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annotate lwbasic/attic/lexer.c @ 236:ce1fdc8d6568
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| author | William Astle <lost@l-w.ca> |
|---|---|
| date | Sat, 11 Aug 2012 23:29:57 -0600 |
| parents | cca933d32298 |
| children |
| rev | line source |
|---|---|
| 25 | 1 /* |
| 2 lexer.c | |
| 3 | |
| 4 Copyright © 2011 William Astle | |
| 5 | |
| 6 This file is part of LWTOOLS. | |
| 7 | |
| 8 LWTOOLS is free software: you can redistribute it and/or modify it under the | |
| 9 terms of the GNU General Public License as published by the Free Software | |
| 10 Foundation, either version 3 of the License, or (at your option) any later | |
| 11 version. | |
| 12 | |
| 13 This program is distributed in the hope that it will be useful, but WITHOUT | |
| 14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
| 16 more details. | |
| 17 | |
| 18 You should have received a copy of the GNU General Public License along with | |
| 19 this program. If not, see <http://www.gnu.org/licenses/>. | |
| 20 */ | |
| 21 | |
| 22 /* | |
| 23 This handles the gritty details of parsing tokens | |
| 24 */ | |
| 25 | |
| 26 #include <stdlib.h> | |
| 27 #include <stdio.h> | |
| 28 #include <string.h> | |
| 29 | |
| 30 #include <lw_alloc.h> | |
| 31 #include <lw_string.h> | |
| 32 | |
| 33 #define __lexer_c_seen__ | |
| 34 #include "lwbasic.h" | |
| 35 | |
| 36 /* | |
| 37 A token idenfier is returned by lexer(). The actual string value | |
| 38 is found in state->lexer_lexer_token_string; if the token as an integer value, | |
| 39 it will be found in state->lexer_token_number in the appropriate "value" | |
| 40 slot. | |
| 41 */ | |
| 42 | |
| 43 struct token_list | |
| 44 { | |
| 45 char *string; | |
| 46 int token; | |
| 47 }; | |
| 48 | |
| 35 | 49 /* keywords that appear as part of normal expressions */ |
| 25 | 50 static struct token_list lexer_global_tokens[] = |
| 51 { | |
| 52 { "function", token_kw_function }, | |
| 53 { "sub", token_kw_sub }, | |
| 54 { "public", token_kw_public }, | |
| 55 { "private", token_kw_private }, | |
| 56 { "as", token_kw_as }, | |
| 57 { "params", token_kw_params }, | |
| 58 { "returns", token_kw_returns }, | |
|
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59 { "integer", token_kw_integer }, |
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60 { "endsub", token_kw_endsub }, |
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61 { "endfunction", token_kw_endfunction }, |
| 33 | 62 { "dim", token_kw_dim }, |
| 35 | 63 { NULL } |
| 64 }; | |
| 65 | |
| 66 /* contains "built in" function names */ | |
| 67 static struct token_list lexer_expr_tokens[] = | |
| 68 { | |
| 69 { "and", token_op_and }, | |
| 70 { "or", token_op_or }, | |
| 71 { "band", token_op_band }, | |
| 72 { "bor", token_op_bor }, | |
| 73 { "bxor", token_op_bxor }, | |
| 74 { "xor", token_op_xor }, | |
| 36 | 75 { "not", token_op_not }, |
| 76 { "bnot", token_op_bnot }, | |
| 25 | 77 { NULL } |
| 78 }; | |
| 79 | |
| 34 | 80 static char *lexer_token_names[] = |
| 81 { | |
| 82 "SUB", | |
| 83 "FUNCTION", | |
| 84 "AS", | |
| 85 "PUBLIC", | |
| 86 "PRIVATE", | |
| 87 "PARAMS", | |
| 88 "RETURNS", | |
| 89 "INTEGER", | |
| 90 "ENDSUB", | |
| 91 "ENDFUNCTION", | |
| 92 "DIM", | |
| 93 "<assignment>", | |
| 35 | 94 "<equality>", |
| 95 "<greater>", | |
| 96 "<less>", | |
| 97 "<greaterequal>", | |
| 98 "<lessequal>", | |
| 99 "<notequal>", | |
| 100 "<and>", | |
| 101 "<or>", | |
| 102 "<xor>", | |
| 103 "<bitwiseand>", | |
| 104 "<bitwiseor>", | |
| 105 "<bitwisexor>", | |
| 106 "<plus>", | |
| 107 "<minus>", | |
| 108 "<times>", | |
| 109 "<divide>", | |
| 110 "<modulus>", | |
| 36 | 111 "<openparen>", |
| 112 "<closeparen>", | |
| 113 "<not>", | |
| 114 "<bitwisenot>", | |
| 34 | 115 "<identifier>", |
| 116 "<char>", | |
| 117 "<uint>", | |
| 118 "<int>", | |
| 119 "<eol>", | |
| 120 "<eof>" | |
| 121 }; | |
| 122 | |
| 123 char *lexer_token_name(int token) | |
| 124 { | |
| 125 if (token > token_eol) | |
| 126 return "???"; | |
| 127 return lexer_token_names[token]; | |
| 128 } | |
| 129 | |
| 25 | 130 static int lexer_getchar(cstate *state) |
| 131 { | |
| 132 int c; | |
| 133 c = input_getchar(state); | |
| 134 if (c == -2) | |
| 135 { | |
| 136 lwb_error("Error reading input stream."); | |
| 137 } | |
| 138 return c; | |
| 139 } | |
| 140 | |
| 141 static void lexer_nextchar(cstate *state) | |
| 142 { | |
| 143 state -> lexer_curchar = lexer_getchar(state); | |
| 144 if (state -> lexer_curchar == state -> lexer_ignorechar) | |
| 145 state -> lexer_curchar = lexer_getchar(state); | |
| 146 state -> lexer_ignorechar = 0; | |
| 147 } | |
| 148 | |
| 149 static int lexer_curchar(cstate *state) | |
| 150 { | |
| 151 if (state -> lexer_curchar == -1) | |
| 152 { | |
| 153 lexer_nextchar(state); | |
| 154 } | |
| 155 | |
| 156 return state -> lexer_curchar; | |
| 157 } | |
| 158 | |
| 159 static void lexer_skip_white(cstate *state) | |
| 160 { | |
| 161 int c; | |
| 162 | |
| 163 for (;;) | |
| 164 { | |
| 165 c = lexer_curchar(state); | |
| 166 if (!(c == 0 || c == ' ' || c == '\t')) | |
| 167 return; | |
| 168 lexer_nextchar(state); | |
| 169 } | |
| 170 } | |
| 171 | |
| 172 /* must not be called unless the word will be non-zero length */ | |
| 173 static void lexer_word(cstate *state) | |
| 174 { | |
| 175 int wordlen = 0; | |
| 176 int wordpos = 0; | |
| 177 char *word = NULL; | |
| 178 int c; | |
| 179 struct token_list *tok = NULL; | |
| 180 | |
| 181 for (;;) { | |
| 182 c = lexer_curchar(state); | |
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183 if (c == '_' || (c >= '0' && c <= '9' ) || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c >= 0x80) |
| 25 | 184 { |
| 185 /* character is part of word */ | |
| 186 if (wordpos >= wordlen) | |
| 187 { | |
| 188 word = lw_realloc(word, wordlen + 32); | |
| 189 wordlen += 32; | |
| 190 } | |
| 191 word[wordpos++] = c; | |
| 192 } | |
| 193 else | |
| 194 break; | |
| 195 | |
| 196 lexer_nextchar(state); | |
| 197 } | |
| 198 | |
| 199 word[wordpos] = 0; | |
| 200 lw_free(state -> lexer_token_string); | |
| 201 state -> lexer_token_string = lw_strdup(word); | |
| 202 | |
| 203 switch (state -> parser_state) | |
| 204 { | |
| 205 default: | |
| 206 tok = lexer_global_tokens; | |
| 207 } | |
| 208 | |
| 35 | 209 if (state -> expression) |
| 210 { | |
| 211 tok = lexer_expr_tokens; | |
| 212 } | |
| 213 | |
| 25 | 214 /* check for tokens if appropriate */ |
| 215 /* force uppercase */ | |
| 216 if (tok) | |
| 217 { | |
| 218 for (c = 0; word[c]; c++) | |
| 219 if (word[c] >= 'A' && word[c] <= 'Z') | |
| 220 word[c] = word[c] + 0x20; | |
| 221 | |
| 222 while (tok -> string) | |
| 223 { | |
| 224 if (strcmp(tok -> string, word) == 0) | |
| 225 break; | |
| 226 tok++; | |
| 227 } | |
| 228 } | |
| 229 | |
| 230 lw_free(word); | |
| 231 if (tok && tok -> string) | |
| 232 state -> lexer_token = tok -> token; | |
| 233 else | |
| 234 state -> lexer_token = token_identifier; | |
| 235 } | |
| 236 | |
| 35 | 237 static void lexer_parse_number(cstate *state, int neg) |
| 238 { | |
| 239 unsigned long tint = 0; | |
| 240 int c; | |
| 241 | |
| 242 for (;;) | |
| 243 { | |
| 244 c = lexer_curchar(state); | |
| 245 if (c >= '0' && c <= '9') | |
| 246 { | |
| 247 tint *= 10 + (c - '0'); | |
| 248 } | |
| 249 else | |
| 250 { | |
| 251 /* end of the number here */ | |
| 252 if (neg) | |
| 253 { | |
| 254 if (tint > 0x80000000) | |
| 255 lwb_error("Integer overflow\n"); | |
| 256 state -> lexer_token_number.integer = -tint; | |
| 257 state -> lexer_token = token_int; | |
| 258 } | |
| 259 else | |
| 260 { | |
| 261 state -> lexer_token = token_uint; | |
| 262 state -> lexer_token_number.uinteger = tint; | |
| 263 } | |
| 264 return; | |
| 265 } | |
| 266 lexer_nextchar(state); | |
| 267 } | |
| 268 } | |
| 269 | |
| 25 | 270 static void lexer_empty_token(cstate *state) |
| 271 { | |
| 272 lw_free(state -> lexer_token_string); | |
| 273 state -> lexer_token_string = NULL; | |
| 274 } | |
| 275 | |
| 276 void lexer(cstate *state) | |
| 277 { | |
| 278 int c; | |
| 279 | |
| 280 lexer_skip_white(state); | |
| 281 | |
| 282 lexer_empty_token(state); | |
| 283 | |
| 284 c = lexer_curchar(state); | |
| 285 if (c == -1) | |
| 286 { | |
| 287 state -> lexer_token = token_eof; | |
| 288 return; | |
| 289 } | |
| 290 | |
| 291 if (c == '\n') | |
| 292 { | |
| 293 /* LF */ | |
| 294 lexer_nextchar(state); | |
| 295 state -> lexer_ignorechar = '\r'; | |
| 296 state -> lexer_token = token_eol; | |
| 297 return; | |
| 298 } | |
| 299 | |
| 300 if (c == '\r') | |
| 301 { | |
| 302 /* CR */ | |
| 303 lexer_nextchar(state); | |
| 304 state -> lexer_ignorechar = '\n'; | |
| 305 state -> lexer_token = token_eol; | |
| 306 return; | |
| 307 } | |
| 308 | |
| 309 if (c == '_' || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c >= 0x80) | |
| 310 { | |
| 311 /* we have a word here; identifier, keyword, etc. */ | |
| 312 lexer_word(state); | |
| 313 return; | |
| 314 } | |
| 35 | 315 |
| 316 if (state -> expression && c >= '0' && c <= '9') | |
| 317 { | |
| 318 /* we have a number */ | |
| 319 lexer_parse_number(state, 0); | |
| 320 return; | |
| 321 } | |
| 322 | |
| 323 lexer_nextchar(state); | |
| 324 if (state -> expression) | |
| 325 { | |
| 326 if (c == '-' && lexer_curchar(state) >= '0' && lexer_curchar(state) <= '9') | |
| 327 { | |
| 328 /* we have a negative number here */ | |
| 329 lexer_parse_number(state, 1); | |
| 330 return; | |
| 331 } | |
| 332 if (c == '=') | |
| 333 { | |
| 334 state -> lexer_token = token_op_equality; | |
| 335 return; | |
| 336 } | |
| 337 if (c == '<') | |
| 338 { | |
| 339 if (lexer_curchar(state) == '=') | |
| 340 { | |
| 341 lexer_nextchar(state); | |
| 342 state -> lexer_token = token_op_lessequal; | |
| 343 return; | |
| 344 } | |
| 345 if (lexer_curchar(state) == '>') | |
| 346 { | |
| 347 lexer_nextchar(state); | |
| 348 state -> lexer_token = token_op_notequal; | |
| 349 return; | |
| 350 } | |
| 351 state -> lexer_token = token_op_less; | |
| 352 return; | |
| 353 } | |
| 354 if (c == '>') | |
| 355 { | |
| 356 if (lexer_curchar(state) == '>') | |
| 357 { | |
| 358 lexer_nextchar(state); | |
| 359 state -> lexer_token = token_op_greaterequal; | |
| 360 return; | |
| 361 } | |
| 362 if (lexer_curchar(state) == '<') | |
| 363 { | |
| 364 state -> lexer_token = token_op_notequal; | |
| 365 lexer_nextchar(state); | |
| 366 return; | |
| 367 } | |
| 368 state -> lexer_token = token_op_greater; | |
| 369 return; | |
| 370 } | |
| 371 switch(c) | |
| 372 { | |
| 373 case '+': | |
| 374 state -> lexer_token = token_op_plus; | |
| 375 return; | |
| 376 | |
| 377 case '-': | |
| 378 state -> lexer_token = token_op_minus; | |
| 379 return; | |
| 380 | |
| 381 case '/': | |
| 382 state -> lexer_token = token_op_divide; | |
| 383 return; | |
| 384 | |
| 385 case '*': | |
| 386 state -> lexer_token = token_op_times; | |
| 387 return; | |
| 388 | |
| 389 case '%': | |
| 390 state -> lexer_token = token_op_modulus; | |
| 391 return; | |
| 392 | |
| 36 | 393 case '(': |
| 394 state -> lexer_token = token_op_oparen; | |
| 395 return; | |
| 396 | |
| 397 case ')': | |
| 398 state -> lexer_token = token_op_cparen; | |
| 399 return; | |
| 35 | 400 |
| 401 } | |
| 402 } | |
| 403 else | |
| 404 { | |
| 405 if (c == '=') | |
| 406 { | |
| 407 state -> lexer_token = token_op_assignment; | |
| 408 return; | |
| 409 } | |
| 410 } | |
| 25 | 411 |
| 412 /* return the character if all else fails */ | |
| 35 | 413 state -> lexer_token = token_char; |
| 25 | 414 state -> lexer_token_string = lw_realloc(state -> lexer_token_string, 2); |
| 415 state -> lexer_token_string[0] = c; | |
| 416 state -> lexer_token_string[1] = 0; | |
| 417 return; | |
| 418 } | |
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419 |
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420 char *lexer_return_token(cstate *state) |
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421 { |
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422 static char *buffer = NULL; |
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423 static int buflen = 0; |
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424 int l; |
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425 |
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426 if (buflen == 0) |
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427 { |
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428 buffer = lw_alloc(128); |
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429 buflen = 128; |
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430 } |
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431 |
| 34 | 432 l = snprintf(buffer, buflen, "%s (%s)", state -> lexer_token_string, lexer_token_name(state -> lexer_token)); |
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433 if (l >= buflen) |
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434 { |
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435 buffer = lw_realloc(buffer, l + 1); |
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436 buflen = l + 1; |
| 34 | 437 snprintf(buffer, buflen, "%s (%s)", state -> lexer_token_string, lexer_token_name(state -> lexer_token)); |
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438 } |
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439 return buffer; |
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440 } |