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