/src/middleware/lua/lparser.c
C | 1339 lines | 1072 code | 182 blank | 85 comment | 183 complexity | ee183362e7aa77276b08be18083d77dc MD5 | raw file
1/* 2** $Id: lparser.c,v 2.42.1.3 2007/12/28 15:32:23 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#define hasmultret(k) ((k) == VCALL || (k) == VVARARG) 31 32#define getlocvar(fs, i) ((fs)->f->locvars[(fs)->actvar[i]]) 33 34#define luaY_checklimit(fs,v,l,m) if ((v)>(l)) errorlimit(fs,l,m) 35 36 37/* 38** nodes for block list (list of active blocks) 39*/ 40typedef struct BlockCnt { 41 struct BlockCnt *previous; /* chain */ 42 int breaklist; /* list of jumps out of this loop */ 43 lu_byte nactvar; /* # active locals outside the breakable structure */ 44 lu_byte upval; /* true if some variable in the block is an upvalue */ 45 lu_byte isbreakable; /* true if `block' is a loop */ 46} BlockCnt; 47 48 49 50/* 51** prototypes for recursive non-terminal functions 52*/ 53static void chunk (LexState *ls); 54static void expr (LexState *ls, expdesc *v); 55 56 57static void anchor_token (LexState *ls) { 58 if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) { 59 TString *ts = ls->t.seminfo.ts; 60 luaX_newstring(ls, getstr(ts), ts->tsv.len); 61 } 62} 63 64 65static void error_expected (LexState *ls, int token) { 66 luaX_syntaxerror(ls, 67 luaO_pushfstring(ls->L, LUA_QS " expected", luaX_token2str(ls, token))); 68} 69 70 71static void errorlimit (FuncState *fs, int limit, const char *what) { 72 const char *msg = (fs->f->linedefined == 0) ? 73 luaO_pushfstring(fs->L, "main function has more than %d %s", limit, what) : 74 luaO_pushfstring(fs->L, "function at line %d has more than %d %s", 75 fs->f->linedefined, limit, what); 76 luaX_lexerror(fs->ls, msg, 0); 77} 78 79 80static int testnext (LexState *ls, int c) { 81 if (ls->t.token == c) { 82 luaX_next(ls); 83 return 1; 84 } 85 else return 0; 86} 87 88 89static void check (LexState *ls, int c) { 90 if (ls->t.token != c) 91 error_expected(ls, c); 92} 93 94static void checknext (LexState *ls, int c) { 95 check(ls, c); 96 luaX_next(ls); 97} 98 99 100#define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); } 101 102 103 104static void check_match (LexState *ls, int what, int who, int where) { 105 if (!testnext(ls, what)) { 106 if (where == ls->linenumber) 107 error_expected(ls, what); 108 else { 109 luaX_syntaxerror(ls, luaO_pushfstring(ls->L, 110 LUA_QS " expected (to close " LUA_QS " at line %d)", 111 luaX_token2str(ls, what), luaX_token2str(ls, who), where)); 112 } 113 } 114} 115 116 117static TString *str_checkname (LexState *ls) { 118 TString *ts; 119 check(ls, TK_NAME); 120 ts = ls->t.seminfo.ts; 121 luaX_next(ls); 122 return ts; 123} 124 125 126static void init_exp (expdesc *e, expkind k, int i) { 127 e->f = e->t = NO_JUMP; 128 e->k = k; 129 e->u.s.info = i; 130} 131 132 133static void codestring (LexState *ls, expdesc *e, TString *s) { 134 init_exp(e, VK, luaK_stringK(ls->fs, s)); 135} 136 137 138static void checkname(LexState *ls, expdesc *e) { 139 codestring(ls, e, str_checkname(ls)); 140} 141 142 143static int registerlocalvar (LexState *ls, TString *varname) { 144 FuncState *fs = ls->fs; 145 Proto *f = fs->f; 146 int oldsize = f->sizelocvars; 147 luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars, 148 LocVar, SHRT_MAX, "too many local variables"); 149 while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL; 150 f->locvars[fs->nlocvars].varname = varname; 151 luaC_objbarrier(ls->L, f, varname); 152 return fs->nlocvars++; 153} 154 155 156#define new_localvarliteral(ls,v,n) \ 157 new_localvar(ls, luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char))-1), n) 158 159 160static void new_localvar (LexState *ls, TString *name, int n) { 161 FuncState *fs = ls->fs; 162 luaY_checklimit(fs, fs->nactvar+n+1, LUAI_MAXVARS, "local variables"); 163 fs->actvar[fs->nactvar+n] = cast(unsigned short, registerlocalvar(ls, name)); 164} 165 166 167static void adjustlocalvars (LexState *ls, int nvars) { 168 FuncState *fs = ls->fs; 169 fs->nactvar = cast_byte(fs->nactvar + nvars); 170 for (; nvars; nvars--) { 171 getlocvar(fs, fs->nactvar - nvars).startpc = fs->pc; 172 } 173} 174 175 176static void removevars (LexState *ls, int tolevel) { 177 FuncState *fs = ls->fs; 178 while (fs->nactvar > tolevel) 179 getlocvar(fs, --fs->nactvar).endpc = fs->pc; 180} 181 182 183static int indexupvalue (FuncState *fs, TString *name, expdesc *v) { 184 int i; 185 Proto *f = fs->f; 186 int oldsize = f->sizeupvalues; 187 for (i=0; i<f->nups; i++) { 188 if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->u.s.info) { 189 lua_assert(f->upvalues[i] == name); 190 return i; 191 } 192 } 193 /* new one */ 194 luaY_checklimit(fs, f->nups + 1, LUAI_MAXUPVALUES, "upvalues"); 195 luaM_growvector(fs->L, f->upvalues, f->nups, f->sizeupvalues, 196 TString *, MAX_INT, ""); 197 while (oldsize < f->sizeupvalues) f->upvalues[oldsize++] = NULL; 198 f->upvalues[f->nups] = name; 199 luaC_objbarrier(fs->L, f, name); 200 lua_assert(v->k == VLOCAL || v->k == VUPVAL); 201 fs->upvalues[f->nups].k = cast_byte(v->k); 202 fs->upvalues[f->nups].info = cast_byte(v->u.s.info); 203 return f->nups++; 204} 205 206 207static int searchvar (FuncState *fs, TString *n) { 208 int i; 209 for (i=fs->nactvar-1; i >= 0; i--) { 210 if (n == getlocvar(fs, i).varname) 211 return i; 212 } 213 return -1; /* not found */ 214} 215 216 217static void markupval (FuncState *fs, int level) { 218 BlockCnt *bl = fs->bl; 219 while (bl && bl->nactvar > level) bl = bl->previous; 220 if (bl) bl->upval = 1; 221} 222 223 224static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { 225 if (fs == NULL) { /* no more levels? */ 226 init_exp(var, VGLOBAL, NO_REG); /* default is global variable */ 227 return VGLOBAL; 228 } 229 else { 230 int v = searchvar(fs, n); /* look up at current level */ 231 if (v >= 0) { 232 init_exp(var, VLOCAL, v); 233 if (!base) 234 markupval(fs, v); /* local will be used as an upval */ 235 return VLOCAL; 236 } 237 else { /* not found at current level; try upper one */ 238 if (singlevaraux(fs->prev, n, var, 0) == VGLOBAL) 239 return VGLOBAL; 240 var->u.s.info = indexupvalue(fs, n, var); /* else was LOCAL or UPVAL */ 241 var->k = VUPVAL; /* upvalue in this level */ 242 return VUPVAL; 243 } 244 } 245} 246 247 248static void singlevar (LexState *ls, expdesc *var) { 249 TString *varname = str_checkname(ls); 250 FuncState *fs = ls->fs; 251 if (singlevaraux(fs, varname, var, 1) == VGLOBAL) 252 var->u.s.info = luaK_stringK(fs, varname); /* info points to global name */ 253} 254 255 256static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) { 257 FuncState *fs = ls->fs; 258 int extra = nvars - nexps; 259 if (hasmultret(e->k)) { 260 extra++; /* includes call itself */ 261 if (extra < 0) extra = 0; 262 luaK_setreturns(fs, e, extra); /* last exp. provides the difference */ 263 if (extra > 1) luaK_reserveregs(fs, extra-1); 264 } 265 else { 266 if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */ 267 if (extra > 0) { 268 int reg = fs->freereg; 269 luaK_reserveregs(fs, extra); 270 luaK_nil(fs, reg, extra); 271 } 272 } 273} 274 275 276static void enterlevel (LexState *ls) { 277 if (++ls->L->nCcalls > LUAI_MAXCCALLS) 278 luaX_lexerror(ls, "chunk has too many syntax levels", 0); 279} 280 281 282#define leavelevel(ls) ((ls)->L->nCcalls--) 283 284 285static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isbreakable) { 286 bl->breaklist = NO_JUMP; 287 bl->isbreakable = isbreakable; 288 bl->nactvar = fs->nactvar; 289 bl->upval = 0; 290 bl->previous = fs->bl; 291 fs->bl = bl; 292 lua_assert(fs->freereg == fs->nactvar); 293} 294 295 296static void leaveblock (FuncState *fs) { 297 BlockCnt *bl = fs->bl; 298 fs->bl = bl->previous; 299 removevars(fs->ls, bl->nactvar); 300 if (bl->upval) 301 luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0); 302 /* a block either controls scope or breaks (never both) */ 303 lua_assert(!bl->isbreakable || !bl->upval); 304 lua_assert(bl->nactvar == fs->nactvar); 305 fs->freereg = fs->nactvar; /* free registers */ 306 luaK_patchtohere(fs, bl->breaklist); 307} 308 309 310static void pushclosure (LexState *ls, FuncState *func, expdesc *v) { 311 FuncState *fs = ls->fs; 312 Proto *f = fs->f; 313 int oldsize = f->sizep; 314 int i; 315 luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *, 316 MAXARG_Bx, "constant table overflow"); 317 while (oldsize < f->sizep) f->p[oldsize++] = NULL; 318 f->p[fs->np++] = func->f; 319 luaC_objbarrier(ls->L, f, func->f); 320 init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np-1)); 321 for (i=0; i<func->f->nups; i++) { 322 OpCode o = (func->upvalues[i].k == VLOCAL) ? OP_MOVE : OP_GETUPVAL; 323 luaK_codeABC(fs, o, 0, func->upvalues[i].info, 0); 324 } 325} 326 327 328static void open_func (LexState *ls, FuncState *fs) { 329 lua_State *L = ls->L; 330 Proto *f = luaF_newproto(L); 331 fs->f = f; 332 fs->prev = ls->fs; /* linked list of funcstates */ 333 fs->ls = ls; 334 fs->L = L; 335 ls->fs = fs; 336 fs->pc = 0; 337 fs->lasttarget = -1; 338 fs->jpc = NO_JUMP; 339 fs->freereg = 0; 340 fs->nk = 0; 341 fs->np = 0; 342 fs->nlocvars = 0; 343 fs->nactvar = 0; 344 fs->bl = NULL; 345 f->source = ls->source; 346 f->maxstacksize = 2; /* registers 0/1 are always valid */ 347 fs->h = luaH_new(L, 0, 0); 348 /* anchor table of constants and prototype (to avoid being collected) */ 349 sethvalue2s(L, L->top, fs->h); 350 incr_top(L); 351 setptvalue2s(L, L->top, f); 352 incr_top(L); 353} 354 355 356static void close_func (LexState *ls) { 357 lua_State *L = ls->L; 358 FuncState *fs = ls->fs; 359 Proto *f = fs->f; 360 removevars(ls, 0); 361 luaK_ret(fs, 0, 0); /* final return */ 362 luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction); 363 f->sizecode = fs->pc; 364 luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int); 365 f->sizelineinfo = fs->pc; 366 luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue); 367 f->sizek = fs->nk; 368 luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *); 369 f->sizep = fs->np; 370 luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar); 371 f->sizelocvars = fs->nlocvars; 372 luaM_reallocvector(L, f->upvalues, f->sizeupvalues, f->nups, TString *); 373 f->sizeupvalues = f->nups; 374 lua_assert(luaG_checkcode(f)); 375 lua_assert(fs->bl == NULL); 376 ls->fs = fs->prev; 377 L->top -= 2; /* remove table and prototype from the stack */ 378 /* last token read was anchored in defunct function; must reanchor it */ 379 if (fs) anchor_token(ls); 380} 381 382 383Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) { 384 struct LexState lexstate; 385 struct FuncState funcstate; 386 lexstate.buff = buff; 387 luaX_setinput(L, &lexstate, z, luaS_new(L, name)); 388 open_func(&lexstate, &funcstate); 389 funcstate.f->is_vararg = VARARG_ISVARARG; /* main func. is always vararg */ 390 luaX_next(&lexstate); /* read first token */ 391 chunk(&lexstate); 392 check(&lexstate, TK_EOS); 393 close_func(&lexstate); 394 lua_assert(funcstate.prev == NULL); 395 lua_assert(funcstate.f->nups == 0); 396 lua_assert(lexstate.fs == NULL); 397 return funcstate.f; 398} 399 400 401 402/*============================================================*/ 403/* GRAMMAR RULES */ 404/*============================================================*/ 405 406 407static void field (LexState *ls, expdesc *v) { 408 /* field -> ['.' | ':'] NAME */ 409 FuncState *fs = ls->fs; 410 expdesc key; 411 luaK_exp2anyreg(fs, v); 412 luaX_next(ls); /* skip the dot or colon */ 413 checkname(ls, &key); 414 luaK_indexed(fs, v, &key); 415} 416 417 418static void yindex (LexState *ls, expdesc *v) { 419 /* index -> '[' expr ']' */ 420 luaX_next(ls); /* skip the '[' */ 421 expr(ls, v); 422 luaK_exp2val(ls->fs, v); 423 checknext(ls, ']'); 424} 425 426 427/* 428** {====================================================================== 429** Rules for Constructors 430** ======================================================================= 431*/ 432 433 434struct ConsControl { 435 expdesc v; /* last list item read */ 436 expdesc *t; /* table descriptor */ 437 int nh; /* total number of `record' elements */ 438 int na; /* total number of array elements */ 439 int tostore; /* number of array elements pending to be stored */ 440}; 441 442 443static void recfield (LexState *ls, struct ConsControl *cc) { 444 /* recfield -> (NAME | `['exp1`]') = exp1 */ 445 FuncState *fs = ls->fs; 446 int reg = ls->fs->freereg; 447 expdesc key, val; 448 int rkkey; 449 if (ls->t.token == TK_NAME) { 450 luaY_checklimit(fs, cc->nh, MAX_INT, "items in a constructor"); 451 checkname(ls, &key); 452 } 453 else /* ls->t.token == '[' */ 454 yindex(ls, &key); 455 cc->nh++; 456 checknext(ls, '='); 457 rkkey = luaK_exp2RK(fs, &key); 458 expr(ls, &val); 459 luaK_codeABC(fs, OP_SETTABLE, cc->t->u.s.info, rkkey, luaK_exp2RK(fs, &val)); 460 fs->freereg = reg; /* free registers */ 461} 462 463 464static void closelistfield (FuncState *fs, struct ConsControl *cc) { 465 if (cc->v.k == VVOID) return; /* there is no list item */ 466 luaK_exp2nextreg(fs, &cc->v); 467 cc->v.k = VVOID; 468 if (cc->tostore == LFIELDS_PER_FLUSH) { 469 luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore); /* flush */ 470 cc->tostore = 0; /* no more items pending */ 471 } 472} 473 474 475static void lastlistfield (FuncState *fs, struct ConsControl *cc) { 476 if (cc->tostore == 0) return; 477 if (hasmultret(cc->v.k)) { 478 luaK_setmultret(fs, &cc->v); 479 luaK_setlist(fs, cc->t->u.s.info, cc->na, LUA_MULTRET); 480 cc->na--; /* do not count last expression (unknown number of elements) */ 481 } 482 else { 483 if (cc->v.k != VVOID) 484 luaK_exp2nextreg(fs, &cc->v); 485 luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore); 486 } 487} 488 489 490static void listfield (LexState *ls, struct ConsControl *cc) { 491 expr(ls, &cc->v); 492 luaY_checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor"); 493 cc->na++; 494 cc->tostore++; 495} 496 497 498static void constructor (LexState *ls, expdesc *t) { 499 /* constructor -> ?? */ 500 FuncState *fs = ls->fs; 501 int line = ls->linenumber; 502 int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0); 503 struct ConsControl cc; 504 cc.na = cc.nh = cc.tostore = 0; 505 cc.t = t; 506 init_exp(t, VRELOCABLE, pc); 507 init_exp(&cc.v, VVOID, 0); /* no value (yet) */ 508 luaK_exp2nextreg(ls->fs, t); /* fix it at stack top (for gc) */ 509 checknext(ls, '{'); 510 do { 511 lua_assert(cc.v.k == VVOID || cc.tostore > 0); 512 if (ls->t.token == '}') break; 513 closelistfield(fs, &cc); 514 switch(ls->t.token) { 515 case TK_NAME: { /* may be listfields or recfields */ 516 luaX_lookahead(ls); 517 if (ls->lookahead.token != '=') /* expression? */ 518 listfield(ls, &cc); 519 else 520 recfield(ls, &cc); 521 break; 522 } 523 case '[': { /* constructor_item -> recfield */ 524 recfield(ls, &cc); 525 break; 526 } 527 default: { /* constructor_part -> listfield */ 528 listfield(ls, &cc); 529 break; 530 } 531 } 532 } while (testnext(ls, ',') || testnext(ls, ';')); 533 check_match(ls, '}', '{', line); 534 lastlistfield(fs, &cc); 535 SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */ 536 SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */ 537} 538 539/* }====================================================================== */ 540 541 542 543static void parlist (LexState *ls) { 544 /* parlist -> [ param { `,' param } ] */ 545 FuncState *fs = ls->fs; 546 Proto *f = fs->f; 547 int nparams = 0; 548 f->is_vararg = 0; 549 if (ls->t.token != ')') { /* is `parlist' not empty? */ 550 do { 551 switch (ls->t.token) { 552 case TK_NAME: { /* param -> NAME */ 553 new_localvar(ls, str_checkname(ls), nparams++); 554 break; 555 } 556 case TK_DOTS: { /* param -> `...' */ 557 luaX_next(ls); 558#if defined(LUA_COMPAT_VARARG) 559 /* use `arg' as default name */ 560 new_localvarliteral(ls, "arg", nparams++); 561 f->is_vararg = VARARG_HASARG | VARARG_NEEDSARG; 562#endif 563 f->is_vararg |= VARARG_ISVARARG; 564 break; 565 } 566 default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected"); 567 } 568 } while (!f->is_vararg && testnext(ls, ',')); 569 } 570 adjustlocalvars(ls, nparams); 571 f->numparams = cast_byte(fs->nactvar - (f->is_vararg & VARARG_HASARG)); 572 luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */ 573} 574 575 576static void body (LexState *ls, expdesc *e, int needself, int line) { 577 /* body -> `(' parlist `)' chunk END */ 578 FuncState new_fs; 579 open_func(ls, &new_fs); 580 new_fs.f->linedefined = line; 581 checknext(ls, '('); 582 if (needself) { 583 new_localvarliteral(ls, "self", 0); 584 adjustlocalvars(ls, 1); 585 } 586 parlist(ls); 587 checknext(ls, ')'); 588 chunk(ls); 589 new_fs.f->lastlinedefined = ls->linenumber; 590 check_match(ls, TK_END, TK_FUNCTION, line); 591 close_func(ls); 592 pushclosure(ls, &new_fs, e); 593} 594 595 596static int explist1 (LexState *ls, expdesc *v) { 597 /* explist1 -> expr { `,' expr } */ 598 int n = 1; /* at least one expression */ 599 expr(ls, v); 600 while (testnext(ls, ',')) { 601 luaK_exp2nextreg(ls->fs, v); 602 expr(ls, v); 603 n++; 604 } 605 return n; 606} 607 608 609static void funcargs (LexState *ls, expdesc *f) { 610 FuncState *fs = ls->fs; 611 expdesc args; 612 int base, nparams; 613 int line = ls->linenumber; 614 switch (ls->t.token) { 615 case '(': { /* funcargs -> `(' [ explist1 ] `)' */ 616 if (line != ls->lastline) 617 luaX_syntaxerror(ls,"ambiguous syntax (function call x new statement)"); 618 luaX_next(ls); 619 if (ls->t.token == ')') /* arg list is empty? */ 620 args.k = VVOID; 621 else { 622 explist1(ls, &args); 623 luaK_setmultret(fs, &args); 624 } 625 check_match(ls, ')', '(', line); 626 break; 627 } 628 case '{': { /* funcargs -> constructor */ 629 constructor(ls, &args); 630 break; 631 } 632 case TK_STRING: { /* funcargs -> STRING */ 633 codestring(ls, &args, ls->t.seminfo.ts); 634 luaX_next(ls); /* must use `seminfo' before `next' */ 635 break; 636 } 637 default: { 638 luaX_syntaxerror(ls, "function arguments expected"); 639 return; 640 } 641 } 642 lua_assert(f->k == VNONRELOC); 643 base = f->u.s.info; /* base register for call */ 644 if (hasmultret(args.k)) 645 nparams = LUA_MULTRET; /* open call */ 646 else { 647 if (args.k != VVOID) 648 luaK_exp2nextreg(fs, &args); /* close last argument */ 649 nparams = fs->freereg - (base+1); 650 } 651 init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2)); 652 luaK_fixline(fs, line); 653 fs->freereg = base+1; /* call remove function and arguments and leaves 654 (unless changed) one result */ 655} 656 657 658 659 660/* 661** {====================================================================== 662** Expression parsing 663** ======================================================================= 664*/ 665 666 667static void prefixexp (LexState *ls, expdesc *v) { 668 /* prefixexp -> NAME | '(' expr ')' */ 669 switch (ls->t.token) { 670 case '(': { 671 int line = ls->linenumber; 672 luaX_next(ls); 673 expr(ls, v); 674 check_match(ls, ')', '(', line); 675 luaK_dischargevars(ls->fs, v); 676 return; 677 } 678 case TK_NAME: { 679 singlevar(ls, v); 680 return; 681 } 682 default: { 683 luaX_syntaxerror(ls, "unexpected symbol"); 684 return; 685 } 686 } 687} 688 689 690static void primaryexp (LexState *ls, expdesc *v) { 691 /* primaryexp -> 692 prefixexp { `.' NAME | `[' exp `]' | `:' NAME funcargs | funcargs } */ 693 FuncState *fs = ls->fs; 694 prefixexp(ls, v); 695 for (;;) { 696 switch (ls->t.token) { 697 case '.': { /* field */ 698 field(ls, v); 699 break; 700 } 701 case '[': { /* `[' exp1 `]' */ 702 expdesc key; 703 luaK_exp2anyreg(fs, v); 704 yindex(ls, &key); 705 luaK_indexed(fs, v, &key); 706 break; 707 } 708 case ':': { /* `:' NAME funcargs */ 709 expdesc key; 710 luaX_next(ls); 711 checkname(ls, &key); 712 luaK_self(fs, v, &key); 713 funcargs(ls, v); 714 break; 715 } 716 case '(': case TK_STRING: case '{': { /* funcargs */ 717 luaK_exp2nextreg(fs, v); 718 funcargs(ls, v); 719 break; 720 } 721 default: return; 722 } 723 } 724} 725 726 727static void simpleexp (LexState *ls, expdesc *v) { 728 /* simpleexp -> NUMBER | STRING | NIL | true | false | ... | 729 constructor | FUNCTION body | primaryexp */ 730 switch (ls->t.token) { 731 case TK_NUMBER: { 732 init_exp(v, VKNUM, 0); 733 v->u.nval = ls->t.seminfo.r; 734 break; 735 } 736 case TK_STRING: { 737 codestring(ls, v, ls->t.seminfo.ts); 738 break; 739 } 740 case TK_NIL: { 741 init_exp(v, VNIL, 0); 742 break; 743 } 744 case TK_TRUE: { 745 init_exp(v, VTRUE, 0); 746 break; 747 } 748 case TK_FALSE: { 749 init_exp(v, VFALSE, 0); 750 break; 751 } 752 case TK_DOTS: { /* vararg */ 753 FuncState *fs = ls->fs; 754 check_condition(ls, fs->f->is_vararg, 755 "cannot use " LUA_QL("...") " outside a vararg function"); 756 fs->f->is_vararg &= ~VARARG_NEEDSARG; /* don't need 'arg' */ 757 init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0)); 758 break; 759 } 760 case '{': { /* constructor */ 761 constructor(ls, v); 762 return; 763 } 764 case TK_FUNCTION: { 765 luaX_next(ls); 766 body(ls, v, 0, ls->linenumber); 767 return; 768 } 769 default: { 770 primaryexp(ls, v); 771 return; 772 } 773 } 774 luaX_next(ls); 775} 776 777 778static UnOpr getunopr (int op) { 779 switch (op) { 780 case TK_NOT: return OPR_NOT; 781 case '-': return OPR_MINUS; 782 case '#': return OPR_LEN; 783 default: return OPR_NOUNOPR; 784 } 785} 786 787 788static BinOpr getbinopr (int op) { 789 switch (op) { 790 case '+': return OPR_ADD; 791 case '-': return OPR_SUB; 792 case '*': return OPR_MUL; 793 case '/': return OPR_DIV; 794 case '%': return OPR_MOD; 795 case '^': return OPR_POW; 796 case TK_CONCAT: return OPR_CONCAT; 797 case TK_NE: return OPR_NE; 798 case TK_EQ: return OPR_EQ; 799 case '<': return OPR_LT; 800 case TK_LE: return OPR_LE; 801 case '>': return OPR_GT; 802 case TK_GE: return OPR_GE; 803 case TK_AND: return OPR_AND; 804 case TK_OR: return OPR_OR; 805 default: return OPR_NOBINOPR; 806 } 807} 808 809 810static const struct { 811 lu_byte left; /* left priority for each binary operator */ 812 lu_byte right; /* right priority */ 813} priority[] = { /* ORDER OPR */ 814 {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `/' `%' */ 815 {10, 9}, {5, 4}, /* power and concat (right associative) */ 816 {3, 3}, {3, 3}, /* equality and inequality */ 817 {3, 3}, {3, 3}, {3, 3}, {3, 3}, /* order */ 818 {2, 2}, {1, 1} /* logical (and/or) */ 819}; 820 821#define UNARY_PRIORITY 8 /* priority for unary operators */ 822 823 824/* 825** subexpr -> (simpleexp | unop subexpr) { binop subexpr } 826** where `binop' is any binary operator with a priority higher than `limit' 827*/ 828static BinOpr subexpr (LexState *ls, expdesc *v, unsigned int limit) { 829 BinOpr op; 830 UnOpr uop; 831 enterlevel(ls); 832 uop = getunopr(ls->t.token); 833 if (uop != OPR_NOUNOPR) { 834 luaX_next(ls); 835 subexpr(ls, v, UNARY_PRIORITY); 836 luaK_prefix(ls->fs, uop, v); 837 } 838 else simpleexp(ls, v); 839 /* expand while operators have priorities higher than `limit' */ 840 op = getbinopr(ls->t.token); 841 while (op != OPR_NOBINOPR && priority[op].left > limit) { 842 expdesc v2; 843 BinOpr nextop; 844 luaX_next(ls); 845 luaK_infix(ls->fs, op, v); 846 /* read sub-expression with higher priority */ 847 nextop = subexpr(ls, &v2, priority[op].right); 848 luaK_posfix(ls->fs, op, v, &v2); 849 op = nextop; 850 } 851 leavelevel(ls); 852 return op; /* return first untreated operator */ 853} 854 855 856static void expr (LexState *ls, expdesc *v) { 857 subexpr(ls, v, 0); 858} 859 860/* }==================================================================== */ 861 862 863 864/* 865** {====================================================================== 866** Rules for Statements 867** ======================================================================= 868*/ 869 870 871static int block_follow (int token) { 872 switch (token) { 873 case TK_ELSE: case TK_ELSEIF: case TK_END: 874 case TK_UNTIL: case TK_EOS: 875 return 1; 876 default: return 0; 877 } 878} 879 880 881static void block (LexState *ls) { 882 /* block -> chunk */ 883 FuncState *fs = ls->fs; 884 BlockCnt bl; 885 enterblock(fs, &bl, 0); 886 chunk(ls); 887 lua_assert(bl.breaklist == NO_JUMP); 888 leaveblock(fs); 889} 890 891 892/* 893** structure to chain all variables in the left-hand side of an 894** assignment 895*/ 896struct LHS_assign { 897 struct LHS_assign *prev; 898 expdesc v; /* variable (global, local, upvalue, or indexed) */ 899}; 900 901 902/* 903** check whether, in an assignment to a local variable, the local variable 904** is needed in a previous assignment (to a table). If so, save original 905** local value in a safe place and use this safe copy in the previous 906** assignment. 907*/ 908static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) { 909 FuncState *fs = ls->fs; 910 int extra = fs->freereg; /* eventual position to save local variable */ 911 int conflict = 0; 912 for (; lh; lh = lh->prev) { 913 if (lh->v.k == VINDEXED) { 914 if (lh->v.u.s.info == v->u.s.info) { /* conflict? */ 915 conflict = 1; 916 lh->v.u.s.info = extra; /* previous assignment will use safe copy */ 917 } 918 if (lh->v.u.s.aux == v->u.s.info) { /* conflict? */ 919 conflict = 1; 920 lh->v.u.s.aux = extra; /* previous assignment will use safe copy */ 921 } 922 } 923 } 924 if (conflict) { 925 luaK_codeABC(fs, OP_MOVE, fs->freereg, v->u.s.info, 0); /* make copy */ 926 luaK_reserveregs(fs, 1); 927 } 928} 929 930 931static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) { 932 expdesc e; 933 check_condition(ls, VLOCAL <= lh->v.k && lh->v.k <= VINDEXED, 934 "syntax error"); 935 if (testnext(ls, ',')) { /* assignment -> `,' primaryexp assignment */ 936 struct LHS_assign nv; 937 nv.prev = lh; 938 primaryexp(ls, &nv.v); 939 if (nv.v.k == VLOCAL) 940 check_conflict(ls, lh, &nv.v); 941 luaY_checklimit(ls->fs, nvars, LUAI_MAXCCALLS - ls->L->nCcalls, 942 "variables in assignment"); 943 assignment(ls, &nv, nvars+1); 944 } 945 else { /* assignment -> `=' explist1 */ 946 int nexps; 947 checknext(ls, '='); 948 nexps = explist1(ls, &e); 949 if (nexps != nvars) { 950 adjust_assign(ls, nvars, nexps, &e); 951 if (nexps > nvars) 952 ls->fs->freereg -= nexps - nvars; /* remove extra values */ 953 } 954 else { 955 luaK_setoneret(ls->fs, &e); /* close last expression */ 956 luaK_storevar(ls->fs, &lh->v, &e); 957 return; /* avoid default */ 958 } 959 } 960 init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */ 961 luaK_storevar(ls->fs, &lh->v, &e); 962} 963 964 965static int cond (LexState *ls) { 966 /* cond -> exp */ 967 expdesc v; 968 expr(ls, &v); /* read condition */ 969 if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */ 970 luaK_goiftrue(ls->fs, &v); 971 return v.f; 972} 973 974 975static void breakstat (LexState *ls) { 976 FuncState *fs = ls->fs; 977 BlockCnt *bl = fs->bl; 978 int upval = 0; 979 while (bl && !bl->isbreakable) { 980 upval |= bl->upval; 981 bl = bl->previous; 982 } 983 if (!bl) 984 luaX_syntaxerror(ls, "no loop to break"); 985 if (upval) 986 luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0); 987 luaK_concat(fs, &bl->breaklist, luaK_jump(fs)); 988} 989 990 991static void whilestat (LexState *ls, int line) { 992 /* whilestat -> WHILE cond DO block END */ 993 FuncState *fs = ls->fs; 994 int whileinit; 995 int condexit; 996 BlockCnt bl; 997 luaX_next(ls); /* skip WHILE */ 998 whileinit = luaK_getlabel(fs); 999 condexit = cond(ls); 1000 enterblock(fs, &bl, 1); 1001 checknext(ls, TK_DO); 1002 block(ls); 1003 luaK_patchlist(fs, luaK_jump(fs), whileinit); 1004 check_match(ls, TK_END, TK_WHILE, line); 1005 leaveblock(fs); 1006 luaK_patchtohere(fs, condexit); /* false conditions finish the loop */ 1007} 1008 1009 1010static void repeatstat (LexState *ls, int line) { 1011 /* repeatstat -> REPEAT block UNTIL cond */ 1012 int condexit; 1013 FuncState *fs = ls->fs; 1014 int repeat_init = luaK_getlabel(fs); 1015 BlockCnt bl1, bl2; 1016 enterblock(fs, &bl1, 1); /* loop block */ 1017 enterblock(fs, &bl2, 0); /* scope block */ 1018 luaX_next(ls); /* skip REPEAT */ 1019 chunk(ls); 1020 check_match(ls, TK_UNTIL, TK_REPEAT, line); 1021 condexit = cond(ls); /* read condition (inside scope block) */ 1022 if (!bl2.upval) { /* no upvalues? */ 1023 leaveblock(fs); /* finish scope */ 1024 luaK_patchlist(ls->fs, condexit, repeat_init); /* close the loop */ 1025 } 1026 else { /* complete semantics when there are upvalues */ 1027 breakstat(ls); /* if condition then break */ 1028 luaK_patchtohere(ls->fs, condexit); /* else... */ 1029 leaveblock(fs); /* finish scope... */ 1030 luaK_patchlist(ls->fs, luaK_jump(fs), repeat_init); /* and repeat */ 1031 } 1032 leaveblock(fs); /* finish loop */ 1033} 1034 1035 1036static int exp1 (LexState *ls) { 1037 expdesc e; 1038 int k; 1039 expr(ls, &e); 1040 k = e.k; 1041 luaK_exp2nextreg(ls->fs, &e); 1042 return k; 1043} 1044 1045 1046static void forbody (LexState *ls, int base, int line, int nvars, int isnum) { 1047 /* forbody -> DO block */ 1048 BlockCnt bl; 1049 FuncState *fs = ls->fs; 1050 int prep, endfor; 1051 adjustlocalvars(ls, 3); /* control variables */ 1052 checknext(ls, TK_DO); 1053 prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs); 1054 enterblock(fs, &bl, 0); /* scope for declared variables */ 1055 adjustlocalvars(ls, nvars); 1056 luaK_reserveregs(fs, nvars); 1057 block(ls); 1058 leaveblock(fs); /* end of scope for declared variables */ 1059 luaK_patchtohere(fs, prep); 1060 endfor = (isnum) ? luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP) : 1061 luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars); 1062 luaK_fixline(fs, line); /* pretend that `OP_FOR' starts the loop */ 1063 luaK_patchlist(fs, (isnum ? endfor : luaK_jump(fs)), prep + 1); 1064} 1065 1066 1067static void fornum (LexState *ls, TString *varname, int line) { 1068 /* fornum -> NAME = exp1,exp1[,exp1] forbody */ 1069 FuncState *fs = ls->fs; 1070 int base = fs->freereg; 1071 new_localvarliteral(ls, "(for index)", 0); 1072 new_localvarliteral(ls, "(for limit)", 1); 1073 new_localvarliteral(ls, "(for step)", 2); 1074 new_localvar(ls, varname, 3); 1075 checknext(ls, '='); 1076 exp1(ls); /* initial value */ 1077 checknext(ls, ','); 1078 exp1(ls); /* limit */ 1079 if (testnext(ls, ',')) 1080 exp1(ls); /* optional step */ 1081 else { /* default step = 1 */ 1082 luaK_codeABx(fs, OP_LOADK, fs->freereg, luaK_numberK(fs, 1)); 1083 luaK_reserveregs(fs, 1); 1084 } 1085 forbody(ls, base, line, 1, 1); 1086} 1087 1088 1089static void forlist (LexState *ls, TString *indexname) { 1090 /* forlist -> NAME {,NAME} IN explist1 forbody */ 1091 FuncState *fs = ls->fs; 1092 expdesc e; 1093 int nvars = 0; 1094 int line; 1095 int base = fs->freereg; 1096 /* create control variables */ 1097 new_localvarliteral(ls, "(for generator)", nvars++); 1098 new_localvarliteral(ls, "(for state)", nvars++); 1099 new_localvarliteral(ls, "(for control)", nvars++); 1100 /* create declared variables */ 1101 new_localvar(ls, indexname, nvars++); 1102 while (testnext(ls, ',')) 1103 new_localvar(ls, str_checkname(ls), nvars++); 1104 checknext(ls, TK_IN); 1105 line = ls->linenumber; 1106 adjust_assign(ls, 3, explist1(ls, &e), &e); 1107 luaK_checkstack(fs, 3); /* extra space to call generator */ 1108 forbody(ls, base, line, nvars - 3, 0); 1109} 1110 1111 1112static void forstat (LexState *ls, int line) { 1113 /* forstat -> FOR (fornum | forlist) END */ 1114 FuncState *fs = ls->fs; 1115 TString *varname; 1116 BlockCnt bl; 1117 enterblock(fs, &bl, 1); /* scope for loop and control variables */ 1118 luaX_next(ls); /* skip `for' */ 1119 varname = str_checkname(ls); /* first variable name */ 1120 switch (ls->t.token) { 1121 case '=': fornum(ls, varname, line); break; 1122 case ',': case TK_IN: forlist(ls, varname); break; 1123 default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected"); 1124 } 1125 check_match(ls, TK_END, TK_FOR, line); 1126 leaveblock(fs); /* loop scope (`break' jumps to this point) */ 1127} 1128 1129 1130static int test_then_block (LexState *ls) { 1131 /* test_then_block -> [IF | ELSEIF] cond THEN block */ 1132 int condexit; 1133 luaX_next(ls); /* skip IF or ELSEIF */ 1134 condexit = cond(ls); 1135 checknext(ls, TK_THEN); 1136 block(ls); /* `then' part */ 1137 return condexit; 1138} 1139 1140 1141static void ifstat (LexState *ls, int line) { 1142 /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */ 1143 FuncState *fs = ls->fs; 1144 int flist; 1145 int escapelist = NO_JUMP; 1146 flist = test_then_block(ls); /* IF cond THEN block */ 1147 while (ls->t.token == TK_ELSEIF) { 1148 luaK_concat(fs, &escapelist, luaK_jump(fs)); 1149 luaK_patchtohere(fs, flist); 1150 flist = test_then_block(ls); /* ELSEIF cond THEN block */ 1151 } 1152 if (ls->t.token == TK_ELSE) { 1153 luaK_concat(fs, &escapelist, luaK_jump(fs)); 1154 luaK_patchtohere(fs, flist); 1155 luaX_next(ls); /* skip ELSE (after patch, for correct line info) */ 1156 block(ls); /* `else' part */ 1157 } 1158 else 1159 luaK_concat(fs, &escapelist, flist); 1160 luaK_patchtohere(fs, escapelist); 1161 check_match(ls, TK_END, TK_IF, line); 1162} 1163 1164 1165static void localfunc (LexState *ls) { 1166 expdesc v, b; 1167 FuncState *fs = ls->fs; 1168 new_localvar(ls, str_checkname(ls), 0); 1169 init_exp(&v, VLOCAL, fs->freereg); 1170 luaK_reserveregs(fs, 1); 1171 adjustlocalvars(ls, 1); 1172 body(ls, &b, 0, ls->linenumber); 1173 luaK_storevar(fs, &v, &b); 1174 /* debug information will only see the variable after this point! */ 1175 getlocvar(fs, fs->nactvar - 1).startpc = fs->pc; 1176} 1177 1178 1179static void localstat (LexState *ls) { 1180 /* stat -> LOCAL NAME {`,' NAME} [`=' explist1] */ 1181 int nvars = 0; 1182 int nexps; 1183 expdesc e; 1184 do { 1185 new_localvar(ls, str_checkname(ls), nvars++); 1186 } while (testnext(ls, ',')); 1187 if (testnext(ls, '=')) 1188 nexps = explist1(ls, &e); 1189 else { 1190 e.k = VVOID; 1191 nexps = 0; 1192 } 1193 adjust_assign(ls, nvars, nexps, &e); 1194 adjustlocalvars(ls, nvars); 1195} 1196 1197 1198static int funcname (LexState *ls, expdesc *v) { 1199 /* funcname -> NAME {field} [`:' NAME] */ 1200 int needself = 0; 1201 singlevar(ls, v); 1202 while (ls->t.token == '.') 1203 field(ls, v); 1204 if (ls->t.token == ':') { 1205 needself = 1; 1206 field(ls, v); 1207 } 1208 return needself; 1209} 1210 1211 1212static void funcstat (LexState *ls, int line) { 1213 /* funcstat -> FUNCTION funcname body */ 1214 int needself; 1215 expdesc v, b; 1216 luaX_next(ls); /* skip FUNCTION */ 1217 needself = funcname(ls, &v); 1218 body(ls, &b, needself, line); 1219 luaK_storevar(ls->fs, &v, &b); 1220 luaK_fixline(ls->fs, line); /* definition `happens' in the first line */ 1221} 1222 1223 1224static void exprstat (LexState *ls) { 1225 /* stat -> func | assignment */ 1226 FuncState *fs = ls->fs; 1227 struct LHS_assign v; 1228 primaryexp(ls, &v.v); 1229 if (v.v.k == VCALL) /* stat -> func */ 1230 SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */ 1231 else { /* stat -> assignment */ 1232 v.prev = NULL; 1233 assignment(ls, &v, 1); 1234 } 1235} 1236 1237 1238static void retstat (LexState *ls) { 1239 /* stat -> RETURN explist */ 1240 FuncState *fs = ls->fs; 1241 expdesc e; 1242 int first, nret; /* registers with returned values */ 1243 luaX_next(ls); /* skip RETURN */ 1244 if (block_follow(ls->t.token) || ls->t.token == ';') 1245 first = nret = 0; /* return no values */ 1246 else { 1247 nret = explist1(ls, &e); /* optional return values */ 1248 if (hasmultret(e.k)) { 1249 luaK_setmultret(fs, &e); 1250 if (e.k == VCALL && nret == 1) { /* tail call? */ 1251 SET_OPCODE(getcode(fs,&e), OP_TAILCALL); 1252 lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar); 1253 } 1254 first = fs->nactvar; 1255 nret = LUA_MULTRET; /* return all values */ 1256 } 1257 else { 1258 if (nret == 1) /* only one single value? */ 1259 first = luaK_exp2anyreg(fs, &e); 1260 else { 1261 luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */ 1262 first = fs->nactvar; /* return all `active' values */ 1263 lua_assert(nret == fs->freereg - first); 1264 } 1265 } 1266 } 1267 luaK_ret(fs, first, nret); 1268} 1269 1270 1271static int statement (LexState *ls) { 1272 int line = ls->linenumber; /* may be needed for error messages */ 1273 switch (ls->t.token) { 1274 case TK_IF: { /* stat -> ifstat */ 1275 ifstat(ls, line); 1276 return 0; 1277 } 1278 case TK_WHILE: { /* stat -> whilestat */ 1279 whilestat(ls, line); 1280 return 0; 1281 } 1282 case TK_DO: { /* stat -> DO block END */ 1283 luaX_next(ls); /* skip DO */ 1284 block(ls); 1285 check_match(ls, TK_END, TK_DO, line); 1286 return 0; 1287 } 1288 case TK_FOR: { /* stat -> forstat */ 1289 forstat(ls, line); 1290 return 0; 1291 } 1292 case TK_REPEAT: { /* stat -> repeatstat */ 1293 repeatstat(ls, line); 1294 return 0; 1295 } 1296 case TK_FUNCTION: { 1297 funcstat(ls, line); /* stat -> funcstat */ 1298 return 0; 1299 } 1300 case TK_LOCAL: { /* stat -> localstat */ 1301 luaX_next(ls); /* skip LOCAL */ 1302 if (testnext(ls, TK_FUNCTION)) /* local function? */ 1303 localfunc(ls); 1304 else 1305 localstat(ls); 1306 return 0; 1307 } 1308 case TK_RETURN: { /* stat -> retstat */ 1309 retstat(ls); 1310 return 1; /* must be last statement */ 1311 } 1312 case TK_BREAK: { /* stat -> breakstat */ 1313 luaX_next(ls); /* skip BREAK */ 1314 breakstat(ls); 1315 return 1; /* must be last statement */ 1316 } 1317 default: { 1318 exprstat(ls); 1319 return 0; /* to avoid warnings */ 1320 } 1321 } 1322} 1323 1324 1325static void chunk (LexState *ls) { 1326 /* chunk -> { stat [`;'] } */ 1327 int islast = 0; 1328 enterlevel(ls); 1329 while (!islast && !block_follow(ls->t.token)) { 1330 islast = statement(ls); 1331 testnext(ls, ';'); 1332 lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg && 1333 ls->fs->freereg >= ls->fs->nactvar); 1334 ls->fs->freereg = ls->fs->nactvar; /* free registers */ 1335 } 1336 leavelevel(ls); 1337} 1338 1339/* }====================================================================== */