul: return ((mask & MASK_DIV) == 0) ? op0 * op1 : op0 / op1;
 851     case Div: return ((mask & MASK_DIV) == 0) ? op0 / op1 : op0 * op1;
 852     case Mod: return fmod (op0, op1);
 853     case Pow: return pow (op0, op1);
 854     case Sqr: return sqrt (op0);
 855     case Cos: return cos (op0);
 856     case Sin: return sin (op0);
 857     case Tan: return tan (op0);
 858     case Acos: return acos (op0);
 859     case Asin: return asin (op0);
 860     case Atan: return atan (op0);
 861     case Log: return log (op0);
 862     case Exp: return exp (op0);
 863     case Abs: return fabs (op0);
 864     case Ceil: return ceil (op0);
 865     case Floor: return floor (op0);
 866     case Store: return store ((int)op0, (op1) ? op1 : answer);
 867     case Recall: return recall ((int)op0);
 868     case Inc: return increase ((int)op0);
 869     case Dec: return decrease ((int)op0);
 870     case Disp: display (); break;
 871     case Mem: memory ((int)op0); break;
 872     case Quit: quit (); break;
 873     case Help: help (); break;
 874     case Ans: return answer;
 875     case Pi: return M_PI;
 876     case E: return M_E;
 877     case Equal: return op0 == op1;
 878     case Diff: return op0 != op1;
 879     case Ge: return op0 >= op1;
 880     case Le: return op0 <= op1;
 881     case Gt: return op0 > op1;
 882     case Lt: return op0 < op1;
 883     case And: return (op0 != 0) && (op1 != 0);
 884     case Or: return (op0 != 0) || (op1 != 0);
 885     case Not: return (op0 == 0);
 886     case Cond:
 887         if ((op0) && (root->ops[1])) {
 888             return evaluate_element (root->ops[1], 0);
 889         } else if ((!op0) && (root->ops[2])) {
 890             return evaluate_element (root->ops[2], 0);
 891         } else {
 892             return 0;
 893         }
 894     case While: return while_do (root->ops[0], root->ops[1]);
 895     case Prog: return program_do (root->ops, root->nbops);
 896     case Print: return print (op0);
 897     }
 898
 899     return 0;
 900 }
 901
 902 char **generate_completion_list ()
 903 {
 904     int i, j, l = 0;
 905     char **list = (char **) calloc (NB_OPERATORS + NB_FUNCTIONS + NB_CONSTANTS + NB_SYMBOLS + 1, sizeof (char *));
 906     if (list == NULL) {
 907         VERBOSE (ERROR, fprintf (stderr, "can't allocate memory\n"));
 908         exit (1);
 909     }
 910
 911     for (i = 0; i < NB_OPERATORS; i++) {
 912         list[l] = strdup ((operators + i)->keyword);
 913         for (j = 0; j < (int)strlen (list[l]); j++) {
 914             if (list[i][j] == '\t') {
 915                 list[i][j] = '\0';
 916             }
 917         }
 918         if (list[l] != NULL) {
 919             l++;
 920         }
 921     }
 922
 923     for (i = 0; i < NB_FUNCTIONS; i++) {
 924         list[l] = strdup ((functions + i)->keyword);
 925         if (list[l] != NULL) {
 926             l++;
 927         }
 928     }
 929
 930     for (i = 0; i < NB_CONSTANTS; i++) {
 931         list[l] = strdup ((constants + i)->keyword);
 932         if (list[l] != NULL) {
 933             l++;
 934         }
 935     }
 936
 937     for (i = 0; i < NB_SYMBOLS; i++) {
 938         list[l] = strdup (symbols[i]);
 939         if (list[l] != NULL) {
 940             l++;
 941         }
 942     }
 943
 944     return (list);
 945 }
 946
 947 void free_completion_list (char **list)
 948 {
 949     int i;
 950
 951     if (list) {
 952         for (i = 0; i < NB_FUNCTIONS + NB_CONSTANTS; i++) {
 953             if (list[i] != NULL) {
 954                 free (list[i]);
 955             }
 956         }
 957         free (list);
 958     }
 959 }
 960
 961
 962 /* vim: set ts=4 sw=4 et: */