| File: | lexer.c |
| Warning: | line 123, column 13 Although the value stored to 'type' is used in the enclosing expression, the value is never actually read from 'type' |
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| 1 | #include <stdlib.h> |
| 2 | #include <assert.h> |
| 3 | #include <string.h> |
| 4 | |
| 5 | #include "lexer.h" |
| 6 | #include "parserfunc.h" |
| 7 | #include "mp-equation.h" |
| 8 | |
| 9 | static gboolean |
| 10 | l_check_if_function(LexerState* state) |
| 11 | { |
| 12 | gchar* name = pl_get_marked_substring(state->prelexer); |
| 13 | if(!state->parent->function_is_defined) |
| 14 | { |
| 15 | free(name); |
| 16 | return FALSE(0); |
| 17 | } |
| 18 | if ((*(state->parent->function_is_defined))(state->parent, name)) |
| 19 | { |
| 20 | free(name); |
| 21 | return TRUE(!(0)); |
| 22 | } |
| 23 | else |
| 24 | { |
| 25 | free(name); |
| 26 | return FALSE(0); |
| 27 | } |
| 28 | } |
| 29 | |
| 30 | static gboolean |
| 31 | l_check_if_number(LexerState* state) |
| 32 | { |
| 33 | MPNumber tmp; |
| 34 | gchar* text = pl_get_marked_substring(state->prelexer); |
| 35 | if(mp_set_from_string(text, state->parent->options->base, &tmp) == 0) |
| 36 | { |
| 37 | free(text); |
| 38 | return TRUE(!(0)); |
| 39 | } |
| 40 | else |
| 41 | { |
| 42 | int count = 0; |
| 43 | |
| 44 | /* Try to rollback several characters to see, if that yeilds any number. */ |
| 45 | while(strlen (text) > 0) |
| 46 | { |
| 47 | if(mp_set_from_string(text, state->parent->options->base, &tmp) == 0) |
| 48 | { |
| 49 | free(text); |
| 50 | return TRUE(!(0)); |
| 51 | } |
| 52 | free(text); |
| 53 | count++; |
| 54 | pl_roll_back(state->prelexer); |
| 55 | text = pl_get_marked_substring(state->prelexer); |
| 56 | } |
| 57 | /* Undo all rollbacks. */ |
| 58 | while(count--) |
| 59 | pl_get_next_token (state->prelexer); |
| 60 | free(text); |
| 61 | return FALSE(0); |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | /* Insert generated token to the LexerState structure. */ |
| 66 | static LexerToken* |
| 67 | l_insert_token(LexerState* state, const LexerTokenType type) |
| 68 | { |
| 69 | state->tokens = (LexerToken *) realloc(state->tokens, (state->token_count + 1) * sizeof(LexerToken)); |
| 70 | assert(state->tokens != NULL)((void) sizeof ((state->tokens != ((void*)0)) ? 1 : 0), __extension__ ({ if (state->tokens != ((void*)0)) ; else __assert_fail ( "state->tokens != NULL", "lexer.c", 70, __extension__ __PRETTY_FUNCTION__ ); })); |
| 71 | state->tokens[state->token_count].string = pl_get_marked_substring(state->prelexer); |
| 72 | state->tokens[state->token_count].start_index = state->prelexer->mark_index; |
| 73 | state->tokens[state->token_count].end_index = state->prelexer->next_index; |
| 74 | state->tokens[state->token_count].token_type = type; |
| 75 | state->token_count++; |
| 76 | return &state->tokens[state->token_count - 1]; |
| 77 | } |
| 78 | |
| 79 | /* Generates next token from pre-lexer stream and call l_insert_token() to insert it at the end. */ |
| 80 | static LexerToken* |
| 81 | l_insert_next_token(LexerState* lstate) |
| 82 | { |
| 83 | PreLexerState* state = lstate->prelexer; |
| 84 | LexerTokenType type; |
| 85 | gchar* tmp; |
| 86 | pl_set_marker(state); |
| 87 | /* Ignore all blank spaces. :) */ |
| 88 | while((type = pl_get_next_token(state)) == PL_SKIP) |
| 89 | /* Set marker. Beginning of new token. */ |
| 90 | pl_set_marker(state); |
| 91 | if(type == T_AND |
| 92 | ||type == T_OR |
| 93 | ||type == T_XOR |
| 94 | ||type == T_NOT |
| 95 | ||type == T_ADD |
| 96 | ||type == T_SUBTRACT |
| 97 | ||type == T_MULTIPLY |
| 98 | ||type == T_DIV |
| 99 | ||type == T_L_FLOOR |
| 100 | ||type == T_R_FLOOR |
| 101 | ||type == T_L_CEILING |
| 102 | ||type == T_R_CEILING |
| 103 | ||type == T_ROOT |
| 104 | ||type == T_ROOT_3 |
| 105 | ||type == T_ROOT_4 |
| 106 | ||type == T_ASSIGN |
| 107 | ||type == T_L_R_BRACKET |
| 108 | ||type == T_R_R_BRACKET |
| 109 | ||type == T_L_S_BRACKET |
| 110 | ||type == T_R_S_BRACKET |
| 111 | ||type == T_L_C_BRACKET |
| 112 | ||type == T_R_C_BRACKET |
| 113 | ||type == T_ABS |
| 114 | ||type == T_POWER |
| 115 | ||type == T_FACTORIAL |
| 116 | ||type == T_PERCENTAGE) |
| 117 | { |
| 118 | return l_insert_token(lstate, type); |
| 119 | } |
| 120 | /* [PL_SUPER_MINUS][PL_SUPER_DIGIT]+ */ |
| 121 | if(type == PL_SUPER_MINUS) |
| 122 | { |
| 123 | if((type = pl_get_next_token(state)) != PL_SUPER_DIGIT) |
Although the value stored to 'type' is used in the enclosing expression, the value is never actually read from 'type' | |
| 124 | { |
| 125 | /* ERROR: expected PL_SUP_DIGIT */ |
| 126 | set_error(lstate->parent, PARSER_ERR_MP, tmp = pl_get_marked_substring (state)); |
| 127 | free(tmp); |
| 128 | return l_insert_token(lstate, T_UNKNOWN); |
| 129 | } |
| 130 | /* Get all PL_SUPER_DIGITs. */ |
| 131 | while (pl_get_next_token(state) == PL_SUPER_DIGIT); |
| 132 | pl_roll_back(state); |
| 133 | return l_insert_token(lstate, T_NSUP_NUMBER); |
| 134 | } |
| 135 | /* [PL_SUPER_DIGIT]+ */ |
| 136 | if(type == PL_SUPER_DIGIT) |
| 137 | { |
| 138 | while(pl_get_next_token(state) == PL_SUPER_DIGIT); |
| 139 | pl_roll_back(state); |
| 140 | return l_insert_token(lstate, T_SUP_NUMBER); |
| 141 | } |
| 142 | /* [PL_SUB_DIGIT]+ */ |
| 143 | if(type == PL_SUB_DIGIT) |
| 144 | { |
| 145 | while(pl_get_next_token(state) == PL_SUB_DIGIT); |
| 146 | pl_roll_back(state); |
| 147 | return l_insert_token(lstate, T_SUB_NUMBER); |
| 148 | } |
| 149 | /* [PL_FRACTION] */ |
| 150 | if(type == PL_FRACTION) |
| 151 | { |
| 152 | return l_insert_token(lstate, T_NUMBER); |
| 153 | } |
| 154 | if(type == PL_DIGIT) |
| 155 | { |
| 156 | while((type = pl_get_next_token(state)) == PL_DIGIT); |
| 157 | if(type == PL_FRACTION) |
| 158 | { |
| 159 | return l_insert_token(lstate, T_NUMBER); |
| 160 | } |
| 161 | else if(type == PL_SUB_DIGIT) |
| 162 | { |
| 163 | while(pl_get_next_token(state) == PL_SUB_DIGIT); |
| 164 | pl_roll_back(state); |
| 165 | return l_insert_token(lstate, T_NUMBER); |
| 166 | } |
| 167 | else if(type == PL_DEGREE) |
| 168 | { |
| 169 | type = pl_get_next_token(state); |
| 170 | if(type == PL_DIGIT) |
| 171 | { |
| 172 | while((type = pl_get_next_token(state)) == PL_DIGIT); |
| 173 | if(type == PL_DECIMAL) |
| 174 | { |
| 175 | goto ANGLE_NUM_DM_STATE; |
| 176 | } |
| 177 | else if(type == PL_MINUTE) |
| 178 | { |
| 179 | type = pl_get_next_token(state); |
| 180 | if(type == PL_DIGIT) |
| 181 | { |
| 182 | while((type = pl_get_next_token(state)) == PL_DIGIT); |
| 183 | if(type == PL_DECIMAL) |
| 184 | { |
| 185 | goto ANGLE_NUM_DMS_STATE; |
| 186 | } |
| 187 | else if(type == PL_SECOND) |
| 188 | { |
| 189 | return l_insert_token(lstate, T_NUMBER); |
| 190 | } |
| 191 | else |
| 192 | { |
| 193 | /* ERROR: expected PL_SECOND */ |
| 194 | set_error(lstate->parent, PARSER_ERR_MP, tmp = pl_get_marked_substring (state)); |
| 195 | free(tmp); |
| 196 | return l_insert_token(lstate, T_UNKNOWN); |
| 197 | } |
| 198 | } |
| 199 | else if(type == PL_DECIMAL) |
| 200 | { |
| 201 | ANGLE_NUM_DMS_STATE: |
| 202 | if((type = pl_get_next_token (state)) != PL_DIGIT) |
| 203 | { |
| 204 | /* ERROR: expected PL_DIGIT */ |
| 205 | set_error(lstate->parent, PARSER_ERR_MP, tmp = pl_get_marked_substring(state)); |
| 206 | free(tmp); |
| 207 | return l_insert_token(lstate, T_UNKNOWN); |
| 208 | } |
| 209 | while((type = pl_get_next_token(state)) == PL_DIGIT); |
| 210 | if(type == PL_SECOND) |
| 211 | { |
| 212 | return l_insert_token(lstate, T_NUMBER); |
| 213 | } |
| 214 | else |
| 215 | { |
| 216 | /* ERROR: expected PL_SECOND */ |
| 217 | set_error(lstate->parent, PARSER_ERR_MP, tmp = pl_get_marked_substring(state)); |
| 218 | free(tmp); |
| 219 | return l_insert_token(lstate, T_UNKNOWN); |
| 220 | } |
| 221 | } |
| 222 | else |
| 223 | { |
| 224 | pl_roll_back(state); |
| 225 | return l_insert_token(lstate, T_NUMBER); |
| 226 | } |
| 227 | } |
| 228 | else |
| 229 | { |
| 230 | /* ERROR: expected PL_MINUTE | PL_DIGIT */ |
| 231 | set_error(lstate->parent, PARSER_ERR_MP, tmp = pl_get_marked_substring(state)); |
| 232 | free(tmp); |
| 233 | return l_insert_token(lstate, T_UNKNOWN); |
| 234 | } |
| 235 | } |
| 236 | else if(type == PL_DECIMAL) |
| 237 | { |
| 238 | ANGLE_NUM_DM_STATE: |
| 239 | if((type = pl_get_next_token(state)) != PL_DIGIT) |
| 240 | { |
| 241 | /* ERROR: expected PL_DIGIT */ |
| 242 | set_error(lstate->parent, PARSER_ERR_MP, tmp = pl_get_marked_substring(state)); |
| 243 | free(tmp); |
| 244 | return l_insert_token(lstate, T_UNKNOWN); |
| 245 | } |
| 246 | while((type = pl_get_next_token(state)) == PL_DIGIT); |
| 247 | if(type == PL_MINUTE) |
| 248 | { |
| 249 | return l_insert_token(lstate, T_NUMBER); |
| 250 | } |
| 251 | else |
| 252 | { |
| 253 | /* ERROR: expected PL_MINUTE */ |
| 254 | set_error(lstate->parent, PARSER_ERR_MP, tmp = pl_get_marked_substring(state)); |
| 255 | free(tmp); |
| 256 | return l_insert_token(lstate, T_UNKNOWN); |
| 257 | } |
| 258 | } |
| 259 | else |
| 260 | { |
| 261 | return l_insert_token(lstate, T_NUMBER); |
| 262 | } |
| 263 | } |
| 264 | else if(type == PL_DECIMAL) |
| 265 | { |
| 266 | goto DECIMAL_STATE; |
| 267 | } |
| 268 | else if(type == PL_HEX) |
| 269 | { |
| 270 | goto HEX_DEC_STATE; |
| 271 | } |
| 272 | else |
| 273 | { |
| 274 | pl_roll_back(state); |
| 275 | return l_insert_token(lstate, T_NUMBER); |
| 276 | } |
| 277 | } |
| 278 | if(type == PL_DECIMAL) |
| 279 | { |
| 280 | DECIMAL_STATE: |
| 281 | type = pl_get_next_token(state); |
| 282 | if(type == PL_DIGIT) |
| 283 | { |
| 284 | while((type = pl_get_next_token(state)) == PL_DIGIT); |
| 285 | if(type == PL_DEGREE) |
| 286 | { |
| 287 | return l_insert_token(lstate, T_NUMBER); |
| 288 | } |
| 289 | else if(type == PL_HEX) |
| 290 | { |
| 291 | goto DECIMAL_HEX_STATE; |
| 292 | } |
| 293 | else if(type == PL_SUB_DIGIT) |
| 294 | { |
| 295 | while(pl_get_next_token(state) == PL_SUB_DIGIT); |
| 296 | pl_roll_back(state); |
| 297 | return l_insert_token(lstate, T_NUMBER); |
| 298 | } |
| 299 | else |
| 300 | { |
| 301 | pl_roll_back(state); |
| 302 | return l_insert_token(lstate, T_NUMBER); |
| 303 | } |
| 304 | } |
| 305 | else if(type == PL_HEX) |
| 306 | { |
| 307 | goto DECIMAL_HEX_STATE; |
| 308 | } |
| 309 | else |
| 310 | { |
| 311 | /* ERROR: expected PL_DIGIT | PL_HEX */ |
| 312 | set_error(lstate->parent, PARSER_ERR_MP, tmp = pl_get_marked_substring(state)); |
| 313 | free(tmp); |
| 314 | return l_insert_token(lstate, T_UNKNOWN); |
| 315 | } |
| 316 | } |
| 317 | if(type == PL_HEX) |
| 318 | { |
| 319 | while((type = pl_get_next_token(state)) == PL_HEX); |
| 320 | if(type == PL_DIGIT) |
| 321 | { |
| 322 | HEX_DEC_STATE: |
| 323 | while(1) |
| 324 | { |
| 325 | type = pl_get_next_token(state); |
| 326 | if(type == PL_DIGIT || type == PL_HEX) |
| 327 | { |
| 328 | continue; |
| 329 | } |
| 330 | else if(type == PL_DECIMAL) |
| 331 | { |
| 332 | goto DECIMAL_HEX_STATE; |
| 333 | } |
| 334 | else if(type == PL_SUB_DIGIT) |
| 335 | { |
| 336 | while(pl_get_next_token(state) == PL_SUB_DIGIT); |
| 337 | pl_roll_back(state); |
| 338 | return l_insert_token(lstate, T_NUMBER); |
| 339 | } |
| 340 | else |
| 341 | { |
| 342 | if(l_check_if_number(lstate)) |
| 343 | return l_insert_token(lstate, T_NUMBER); |
| 344 | /* ERROR: expected PL_DECIMAL | PL_DIGIT | PL_HEX */ |
| 345 | set_error(lstate->parent, PARSER_ERR_MP, tmp = pl_get_marked_substring(state)); |
| 346 | free(tmp); |
| 347 | return l_insert_token(lstate, T_UNKNOWN); |
| 348 | } |
| 349 | } |
| 350 | } |
| 351 | else if(type == PL_DECIMAL) |
| 352 | { |
| 353 | DECIMAL_HEX_STATE: |
| 354 | type = pl_get_next_token(state); |
| 355 | if(!(type == PL_DIGIT || type == PL_HEX)) |
| 356 | { |
| 357 | /* ERROR: expected PL_DIGIT | PL_HEX */ |
| 358 | set_error(lstate->parent, PARSER_ERR_MP, tmp = pl_get_marked_substring(state)); |
| 359 | free(tmp); |
| 360 | return l_insert_token(lstate, T_UNKNOWN); |
| 361 | } |
| 362 | while(1) |
| 363 | { |
| 364 | type = pl_get_next_token(state); |
| 365 | if(type == PL_DIGIT || type == PL_HEX) |
| 366 | { |
| 367 | continue; |
| 368 | } |
| 369 | else if(type == PL_SUB_DIGIT) |
| 370 | { |
| 371 | while(pl_get_next_token(state) == PL_SUB_DIGIT); |
| 372 | pl_roll_back(state); |
| 373 | return l_insert_token(lstate, T_NUMBER); |
| 374 | } |
| 375 | else |
| 376 | { |
| 377 | pl_roll_back(state); |
| 378 | return l_insert_token(lstate, T_NUMBER); |
| 379 | } |
| 380 | } |
| 381 | } |
| 382 | else if(type == PL_SUB_DIGIT) |
| 383 | { |
| 384 | while(pl_get_next_token(state) == PL_SUB_DIGIT); |
| 385 | pl_roll_back(state); |
| 386 | if(l_check_if_number(lstate)) |
| 387 | { |
| 388 | /* NUMBER */ |
| 389 | return l_insert_token(lstate, T_NUMBER); |
| 390 | } |
| 391 | else |
| 392 | { |
| 393 | /* VARIABLE */ |
| 394 | if(l_check_if_function(lstate)) |
| 395 | { |
| 396 | return l_insert_token(lstate, T_FUNCTION); |
| 397 | } |
| 398 | else |
| 399 | { |
| 400 | return l_insert_token(lstate, T_VARIABLE); |
| 401 | } |
| 402 | } |
| 403 | } |
| 404 | else if(type == PL_LETTER) |
| 405 | { |
| 406 | goto LETTER_STATE; |
| 407 | } |
| 408 | else |
| 409 | { |
| 410 | pl_roll_back(state); |
| 411 | if(l_check_if_number(lstate)) |
| 412 | { |
| 413 | /* NUMBER */ |
| 414 | return l_insert_token(lstate, T_NUMBER); |
| 415 | } |
| 416 | else |
| 417 | { |
| 418 | /* VARIABLE */ |
| 419 | if(l_check_if_function(lstate)) |
| 420 | { |
| 421 | return l_insert_token(lstate, T_FUNCTION); |
| 422 | } |
| 423 | else |
| 424 | { |
| 425 | return l_insert_token(lstate, T_VARIABLE); |
| 426 | } |
| 427 | } |
| 428 | } |
| 429 | } |
| 430 | if(type == PL_LETTER) |
| 431 | { |
| 432 | LETTER_STATE: |
| 433 | while(1) |
| 434 | { |
| 435 | type = pl_get_next_token(state); |
| 436 | if(type == PL_LETTER || type == PL_HEX) |
| 437 | { |
| 438 | continue; |
| 439 | } |
| 440 | else if(type == PL_SUB_DIGIT) |
| 441 | { |
| 442 | while(pl_get_next_token(state) == PL_SUB_DIGIT); |
| 443 | pl_roll_back(state); |
| 444 | tmp = g_ascii_strdown(pl_get_marked_substring(state), -1); |
| 445 | if(g_strcmp0(tmp, "mod") == 0) |
| 446 | { |
| 447 | return l_insert_token(lstate, T_MOD); |
| 448 | } |
| 449 | if(g_strcmp0(tmp, "and") == 0) |
| 450 | { |
| 451 | return l_insert_token(lstate, T_AND); |
| 452 | } |
| 453 | if(g_strcmp0(tmp, "or") == 0) |
| 454 | { |
| 455 | return l_insert_token(lstate, T_OR); |
| 456 | } |
| 457 | if(g_strcmp0(tmp, "xor") == 0) |
| 458 | { |
| 459 | return l_insert_token(lstate, T_XOR); |
| 460 | } |
| 461 | if(g_strcmp0(tmp, "not") == 0) |
| 462 | { |
| 463 | return l_insert_token(lstate, T_NOT); |
| 464 | } |
| 465 | if(g_strcmp0(tmp, "in") == 0) |
| 466 | { |
| 467 | return l_insert_token(lstate, T_IN); |
| 468 | } |
| 469 | if(l_check_if_function(lstate)) |
| 470 | { |
| 471 | return l_insert_token(lstate, T_FUNCTION); |
| 472 | } |
| 473 | else |
| 474 | { |
| 475 | return l_insert_token(lstate, T_VARIABLE); |
| 476 | } |
| 477 | } |
| 478 | else |
| 479 | { |
| 480 | pl_roll_back(state); |
| 481 | tmp = g_ascii_strdown(pl_get_marked_substring(state), -1); |
| 482 | if(g_strcmp0(tmp, "mod") == 0) |
| 483 | { |
| 484 | return l_insert_token(lstate, T_MOD); |
| 485 | } |
| 486 | if(g_strcmp0(tmp, "and") == 0) |
| 487 | { |
| 488 | return l_insert_token(lstate, T_AND); |
| 489 | } |
| 490 | if(g_strcmp0(tmp, "or") == 0) |
| 491 | { |
| 492 | return l_insert_token(lstate, T_OR); |
| 493 | } |
| 494 | if(g_strcmp0(tmp, "xor") == 0) |
| 495 | { |
| 496 | return l_insert_token(lstate, T_XOR); |
| 497 | } |
| 498 | if(g_strcmp0(tmp, "not") == 0) |
| 499 | { |
| 500 | return l_insert_token(lstate, T_NOT); |
| 501 | } |
| 502 | if(g_strcmp0(tmp, "in") == 0) |
| 503 | { |
| 504 | return l_insert_token(lstate, T_IN); |
| 505 | } |
| 506 | if(l_check_if_function(lstate)) |
| 507 | { |
| 508 | return l_insert_token(lstate, T_FUNCTION); |
| 509 | } |
| 510 | else |
| 511 | { |
| 512 | return l_insert_token(lstate, T_VARIABLE); |
| 513 | } |
| 514 | } |
| 515 | } |
| 516 | } |
| 517 | if(type == PL_EOS) |
| 518 | { |
| 519 | return l_insert_token(lstate, PL_EOS); |
| 520 | } |
| 521 | /* ERROR: Unexpected token.. X( */ |
| 522 | set_error(lstate->parent, PARSER_ERR_INVALID, tmp = pl_get_marked_substring(state)); |
| 523 | free(tmp); |
| 524 | return l_insert_token(lstate, T_UNKNOWN); |
| 525 | } |
| 526 | |
| 527 | /* Call l_insert_next_token() as many times as needed to completely tokenize the string. */ |
| 528 | void |
| 529 | l_insert_all_tokens(LexerState* state) |
| 530 | { |
| 531 | while(1) |
| 532 | { |
| 533 | LexerToken* token = NULL((void*)0); |
| 534 | |
| 535 | token = l_insert_next_token(state); |
| 536 | assert(token != NULL)((void) sizeof ((token != ((void*)0)) ? 1 : 0), __extension__ ({ if (token != ((void*)0)) ; else __assert_fail ("token != NULL" , "lexer.c", 536, __extension__ __PRETTY_FUNCTION__); })); |
| 537 | if(token->token_type == PL_EOS) |
| 538 | { |
| 539 | break; |
| 540 | } |
| 541 | } |
| 542 | } |
| 543 | |
| 544 | /* Create a lexer state from given input string. This will take care of pre-lexer state. */ |
| 545 | LexerState* |
| 546 | l_create_lexer(const gchar* input, struct parser_state* parent) |
| 547 | { |
| 548 | LexerState* ret; |
| 549 | ret = (LexerState *) malloc(sizeof(LexerState)); |
| 550 | assert(ret != NULL)((void) sizeof ((ret != ((void*)0)) ? 1 : 0), __extension__ ( { if (ret != ((void*)0)) ; else __assert_fail ("ret != NULL", "lexer.c", 550, __extension__ __PRETTY_FUNCTION__); })); |
| 551 | ret->prelexer = pl_create_scanner(input); |
| 552 | ret->tokens = NULL((void*)0); |
| 553 | ret->token_count = 0; |
| 554 | ret->next_token = 0; |
| 555 | ret->parent = parent; |
| 556 | return ret; |
| 557 | } |
| 558 | |
| 559 | /* Destroy lexer state and free memory. */ |
| 560 | void |
| 561 | l_destroy_lexer(LexerState* state) |
| 562 | { |
| 563 | int l; |
| 564 | pl_destroy_scanner(state->prelexer); |
| 565 | for(l = 0; l < state->token_count; l++) |
| 566 | { |
| 567 | free(state->tokens[l].string); |
| 568 | } |
| 569 | free(state->tokens); |
| 570 | free(state); |
| 571 | } |
| 572 | |
| 573 | /* Get next token interface. Will be called by parser to get pointer to next token in token stream. */ |
| 574 | LexerToken* |
| 575 | l_get_next_token(LexerState* state) |
| 576 | { |
| 577 | /* Return PL_EOS token after token stream reaches to its end. */ |
| 578 | if(state->next_token >= state->token_count) |
| 579 | return &state->tokens[state->token_count - 1]; |
| 580 | return &state->tokens[state->next_token++]; |
| 581 | } |
| 582 | |
| 583 | /* Roll back one lexer token. */ |
| 584 | void |
| 585 | l_roll_back(LexerState* state) |
| 586 | { |
| 587 | if(state->next_token > 0) |
| 588 | state->next_token--; |
| 589 | } |