external/mit/lua/dist/src/lparser.c

   1 /*      $NetBSD: lparser.c,v 1.1.1.2 2012/03/15 00:08:07 alnsn Exp $    */
   2
   3 /*
   4 ** $Id: lparser.c,v 1.1.1.2 2012/03/15 00:08:07 alnsn Exp $
   5 ** Lua Parser
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9
  10 #include <string.h>
  11
  12 #define lparser_c
  13 #define LUA_CORE
  14
  15 #include "lua.h"
  16
  17 #include "lcode.h"
  18 #include "ldebug.h"
  19 #include "ldo.h"
  20 #include "lfunc.h"
  21 #include "llex.h"
  22 #include "lmem.h"
  23 #include "lobject.h"
  24 #include "lopcodes.h"
  25 #include "lparser.h"
  26 #include "lstate.h"
  27 #include "lstring.h"
  28 #include "ltable.h"
  29
  30
  31
  32 #define hasmultret(k)           ((k) == VCALL || (k) == VVARARG)
  33
  34 #define getlocvar(fs, i)        ((fs)->f->locvars[(fs)->actvar[i]])
  35
  36 #define luaY_checklimit(fs,v,l,m)       if ((v)>(l)) errorlimit(fs,l,m)
  37
  38
  39 /*
  40 ** nodes for block list (list of active blocks)
  41 */
  42 typedef struct BlockCnt {
  43   struct BlockCnt *previous;  /* chain */
  44   int breaklist;  /* list of jumps out of this loop */
  45   lu_byte nactvar;  /* # active locals outside the breakable structure */
  46   lu_byte upval;  /* true if some variable in the block is an upvalue */
  47   lu_byte isbreakable;  /* true if `block' is a loop */
  48 } BlockCnt;
  49
  50
  51
  52 /*
  53 ** prototypes for recursive non-terminal functions
  54 */
  55 static void chunk (LexState *ls);
  56 static void expr (LexState *ls, expdesc *v);
  57
  58
  59 static void anchor_token (LexState *ls) {
  60   if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) {
  61     TString *ts = ls->t.seminfo.ts;
  62     luaX_newstring(ls, getstr(ts), ts->tsv.len);
  63   }
  64 }
  65
  66
  67 static void error_expected (LexState *ls, int token) {
  68   luaX_syntaxerror(ls,
  69       luaO_pushfstring(ls->L, LUA_QS " expected", luaX_token2str(ls, token)));
  70 }
  71
  72
  73 static void errorlimit (FuncState *fs, int limit, const char *what) {
  74   const char *msg = (fs->f->linedefined == 0) ?
  75     luaO_pushfstring(fs->L, "main function has more than %d %s", limit, what) :
  76     luaO_pushfstring(fs->L, "function at line %d has more than %d %s",
  77                             fs->f->linedefined, limit, what);
  78   luaX_lexerror(fs->ls, msg, 0);
  79 }
  80
  81
  82 static int testnext (LexState *ls, int c) {
  83   if (ls->t.token == c) {
  84     luaX_next(ls);
  85     return 1;
  86   }
  87   else return 0;
  88 }
  89
  90
  91 static void check (LexState *ls, int c) {
  92   if (ls->t.token != c)
  93     error_expected(ls, c);
  94 }
  95
  96 static void checknext (LexState *ls, int c) {
  97   check(ls, c);
  98   luaX_next(ls);
  99 }
 100
 101
 102 #define check_condition(ls,c,msg)       { if (!(c)) luaX_syntaxerror(ls, msg); }
 103
 104
 105
 106 static void check_match (LexState *ls, int what, int who, int where) {
 107   if (!testnext(ls, what)) {
 108     if (where == ls->linenumber)
 109       error_expected(ls, what);
 110     else {
 111       luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
 112              LUA_QS " expected (to close " LUA_QS " at line %d)",
 113               luaX_token2str(ls, what), luaX_token2str(ls, who), where));
 114     }
 115   }
 116 }
 117
 118
 119 static TString *str_checkname (LexState *ls) {
 120   TString *ts;
 121   check(ls, TK_NAME);
 122   ts = ls->t.seminfo.ts;
 123   luaX_next(ls);
 124   return ts;
 125 }
 126
 127
 128 static void init_exp (expdesc *e, expkind k, int i) {
 129   e->f = e->t = NO_JUMP;
 130   e->k = k;
 131   e->u.s.info = i;
 132 }
 133
 134
 135 static void codestring (LexState *ls, expdesc *e, TString *s) {
 136   init_exp(e, VK, luaK_stringK(ls->fs, s));
 137 }
 138
 139
 140 static void checkname(LexState *ls, expdesc *e) {
 141   codestring(ls, e, str_checkname(ls));
 142 }
 143
 144
 145 static int registerlocalvar (LexState *ls, TString *varname) {
 146   FuncState *fs = ls->fs;
 147   Proto *f = fs->f;
 148   int oldsize = f->sizelocvars;
 149   luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
 150                   LocVar, SHRT_MAX, "too many local variables");
 151   while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL;
 152   f->locvars[fs->nlocvars].varname = varname;
 153   luaC_objbarrier(ls->L, f, varname);
 154   return fs->nlocvars++;
 155 }
 156
 157
 158 #define new_localvarliteral(ls,v,n) \
 159   new_localvar(ls, luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char))-1), n)
 160
 161
 162 static void new_localvar (LexState *ls, TString *name, int n) {
 163   FuncState *fs = ls->fs;
 164   luaY_checklimit(fs, fs->nactvar+n+1, LUAI_MAXVARS, "local variables");
 165   fs->actvar[fs->nactvar+n] = cast(unsigned short, registerlocalvar(ls, name));
 166 }
 167
 168
 169 static void adjustlocalvars (LexState *ls, int nvars) {
 170   FuncState *fs = ls->fs;
 171   fs->nactvar = cast_byte(fs->nactvar + nvars);
 172   for (; nvars; nvars--) {
 173     getlocvar(fs, fs->nactvar - nvars).startpc = fs->pc;
 174   }
 175 }
 176
 177
 178 static void removevars (LexState *ls, int tolevel) {
 179   FuncState *fs = ls->fs;
 180   while (fs->nactvar > tolevel)
 181     getlocvar(fs, --fs->nactvar).endpc = fs->pc;
 182 }
 183
 184
 185 static int indexupvalue (FuncState *fs, TString *name, expdesc *v) {
 186   int i;
 187   Proto *f = fs->f;
 188   int oldsize = f->sizeupvalues;
 189   for (i=0; i<f->nups; i++) {
 190     if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->u.s.info) {
 191       lua_assert(f->upvalues[i] == name);
 192       return i;
 193     }
 194   }
 195   /* new one */
 196   luaY_checklimit(fs, f->nups + 1, LUAI_MAXUPVALUES, "upvalues");
 197   luaM_growvector(fs->L, f->upvalues, f->nups, f->sizeupvalues,
 198                   TString *, MAX_INT, "");
 199   while (oldsize < f->sizeupvalues) f->upvalues[oldsize++] = NULL;
 200   f->upvalues[f->nups] = name;
 201   luaC_objbarrier(fs->L, f, name);
 202   lua_assert(v->k == VLOCAL || v->k == VUPVAL);
 203   fs->upvalues[f->nups].k = cast_byte(v->k);
 204   fs->upvalues[f->nups].info = cast_byte(v->u.s.info);
 205   return f->nups++;
 206 }
 207
 208
 209 static int searchvar (FuncState *fs, TString *n) {
 210   int i;
 211   for (i=fs->nactvar-1; i >= 0; i--) {
 212     if (n == getlocvar(fs, i).varname)
 213       return i;
 214   }
 215   return -1;  /* not found */
 216 }
 217
 218
 219 static void markupval (FuncState *fs, int level) {
 220   BlockCnt *bl = fs->bl;
 221   while (bl && bl->nactvar > level) bl = bl->previous;
 222   if (bl) bl->upval = 1;
 223 }
 224
 225
 226 static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
 227   if (fs == NULL) {  /* no more levels? */
 228     init_exp(var, VGLOBAL, NO_REG);  /* default is global variable */
 229     return VGLOBAL;
 230   }
 231   else {
 232     int v = searchvar(fs, n);  /* look up at current level */
 233     if (v >= 0) {
 234       init_exp(var, VLOCAL, v);
 235       if (!base)
 236         markupval(fs, v);  /* local will be used as an upval */
 237       return VLOCAL;
 238     }
 239     else {  /* not found at current level; try upper one */
 240       if (singlevaraux(fs->prev, n, var, 0) == VGLOBAL)
 241         return VGLOBAL;
 242       var->u.s.info = indexupvalue(fs, n, var);  /* else was LOCAL or UPVAL */
 243       var->k = VUPVAL;  /* upvalue in this level */
 244       return VUPVAL;
 245     }
 246   }
 247 }
 248
 249
 250 static void singlevar (LexState *ls, expdesc *var) {
 251   TString *varname = str_checkname(ls);
 252   FuncState *fs = ls->fs;
 253   if (singlevaraux(fs, varname, var, 1) == VGLOBAL)
 254     var->u.s.info = luaK_stringK(fs, varname);  /* info points to global name */
 255 }
 256
 257
 258 static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
 259   FuncState *fs = ls->fs;
 260   int extra = nvars - nexps;
 261   if (hasmultret(e->k)) {
 262     extra++;  /* includes call itself */
 263     if (extra < 0) extra = 0;
 264     luaK_setreturns(fs, e, extra);  /* last exp. provides the difference */
 265     if (extra > 1) luaK_reserveregs(fs, extra-1);
 266   }
 267   else {
 268     if (e->k != VVOID) luaK_exp2nextreg(fs, e);  /* close last expression */
 269     if (extra > 0) {
 270       int reg = fs->freereg;
 271       luaK_reserveregs(fs, extra);
 272       luaK_nil(fs, reg, extra);
 273     }
 274   }
 275 }
 276
 277
 278 static void enterlevel (LexState *ls) {
 279   if (++ls->L->nCcalls > LUAI_MAXCCALLS)
 280         luaX_lexerror(ls, "chunk has too many syntax levels", 0);
 281 }
 282
 283
 284 #define leavelevel(ls)  ((ls)->L->nCcalls--)
 285
 286
 287 static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isbreakable) {
 288   bl->breaklist = NO_JUMP;
 289   bl->isbreakable = isbreakable;
 290   bl->nactvar = fs->nactvar;
 291   bl->upval = 0;
 292   bl->previous = fs->bl;
 293   fs->bl = bl;
 294   lua_assert(fs->freereg == fs->nactvar);
 295 }
 296
 297
 298 static void leaveblock (FuncState *fs) {
 299   BlockCnt *bl = fs->bl;
 300   fs->bl = bl->previous;
 301   removevars(fs->ls, bl->nactvar);
 302   if (bl->upval)
 303     luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
 304   /* a block either controls scope or breaks (never both) */
 305   lua_assert(!bl->isbreakable || !bl->upval);
 306   lua_assert(bl->nactvar == fs->nactvar);
 307   fs->freereg = fs->nactvar;  /* free registers */
 308   luaK_patchtohere(fs, bl->breaklist);
 309 }
 310
 311
 312 static void pushclosure (LexState *ls, FuncState *func, expdesc *v) {
 313   FuncState *fs = ls->fs;
 314   Proto *f = fs->f;
 315   int oldsize = f->sizep;
 316   int i;
 317   luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *,
 318                   MAXARG_Bx, "constant table overflow");
 319   while (oldsize < f->sizep) f->p[oldsize++] = NULL;
 320   f->p[fs->np++] = func->f;
 321   luaC_objbarrier(ls->L, f, func->f);
 322   init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np-1));
 323   for (i=0; i<func->f->nups; i++) {
 324     OpCode o = (func->upvalues[i].k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
 325     luaK_codeABC(fs, o, 0, func->upvalues[i].info, 0);
 326   }
 327 }
 328
 329
 330 static void open_func (LexState *ls, FuncState *fs) {
 331   lua_State *L = ls->L;
 332   Proto *f = luaF_newproto(L);
 333   fs->f = f;
 334   fs->prev = ls->fs;  /* linked list of funcstates */
 335   fs->ls = ls;
 336   fs->L = L;
 337   ls->fs = fs;
 338   fs->pc = 0;
 339   fs->lasttarget = -1;
 340   fs->jpc = NO_JUMP;
 341   fs->freereg = 0;
 342   fs->nk = 0;
 343   fs->np = 0;
 344   fs->nlocvars = 0;
 345   fs->nactvar = 0;
 346   fs->bl = NULL;
 347   f->source = ls->source;
 348   f->maxstacksize = 2;  /* registers 0/1 are always valid */
 349   fs->h = luaH_new(L, 0, 0);
 350   /* anchor table of constants and prototype (to avoid being collected) */
 351   sethvalue2s(L, L->top, fs->h);
 352   incr_top(L);
 353   setptvalue2s(L, L->top, f);
 354   incr_top(L);
 355 }
 356
 357
 358 static void close_func (LexState *ls) {
 359   lua_State *L = ls->L;
 360   FuncState *fs = ls->fs;
 361   Proto *f = fs->f;
 362   removevars(ls, 0);
 363   luaK_ret(fs, 0, 0);  /* final return */
 364   luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
 365   f->sizecode = fs->pc;
 366   luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
 367   f->sizelineinfo = fs->pc;
 368   luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
 369   f->sizek = fs->nk;
 370   luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
 371   f->sizep = fs->np;
 372   luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
 373   f->sizelocvars = fs->nlocvars;
 374   luaM_reallocvector(L, f->upvalues, f->sizeupvalues, f->nups, TString *);
 375   f->sizeupvalues = f->nups;
 376   lua_assert(luaG_checkcode(f));
 377   lua_assert(fs->bl == NULL);
 378   ls->fs = fs->prev;
 379   /* last token read was anchored in defunct function; must reanchor it */
 380   if (fs) anchor_token(ls);
 381   L->top -= 2;  /* remove table and prototype from the stack */
 382 }
 383
 384
 385 Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
 386   struct LexState lexstate;
 387   struct FuncState funcstate;
 388   lexstate.buff = buff;
 389   luaX_setinput(L, &lexstate, z, luaS_new(L, name));
 390   open_func(&lexstate, &funcstate);
 391   funcstate.f->is_vararg = VARARG_ISVARARG;  /* main func. is always vararg */
 392   luaX_next(&lexstate);  /* read first token */
 393   chunk(&lexstate);
 394   check(&lexstate, TK_EOS);
 395   close_func(&lexstate);
 396   lua_assert(funcstate.prev == NULL);
 397   lua_assert(funcstate.f->nups == 0);
 398   lua_assert(lexstate.fs == NULL);
 399   return funcstate.f;
 400 }
 401
 402
 403
 404 /*============================================================*/
 405 /* GRAMMAR RULES */
 406 /*============================================================*/
 407
 408
 409 static void field (LexState *ls, expdesc *v) {
 410   /* field -> ['.' | ':'] NAME */
 411   FuncState *fs = ls->fs;
 412   expdesc key;
 413   luaK_exp2anyreg(fs, v);
 414   luaX_next(ls);  /* skip the dot or colon */
 415   checkname(ls, &key);
 416   luaK_indexed(fs, v, &key);
 417 }
 418
 419
 420 static void yindex (LexState *ls, expdesc *v) {
 421   /* index -> '[' expr ']' */
 422   luaX_next(ls);  /* skip the '[' */
 423   expr(ls, v);
 424   luaK_exp2val(ls->fs, v);
 425   checknext(ls, ']');
 426 }
 427
 428
 429 /*
 430 ** {======================================================================
 431 ** Rules for Constructors
 432 ** =======================================================================
 433 */
 434
 435
 436 struct ConsControl {
 437   expdesc v;  /* last list item read */
 438   expdesc *t;  /* table descriptor */
 439   int nh;  /* total number of `record' elements */
 440   int na;  /* total number of array elements */
 441   int tostore;  /* number of array elements pending to be stored */
 442 };
 443
 444
 445 static void recfield (LexState *ls, struct ConsControl *cc) {
 446   /* recfield -> (NAME | `['exp1`]') = exp1 */
 447   FuncState *fs = ls->fs;
 448   int reg = ls->fs->freereg;
 449   expdesc key, val;
 450   int rkkey;
 451   if (ls->t.token == TK_NAME) {
 452     luaY_checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
 453     checkname(ls, &key);
 454   }
 455   else  /* ls->t.token == '[' */
 456     yindex(ls, &key);
 457   cc->nh++;
 458   checknext(ls, '=');
 459   rkkey = luaK_exp2RK(fs, &key);
 460   expr(ls, &val);
 461   luaK_codeABC(fs, OP_SETTABLE, cc->t->u.s.info, rkkey, luaK_exp2RK(fs, &val));
 462   fs->freereg = reg;  /* free registers */
 463 }
 464
 465
 466 static void closelistfield (FuncState *fs, struct ConsControl *cc) {
 467   if (cc->v.k == VVOID) return;  /* there is no list item */
 468   luaK_exp2nextreg(fs, &cc->v);
 469   cc->v.k = VVOID;
 470   if (cc->tostore == LFIELDS_PER_FLUSH) {
 471     luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore);  /* flush */
 472     cc->tostore = 0;  /* no more items pending */
 473   }
 474 }
 475
 476
 477 static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
 478   if (cc->tostore == 0) return;
 479   if (hasmultret(cc->v.k)) {
 480     luaK_setmultret(fs, &cc->v);
 481     luaK_setlist(fs, cc->t->u.s.info, cc->na, LUA_MULTRET);
 482     cc->na--;  /* do not count last expression (unknown number of elements) */
 483   }
 484   else {
 485     if (cc->v.k != VVOID)
 486       luaK_exp2nextreg(fs, &cc->v);
 487     luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore);
 488   }
 489 }
 490
 491
 492 static void listfield (LexState *ls, struct ConsControl *cc) {
 493   expr(ls, &cc->v);
 494   luaY_checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
 495   cc->na++;
 496   cc->tostore++;
 497 }
 498
 499
 500 static void constructor (LexState *ls, expdesc *t) {
 501   /* constructor -> ?? */
 502   FuncState *fs = ls->fs;
 503   int line = ls->linenumber;
 504   int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
 505   struct ConsControl cc;
 506   cc.na = cc.nh = cc.tostore = 0;
 507   cc.t = t;
 508   init_exp(t, VRELOCABLE, pc);
 509   init_exp(&cc.v, VVOID, 0);  /* no value (yet) */
 510   luaK_exp2nextreg(ls->fs, t);  /* fix it at stack top (for gc) */
 511   checknext(ls, '{');
 512   do {
 513     lua_assert(cc.v.k == VVOID || cc.tostore > 0);
 514     if (ls->t.token == '}') break;
 515     closelistfield(fs, &cc);
 516     switch(ls->t.token) {
 517       case TK_NAME: {  /* may be listfields or recfields */
 518         luaX_lookahead(ls);
 519         if (ls->lookahead.token != '=')  /* expression? */
 520           listfield(ls, &cc);
 521         else
 522           recfield(ls, &cc);
 523         break;
 524       }
 525       case '[': {  /* constructor_item -> recfield */
 526         recfield(ls, &cc);
 527         break;
 528       }
 529       default: {  /* constructor_part -> listfield */
 530         listfield(ls, &cc);
 531         break;
 532       }
 533     }
 534   } while (testnext(ls, ',') || testnext(ls, ';'));
 535   check_match(ls, '}', '{', line);
 536   lastlistfield(fs, &cc);
 537   SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
 538   SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh));  /* set initial table size */
 539 }
 540
 541 /* }====================================================================== */
 542
 543
 544
 545 static void parlist (LexState *ls) {
 546   /* parlist -> [ param { `,' param } ] */
 547   FuncState *fs = ls->fs;
 548   Proto *f = fs->f;
 549   int nparams = 0;
 550   f->is_vararg = 0;
 551   if (ls->t.token != ')') {  /* is `parlist' not empty? */
 552     do {
 553       switch (ls->t.token) {
 554         case TK_NAME: {  /* param -> NAME */
 555           new_localvar(ls, str_checkname(ls), nparams++);
 556           break;
 557         }
 558         case TK_DOTS: {  /* param -> `...' */
 559           luaX_next(ls);
 560 #if defined(LUA_COMPAT_VARARG)
 561           /* use `arg' as default name */
 562           new_localvarliteral(ls, "arg", nparams++);
 563           f->is_vararg = VARARG_HASARG | VARARG_NEEDSARG;
 564 #endif
 565           f->is_vararg |= VARARG_ISVARARG;
 566           break;
 567         }
 568         default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected");
 569       }
 570     } while (!f->is_vararg && testnext(ls, ','));
 571   }
 572   adjustlocalvars(ls, nparams);
 573   f->numparams = cast_byte(fs->nactvar - (f->is_vararg & VARARG_HASARG));
 574   luaK_reserveregs(fs, fs->nactvar);  /* reserve register for parameters */
 575 }
 576
 577
 578 static void body (LexState *ls, expdesc *e, int needself, int line) {
 579   /* body ->  `(' parlist `)' chunk END */
 580   FuncState new_fs;
 581   open_func(ls, &new_fs);
 582   new_fs.f->linedefined = line;
 583   checknext(ls, '(');
 584   if (needself) {
 585     new_localvarliteral(ls, "self", 0);
 586     adjustlocalvars(ls, 1);
 587   }
 588   parlist(ls);
 589   checknext(ls, ')');
 590   chunk(ls);
 591   new_fs.f->lastlinedefined = ls->linenumber;
 592   check_match(ls, TK_END, TK_FUNCTION, line);
 593   close_func(ls);
 594   pushclosure(ls, &new_fs, e);
 595 }
 596
 597
 598 static int explist1 (LexState *ls, expdesc *v) {
 599   /* explist1 -> expr { `,' expr } */
 600   int n = 1;  /* at least one expression */
 601   expr(ls, v);
 602   while (testnext(ls, ',')) {
 603     luaK_exp2nextreg(ls->fs, v);
 604     expr(ls, v);
 605     n++;
 606   }
 607   return n;
 608 }
 609
 610
 611 static void funcargs (LexState *ls, expdesc *f) {
 612   FuncState *fs = ls->fs;
 613   expdesc args;
 614   int base, nparams;
 615   int line = ls->linenumber;
 616   switch (ls->t.token) {
 617     case '(': {  /* funcargs -> `(' [ explist1 ] `)' */
 618       if (line != ls->lastline)
 619         luaX_syntaxerror(ls,"ambiguous syntax (function call x new statement)");
 620       luaX_next(ls);
 621       if (ls->t.token == ')')  /* arg list is empty? */
 622         args.k = VVOID;
 623       else {
 624         explist1(ls, &args);
 625         luaK_setmultret(fs, &args);
 626       }
 627       check_match(ls, ')', '(', line);
 628       break;
 629     }
 630     case '{': {  /* funcargs -> constructor */
 631       constructor(ls, &args);
 632       break;
 633     }
 634     case TK_STRING: {  /* funcargs -> STRING */
 635       codestring(ls, &args, ls->t.seminfo.ts);
 636       luaX_next(ls);  /* must use `seminfo' before `next' */
 637       break;
 638     }
 639     default: {
 640       luaX_syntaxerror(ls, "function arguments expected");
 641       return;
 642     }
 643   }
 644   lua_assert(f->k == VNONRELOC);
 645   base = f->u.s.info;  /* base register for call */
 646   if (hasmultret(args.k))
 647     nparams = LUA_MULTRET;  /* open call */
 648   else {
 649     if (args.k != VVOID)
 650       luaK_exp2nextreg(fs, &args);  /* close last argument */
 651     nparams = fs->freereg - (base+1);
 652   }
 653   init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
 654   luaK_fixline(fs, line);
 655   fs->freereg = base+1;  /* call remove function and arguments and leaves
 656                             (unless changed) one result */
 657 }
 658
 659
 660
 661
 662 /*
 663 ** {======================================================================
 664 ** Expression parsing
 665 ** =======================================================================
 666 */
 667
 668
 669 static void prefixexp (LexState *ls, expdesc *v) {
 670   /* prefixexp -> NAME | '(' expr ')' */
 671   switch (ls->t.token) {
 672     case '(': {
 673       int line = ls->linenumber;
 674       luaX_next(ls);
 675       expr(ls, v);
 676       check_match(ls, ')', '(', line);
 677       luaK_dischargevars(ls->fs, v);
 678       return;
 679     }
 680     case TK_NAME: {
 681       singlevar(ls, v);
 682       return;
 683     }
 684     default: {
 685       luaX_syntaxerror(ls, "unexpected symbol");
 686       return;
 687     }
 688   }
 689 }
 690
 691
 692 static void primaryexp (LexState *ls, expdesc *v) {
 693   /* primaryexp ->
 694         prefixexp { `.' NAME | `[' exp `]' | `:' NAME funcargs | funcargs } */
 695   FuncState *fs = ls->fs;
 696   prefixexp(ls, v);
 697   for (;;) {
 698     switch (ls->t.token) {
 699       case '.': {  /* field */
 700         field(ls, v);
 701         break;
 702       }
 703       case '[': {  /* `[' exp1 `]' */
 704         expdesc key;
 705         luaK_exp2anyreg(fs, v);
 706         yindex(ls, &key);
 707         luaK_indexed(fs, v, &key);
 708         break;
 709       }
 710       case ':': {  /* `:' NAME funcargs */
 711         expdesc key;
 712         luaX_next(ls);
 713         checkname(ls, &key);
 714         luaK_self(fs, v, &key);
 715         funcargs(ls, v);
 716         break;
 717       }
 718       case '(': case TK_STRING: case '{': {  /* funcargs */
 719         luaK_exp2nextreg(fs, v);
 720         funcargs(ls, v);
 721         break;
 722       }
 723       default: return;
 724     }
 725   }
 726 }
 727
 728
 729 static void simpleexp (LexState *ls, expdesc *v) {
 730   /* simpleexp -> NUMBER | STRING | NIL | true | false | ... |
 731                   constructor | FUNCTION body | primaryexp */
 732   switch (ls->t.token) {
 733     case TK_NUMBER: {
 734       init_exp(v, VKNUM, 0);
 735       v->u.nval = ls->t.seminfo.r;
 736       break;
 737     }
 738     case TK_STRING: {
 739       codestring(ls, v, ls->t.seminfo.ts);
 740       break;
 741     }
 742     case TK_NIL: {
 743       init_exp(v, VNIL, 0);
 744       break;
 745     }
 746     case TK_TRUE: {
 747       init_exp(v, VTRUE, 0);
 748       break;
 749     }
 750     case TK_FALSE: {
 751       init_exp(v, VFALSE, 0);
 752       break;
 753     }
 754     case TK_DOTS: {  /* vararg */
 755       FuncState *fs = ls->fs;
 756       check_condition(ls, fs->f->is_vararg,
 757                       "cannot use " LUA_QL("...") " outside a vararg function");
 758       fs->f->is_vararg &= ~VARARG_NEEDSARG;  /* don't need 'arg' */
 759       init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
 760       break;
 761     }
 762     case '{': {  /* constructor */
 763       constructor(ls, v);
 764       return;
 765     }
 766     case TK_FUNCTION: {
 767       luaX_next(ls);
 768       body(ls, v, 0, ls->linenumber);
 769       return;
 770     }
 771     default: {
 772       primaryexp(ls, v);
 773       return;
 774     }
 775   }
 776   luaX_next(ls);
 777 }
 778
 779
 780 static UnOpr getunopr (int op) {
 781   switch (op) {
 782     case TK_NOT: return OPR_NOT;
 783     case '-': return OPR_MINUS;
 784     case '#': return OPR_LEN;
 785     default: return OPR_NOUNOPR;
 786   }
 787 }
 788
 789
 790 static BinOpr getbinopr (int op) {
 791   switch (op) {
 792     case '+': return OPR_ADD;
 793     case '-': return OPR_SUB;
 794     case '*': return OPR_MUL;
 795     case '/': return OPR_DIV;
 796     case '%': return OPR_MOD;
 797     case '^': return OPR_POW;
 798     case TK_CONCAT: return OPR_CONCAT;
 799     case TK_NE: return OPR_NE;
 800     case TK_EQ: return OPR_EQ;
 801     case '<': return OPR_LT;
 802     case TK_LE: return OPR_LE;
 803     case '>': return OPR_GT;
 804     case TK_GE: return OPR_GE;
 805     case TK_AND: return OPR_AND;
 806     case TK_OR: return OPR_OR;
 807     default: return OPR_NOBINOPR;
 808   }
 809 }
 810
 811
 812 static const struct {
 813   lu_byte left;  /* left priority for each binary operator */
 814   lu_byte right; /* right priority */
 815 } priority[] = {  /* ORDER OPR */
 816    {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7},  /* `+' `-' `/' `%' */
 817    {10, 9}, {5, 4},                 /* power and concat (right associative) */
 818    {3, 3}, {3, 3},                  /* equality and inequality */
 819    {3, 3}, {3, 3}, {3, 3}, {3, 3},  /* order */
 820    {2, 2}, {1, 1}                   /* logical (and/or) */
 821 };
 822
 823 #define UNARY_PRIORITY  8  /* priority for unary operators */
 824
 825
 826 /*
 827 ** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
 828 ** where `binop' is any binary operator with a priority higher than `limit'
 829 */
 830 static BinOpr subexpr (LexState *ls, expdesc *v, unsigned int limit) {
 831   BinOpr op;
 832   UnOpr uop;
 833   enterlevel(ls);
 834   uop = getunopr(ls->t.token);
 835   if (uop != OPR_NOUNOPR) {
 836     luaX_next(ls);
 837     subexpr(ls, v, UNARY_PRIORITY);
 838     luaK_prefix(ls->fs, uop, v);
 839   }
 840   else simpleexp(ls, v);
 841   /* expand while operators have priorities higher than `limit' */
 842   op = getbinopr(ls->t.token);
 843   while (op != OPR_NOBINOPR && priority[op].left > limit) {
 844     expdesc v2;
 845     BinOpr nextop;
 846     luaX_next(ls);
 847     luaK_infix(ls->fs, op, v);
 848     /* read sub-expression with higher priority */
 849     nextop = subexpr(ls, &v2, priority[op].right);
 850     luaK_posfix(ls->fs, op, v, &v2);
 851     op = nextop;
 852   }
 853   leavelevel(ls);
 854   return op;  /* return first untreated operator */
 855 }
 856
 857
 858 static void expr (LexState *ls, expdesc *v) {
 859   subexpr(ls, v, 0);
 860 }
 861
 862 /* }==================================================================== */
 863
 864
 865
 866 /*
 867 ** {======================================================================
 868 ** Rules for Statements
 869 ** =======================================================================
 870 */
 871
 872
 873 static int block_follow (int token) {
 874   switch (token) {
 875     case TK_ELSE: case TK_ELSEIF: case TK_END:
 876     case TK_UNTIL: case TK_EOS:
 877       return 1;
 878     default: return 0;
 879   }
 880 }
 881
 882
 883 static void block (LexState *ls) {
 884   /* block -> chunk */
 885   FuncState *fs = ls->fs;
 886   BlockCnt bl;
 887   enterblock(fs, &bl, 0);
 888   chunk(ls);
 889   lua_assert(bl.breaklist == NO_JUMP);
 890   leaveblock(fs);
 891 }
 892
 893
 894 /*
 895 ** structure to chain all variables in the left-hand side of an
 896 ** assignment
 897 */
 898 struct LHS_assign {
 899   struct LHS_assign *prev;
 900   expdesc v;  /* variable (global, local, upvalue, or indexed) */
 901 };
 902
 903
 904 /*
 905 ** check whether, in an assignment to a local variable, the local variable
 906 ** is needed in a previous assignment (to a table). If so, save original
 907 ** local value in a safe place and use this safe copy in the previous
 908 ** assignment.
 909 */
 910 static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
 911   FuncState *fs = ls->fs;
 912   int extra = fs->freereg;  /* eventual position to save local variable */
 913   int conflict = 0;
 914   for (; lh; lh = lh->prev) {
 915     if (lh->v.k == VINDEXED) {
 916       if (lh->v.u.s.info == v->u.s.info) {  /* conflict? */
 917         conflict = 1;
 918         lh->v.u.s.info = extra;  /* previous assignment will use safe copy */
 919       }
 920       if (lh->v.u.s.aux == v->u.s.info) {  /* conflict? */
 921         conflict = 1;
 922         lh->v.u.s.aux = extra;  /* previous assignment will use safe copy */
 923       }
 924     }
 925   }
 926   if (conflict) {
 927     luaK_codeABC(fs, OP_MOVE, fs->freereg, v->u.s.info, 0);  /* make copy */
 928     luaK_reserveregs(fs, 1);
 929   }
 930 }
 931
 932
 933 static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
 934   expdesc e;
 935   check_condition(ls, VLOCAL <= lh->v.k && lh->v.k <= VINDEXED,
 936                       "syntax error");
 937   if (testnext(ls, ',')) {  /* assignment -> `,' primaryexp assignment */
 938     struct LHS_assign nv;
 939     nv.prev = lh;
 940     primaryexp(ls, &nv.v);
 941     if (nv.v.k == VLOCAL)
 942       check_conflict(ls, lh, &nv.v);
 943     luaY_checklimit(ls->fs, nvars, LUAI_MAXCCALLS - ls->L->nCcalls,
 944                     "variables in assignment");
 945     assignment(ls, &nv, nvars+1);
 946   }
 947   else {  /* assignment -> `=' explist1 */
 948     int nexps;
 949     checknext(ls, '=');
 950     nexps = explist1(ls, &e);
 951     if (nexps != nvars) {
 952       adjust_assign(ls, nvars, nexps, &e);
 953       if (nexps > nvars)
 954         ls->fs->freereg -= nexps - nvars;  /* remove extra values */
 955     }
 956     else {
 957       luaK_setoneret(ls->fs, &e);  /* close last expression */
 958       luaK_storevar(ls->fs, &lh->v, &e);
 959       return;  /* avoid default */
 960     }
 961   }
 962   init_exp(&e, VNONRELOC, ls->fs->freereg-1);  /* default assignment */
 963   luaK_storevar(ls->fs, &lh->v, &e);
 964 }
 965
 966
 967 static int cond (LexState *ls) {
 968   /* cond -> exp */
 969   expdesc v;
 970   expr(ls, &v);  /* read condition */
 971   if (v.k == VNIL) v.k = VFALSE;  /* `falses' are all equal here */
 972   luaK_goiftrue(ls->fs, &v);
 973   return v.f;
 974 }
 975
 976
 977 static void breakstat (LexState *ls) {
 978   FuncState *fs = ls->fs;
 979   BlockCnt *bl = fs->bl;
 980   int upval = 0;
 981   while (bl && !bl->isbreakable) {
 982     upval |= bl->upval;
 983     bl = bl->previous;
 984   }
 985   if (!bl)
 986     luaX_syntaxerror(ls, "no loop to break");
 987   if (upval)
 988     luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
 989   luaK_concat(fs, &bl->breaklist, luaK_jump(fs));
 990 }
 991
 992
 993 static void whilestat (LexState *ls, int line) {
 994   /* whilestat -> WHILE cond DO block END */
 995   FuncState *fs = ls->fs;
 996   int whileinit;
 997   int condexit;
 998   BlockCnt bl;
 999   luaX_next(ls);  /* skip WHILE */
1000   whileinit = luaK_getlabel(fs);
1001   condexit = cond(ls);
1002   enterblock(fs, &bl, 1);
1003   checknext(ls, TK_DO);
1004   block(ls);
1005   luaK_patchlist(fs, luaK_jump(fs), whileinit);
1006   check_match(ls, TK_END, TK_WHILE, line);
1007   leaveblock(fs);
1008   luaK_patchtohere(fs, condexit);  /* false conditions finish the loop */
1009 }
1010
1011
1012 static void repeatstat (LexState *ls, int line) {
1013   /* repeatstat -> REPEAT block UNTIL cond */
1014   int condexit;
1015   FuncState *fs = ls->fs;
1016   int repeat_init = luaK_getlabel(fs);
1017   BlockCnt bl1, bl2;
1018   enterblock(fs, &bl1, 1);  /* loop block */
1019   enterblock(fs, &bl2, 0);  /* scope block */
1020   luaX_next(ls);  /* skip REPEAT */
1021   chunk(ls);
1022   check_match(ls, TK_UNTIL, TK_REPEAT, line);
1023   condexit = cond(ls);  /* read condition (inside scope block) */
1024   if (!bl2.upval) {  /* no upvalues? */
1025     leaveblock(fs);  /* finish scope */
1026     luaK_patchlist(ls->fs, condexit, repeat_init);  /* close the loop */
1027   }
1028   else {  /* complete semantics when there are upvalues */
1029     breakstat(ls);  /* if condition then break */
1030     luaK_patchtohere(ls->fs, condexit);  /* else... */
1031     leaveblock(fs);  /* finish scope... */
1032     luaK_patchlist(ls->fs, luaK_jump(fs), repeat_init);  /* and repeat */
1033   }
1034   leaveblock(fs);  /* finish loop */
1035 }
1036
1037
1038 static int exp1 (LexState *ls) {
1039   expdesc e;
1040   int k;
1041   expr(ls, &e);
1042   k = e.k;
1043   luaK_exp2nextreg(ls->fs, &e);
1044   return k;
1045 }
1046
1047
1048 static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
1049   /* forbody -> DO block */
1050   BlockCnt bl;
1051   FuncState *fs = ls->fs;
1052   int prep, endfor;
1053   adjustlocalvars(ls, 3);  /* control variables */
1054   checknext(ls, TK_DO);
1055   prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
1056   enterblock(fs, &bl, 0);  /* scope for declared variables */
1057   adjustlocalvars(ls, nvars);
1058   luaK_reserveregs(fs, nvars);
1059   block(ls);
1060   leaveblock(fs);  /* end of scope for declared variables */
1061   luaK_patchtohere(fs, prep);
1062   endfor = (isnum) ? luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP) :
1063                      luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars);
1064   luaK_fixline(fs, line);  /* pretend that `OP_FOR' starts the loop */
1065   luaK_patchlist(fs, (isnum ? endfor : luaK_jump(fs)), prep + 1);
1066 }
1067
1068
1069 static void fornum (LexState *ls, TString *varname, int line) {
1070   /* fornum -> NAME = exp1,exp1[,exp1] forbody */
1071   FuncState *fs = ls->fs;
1072   int base = fs->freereg;
1073   new_localvarliteral(ls, "(for index)", 0);
1074   new_localvarliteral(ls, "(for limit)", 1);
1075   new_localvarliteral(ls, "(for step)", 2);
1076   new_localvar(ls, varname, 3);
1077   checknext(ls, '=');
1078   exp1(ls);  /* initial value */
1079   checknext(ls, ',');
1080   exp1(ls);  /* limit */
1081   if (testnext(ls, ','))
1082     exp1(ls);  /* optional step */
1083   else {  /* default step = 1 */
1084     luaK_codeABx(fs, OP_LOADK, fs->freereg, luaK_numberK(fs, 1));
1085     luaK_reserveregs(fs, 1);
1086   }
1087   forbody(ls, base, line, 1, 1);
1088 }
1089
1090
1091 static void forlist (LexState *ls, TString *indexname) {
1092   /* forlist -> NAME {,NAME} IN explist1 forbody */
1093   FuncState *fs = ls->fs;
1094   expdesc e;
1095   int nvars = 0;
1096   int line;
1097   int base = fs->freereg;
1098   /* create control variables */
1099   new_localvarliteral(ls, "(for generator)", nvars++);
1100   new_localvarliteral(ls, "(for state)", nvars++);
1101   new_localvarliteral(ls, "(for control)", nvars++);
1102   /* create declared variables */
1103   new_localvar(ls, indexname, nvars++);
1104   while (testnext(ls, ','))
1105     new_localvar(ls, str_checkname(ls), nvars++);
1106   checknext(ls, TK_IN);
1107   line = ls->linenumber;
1108   adjust_assign(ls, 3, explist1(ls, &e), &e);
1109   luaK_checkstack(fs, 3);  /* extra space to call generator */
1110   forbody(ls, base, line, nvars - 3, 0);
1111 }
1112
1113
1114 static void forstat (LexState *ls, int line) {
1115   /* forstat -> FOR (fornum | forlist) END */
1116   FuncState *fs = ls->fs;
1117   TString *varname;
1118   BlockCnt bl;
1119   enterblock(fs, &bl, 1);  /* scope for loop and control variables */
1120   luaX_next(ls);  /* skip `for' */
1121   varname = str_checkname(ls);  /* first variable name */
1122   switch (ls->t.token) {
1123     case '=': fornum(ls, varname, line); break;
1124     case ',': case TK_IN: forlist(ls, varname); break;
1125     default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected");
1126   }
1127   check_match(ls, TK_END, TK_FOR, line);
1128   leaveblock(fs);  /* loop scope (`break' jumps to this point) */
1129 }
1130
1131
1132 static int test_then_block (LexState *ls) {
1133   /* test_then_block -> [IF | ELSEIF] cond THEN block */
1134   int condexit;
1135   luaX_next(ls);  /* skip IF or ELSEIF */
1136   condexit = cond(ls);
1137   checknext(ls, TK_THEN);
1138   block(ls);  /* `then' part */
1139   return condexit;
1140 }
1141
1142
1143 static void ifstat (LexState *ls, int line) {
1144   /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
1145   FuncState *fs = ls->fs;
1146   int flist;
1147   int escapelist = NO_JUMP;
1148   flist = test_then_block(ls);  /* IF cond THEN block */
1149   while (ls->t.token == TK_ELSEIF) {
1150     luaK_concat(fs, &escapelist, luaK_jump(fs));
1151     luaK_patchtohere(fs, flist);
1152     flist = test_then_block(ls);  /* ELSEIF cond THEN block */
1153   }
1154   if (ls->t.token == TK_ELSE) {
1155     luaK_concat(fs, &escapelist, luaK_jump(fs));
1156     luaK_patchtohere(fs, flist);
1157     luaX_next(ls);  /* skip ELSE (after patch, for correct line info) */
1158     block(ls);  /* `else' part */
1159   }
1160   else
1161     luaK_concat(fs, &escapelist, flist);
1162   luaK_patchtohere(fs, escapelist);
1163   check_match(ls, TK_END, TK_IF, line);
1164 }
1165
1166
1167 static void localfunc (LexState *ls) {
1168   expdesc v, b;
1169   FuncState *fs = ls->fs;
1170   new_localvar(ls, str_checkname(ls), 0);
1171   init_exp(&v, VLOCAL, fs->freereg);
1172   luaK_reserveregs(fs, 1);
1173   adjustlocalvars(ls, 1);
1174   body(ls, &b, 0, ls->linenumber);
1175   luaK_storevar(fs, &v, &b);
1176   /* debug information will only see the variable after this point! */
1177   getlocvar(fs, fs->nactvar - 1).startpc = fs->pc;
1178 }
1179
1180
1181 static void localstat (LexState *ls) {
1182   /* stat -> LOCAL NAME {`,' NAME} [`=' explist1] */
1183   int nvars = 0;
1184   int nexps;
1185   expdesc e;
1186   do {
1187     new_localvar(ls, str_checkname(ls), nvars++);
1188   } while (testnext(ls, ','));
1189   if (testnext(ls, '='))
1190     nexps = explist1(ls, &e);
1191   else {
1192     e.k = VVOID;
1193     nexps = 0;
1194   }
1195   adjust_assign(ls, nvars, nexps, &e);
1196   adjustlocalvars(ls, nvars);
1197 }
1198
1199
1200 static int funcname (LexState *ls, expdesc *v) {
1201   /* funcname -> NAME {field} [`:' NAME] */
1202   int needself = 0;
1203   singlevar(ls, v);
1204   while (ls->t.token == '.')
1205     field(ls, v);
1206   if (ls->t.token == ':') {
1207     needself = 1;
1208     field(ls, v);
1209   }
1210   return needself;
1211 }
1212
1213
1214 static void funcstat (LexState *ls, int line) {
1215   /* funcstat -> FUNCTION funcname body */
1216   int needself;
1217   expdesc v, b;
1218   luaX_next(ls);  /* skip FUNCTION */
1219   needself = funcname(ls, &v);
1220   body(ls, &b, needself, line);
1221   luaK_storevar(ls->fs, &v, &b);
1222   luaK_fixline(ls->fs, line);  /* definition `happens' in the first line */
1223 }
1224
1225
1226 static void exprstat (LexState *ls) {
1227   /* stat -> func | assignment */
1228   FuncState *fs = ls->fs;
1229   struct LHS_assign v;
1230   primaryexp(ls, &v.v);
1231   if (v.v.k == VCALL)  /* stat -> func */
1232     SETARG_C(getcode(fs, &v.v), 1);  /* call statement uses no results */
1233   else {  /* stat -> assignment */
1234     v.prev = NULL;
1235     assignment(ls, &v, 1);
1236   }
1237 }
1238
1239
1240 static void retstat (LexState *ls) {
1241   /* stat -> RETURN explist */
1242   FuncState *fs = ls->fs;
1243   expdesc e;
1244   int first, nret;  /* registers with returned values */
1245   luaX_next(ls);  /* skip RETURN */
1246   if (block_follow(ls->t.token) || ls->t.token == ';')
1247     first = nret = 0;  /* return no values */
1248   else {
1249     nret = explist1(ls, &e);  /* optional return values */
1250     if (hasmultret(e.k)) {
1251       luaK_setmultret(fs, &e);
1252       if (e.k == VCALL && nret == 1) {  /* tail call? */
1253         SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
1254         lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
1255       }
1256       first = fs->nactvar;
1257       nret = LUA_MULTRET;  /* return all values */
1258     }
1259     else {
1260       if (nret == 1)  /* only one single value? */
1261         first = luaK_exp2anyreg(fs, &e);
1262       else {
1263         luaK_exp2nextreg(fs, &e);  /* values must go to the `stack' */
1264         first = fs->nactvar;  /* return all `active' values */
1265         lua_assert(nret == fs->freereg - first);
1266       }
1267     }
1268   }
1269   luaK_ret(fs, first, nret);
1270 }
1271
1272
1273 static int statement (LexState *ls) {
1274   int line = ls->linenumber;  /* may be needed for error messages */
1275   switch (ls->t.token) {
1276     case TK_IF: {  /* stat -> ifstat */
1277       ifstat(ls, line);
1278       return 0;
1279     }
1280     case TK_WHILE: {  /* stat -> whilestat */
1281       whilestat(ls, line);
1282       return 0;
1283     }
1284     case TK_DO: {  /* stat -> DO block END */
1285       luaX_next(ls);  /* skip DO */
1286       block(ls);
1287       check_match(ls, TK_END, TK_DO, line);
1288       return 0;
1289     }
1290     case TK_FOR: {  /* stat -> forstat */
1291       forstat(ls, line);
1292       return 0;
1293     }
1294     case TK_REPEAT: {  /* stat -> repeatstat */
1295       repeatstat(ls, line);
1296       return 0;
1297     }
1298     case TK_FUNCTION: {
1299       funcstat(ls, line);  /* stat -> funcstat */
1300       return 0;
1301     }
1302     case TK_LOCAL: {  /* stat -> localstat */
1303       luaX_next(ls);  /* skip LOCAL */
1304       if (testnext(ls, TK_FUNCTION))  /* local function? */
1305         localfunc(ls);
1306       else
1307         localstat(ls);
1308       return 0;
1309     }
1310     case TK_RETURN: {  /* stat -> retstat */
1311       retstat(ls);
1312       return 1;  /* must be last statement */
1313     }
1314     case TK_BREAK: {  /* stat -> breakstat */
1315       luaX_next(ls);  /* skip BREAK */
1316       breakstat(ls);
1317       return 1;  /* must be last statement */
1318     }
1319     default: {
1320       exprstat(ls);
1321       return 0;  /* to avoid warnings */
1322     }
1323   }
1324 }
1325
1326
1327 static void chunk (LexState *ls) {
1328   /* chunk -> { stat [`;'] } */
1329   int islast = 0;
1330   enterlevel(ls);
1331   while (!islast && !block_follow(ls->t.token)) {
1332     islast = statement(ls);
1333     testnext(ls, ';');
1334     lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
1335                ls->fs->freereg >= ls->fs->nactvar);
1336     ls->fs->freereg = ls->fs->nactvar;  /* free registers */
1337   }
1338   leavelevel(ls);
1339 }
1340
1341 /* }====================================================================== */