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