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