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| 1 /* |
| 2 ** $Id: lparser.c,v 2.130 2013/02/06 13:37:39 roberto Exp $ |
| 3 ** Lua Parser |
| 4 ** See Copyright Notice in lua.h |
| 5 */ |
| 6 |
| 7 |
| 8 #include <string.h> |
| 9 |
| 10 #define lparser_c |
| 11 #define LUA_CORE |
| 12 |
| 13 #include "lua.h" |
| 14 |
| 15 #include "lcode.h" |
| 16 #include "ldebug.h" |
| 17 #include "ldo.h" |
| 18 #include "lfunc.h" |
| 19 #include "llex.h" |
| 20 #include "lmem.h" |
| 21 #include "lobject.h" |
| 22 #include "lopcodes.h" |
| 23 #include "lparser.h" |
| 24 #include "lstate.h" |
| 25 #include "lstring.h" |
| 26 #include "ltable.h" |
| 27 |
| 28 |
| 29 |
| 30 /* maximum number of local variables per function (must be smaller |
| 31 than 250, due to the bytecode format) */ |
| 32 #define MAXVARS 200 |
| 33 |
| 34 |
| 35 #define hasmultret(k) ((k) == VCALL || (k) == VVARARG) |
| 36 |
| 37 |
| 38 |
| 39 /* |
| 40 ** nodes for block list (list of active blocks) |
| 41 */ |
| 42 typedef struct BlockCnt { |
| 43 struct BlockCnt *previous; /* chain */ |
| 44 short firstlabel; /* index of first label in this block */ |
| 45 short firstgoto; /* index of first pending goto in this block */ |
| 46 lu_byte nactvar; /* # active locals outside the block */ |
| 47 lu_byte upval; /* true if some variable in the block is an upvalue */ |
| 48 lu_byte isloop; /* true if `block' is a loop */ |
| 49 } BlockCnt; |
| 50 |
| 51 |
| 52 |
| 53 /* |
| 54 ** prototypes for recursive non-terminal functions |
| 55 */ |
| 56 static void statement (LexState *ls); |
| 57 static void expr (LexState *ls, expdesc *v); |
| 58 |
| 59 |
| 60 static void anchor_token (LexState *ls) { |
| 61 /* last token from outer function must be EOS */ |
| 62 lua_assert(ls->fs != NULL || ls->t.token == TK_EOS); |
| 63 if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) { |
| 64 TString *ts = ls->t.seminfo.ts; |
| 65 luaX_newstring(ls, getstr(ts), ts->tsv.len); |
| 66 } |
| 67 } |
| 68 |
| 69 |
| 70 /* semantic error */ |
| 71 static l_noret semerror (LexState *ls, const char *msg) { |
| 72 ls->t.token = 0; /* remove 'near to' from final message */ |
| 73 luaX_syntaxerror(ls, msg); |
| 74 } |
| 75 |
| 76 |
| 77 static l_noret error_expected (LexState *ls, int token) { |
| 78 luaX_syntaxerror(ls, |
| 79 luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token))); |
| 80 } |
| 81 |
| 82 |
| 83 static l_noret errorlimit (FuncState *fs, int limit, const char *what) { |
| 84 lua_State *L = fs->ls->L; |
| 85 const char *msg; |
| 86 int line = fs->f->linedefined; |
| 87 const char *where = (line == 0) |
| 88 ? "main function" |
| 89 : luaO_pushfstring(L, "function at line %d", line); |
| 90 msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s", |
| 91 what, limit, where); |
| 92 luaX_syntaxerror(fs->ls, msg); |
| 93 } |
| 94 |
| 95 |
| 96 static void checklimit (FuncState *fs, int v, int l, const char *what) { |
| 97 if (v > l) errorlimit(fs, l, what); |
| 98 } |
| 99 |
| 100 |
| 101 static int testnext (LexState *ls, int c) { |
| 102 if (ls->t.token == c) { |
| 103 luaX_next(ls); |
| 104 return 1; |
| 105 } |
| 106 else return 0; |
| 107 } |
| 108 |
| 109 |
| 110 static void check (LexState *ls, int c) { |
| 111 if (ls->t.token != c) |
| 112 error_expected(ls, c); |
| 113 } |
| 114 |
| 115 |
| 116 static void checknext (LexState *ls, int c) { |
| 117 check(ls, c); |
| 118 luaX_next(ls); |
| 119 } |
| 120 |
| 121 |
| 122 #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); } |
| 123 |
| 124 |
| 125 |
| 126 static void check_match (LexState *ls, int what, int who, int where) { |
| 127 if (!testnext(ls, what)) { |
| 128 if (where == ls->linenumber) |
| 129 error_expected(ls, what); |
| 130 else { |
| 131 luaX_syntaxerror(ls, luaO_pushfstring(ls->L, |
| 132 "%s expected (to close %s at line %d)", |
| 133 luaX_token2str(ls, what), luaX_token2str(ls, who), where)); |
| 134 } |
| 135 } |
| 136 } |
| 137 |
| 138 |
| 139 static TString *str_checkname (LexState *ls) { |
| 140 TString *ts; |
| 141 check(ls, TK_NAME); |
| 142 ts = ls->t.seminfo.ts; |
| 143 luaX_next(ls); |
| 144 return ts; |
| 145 } |
| 146 |
| 147 |
| 148 static void init_exp (expdesc *e, expkind k, int i) { |
| 149 e->f = e->t = NO_JUMP; |
| 150 e->k = k; |
| 151 e->u.info = i; |
| 152 } |
| 153 |
| 154 |
| 155 static void codestring (LexState *ls, expdesc *e, TString *s) { |
| 156 init_exp(e, VK, luaK_stringK(ls->fs, s)); |
| 157 } |
| 158 |
| 159 |
| 160 static void checkname (LexState *ls, expdesc *e) { |
| 161 codestring(ls, e, str_checkname(ls)); |
| 162 } |
| 163 |
| 164 |
| 165 static int registerlocalvar (LexState *ls, TString *varname) { |
| 166 FuncState *fs = ls->fs; |
| 167 Proto *f = fs->f; |
| 168 int oldsize = f->sizelocvars; |
| 169 luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars, |
| 170 LocVar, SHRT_MAX, "local variables"); |
| 171 while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL; |
| 172 f->locvars[fs->nlocvars].varname = varname; |
| 173 luaC_objbarrier(ls->L, f, varname); |
| 174 return fs->nlocvars++; |
| 175 } |
| 176 |
| 177 |
| 178 static void new_localvar (LexState *ls, TString *name) { |
| 179 FuncState *fs = ls->fs; |
| 180 Dyndata *dyd = ls->dyd; |
| 181 int reg = registerlocalvar(ls, name); |
| 182 checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal, |
| 183 MAXVARS, "local variables"); |
| 184 luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1, |
| 185 dyd->actvar.size, Vardesc, MAX_INT, "local variables"); |
| 186 dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg); |
| 187 } |
| 188 |
| 189 |
| 190 static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) { |
| 191 new_localvar(ls, luaX_newstring(ls, name, sz)); |
| 192 } |
| 193 |
| 194 #define new_localvarliteral(ls,v) \ |
| 195 new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1) |
| 196 |
| 197 |
| 198 static LocVar *getlocvar (FuncState *fs, int i) { |
| 199 int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx; |
| 200 lua_assert(idx < fs->nlocvars); |
| 201 return &fs->f->locvars[idx]; |
| 202 } |
| 203 |
| 204 |
| 205 static void adjustlocalvars (LexState *ls, int nvars) { |
| 206 FuncState *fs = ls->fs; |
| 207 fs->nactvar = cast_byte(fs->nactvar + nvars); |
| 208 for (; nvars; nvars--) { |
| 209 getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc; |
| 210 } |
| 211 } |
| 212 |
| 213 |
| 214 static void removevars (FuncState *fs, int tolevel) { |
| 215 fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel); |
| 216 while (fs->nactvar > tolevel) |
| 217 getlocvar(fs, --fs->nactvar)->endpc = fs->pc; |
| 218 } |
| 219 |
| 220 |
| 221 static int searchupvalue (FuncState *fs, TString *name) { |
| 222 int i; |
| 223 Upvaldesc *up = fs->f->upvalues; |
| 224 for (i = 0; i < fs->nups; i++) { |
| 225 if (luaS_eqstr(up[i].name, name)) return i; |
| 226 } |
| 227 return -1; /* not found */ |
| 228 } |
| 229 |
| 230 |
| 231 static int newupvalue (FuncState *fs, TString *name, expdesc *v) { |
| 232 Proto *f = fs->f; |
| 233 int oldsize = f->sizeupvalues; |
| 234 checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues"); |
| 235 luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues, |
| 236 Upvaldesc, MAXUPVAL, "upvalues"); |
| 237 while (oldsize < f->sizeupvalues) f->upvalues[oldsize++].name = NULL; |
| 238 f->upvalues[fs->nups].instack = (v->k == VLOCAL); |
| 239 f->upvalues[fs->nups].idx = cast_byte(v->u.info); |
| 240 f->upvalues[fs->nups].name = name; |
| 241 luaC_objbarrier(fs->ls->L, f, name); |
| 242 return fs->nups++; |
| 243 } |
| 244 |
| 245 |
| 246 static int searchvar (FuncState *fs, TString *n) { |
| 247 int i; |
| 248 for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) { |
| 249 if (luaS_eqstr(n, getlocvar(fs, i)->varname)) |
| 250 return i; |
| 251 } |
| 252 return -1; /* not found */ |
| 253 } |
| 254 |
| 255 |
| 256 /* |
| 257 Mark block where variable at given level was defined |
| 258 (to emit close instructions later). |
| 259 */ |
| 260 static void markupval (FuncState *fs, int level) { |
| 261 BlockCnt *bl = fs->bl; |
| 262 while (bl->nactvar > level) bl = bl->previous; |
| 263 bl->upval = 1; |
| 264 } |
| 265 |
| 266 |
| 267 /* |
| 268 Find variable with given name 'n'. If it is an upvalue, add this |
| 269 upvalue into all intermediate functions. |
| 270 */ |
| 271 static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { |
| 272 if (fs == NULL) /* no more levels? */ |
| 273 return VVOID; /* default is global */ |
| 274 else { |
| 275 int v = searchvar(fs, n); /* look up locals at current level */ |
| 276 if (v >= 0) { /* found? */ |
| 277 init_exp(var, VLOCAL, v); /* variable is local */ |
| 278 if (!base) |
| 279 markupval(fs, v); /* local will be used as an upval */ |
| 280 return VLOCAL; |
| 281 } |
| 282 else { /* not found as local at current level; try upvalues */ |
| 283 int idx = searchupvalue(fs, n); /* try existing upvalues */ |
| 284 if (idx < 0) { /* not found? */ |
| 285 if (singlevaraux(fs->prev, n, var, 0) == VVOID) /* try upper levels */ |
| 286 return VVOID; /* not found; is a global */ |
| 287 /* else was LOCAL or UPVAL */ |
| 288 idx = newupvalue(fs, n, var); /* will be a new upvalue */ |
| 289 } |
| 290 init_exp(var, VUPVAL, idx); |
| 291 return VUPVAL; |
| 292 } |
| 293 } |
| 294 } |
| 295 |
| 296 |
| 297 static void singlevar (LexState *ls, expdesc *var) { |
| 298 TString *varname = str_checkname(ls); |
| 299 FuncState *fs = ls->fs; |
| 300 if (singlevaraux(fs, varname, var, 1) == VVOID) { /* global name? */ |
| 301 expdesc key; |
| 302 singlevaraux(fs, ls->envn, var, 1); /* get environment variable */ |
| 303 lua_assert(var->k == VLOCAL || var->k == VUPVAL); |
| 304 codestring(ls, &key, varname); /* key is variable name */ |
| 305 luaK_indexed(fs, var, &key); /* env[varname] */ |
| 306 } |
| 307 } |
| 308 |
| 309 |
| 310 static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) { |
| 311 FuncState *fs = ls->fs; |
| 312 int extra = nvars - nexps; |
| 313 if (hasmultret(e->k)) { |
| 314 extra++; /* includes call itself */ |
| 315 if (extra < 0) extra = 0; |
| 316 luaK_setreturns(fs, e, extra); /* last exp. provides the difference */ |
| 317 if (extra > 1) luaK_reserveregs(fs, extra-1); |
| 318 } |
| 319 else { |
| 320 if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */ |
| 321 if (extra > 0) { |
| 322 int reg = fs->freereg; |
| 323 luaK_reserveregs(fs, extra); |
| 324 luaK_nil(fs, reg, extra); |
| 325 } |
| 326 } |
| 327 } |
| 328 |
| 329 |
| 330 static void enterlevel (LexState *ls) { |
| 331 lua_State *L = ls->L; |
| 332 ++L->nCcalls; |
| 333 checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "C levels"); |
| 334 } |
| 335 |
| 336 |
| 337 #define leavelevel(ls) ((ls)->L->nCcalls--) |
| 338 |
| 339 |
| 340 static void closegoto (LexState *ls, int g, Labeldesc *label) { |
| 341 int i; |
| 342 FuncState *fs = ls->fs; |
| 343 Labellist *gl = &ls->dyd->gt; |
| 344 Labeldesc *gt = &gl->arr[g]; |
| 345 lua_assert(luaS_eqstr(gt->name, label->name)); |
| 346 if (gt->nactvar < label->nactvar) { |
| 347 TString *vname = getlocvar(fs, gt->nactvar)->varname; |
| 348 const char *msg = luaO_pushfstring(ls->L, |
| 349 "<goto %s> at line %d jumps into the scope of local " LUA_QS, |
| 350 getstr(gt->name), gt->line, getstr(vname)); |
| 351 semerror(ls, msg); |
| 352 } |
| 353 luaK_patchlist(fs, gt->pc, label->pc); |
| 354 /* remove goto from pending list */ |
| 355 for (i = g; i < gl->n - 1; i++) |
| 356 gl->arr[i] = gl->arr[i + 1]; |
| 357 gl->n--; |
| 358 } |
| 359 |
| 360 |
| 361 /* |
| 362 ** try to close a goto with existing labels; this solves backward jumps |
| 363 */ |
| 364 static int findlabel (LexState *ls, int g) { |
| 365 int i; |
| 366 BlockCnt *bl = ls->fs->bl; |
| 367 Dyndata *dyd = ls->dyd; |
| 368 Labeldesc *gt = &dyd->gt.arr[g]; |
| 369 /* check labels in current block for a match */ |
| 370 for (i = bl->firstlabel; i < dyd->label.n; i++) { |
| 371 Labeldesc *lb = &dyd->label.arr[i]; |
| 372 if (luaS_eqstr(lb->name, gt->name)) { /* correct label? */ |
| 373 if (gt->nactvar > lb->nactvar && |
| 374 (bl->upval || dyd->label.n > bl->firstlabel)) |
| 375 luaK_patchclose(ls->fs, gt->pc, lb->nactvar); |
| 376 closegoto(ls, g, lb); /* close it */ |
| 377 return 1; |
| 378 } |
| 379 } |
| 380 return 0; /* label not found; cannot close goto */ |
| 381 } |
| 382 |
| 383 |
| 384 static int newlabelentry (LexState *ls, Labellist *l, TString *name, |
| 385 int line, int pc) { |
| 386 int n = l->n; |
| 387 luaM_growvector(ls->L, l->arr, n, l->size, |
| 388 Labeldesc, SHRT_MAX, "labels/gotos"); |
| 389 l->arr[n].name = name; |
| 390 l->arr[n].line = line; |
| 391 l->arr[n].nactvar = ls->fs->nactvar; |
| 392 l->arr[n].pc = pc; |
| 393 l->n++; |
| 394 return n; |
| 395 } |
| 396 |
| 397 |
| 398 /* |
| 399 ** check whether new label 'lb' matches any pending gotos in current |
| 400 ** block; solves forward jumps |
| 401 */ |
| 402 static void findgotos (LexState *ls, Labeldesc *lb) { |
| 403 Labellist *gl = &ls->dyd->gt; |
| 404 int i = ls->fs->bl->firstgoto; |
| 405 while (i < gl->n) { |
| 406 if (luaS_eqstr(gl->arr[i].name, lb->name)) |
| 407 closegoto(ls, i, lb); |
| 408 else |
| 409 i++; |
| 410 } |
| 411 } |
| 412 |
| 413 |
| 414 /* |
| 415 ** "export" pending gotos to outer level, to check them against |
| 416 ** outer labels; if the block being exited has upvalues, and |
| 417 ** the goto exits the scope of any variable (which can be the |
| 418 ** upvalue), close those variables being exited. |
| 419 */ |
| 420 static void movegotosout (FuncState *fs, BlockCnt *bl) { |
| 421 int i = bl->firstgoto; |
| 422 Labellist *gl = &fs->ls->dyd->gt; |
| 423 /* correct pending gotos to current block and try to close it |
| 424 with visible labels */ |
| 425 while (i < gl->n) { |
| 426 Labeldesc *gt = &gl->arr[i]; |
| 427 if (gt->nactvar > bl->nactvar) { |
| 428 if (bl->upval) |
| 429 luaK_patchclose(fs, gt->pc, bl->nactvar); |
| 430 gt->nactvar = bl->nactvar; |
| 431 } |
| 432 if (!findlabel(fs->ls, i)) |
| 433 i++; /* move to next one */ |
| 434 } |
| 435 } |
| 436 |
| 437 |
| 438 static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) { |
| 439 bl->isloop = isloop; |
| 440 bl->nactvar = fs->nactvar; |
| 441 bl->firstlabel = fs->ls->dyd->label.n; |
| 442 bl->firstgoto = fs->ls->dyd->gt.n; |
| 443 bl->upval = 0; |
| 444 bl->previous = fs->bl; |
| 445 fs->bl = bl; |
| 446 lua_assert(fs->freereg == fs->nactvar); |
| 447 } |
| 448 |
| 449 |
| 450 /* |
| 451 ** create a label named "break" to resolve break statements |
| 452 */ |
| 453 static void breaklabel (LexState *ls) { |
| 454 TString *n = luaS_new(ls->L, "break"); |
| 455 int l = newlabelentry(ls, &ls->dyd->label, n, 0, ls->fs->pc); |
| 456 findgotos(ls, &ls->dyd->label.arr[l]); |
| 457 } |
| 458 |
| 459 /* |
| 460 ** generates an error for an undefined 'goto'; choose appropriate |
| 461 ** message when label name is a reserved word (which can only be 'break') |
| 462 */ |
| 463 static l_noret undefgoto (LexState *ls, Labeldesc *gt) { |
| 464 const char *msg = isreserved(gt->name) |
| 465 ? "<%s> at line %d not inside a loop" |
| 466 : "no visible label " LUA_QS " for <goto> at line %d"; |
| 467 msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line); |
| 468 semerror(ls, msg); |
| 469 } |
| 470 |
| 471 |
| 472 static void leaveblock (FuncState *fs) { |
| 473 BlockCnt *bl = fs->bl; |
| 474 LexState *ls = fs->ls; |
| 475 if (bl->previous && bl->upval) { |
| 476 /* create a 'jump to here' to close upvalues */ |
| 477 int j = luaK_jump(fs); |
| 478 luaK_patchclose(fs, j, bl->nactvar); |
| 479 luaK_patchtohere(fs, j); |
| 480 } |
| 481 if (bl->isloop) |
| 482 breaklabel(ls); /* close pending breaks */ |
| 483 fs->bl = bl->previous; |
| 484 removevars(fs, bl->nactvar); |
| 485 lua_assert(bl->nactvar == fs->nactvar); |
| 486 fs->freereg = fs->nactvar; /* free registers */ |
| 487 ls->dyd->label.n = bl->firstlabel; /* remove local labels */ |
| 488 if (bl->previous) /* inner block? */ |
| 489 movegotosout(fs, bl); /* update pending gotos to outer block */ |
| 490 else if (bl->firstgoto < ls->dyd->gt.n) /* pending gotos in outer block? */ |
| 491 undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]); /* error */ |
| 492 } |
| 493 |
| 494 |
| 495 /* |
| 496 ** adds a new prototype into list of prototypes |
| 497 */ |
| 498 static Proto *addprototype (LexState *ls) { |
| 499 Proto *clp; |
| 500 lua_State *L = ls->L; |
| 501 FuncState *fs = ls->fs; |
| 502 Proto *f = fs->f; /* prototype of current function */ |
| 503 if (fs->np >= f->sizep) { |
| 504 int oldsize = f->sizep; |
| 505 luaM_growvector(L, f->p, fs->np, f->sizep, Proto *, MAXARG_Bx, "functions"); |
| 506 while (oldsize < f->sizep) f->p[oldsize++] = NULL; |
| 507 } |
| 508 f->p[fs->np++] = clp = luaF_newproto(L); |
| 509 luaC_objbarrier(L, f, clp); |
| 510 return clp; |
| 511 } |
| 512 |
| 513 |
| 514 /* |
| 515 ** codes instruction to create new closure in parent function. |
| 516 ** The OP_CLOSURE instruction must use the last available register, |
| 517 ** so that, if it invokes the GC, the GC knows which registers |
| 518 ** are in use at that time. |
| 519 */ |
| 520 static void codeclosure (LexState *ls, expdesc *v) { |
| 521 FuncState *fs = ls->fs->prev; |
| 522 init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1)); |
| 523 luaK_exp2nextreg(fs, v); /* fix it at the last register */ |
| 524 } |
| 525 |
| 526 |
| 527 static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) { |
| 528 lua_State *L = ls->L; |
| 529 Proto *f; |
| 530 fs->prev = ls->fs; /* linked list of funcstates */ |
| 531 fs->ls = ls; |
| 532 ls->fs = fs; |
| 533 fs->pc = 0; |
| 534 fs->lasttarget = 0; |
| 535 fs->jpc = NO_JUMP; |
| 536 fs->freereg = 0; |
| 537 fs->nk = 0; |
| 538 fs->np = 0; |
| 539 fs->nups = 0; |
| 540 fs->nlocvars = 0; |
| 541 fs->nactvar = 0; |
| 542 fs->firstlocal = ls->dyd->actvar.n; |
| 543 fs->bl = NULL; |
| 544 f = fs->f; |
| 545 f->source = ls->source; |
| 546 f->maxstacksize = 2; /* registers 0/1 are always valid */ |
| 547 fs->h = luaH_new(L); |
| 548 /* anchor table of constants (to avoid being collected) */ |
| 549 sethvalue2s(L, L->top, fs->h); |
| 550 incr_top(L); |
| 551 enterblock(fs, bl, 0); |
| 552 } |
| 553 |
| 554 |
| 555 static void close_func (LexState *ls) { |
| 556 lua_State *L = ls->L; |
| 557 FuncState *fs = ls->fs; |
| 558 Proto *f = fs->f; |
| 559 luaK_ret(fs, 0, 0); /* final return */ |
| 560 leaveblock(fs); |
| 561 luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction); |
| 562 f->sizecode = fs->pc; |
| 563 luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int); |
| 564 f->sizelineinfo = fs->pc; |
| 565 luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue); |
| 566 f->sizek = fs->nk; |
| 567 luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *); |
| 568 f->sizep = fs->np; |
| 569 luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar); |
| 570 f->sizelocvars = fs->nlocvars; |
| 571 luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc); |
| 572 f->sizeupvalues = fs->nups; |
| 573 lua_assert(fs->bl == NULL); |
| 574 ls->fs = fs->prev; |
| 575 /* last token read was anchored in defunct function; must re-anchor it */ |
| 576 anchor_token(ls); |
| 577 L->top--; /* pop table of constants */ |
| 578 luaC_checkGC(L); |
| 579 } |
| 580 |
| 581 |
| 582 |
| 583 /*============================================================*/ |
| 584 /* GRAMMAR RULES */ |
| 585 /*============================================================*/ |
| 586 |
| 587 |
| 588 /* |
| 589 ** check whether current token is in the follow set of a block. |
| 590 ** 'until' closes syntactical blocks, but do not close scope, |
| 591 ** so it handled in separate. |
| 592 */ |
| 593 static int block_follow (LexState *ls, int withuntil) { |
| 594 switch (ls->t.token) { |
| 595 case TK_ELSE: case TK_ELSEIF: |
| 596 case TK_END: case TK_EOS: |
| 597 return 1; |
| 598 case TK_UNTIL: return withuntil; |
| 599 default: return 0; |
| 600 } |
| 601 } |
| 602 |
| 603 |
| 604 static void statlist (LexState *ls) { |
| 605 /* statlist -> { stat [`;'] } */ |
| 606 while (!block_follow(ls, 1)) { |
| 607 if (ls->t.token == TK_RETURN) { |
| 608 statement(ls); |
| 609 return; /* 'return' must be last statement */ |
| 610 } |
| 611 statement(ls); |
| 612 } |
| 613 } |
| 614 |
| 615 |
| 616 static void fieldsel (LexState *ls, expdesc *v) { |
| 617 /* fieldsel -> ['.' | ':'] NAME */ |
| 618 FuncState *fs = ls->fs; |
| 619 expdesc key; |
| 620 luaK_exp2anyregup(fs, v); |
| 621 luaX_next(ls); /* skip the dot or colon */ |
| 622 checkname(ls, &key); |
| 623 luaK_indexed(fs, v, &key); |
| 624 } |
| 625 |
| 626 |
| 627 static void yindex (LexState *ls, expdesc *v) { |
| 628 /* index -> '[' expr ']' */ |
| 629 luaX_next(ls); /* skip the '[' */ |
| 630 expr(ls, v); |
| 631 luaK_exp2val(ls->fs, v); |
| 632 checknext(ls, ']'); |
| 633 } |
| 634 |
| 635 |
| 636 /* |
| 637 ** {====================================================================== |
| 638 ** Rules for Constructors |
| 639 ** ======================================================================= |
| 640 */ |
| 641 |
| 642 |
| 643 struct ConsControl { |
| 644 expdesc v; /* last list item read */ |
| 645 expdesc *t; /* table descriptor */ |
| 646 int nh; /* total number of `record' elements */ |
| 647 int na; /* total number of array elements */ |
| 648 int tostore; /* number of array elements pending to be stored */ |
| 649 }; |
| 650 |
| 651 |
| 652 static void recfield (LexState *ls, struct ConsControl *cc) { |
| 653 /* recfield -> (NAME | `['exp1`]') = exp1 */ |
| 654 FuncState *fs = ls->fs; |
| 655 int reg = ls->fs->freereg; |
| 656 expdesc key, val; |
| 657 int rkkey; |
| 658 if (ls->t.token == TK_NAME) { |
| 659 checklimit(fs, cc->nh, MAX_INT, "items in a constructor"); |
| 660 checkname(ls, &key); |
| 661 } |
| 662 else /* ls->t.token == '[' */ |
| 663 yindex(ls, &key); |
| 664 cc->nh++; |
| 665 checknext(ls, '='); |
| 666 rkkey = luaK_exp2RK(fs, &key); |
| 667 expr(ls, &val); |
| 668 luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val)); |
| 669 fs->freereg = reg; /* free registers */ |
| 670 } |
| 671 |
| 672 |
| 673 static void closelistfield (FuncState *fs, struct ConsControl *cc) { |
| 674 if (cc->v.k == VVOID) return; /* there is no list item */ |
| 675 luaK_exp2nextreg(fs, &cc->v); |
| 676 cc->v.k = VVOID; |
| 677 if (cc->tostore == LFIELDS_PER_FLUSH) { |
| 678 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); /* flush */ |
| 679 cc->tostore = 0; /* no more items pending */ |
| 680 } |
| 681 } |
| 682 |
| 683 |
| 684 static void lastlistfield (FuncState *fs, struct ConsControl *cc) { |
| 685 if (cc->tostore == 0) return; |
| 686 if (hasmultret(cc->v.k)) { |
| 687 luaK_setmultret(fs, &cc->v); |
| 688 luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET); |
| 689 cc->na--; /* do not count last expression (unknown number of elements) */ |
| 690 } |
| 691 else { |
| 692 if (cc->v.k != VVOID) |
| 693 luaK_exp2nextreg(fs, &cc->v); |
| 694 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); |
| 695 } |
| 696 } |
| 697 |
| 698 |
| 699 static void listfield (LexState *ls, struct ConsControl *cc) { |
| 700 /* listfield -> exp */ |
| 701 expr(ls, &cc->v); |
| 702 checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor"); |
| 703 cc->na++; |
| 704 cc->tostore++; |
| 705 } |
| 706 |
| 707 |
| 708 static void field (LexState *ls, struct ConsControl *cc) { |
| 709 /* field -> listfield | recfield */ |
| 710 switch(ls->t.token) { |
| 711 case TK_NAME: { /* may be 'listfield' or 'recfield' */ |
| 712 if (luaX_lookahead(ls) != '=') /* expression? */ |
| 713 listfield(ls, cc); |
| 714 else |
| 715 recfield(ls, cc); |
| 716 break; |
| 717 } |
| 718 case '[': { |
| 719 recfield(ls, cc); |
| 720 break; |
| 721 } |
| 722 default: { |
| 723 listfield(ls, cc); |
| 724 break; |
| 725 } |
| 726 } |
| 727 } |
| 728 |
| 729 |
| 730 static void constructor (LexState *ls, expdesc *t) { |
| 731 /* constructor -> '{' [ field { sep field } [sep] ] '}' |
| 732 sep -> ',' | ';' */ |
| 733 FuncState *fs = ls->fs; |
| 734 int line = ls->linenumber; |
| 735 int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0); |
| 736 struct ConsControl cc; |
| 737 cc.na = cc.nh = cc.tostore = 0; |
| 738 cc.t = t; |
| 739 init_exp(t, VRELOCABLE, pc); |
| 740 init_exp(&cc.v, VVOID, 0); /* no value (yet) */ |
| 741 luaK_exp2nextreg(ls->fs, t); /* fix it at stack top */ |
| 742 checknext(ls, '{'); |
| 743 do { |
| 744 lua_assert(cc.v.k == VVOID || cc.tostore > 0); |
| 745 if (ls->t.token == '}') break; |
| 746 closelistfield(fs, &cc); |
| 747 field(ls, &cc); |
| 748 } while (testnext(ls, ',') || testnext(ls, ';')); |
| 749 check_match(ls, '}', '{', line); |
| 750 lastlistfield(fs, &cc); |
| 751 SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */ |
| 752 SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */ |
| 753 } |
| 754 |
| 755 /* }====================================================================== */ |
| 756 |
| 757 |
| 758 |
| 759 static void parlist (LexState *ls) { |
| 760 /* parlist -> [ param { `,' param } ] */ |
| 761 FuncState *fs = ls->fs; |
| 762 Proto *f = fs->f; |
| 763 int nparams = 0; |
| 764 f->is_vararg = 0; |
| 765 if (ls->t.token != ')') { /* is `parlist' not empty? */ |
| 766 do { |
| 767 switch (ls->t.token) { |
| 768 case TK_NAME: { /* param -> NAME */ |
| 769 new_localvar(ls, str_checkname(ls)); |
| 770 nparams++; |
| 771 break; |
| 772 } |
| 773 case TK_DOTS: { /* param -> `...' */ |
| 774 luaX_next(ls); |
| 775 f->is_vararg = 1; |
| 776 break; |
| 777 } |
| 778 default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected"); |
| 779 } |
| 780 } while (!f->is_vararg && testnext(ls, ',')); |
| 781 } |
| 782 adjustlocalvars(ls, nparams); |
| 783 f->numparams = cast_byte(fs->nactvar); |
| 784 luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */ |
| 785 } |
| 786 |
| 787 |
| 788 static void body (LexState *ls, expdesc *e, int ismethod, int line) { |
| 789 /* body -> `(' parlist `)' block END */ |
| 790 FuncState new_fs; |
| 791 BlockCnt bl; |
| 792 new_fs.f = addprototype(ls); |
| 793 new_fs.f->linedefined = line; |
| 794 open_func(ls, &new_fs, &bl); |
| 795 checknext(ls, '('); |
| 796 if (ismethod) { |
| 797 new_localvarliteral(ls, "self"); /* create 'self' parameter */ |
| 798 adjustlocalvars(ls, 1); |
| 799 } |
| 800 parlist(ls); |
| 801 checknext(ls, ')'); |
| 802 statlist(ls); |
| 803 new_fs.f->lastlinedefined = ls->linenumber; |
| 804 check_match(ls, TK_END, TK_FUNCTION, line); |
| 805 codeclosure(ls, e); |
| 806 close_func(ls); |
| 807 } |
| 808 |
| 809 |
| 810 static int explist (LexState *ls, expdesc *v) { |
| 811 /* explist -> expr { `,' expr } */ |
| 812 int n = 1; /* at least one expression */ |
| 813 expr(ls, v); |
| 814 while (testnext(ls, ',')) { |
| 815 luaK_exp2nextreg(ls->fs, v); |
| 816 expr(ls, v); |
| 817 n++; |
| 818 } |
| 819 return n; |
| 820 } |
| 821 |
| 822 |
| 823 static void funcargs (LexState *ls, expdesc *f, int line) { |
| 824 FuncState *fs = ls->fs; |
| 825 expdesc args; |
| 826 int base, nparams; |
| 827 switch (ls->t.token) { |
| 828 case '(': { /* funcargs -> `(' [ explist ] `)' */ |
| 829 luaX_next(ls); |
| 830 if (ls->t.token == ')') /* arg list is empty? */ |
| 831 args.k = VVOID; |
| 832 else { |
| 833 explist(ls, &args); |
| 834 luaK_setmultret(fs, &args); |
| 835 } |
| 836 check_match(ls, ')', '(', line); |
| 837 break; |
| 838 } |
| 839 case '{': { /* funcargs -> constructor */ |
| 840 constructor(ls, &args); |
| 841 break; |
| 842 } |
| 843 case TK_STRING: { /* funcargs -> STRING */ |
| 844 codestring(ls, &args, ls->t.seminfo.ts); |
| 845 luaX_next(ls); /* must use `seminfo' before `next' */ |
| 846 break; |
| 847 } |
| 848 default: { |
| 849 luaX_syntaxerror(ls, "function arguments expected"); |
| 850 } |
| 851 } |
| 852 lua_assert(f->k == VNONRELOC); |
| 853 base = f->u.info; /* base register for call */ |
| 854 if (hasmultret(args.k)) |
| 855 nparams = LUA_MULTRET; /* open call */ |
| 856 else { |
| 857 if (args.k != VVOID) |
| 858 luaK_exp2nextreg(fs, &args); /* close last argument */ |
| 859 nparams = fs->freereg - (base+1); |
| 860 } |
| 861 init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2)); |
| 862 luaK_fixline(fs, line); |
| 863 fs->freereg = base+1; /* call remove function and arguments and leaves |
| 864 (unless changed) one result */ |
| 865 } |
| 866 |
| 867 |
| 868 |
| 869 |
| 870 /* |
| 871 ** {====================================================================== |
| 872 ** Expression parsing |
| 873 ** ======================================================================= |
| 874 */ |
| 875 |
| 876 |
| 877 static void primaryexp (LexState *ls, expdesc *v) { |
| 878 /* primaryexp -> NAME | '(' expr ')' */ |
| 879 switch (ls->t.token) { |
| 880 case '(': { |
| 881 int line = ls->linenumber; |
| 882 luaX_next(ls); |
| 883 expr(ls, v); |
| 884 check_match(ls, ')', '(', line); |
| 885 luaK_dischargevars(ls->fs, v); |
| 886 return; |
| 887 } |
| 888 case TK_NAME: { |
| 889 singlevar(ls, v); |
| 890 return; |
| 891 } |
| 892 default: { |
| 893 luaX_syntaxerror(ls, "unexpected symbol"); |
| 894 } |
| 895 } |
| 896 } |
| 897 |
| 898 |
| 899 static void suffixedexp (LexState *ls, expdesc *v) { |
| 900 /* suffixedexp -> |
| 901 primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */ |
| 902 FuncState *fs = ls->fs; |
| 903 int line = ls->linenumber; |
| 904 primaryexp(ls, v); |
| 905 for (;;) { |
| 906 switch (ls->t.token) { |
| 907 case '.': { /* fieldsel */ |
| 908 fieldsel(ls, v); |
| 909 break; |
| 910 } |
| 911 case '[': { /* `[' exp1 `]' */ |
| 912 expdesc key; |
| 913 luaK_exp2anyregup(fs, v); |
| 914 yindex(ls, &key); |
| 915 luaK_indexed(fs, v, &key); |
| 916 break; |
| 917 } |
| 918 case ':': { /* `:' NAME funcargs */ |
| 919 expdesc key; |
| 920 luaX_next(ls); |
| 921 checkname(ls, &key); |
| 922 luaK_self(fs, v, &key); |
| 923 funcargs(ls, v, line); |
| 924 break; |
| 925 } |
| 926 case '(': case TK_STRING: case '{': { /* funcargs */ |
| 927 luaK_exp2nextreg(fs, v); |
| 928 funcargs(ls, v, line); |
| 929 break; |
| 930 } |
| 931 default: return; |
| 932 } |
| 933 } |
| 934 } |
| 935 |
| 936 |
| 937 static void simpleexp (LexState *ls, expdesc *v) { |
| 938 /* simpleexp -> NUMBER | STRING | NIL | TRUE | FALSE | ... | |
| 939 constructor | FUNCTION body | suffixedexp */ |
| 940 switch (ls->t.token) { |
| 941 case TK_NUMBER: { |
| 942 init_exp(v, VKNUM, 0); |
| 943 v->u.nval = ls->t.seminfo.r; |
| 944 break; |
| 945 } |
| 946 case TK_STRING: { |
| 947 codestring(ls, v, ls->t.seminfo.ts); |
| 948 break; |
| 949 } |
| 950 case TK_NIL: { |
| 951 init_exp(v, VNIL, 0); |
| 952 break; |
| 953 } |
| 954 case TK_TRUE: { |
| 955 init_exp(v, VTRUE, 0); |
| 956 break; |
| 957 } |
| 958 case TK_FALSE: { |
| 959 init_exp(v, VFALSE, 0); |
| 960 break; |
| 961 } |
| 962 case TK_DOTS: { /* vararg */ |
| 963 FuncState *fs = ls->fs; |
| 964 check_condition(ls, fs->f->is_vararg, |
| 965 "cannot use " LUA_QL("...") " outside a vararg function"); |
| 966 init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0)); |
| 967 break; |
| 968 } |
| 969 case '{': { /* constructor */ |
| 970 constructor(ls, v); |
| 971 return; |
| 972 } |
| 973 case TK_FUNCTION: { |
| 974 luaX_next(ls); |
| 975 body(ls, v, 0, ls->linenumber); |
| 976 return; |
| 977 } |
| 978 default: { |
| 979 suffixedexp(ls, v); |
| 980 return; |
| 981 } |
| 982 } |
| 983 luaX_next(ls); |
| 984 } |
| 985 |
| 986 |
| 987 static UnOpr getunopr (int op) { |
| 988 switch (op) { |
| 989 case TK_NOT: return OPR_NOT; |
| 990 case '-': return OPR_MINUS; |
| 991 case '#': return OPR_LEN; |
| 992 default: return OPR_NOUNOPR; |
| 993 } |
| 994 } |
| 995 |
| 996 |
| 997 static BinOpr getbinopr (int op) { |
| 998 switch (op) { |
| 999 case '+': return OPR_ADD; |
| 1000 case '-': return OPR_SUB; |
| 1001 case '*': return OPR_MUL; |
| 1002 case '/': return OPR_DIV; |
| 1003 case '%': return OPR_MOD; |
| 1004 case '^': return OPR_POW; |
| 1005 case TK_CONCAT: return OPR_CONCAT; |
| 1006 case TK_NE: return OPR_NE; |
| 1007 case TK_EQ: return OPR_EQ; |
| 1008 case '<': return OPR_LT; |
| 1009 case TK_LE: return OPR_LE; |
| 1010 case '>': return OPR_GT; |
| 1011 case TK_GE: return OPR_GE; |
| 1012 case TK_AND: return OPR_AND; |
| 1013 case TK_OR: return OPR_OR; |
| 1014 default: return OPR_NOBINOPR; |
| 1015 } |
| 1016 } |
| 1017 |
| 1018 |
| 1019 static const struct { |
| 1020 lu_byte left; /* left priority for each binary operator */ |
| 1021 lu_byte right; /* right priority */ |
| 1022 } priority[] = { /* ORDER OPR */ |
| 1023 {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `*' `/' `%' */ |
| 1024 {10, 9}, {5, 4}, /* ^, .. (right associative) */ |
| 1025 {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */ |
| 1026 {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */ |
| 1027 {2, 2}, {1, 1} /* and, or */ |
| 1028 }; |
| 1029 |
| 1030 #define UNARY_PRIORITY 8 /* priority for unary operators */ |
| 1031 |
| 1032 |
| 1033 /* |
| 1034 ** subexpr -> (simpleexp | unop subexpr) { binop subexpr } |
| 1035 ** where `binop' is any binary operator with a priority higher than `limit' |
| 1036 */ |
| 1037 static BinOpr subexpr (LexState *ls, expdesc *v, int limit) { |
| 1038 BinOpr op; |
| 1039 UnOpr uop; |
| 1040 enterlevel(ls); |
| 1041 uop = getunopr(ls->t.token); |
| 1042 if (uop != OPR_NOUNOPR) { |
| 1043 int line = ls->linenumber; |
| 1044 luaX_next(ls); |
| 1045 subexpr(ls, v, UNARY_PRIORITY); |
| 1046 luaK_prefix(ls->fs, uop, v, line); |
| 1047 } |
| 1048 else simpleexp(ls, v); |
| 1049 /* expand while operators have priorities higher than `limit' */ |
| 1050 op = getbinopr(ls->t.token); |
| 1051 while (op != OPR_NOBINOPR && priority[op].left > limit) { |
| 1052 expdesc v2; |
| 1053 BinOpr nextop; |
| 1054 int line = ls->linenumber; |
| 1055 luaX_next(ls); |
| 1056 luaK_infix(ls->fs, op, v); |
| 1057 /* read sub-expression with higher priority */ |
| 1058 nextop = subexpr(ls, &v2, priority[op].right); |
| 1059 luaK_posfix(ls->fs, op, v, &v2, line); |
| 1060 op = nextop; |
| 1061 } |
| 1062 leavelevel(ls); |
| 1063 return op; /* return first untreated operator */ |
| 1064 } |
| 1065 |
| 1066 |
| 1067 static void expr (LexState *ls, expdesc *v) { |
| 1068 subexpr(ls, v, 0); |
| 1069 } |
| 1070 |
| 1071 /* }==================================================================== */ |
| 1072 |
| 1073 |
| 1074 |
| 1075 /* |
| 1076 ** {====================================================================== |
| 1077 ** Rules for Statements |
| 1078 ** ======================================================================= |
| 1079 */ |
| 1080 |
| 1081 |
| 1082 static void block (LexState *ls) { |
| 1083 /* block -> statlist */ |
| 1084 FuncState *fs = ls->fs; |
| 1085 BlockCnt bl; |
| 1086 enterblock(fs, &bl, 0); |
| 1087 statlist(ls); |
| 1088 leaveblock(fs); |
| 1089 } |
| 1090 |
| 1091 |
| 1092 /* |
| 1093 ** structure to chain all variables in the left-hand side of an |
| 1094 ** assignment |
| 1095 */ |
| 1096 struct LHS_assign { |
| 1097 struct LHS_assign *prev; |
| 1098 expdesc v; /* variable (global, local, upvalue, or indexed) */ |
| 1099 }; |
| 1100 |
| 1101 |
| 1102 /* |
| 1103 ** check whether, in an assignment to an upvalue/local variable, the |
| 1104 ** upvalue/local variable is begin used in a previous assignment to a |
| 1105 ** table. If so, save original upvalue/local value in a safe place and |
| 1106 ** use this safe copy in the previous assignment. |
| 1107 */ |
| 1108 static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) { |
| 1109 FuncState *fs = ls->fs; |
| 1110 int extra = fs->freereg; /* eventual position to save local variable */ |
| 1111 int conflict = 0; |
| 1112 for (; lh; lh = lh->prev) { /* check all previous assignments */ |
| 1113 if (lh->v.k == VINDEXED) { /* assigning to a table? */ |
| 1114 /* table is the upvalue/local being assigned now? */ |
| 1115 if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) { |
| 1116 conflict = 1; |
| 1117 lh->v.u.ind.vt = VLOCAL; |
| 1118 lh->v.u.ind.t = extra; /* previous assignment will use safe copy */ |
| 1119 } |
| 1120 /* index is the local being assigned? (index cannot be upvalue) */ |
| 1121 if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) { |
| 1122 conflict = 1; |
| 1123 lh->v.u.ind.idx = extra; /* previous assignment will use safe copy */ |
| 1124 } |
| 1125 } |
| 1126 } |
| 1127 if (conflict) { |
| 1128 /* copy upvalue/local value to a temporary (in position 'extra') */ |
| 1129 OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL; |
| 1130 luaK_codeABC(fs, op, extra, v->u.info, 0); |
| 1131 luaK_reserveregs(fs, 1); |
| 1132 } |
| 1133 } |
| 1134 |
| 1135 |
| 1136 static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) { |
| 1137 expdesc e; |
| 1138 check_condition(ls, vkisvar(lh->v.k), "syntax error"); |
| 1139 if (testnext(ls, ',')) { /* assignment -> ',' suffixedexp assignment */ |
| 1140 struct LHS_assign nv; |
| 1141 nv.prev = lh; |
| 1142 suffixedexp(ls, &nv.v); |
| 1143 if (nv.v.k != VINDEXED) |
| 1144 check_conflict(ls, lh, &nv.v); |
| 1145 checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS, |
| 1146 "C levels"); |
| 1147 assignment(ls, &nv, nvars+1); |
| 1148 } |
| 1149 else { /* assignment -> `=' explist */ |
| 1150 int nexps; |
| 1151 checknext(ls, '='); |
| 1152 nexps = explist(ls, &e); |
| 1153 if (nexps != nvars) { |
| 1154 adjust_assign(ls, nvars, nexps, &e); |
| 1155 if (nexps > nvars) |
| 1156 ls->fs->freereg -= nexps - nvars; /* remove extra values */ |
| 1157 } |
| 1158 else { |
| 1159 luaK_setoneret(ls->fs, &e); /* close last expression */ |
| 1160 luaK_storevar(ls->fs, &lh->v, &e); |
| 1161 return; /* avoid default */ |
| 1162 } |
| 1163 } |
| 1164 init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */ |
| 1165 luaK_storevar(ls->fs, &lh->v, &e); |
| 1166 } |
| 1167 |
| 1168 |
| 1169 static int cond (LexState *ls) { |
| 1170 /* cond -> exp */ |
| 1171 expdesc v; |
| 1172 expr(ls, &v); /* read condition */ |
| 1173 if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */ |
| 1174 luaK_goiftrue(ls->fs, &v); |
| 1175 return v.f; |
| 1176 } |
| 1177 |
| 1178 |
| 1179 static void gotostat (LexState *ls, int pc) { |
| 1180 int line = ls->linenumber; |
| 1181 TString *label; |
| 1182 int g; |
| 1183 if (testnext(ls, TK_GOTO)) |
| 1184 label = str_checkname(ls); |
| 1185 else { |
| 1186 luaX_next(ls); /* skip break */ |
| 1187 label = luaS_new(ls->L, "break"); |
| 1188 } |
| 1189 g = newlabelentry(ls, &ls->dyd->gt, label, line, pc); |
| 1190 findlabel(ls, g); /* close it if label already defined */ |
| 1191 } |
| 1192 |
| 1193 |
| 1194 /* check for repeated labels on the same block */ |
| 1195 static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) { |
| 1196 int i; |
| 1197 for (i = fs->bl->firstlabel; i < ll->n; i++) { |
| 1198 if (luaS_eqstr(label, ll->arr[i].name)) { |
| 1199 const char *msg = luaO_pushfstring(fs->ls->L, |
| 1200 "label " LUA_QS " already defined on line %d", |
| 1201 getstr(label), ll->arr[i].line); |
| 1202 semerror(fs->ls, msg); |
| 1203 } |
| 1204 } |
| 1205 } |
| 1206 |
| 1207 |
| 1208 /* skip no-op statements */ |
| 1209 static void skipnoopstat (LexState *ls) { |
| 1210 while (ls->t.token == ';' || ls->t.token == TK_DBCOLON) |
| 1211 statement(ls); |
| 1212 } |
| 1213 |
| 1214 |
| 1215 static void labelstat (LexState *ls, TString *label, int line) { |
| 1216 /* label -> '::' NAME '::' */ |
| 1217 FuncState *fs = ls->fs; |
| 1218 Labellist *ll = &ls->dyd->label; |
| 1219 int l; /* index of new label being created */ |
| 1220 checkrepeated(fs, ll, label); /* check for repeated labels */ |
| 1221 checknext(ls, TK_DBCOLON); /* skip double colon */ |
| 1222 /* create new entry for this label */ |
| 1223 l = newlabelentry(ls, ll, label, line, fs->pc); |
| 1224 skipnoopstat(ls); /* skip other no-op statements */ |
| 1225 if (block_follow(ls, 0)) { /* label is last no-op statement in the block? */ |
| 1226 /* assume that locals are already out of scope */ |
| 1227 ll->arr[l].nactvar = fs->bl->nactvar; |
| 1228 } |
| 1229 findgotos(ls, &ll->arr[l]); |
| 1230 } |
| 1231 |
| 1232 |
| 1233 static void whilestat (LexState *ls, int line) { |
| 1234 /* whilestat -> WHILE cond DO block END */ |
| 1235 FuncState *fs = ls->fs; |
| 1236 int whileinit; |
| 1237 int condexit; |
| 1238 BlockCnt bl; |
| 1239 luaX_next(ls); /* skip WHILE */ |
| 1240 whileinit = luaK_getlabel(fs); |
| 1241 condexit = cond(ls); |
| 1242 enterblock(fs, &bl, 1); |
| 1243 checknext(ls, TK_DO); |
| 1244 block(ls); |
| 1245 luaK_jumpto(fs, whileinit); |
| 1246 check_match(ls, TK_END, TK_WHILE, line); |
| 1247 leaveblock(fs); |
| 1248 luaK_patchtohere(fs, condexit); /* false conditions finish the loop */ |
| 1249 } |
| 1250 |
| 1251 |
| 1252 static void repeatstat (LexState *ls, int line) { |
| 1253 /* repeatstat -> REPEAT block UNTIL cond */ |
| 1254 int condexit; |
| 1255 FuncState *fs = ls->fs; |
| 1256 int repeat_init = luaK_getlabel(fs); |
| 1257 BlockCnt bl1, bl2; |
| 1258 enterblock(fs, &bl1, 1); /* loop block */ |
| 1259 enterblock(fs, &bl2, 0); /* scope block */ |
| 1260 luaX_next(ls); /* skip REPEAT */ |
| 1261 statlist(ls); |
| 1262 check_match(ls, TK_UNTIL, TK_REPEAT, line); |
| 1263 condexit = cond(ls); /* read condition (inside scope block) */ |
| 1264 if (bl2.upval) /* upvalues? */ |
| 1265 luaK_patchclose(fs, condexit, bl2.nactvar); |
| 1266 leaveblock(fs); /* finish scope */ |
| 1267 luaK_patchlist(fs, condexit, repeat_init); /* close the loop */ |
| 1268 leaveblock(fs); /* finish loop */ |
| 1269 } |
| 1270 |
| 1271 |
| 1272 static int exp1 (LexState *ls) { |
| 1273 expdesc e; |
| 1274 int reg; |
| 1275 expr(ls, &e); |
| 1276 luaK_exp2nextreg(ls->fs, &e); |
| 1277 lua_assert(e.k == VNONRELOC); |
| 1278 reg = e.u.info; |
| 1279 return reg; |
| 1280 } |
| 1281 |
| 1282 |
| 1283 static void forbody (LexState *ls, int base, int line, int nvars, int isnum) { |
| 1284 /* forbody -> DO block */ |
| 1285 BlockCnt bl; |
| 1286 FuncState *fs = ls->fs; |
| 1287 int prep, endfor; |
| 1288 adjustlocalvars(ls, 3); /* control variables */ |
| 1289 checknext(ls, TK_DO); |
| 1290 prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs); |
| 1291 enterblock(fs, &bl, 0); /* scope for declared variables */ |
| 1292 adjustlocalvars(ls, nvars); |
| 1293 luaK_reserveregs(fs, nvars); |
| 1294 block(ls); |
| 1295 leaveblock(fs); /* end of scope for declared variables */ |
| 1296 luaK_patchtohere(fs, prep); |
| 1297 if (isnum) /* numeric for? */ |
| 1298 endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP); |
| 1299 else { /* generic for */ |
| 1300 luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars); |
| 1301 luaK_fixline(fs, line); |
| 1302 endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP); |
| 1303 } |
| 1304 luaK_patchlist(fs, endfor, prep + 1); |
| 1305 luaK_fixline(fs, line); |
| 1306 } |
| 1307 |
| 1308 |
| 1309 static void fornum (LexState *ls, TString *varname, int line) { |
| 1310 /* fornum -> NAME = exp1,exp1[,exp1] forbody */ |
| 1311 FuncState *fs = ls->fs; |
| 1312 int base = fs->freereg; |
| 1313 new_localvarliteral(ls, "(for index)"); |
| 1314 new_localvarliteral(ls, "(for limit)"); |
| 1315 new_localvarliteral(ls, "(for step)"); |
| 1316 new_localvar(ls, varname); |
| 1317 checknext(ls, '='); |
| 1318 exp1(ls); /* initial value */ |
| 1319 checknext(ls, ','); |
| 1320 exp1(ls); /* limit */ |
| 1321 if (testnext(ls, ',')) |
| 1322 exp1(ls); /* optional step */ |
| 1323 else { /* default step = 1 */ |
| 1324 luaK_codek(fs, fs->freereg, luaK_numberK(fs, 1)); |
| 1325 luaK_reserveregs(fs, 1); |
| 1326 } |
| 1327 forbody(ls, base, line, 1, 1); |
| 1328 } |
| 1329 |
| 1330 |
| 1331 static void forlist (LexState *ls, TString *indexname) { |
| 1332 /* forlist -> NAME {,NAME} IN explist forbody */ |
| 1333 FuncState *fs = ls->fs; |
| 1334 expdesc e; |
| 1335 int nvars = 4; /* gen, state, control, plus at least one declared var */ |
| 1336 int line; |
| 1337 int base = fs->freereg; |
| 1338 /* create control variables */ |
| 1339 new_localvarliteral(ls, "(for generator)"); |
| 1340 new_localvarliteral(ls, "(for state)"); |
| 1341 new_localvarliteral(ls, "(for control)"); |
| 1342 /* create declared variables */ |
| 1343 new_localvar(ls, indexname); |
| 1344 while (testnext(ls, ',')) { |
| 1345 new_localvar(ls, str_checkname(ls)); |
| 1346 nvars++; |
| 1347 } |
| 1348 checknext(ls, TK_IN); |
| 1349 line = ls->linenumber; |
| 1350 adjust_assign(ls, 3, explist(ls, &e), &e); |
| 1351 luaK_checkstack(fs, 3); /* extra space to call generator */ |
| 1352 forbody(ls, base, line, nvars - 3, 0); |
| 1353 } |
| 1354 |
| 1355 |
| 1356 static void forstat (LexState *ls, int line) { |
| 1357 /* forstat -> FOR (fornum | forlist) END */ |
| 1358 FuncState *fs = ls->fs; |
| 1359 TString *varname; |
| 1360 BlockCnt bl; |
| 1361 enterblock(fs, &bl, 1); /* scope for loop and control variables */ |
| 1362 luaX_next(ls); /* skip `for' */ |
| 1363 varname = str_checkname(ls); /* first variable name */ |
| 1364 switch (ls->t.token) { |
| 1365 case '=': fornum(ls, varname, line); break; |
| 1366 case ',': case TK_IN: forlist(ls, varname); break; |
| 1367 default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected"); |
| 1368 } |
| 1369 check_match(ls, TK_END, TK_FOR, line); |
| 1370 leaveblock(fs); /* loop scope (`break' jumps to this point) */ |
| 1371 } |
| 1372 |
| 1373 |
| 1374 static void test_then_block (LexState *ls, int *escapelist) { |
| 1375 /* test_then_block -> [IF | ELSEIF] cond THEN block */ |
| 1376 BlockCnt bl; |
| 1377 FuncState *fs = ls->fs; |
| 1378 expdesc v; |
| 1379 int jf; /* instruction to skip 'then' code (if condition is false) */ |
| 1380 luaX_next(ls); /* skip IF or ELSEIF */ |
| 1381 expr(ls, &v); /* read condition */ |
| 1382 checknext(ls, TK_THEN); |
| 1383 if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) { |
| 1384 luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */ |
| 1385 enterblock(fs, &bl, 0); /* must enter block before 'goto' */ |
| 1386 gotostat(ls, v.t); /* handle goto/break */ |
| 1387 skipnoopstat(ls); /* skip other no-op statements */ |
| 1388 if (block_follow(ls, 0)) { /* 'goto' is the entire block? */ |
| 1389 leaveblock(fs); |
| 1390 return; /* and that is it */ |
| 1391 } |
| 1392 else /* must skip over 'then' part if condition is false */ |
| 1393 jf = luaK_jump(fs); |
| 1394 } |
| 1395 else { /* regular case (not goto/break) */ |
| 1396 luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */ |
| 1397 enterblock(fs, &bl, 0); |
| 1398 jf = v.f; |
| 1399 } |
| 1400 statlist(ls); /* `then' part */ |
| 1401 leaveblock(fs); |
| 1402 if (ls->t.token == TK_ELSE || |
| 1403 ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */ |
| 1404 luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */ |
| 1405 luaK_patchtohere(fs, jf); |
| 1406 } |
| 1407 |
| 1408 |
| 1409 static void ifstat (LexState *ls, int line) { |
| 1410 /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */ |
| 1411 FuncState *fs = ls->fs; |
| 1412 int escapelist = NO_JUMP; /* exit list for finished parts */ |
| 1413 test_then_block(ls, &escapelist); /* IF cond THEN block */ |
| 1414 while (ls->t.token == TK_ELSEIF) |
| 1415 test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */ |
| 1416 if (testnext(ls, TK_ELSE)) |
| 1417 block(ls); /* `else' part */ |
| 1418 check_match(ls, TK_END, TK_IF, line); |
| 1419 luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */ |
| 1420 } |
| 1421 |
| 1422 |
| 1423 static void localfunc (LexState *ls) { |
| 1424 expdesc b; |
| 1425 FuncState *fs = ls->fs; |
| 1426 new_localvar(ls, str_checkname(ls)); /* new local variable */ |
| 1427 adjustlocalvars(ls, 1); /* enter its scope */ |
| 1428 body(ls, &b, 0, ls->linenumber); /* function created in next register */ |
| 1429 /* debug information will only see the variable after this point! */ |
| 1430 getlocvar(fs, b.u.info)->startpc = fs->pc; |
| 1431 } |
| 1432 |
| 1433 |
| 1434 static void localstat (LexState *ls) { |
| 1435 /* stat -> LOCAL NAME {`,' NAME} [`=' explist] */ |
| 1436 int nvars = 0; |
| 1437 int nexps; |
| 1438 expdesc e; |
| 1439 do { |
| 1440 new_localvar(ls, str_checkname(ls)); |
| 1441 nvars++; |
| 1442 } while (testnext(ls, ',')); |
| 1443 if (testnext(ls, '=')) |
| 1444 nexps = explist(ls, &e); |
| 1445 else { |
| 1446 e.k = VVOID; |
| 1447 nexps = 0; |
| 1448 } |
| 1449 adjust_assign(ls, nvars, nexps, &e); |
| 1450 adjustlocalvars(ls, nvars); |
| 1451 } |
| 1452 |
| 1453 |
| 1454 static int funcname (LexState *ls, expdesc *v) { |
| 1455 /* funcname -> NAME {fieldsel} [`:' NAME] */ |
| 1456 int ismethod = 0; |
| 1457 singlevar(ls, v); |
| 1458 while (ls->t.token == '.') |
| 1459 fieldsel(ls, v); |
| 1460 if (ls->t.token == ':') { |
| 1461 ismethod = 1; |
| 1462 fieldsel(ls, v); |
| 1463 } |
| 1464 return ismethod; |
| 1465 } |
| 1466 |
| 1467 |
| 1468 static void funcstat (LexState *ls, int line) { |
| 1469 /* funcstat -> FUNCTION funcname body */ |
| 1470 int ismethod; |
| 1471 expdesc v, b; |
| 1472 luaX_next(ls); /* skip FUNCTION */ |
| 1473 ismethod = funcname(ls, &v); |
| 1474 body(ls, &b, ismethod, line); |
| 1475 luaK_storevar(ls->fs, &v, &b); |
| 1476 luaK_fixline(ls->fs, line); /* definition `happens' in the first line */ |
| 1477 } |
| 1478 |
| 1479 |
| 1480 static void exprstat (LexState *ls) { |
| 1481 /* stat -> func | assignment */ |
| 1482 FuncState *fs = ls->fs; |
| 1483 struct LHS_assign v; |
| 1484 suffixedexp(ls, &v.v); |
| 1485 if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */ |
| 1486 v.prev = NULL; |
| 1487 assignment(ls, &v, 1); |
| 1488 } |
| 1489 else { /* stat -> func */ |
| 1490 check_condition(ls, v.v.k == VCALL, "syntax error"); |
| 1491 SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */ |
| 1492 } |
| 1493 } |
| 1494 |
| 1495 |
| 1496 static void retstat (LexState *ls) { |
| 1497 /* stat -> RETURN [explist] [';'] */ |
| 1498 FuncState *fs = ls->fs; |
| 1499 expdesc e; |
| 1500 int first, nret; /* registers with returned values */ |
| 1501 if (block_follow(ls, 1) || ls->t.token == ';') |
| 1502 first = nret = 0; /* return no values */ |
| 1503 else { |
| 1504 nret = explist(ls, &e); /* optional return values */ |
| 1505 if (hasmultret(e.k)) { |
| 1506 luaK_setmultret(fs, &e); |
| 1507 if (e.k == VCALL && nret == 1) { /* tail call? */ |
| 1508 SET_OPCODE(getcode(fs,&e), OP_TAILCALL); |
| 1509 lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar); |
| 1510 } |
| 1511 first = fs->nactvar; |
| 1512 nret = LUA_MULTRET; /* return all values */ |
| 1513 } |
| 1514 else { |
| 1515 if (nret == 1) /* only one single value? */ |
| 1516 first = luaK_exp2anyreg(fs, &e); |
| 1517 else { |
| 1518 luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */ |
| 1519 first = fs->nactvar; /* return all `active' values */ |
| 1520 lua_assert(nret == fs->freereg - first); |
| 1521 } |
| 1522 } |
| 1523 } |
| 1524 luaK_ret(fs, first, nret); |
| 1525 testnext(ls, ';'); /* skip optional semicolon */ |
| 1526 } |
| 1527 |
| 1528 |
| 1529 static void statement (LexState *ls) { |
| 1530 int line = ls->linenumber; /* may be needed for error messages */ |
| 1531 enterlevel(ls); |
| 1532 switch (ls->t.token) { |
| 1533 case ';': { /* stat -> ';' (empty statement) */ |
| 1534 luaX_next(ls); /* skip ';' */ |
| 1535 break; |
| 1536 } |
| 1537 case TK_IF: { /* stat -> ifstat */ |
| 1538 ifstat(ls, line); |
| 1539 break; |
| 1540 } |
| 1541 case TK_WHILE: { /* stat -> whilestat */ |
| 1542 whilestat(ls, line); |
| 1543 break; |
| 1544 } |
| 1545 case TK_DO: { /* stat -> DO block END */ |
| 1546 luaX_next(ls); /* skip DO */ |
| 1547 block(ls); |
| 1548 check_match(ls, TK_END, TK_DO, line); |
| 1549 break; |
| 1550 } |
| 1551 case TK_FOR: { /* stat -> forstat */ |
| 1552 forstat(ls, line); |
| 1553 break; |
| 1554 } |
| 1555 case TK_REPEAT: { /* stat -> repeatstat */ |
| 1556 repeatstat(ls, line); |
| 1557 break; |
| 1558 } |
| 1559 case TK_FUNCTION: { /* stat -> funcstat */ |
| 1560 funcstat(ls, line); |
| 1561 break; |
| 1562 } |
| 1563 case TK_LOCAL: { /* stat -> localstat */ |
| 1564 luaX_next(ls); /* skip LOCAL */ |
| 1565 if (testnext(ls, TK_FUNCTION)) /* local function? */ |
| 1566 localfunc(ls); |
| 1567 else |
| 1568 localstat(ls); |
| 1569 break; |
| 1570 } |
| 1571 case TK_DBCOLON: { /* stat -> label */ |
| 1572 luaX_next(ls); /* skip double colon */ |
| 1573 labelstat(ls, str_checkname(ls), line); |
| 1574 break; |
| 1575 } |
| 1576 case TK_RETURN: { /* stat -> retstat */ |
| 1577 luaX_next(ls); /* skip RETURN */ |
| 1578 retstat(ls); |
| 1579 break; |
| 1580 } |
| 1581 case TK_BREAK: /* stat -> breakstat */ |
| 1582 case TK_GOTO: { /* stat -> 'goto' NAME */ |
| 1583 gotostat(ls, luaK_jump(ls->fs)); |
| 1584 break; |
| 1585 } |
| 1586 default: { /* stat -> func | assignment */ |
| 1587 exprstat(ls); |
| 1588 break; |
| 1589 } |
| 1590 } |
| 1591 lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg && |
| 1592 ls->fs->freereg >= ls->fs->nactvar); |
| 1593 ls->fs->freereg = ls->fs->nactvar; /* free registers */ |
| 1594 leavelevel(ls); |
| 1595 } |
| 1596 |
| 1597 /* }====================================================================== */ |
| 1598 |
| 1599 |
| 1600 /* |
| 1601 ** compiles the main function, which is a regular vararg function with an |
| 1602 ** upvalue named LUA_ENV |
| 1603 */ |
| 1604 static void mainfunc (LexState *ls, FuncState *fs) { |
| 1605 BlockCnt bl; |
| 1606 expdesc v; |
| 1607 open_func(ls, fs, &bl); |
| 1608 fs->f->is_vararg = 1; /* main function is always vararg */ |
| 1609 init_exp(&v, VLOCAL, 0); /* create and... */ |
| 1610 newupvalue(fs, ls->envn, &v); /* ...set environment upvalue */ |
| 1611 luaX_next(ls); /* read first token */ |
| 1612 statlist(ls); /* parse main body */ |
| 1613 check(ls, TK_EOS); |
| 1614 close_func(ls); |
| 1615 } |
| 1616 |
| 1617 |
| 1618 Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, |
| 1619 Dyndata *dyd, const char *name, int firstchar) { |
| 1620 LexState lexstate; |
| 1621 FuncState funcstate; |
| 1622 Closure *cl = luaF_newLclosure(L, 1); /* create main closure */ |
| 1623 /* anchor closure (to avoid being collected) */ |
| 1624 setclLvalue(L, L->top, cl); |
| 1625 incr_top(L); |
| 1626 funcstate.f = cl->l.p = luaF_newproto(L); |
| 1627 funcstate.f->source = luaS_new(L, name); /* create and anchor TString */ |
| 1628 lexstate.buff = buff; |
| 1629 lexstate.dyd = dyd; |
| 1630 dyd->actvar.n = dyd->gt.n = dyd->label.n = 0; |
| 1631 luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar); |
| 1632 mainfunc(&lexstate, &funcstate); |
| 1633 lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs); |
| 1634 /* all scopes should be correctly finished */ |
| 1635 lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0); |
| 1636 return cl; /* it's on the stack too */ |
| 1637 } |
| 1638 |
OLD | NEW |