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

   1 /*      $NetBSD: lparser.c,v 1.3 2015/02/02 14:03:05 lneto Exp $        */
   2
   3 /*
   4 ** Id: lparser.c,v 2.147 2014/12/27 20:31:43 roberto Exp
   5 ** Lua Parser
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9 #define lparser_c
  10 #define LUA_CORE
  11
  12 #include "lprefix.h"
  13
  14
  15 #ifndef _KERNEL
  16 #include <string.h>
  17 #endif
  18
  19 #include "lua.h"
  20
  21 #include "lcode.h"
  22 #include "ldebug.h"
  23 #include "ldo.h"
  24 #include "lfunc.h"
  25 #include "llex.h"
  26 #include "lmem.h"
  27 #include "lobject.h"
  28 #include "lopcodes.h"
  29 #include "lparser.h"
  30 #include "lstate.h"
  31 #include "lstring.h"
  32 #include "ltable.h"
  33
  34
  35
  36 /* maximum number of local variables per function (must be smaller
  37    than 250, due to the bytecode format) */
  38 #define MAXVARS         200
  39
  40
  41 #define hasmultret(k)           ((k) == VCALL || (k) == VVARARG)
  42
  43
  44 /* because all strings are unified by the scanner, the parser
  45    can use pointer equality for string equality */
  46 #define eqstr(a,b)      ((a) == (b))
  47
  48
  49 /*
  50 ** nodes for block list (list of active blocks)
  51 */
  52 typedef struct BlockCnt {
  53   struct BlockCnt *previous;  /* chain */
  54   int firstlabel;  /* index of first label in this block */
  55   int firstgoto;  /* index of first pending goto in this block */
  56   lu_byte nactvar;  /* # active locals outside the block */
  57   lu_byte upval;  /* true if some variable in the block is an upvalue */
  58   lu_byte isloop;  /* true if 'block' is a loop */
  59 } BlockCnt;
  60
  61
  62
  63 /*
  64 ** prototypes for recursive non-terminal functions
  65 */
  66 static void statement (LexState *ls);
  67 static void expr (LexState *ls, expdesc *v);
  68
  69
  70 /* semantic error */
  71 static l_noret semerror (LexState *ls, const char *msg) {
  72   ls->t.token = 0;  /* remove "near <token>" 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 (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 (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(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 '%s'",
 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 (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 = n + 1;
 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 (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 '%s' 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   Proto *f;
 529   fs->prev = ls->fs;  /* linked list of funcstates */
 530   fs->ls = ls;
 531   ls->fs = fs;
 532   fs->pc = 0;
 533   fs->lasttarget = 0;
 534   fs->jpc = NO_JUMP;
 535   fs->freereg = 0;
 536   fs->nk = 0;
 537   fs->np = 0;
 538   fs->nups = 0;
 539   fs->nlocvars = 0;
 540   fs->nactvar = 0;
 541   fs->firstlocal = ls->dyd->actvar.n;
 542   fs->bl = NULL;
 543   f = fs->f;
 544   f->source = ls->source;
 545   f->maxstacksize = 2;  /* registers 0/1 are always valid */
 546   enterblock(fs, bl, 0);
 547 }
 548
 549
 550 static void close_func (LexState *ls) {
 551   lua_State *L = ls->L;
 552   FuncState *fs = ls->fs;
 553   Proto *f = fs->f;
 554   luaK_ret(fs, 0, 0);  /* final return */
 555   leaveblock(fs);
 556   luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
 557   f->sizecode = fs->pc;
 558   luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
 559   f->sizelineinfo = fs->pc;
 560   luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
 561   f->sizek = fs->nk;
 562   luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
 563   f->sizep = fs->np;
 564   luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
 565   f->sizelocvars = fs->nlocvars;
 566   luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc);
 567   f->sizeupvalues = fs->nups;
 568   lua_assert(fs->bl == NULL);
 569   ls->fs = fs->prev;
 570   luaC_checkGC(L);
 571 }
 572
 573
 574
 575 /*============================================================*/
 576 /* GRAMMAR RULES */
 577 /*============================================================*/
 578
 579
 580 /*
 581 ** check whether current token is in the follow set of a block.
 582 ** 'until' closes syntactical blocks, but do not close scope,
 583 ** so it is handled in separate.
 584 */
 585 static int block_follow (LexState *ls, int withuntil) {
 586   switch (ls->t.token) {
 587     case TK_ELSE: case TK_ELSEIF:
 588     case TK_END: case TK_EOS:
 589       return 1;
 590     case TK_UNTIL: return withuntil;
 591     default: return 0;
 592   }
 593 }
 594
 595
 596 static void statlist (LexState *ls) {
 597   /* statlist -> { stat [';'] } */
 598   while (!block_follow(ls, 1)) {
 599     if (ls->t.token == TK_RETURN) {
 600       statement(ls);
 601       return;  /* 'return' must be last statement */
 602     }
 603     statement(ls);
 604   }
 605 }
 606
 607
 608 static void fieldsel (LexState *ls, expdesc *v) {
 609   /* fieldsel -> ['.' | ':'] NAME */
 610   FuncState *fs = ls->fs;
 611   expdesc key;
 612   luaK_exp2anyregup(fs, v);
 613   luaX_next(ls);  /* skip the dot or colon */
 614   checkname(ls, &key);
 615   luaK_indexed(fs, v, &key);
 616 }
 617
 618
 619 static void yindex (LexState *ls, expdesc *v) {
 620   /* index -> '[' expr ']' */
 621   luaX_next(ls);  /* skip the '[' */
 622   expr(ls, v);
 623   luaK_exp2val(ls->fs, v);
 624   checknext(ls, ']');
 625 }
 626
 627
 628 /*
 629 ** {======================================================================
 630 ** Rules for Constructors
 631 ** =======================================================================
 632 */
 633
 634
 635 struct ConsControl {
 636   expdesc v;  /* last list item read */
 637   expdesc *t;  /* table descriptor */
 638   int nh;  /* total number of 'record' elements */
 639   int na;  /* total number of array elements */
 640   int tostore;  /* number of array elements pending to be stored */
 641 };
 642
 643
 644 static void recfield (LexState *ls, struct ConsControl *cc) {
 645   /* recfield -> (NAME | '['exp1']') = exp1 */
 646   FuncState *fs = ls->fs;
 647   int reg = ls->fs->freereg;
 648   expdesc key, val;
 649   int rkkey;
 650   if (ls->t.token == TK_NAME) {
 651     checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
 652     checkname(ls, &key);
 653   }
 654   else  /* ls->t.token == '[' */
 655     yindex(ls, &key);
 656   cc->nh++;
 657   checknext(ls, '=');
 658   rkkey = luaK_exp2RK(fs, &key);
 659   expr(ls, &val);
 660   luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val));
 661   fs->freereg = reg;  /* free registers */
 662 }
 663
 664
 665 static void closelistfield (FuncState *fs, struct ConsControl *cc) {
 666   if (cc->v.k == VVOID) return;  /* there is no list item */
 667   luaK_exp2nextreg(fs, &cc->v);
 668   cc->v.k = VVOID;
 669   if (cc->tostore == LFIELDS_PER_FLUSH) {
 670     luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);  /* flush */
 671     cc->tostore = 0;  /* no more items pending */
 672   }
 673 }
 674
 675
 676 static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
 677   if (cc->tostore == 0) return;
 678   if (hasmultret(cc->v.k)) {
 679     luaK_setmultret(fs, &cc->v);
 680     luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET);
 681     cc->na--;  /* do not count last expression (unknown number of elements) */
 682   }
 683   else {
 684     if (cc->v.k != VVOID)
 685       luaK_exp2nextreg(fs, &cc->v);
 686     luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);
 687   }
 688 }
 689
 690
 691 static void listfield (LexState *ls, struct ConsControl *cc) {
 692   /* listfield -> exp */
 693   expr(ls, &cc->v);
 694   checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
 695   cc->na++;
 696   cc->tostore++;
 697 }
 698
 699
 700 static void field (LexState *ls, struct ConsControl *cc) {
 701   /* field -> listfield | recfield */
 702   switch(ls->t.token) {
 703     case TK_NAME: {  /* may be 'listfield' or 'recfield' */
 704       if (luaX_lookahead(ls) != '=')  /* expression? */
 705         listfield(ls, cc);
 706       else
 707         recfield(ls, cc);
 708       break;
 709     }
 710     case '[': {
 711       recfield(ls, cc);
 712       break;
 713     }
 714     default: {
 715       listfield(ls, cc);
 716       break;
 717     }
 718   }
 719 }
 720
 721
 722 static void constructor (LexState *ls, expdesc *t) {
 723   /* constructor -> '{' [ field { sep field } [sep] ] '}'
 724      sep -> ',' | ';' */
 725   FuncState *fs = ls->fs;
 726   int line = ls->linenumber;
 727   int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
 728   struct ConsControl cc;
 729   cc.na = cc.nh = cc.tostore = 0;
 730   cc.t = t;
 731   init_exp(t, VRELOCABLE, pc);
 732   init_exp(&cc.v, VVOID, 0);  /* no value (yet) */
 733   luaK_exp2nextreg(ls->fs, t);  /* fix it at stack top */
 734   checknext(ls, '{');
 735   do {
 736     lua_assert(cc.v.k == VVOID || cc.tostore > 0);
 737     if (ls->t.token == '}') break;
 738     closelistfield(fs, &cc);
 739     field(ls, &cc);
 740   } while (testnext(ls, ',') || testnext(ls, ';'));
 741   check_match(ls, '}', '{', line);
 742   lastlistfield(fs, &cc);
 743   SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
 744   SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh));  /* set initial table size */
 745 }
 746
 747 /* }====================================================================== */
 748
 749
 750
 751 static void parlist (LexState *ls) {
 752   /* parlist -> [ param { ',' param } ] */
 753   FuncState *fs = ls->fs;
 754   Proto *f = fs->f;
 755   int nparams = 0;
 756   f->is_vararg = 0;
 757   if (ls->t.token != ')') {  /* is 'parlist' not empty? */
 758     do {
 759       switch (ls->t.token) {
 760         case TK_NAME: {  /* param -> NAME */
 761           new_localvar(ls, str_checkname(ls));
 762           nparams++;
 763           break;
 764         }
 765         case TK_DOTS: {  /* param -> '...' */
 766           luaX_next(ls);
 767           f->is_vararg = 1;
 768           break;
 769         }
 770         default: luaX_syntaxerror(ls, "<name> or '...' expected");
 771       }
 772     } while (!f->is_vararg && testnext(ls, ','));
 773   }
 774   adjustlocalvars(ls, nparams);
 775   f->numparams = cast_byte(fs->nactvar);
 776   luaK_reserveregs(fs, fs->nactvar);  /* reserve register for parameters */
 777 }
 778
 779
 780 static void body (LexState *ls, expdesc *e, int ismethod, int line) {
 781   /* body ->  '(' parlist ')' block END */
 782   FuncState new_fs;
 783   BlockCnt bl;
 784   new_fs.f = addprototype(ls);
 785   new_fs.f->linedefined = line;
 786   open_func(ls, &new_fs, &bl);
 787   checknext(ls, '(');
 788   if (ismethod) {
 789     new_localvarliteral(ls, "self");  /* create 'self' parameter */
 790     adjustlocalvars(ls, 1);
 791   }
 792   parlist(ls);
 793   checknext(ls, ')');
 794   statlist(ls);
 795   new_fs.f->lastlinedefined = ls->linenumber;
 796   check_match(ls, TK_END, TK_FUNCTION, line);
 797   codeclosure(ls, e);
 798   close_func(ls);
 799 }
 800
 801
 802 static int explist (LexState *ls, expdesc *v) {
 803   /* explist -> expr { ',' expr } */
 804   int n = 1;  /* at least one expression */
 805   expr(ls, v);
 806   while (testnext(ls, ',')) {
 807     luaK_exp2nextreg(ls->fs, v);
 808     expr(ls, v);
 809     n++;
 810   }
 811   return n;
 812 }
 813
 814
 815 static void funcargs (LexState *ls, expdesc *f, int line) {
 816   FuncState *fs = ls->fs;
 817   expdesc args;
 818   int base, nparams;
 819   switch (ls->t.token) {
 820     case '(': {  /* funcargs -> '(' [ explist ] ')' */
 821       luaX_next(ls);
 822       if (ls->t.token == ')')  /* arg list is empty? */
 823         args.k = VVOID;
 824       else {
 825         explist(ls, &args);
 826         luaK_setmultret(fs, &args);
 827       }
 828       check_match(ls, ')', '(', line);
 829       break;
 830     }
 831     case '{': {  /* funcargs -> constructor */
 832       constructor(ls, &args);
 833       break;
 834     }
 835     case TK_STRING: {  /* funcargs -> STRING */
 836       codestring(ls, &args, ls->t.seminfo.ts);
 837       luaX_next(ls);  /* must use 'seminfo' before 'next' */
 838       break;
 839     }
 840     default: {
 841       luaX_syntaxerror(ls, "function arguments expected");
 842     }
 843   }
 844   lua_assert(f->k == VNONRELOC);
 845   base = f->u.info;  /* base register for call */
 846   if (hasmultret(args.k))
 847     nparams = LUA_MULTRET;  /* open call */
 848   else {
 849     if (args.k != VVOID)
 850       luaK_exp2nextreg(fs, &args);  /* close last argument */
 851     nparams = fs->freereg - (base+1);
 852   }
 853   init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
 854   luaK_fixline(fs, line);
 855   fs->freereg = base+1;  /* call remove function and arguments and leaves
 856                             (unless changed) one result */
 857 }
 858
 859
 860
 861
 862 /*
 863 ** {======================================================================
 864 ** Expression parsing
 865 ** =======================================================================
 866 */
 867
 868
 869 static void primaryexp (LexState *ls, expdesc *v) {
 870   /* primaryexp -> NAME | '(' expr ')' */
 871   switch (ls->t.token) {
 872     case '(': {
 873       int line = ls->linenumber;
 874       luaX_next(ls);
 875       expr(ls, v);
 876       check_match(ls, ')', '(', line);
 877       luaK_dischargevars(ls->fs, v);
 878       return;
 879     }
 880     case TK_NAME: {
 881       singlevar(ls, v);
 882       return;
 883     }
 884     default: {
 885       luaX_syntaxerror(ls, "unexpected symbol");
 886     }
 887   }
 888 }
 889
 890
 891 static void suffixedexp (LexState *ls, expdesc *v) {
 892   /* suffixedexp ->
 893        primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */
 894   FuncState *fs = ls->fs;
 895   int line = ls->linenumber;
 896   primaryexp(ls, v);
 897   for (;;) {
 898     switch (ls->t.token) {
 899       case '.': {  /* fieldsel */
 900         fieldsel(ls, v);
 901         break;
 902       }
 903       case '[': {  /* '[' exp1 ']' */
 904         expdesc key;
 905         luaK_exp2anyregup(fs, v);
 906         yindex(ls, &key);
 907         luaK_indexed(fs, v, &key);
 908         break;
 909       }
 910       case ':': {  /* ':' NAME funcargs */
 911         expdesc key;
 912         luaX_next(ls);
 913         checkname(ls, &key);
 914         luaK_self(fs, v, &key);
 915         funcargs(ls, v, line);
 916         break;
 917       }
 918       case '(': case TK_STRING: case '{': {  /* funcargs */
 919         luaK_exp2nextreg(fs, v);
 920         funcargs(ls, v, line);
 921         break;
 922       }
 923       default: return;
 924     }
 925   }
 926 }
 927
 928
 929 static void simpleexp (LexState *ls, expdesc *v) {
 930   /* simpleexp -> FLT | INT | STRING | NIL | TRUE | FALSE | ... |
 931                   constructor | FUNCTION body | suffixedexp */
 932   switch (ls->t.token) {
 933 #ifndef _KERNEL
 934     case TK_FLT: {
 935       init_exp(v, VKFLT, 0);
 936       v->u.nval = ls->t.seminfo.r;
 937       break;
 938     }
 939 #endif
 940     case TK_INT: {
 941       init_exp(v, VKINT, 0);
 942       v->u.ival = ls->t.seminfo.i;
 943       break;
 944     }
 945     case TK_STRING: {
 946       codestring(ls, v, ls->t.seminfo.ts);
 947       break;
 948     }
 949     case TK_NIL: {
 950       init_exp(v, VNIL, 0);
 951       break;
 952     }
 953     case TK_TRUE: {
 954       init_exp(v, VTRUE, 0);
 955       break;
 956     }
 957     case TK_FALSE: {
 958       init_exp(v, VFALSE, 0);
 959       break;
 960     }
 961     case TK_DOTS: {  /* vararg */
 962       FuncState *fs = ls->fs;
 963       check_condition(ls, fs->f->is_vararg,
 964                       "cannot use '...' outside a vararg function");
 965       init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
 966       break;
 967     }
 968     case '{': {  /* constructor */
 969       constructor(ls, v);
 970       return;
 971     }
 972     case TK_FUNCTION: {
 973       luaX_next(ls);
 974       body(ls, v, 0, ls->linenumber);
 975       return;
 976     }
 977     default: {
 978       suffixedexp(ls, v);
 979       return;
 980     }
 981   }
 982   luaX_next(ls);
 983 }
 984
 985
 986 static UnOpr getunopr (int op) {
 987   switch (op) {
 988     case TK_NOT: return OPR_NOT;
 989     case '-': return OPR_MINUS;
 990     case '~': return OPR_BNOT;
 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_MOD;
1003 #ifndef _KERNEL
1004     case '^': return OPR_POW;
1005     case '/': return OPR_DIV;
1006 #else
1007     case '/': return OPR_IDIV;
1008 #endif
1009     case TK_IDIV: return OPR_IDIV;
1010     case '&': return OPR_BAND;
1011     case '|': return OPR_BOR;
1012     case '~': return OPR_BXOR;
1013     case TK_SHL: return OPR_SHL;
1014     case TK_SHR: return OPR_SHR;
1015     case TK_CONCAT: return OPR_CONCAT;
1016     case TK_NE: return OPR_NE;
1017     case TK_EQ: return OPR_EQ;
1018     case '<': return OPR_LT;
1019     case TK_LE: return OPR_LE;
1020     case '>': return OPR_GT;
1021     case TK_GE: return OPR_GE;
1022     case TK_AND: return OPR_AND;
1023     case TK_OR: return OPR_OR;
1024     default: return OPR_NOBINOPR;
1025   }
1026 }
1027
1028
1029 static const struct {
1030   lu_byte left;  /* left priority for each binary operator */
1031   lu_byte right; /* right priority */
1032 } priority[] = {  /* ORDER OPR */
1033    {10, 10}, {10, 10},           /* '+' '-' */
1034    {11, 11}, {11, 11},           /* '*' '%' */
1035    {14, 13},                  /* '^' (right associative) */
1036    {11, 11}, {11, 11},           /* '/' '//' */
1037    {6, 6}, {4, 4}, {5, 5},   /* '&' '|' '~' */
1038    {7, 7}, {7, 7},           /* '<<' '>>' */
1039    {9, 8},                   /* '..' (right associative) */
1040    {3, 3}, {3, 3}, {3, 3},   /* ==, <, <= */
1041    {3, 3}, {3, 3}, {3, 3},   /* ~=, >, >= */
1042    {2, 2}, {1, 1}            /* and, or */
1043 };
1044
1045 #define UNARY_PRIORITY  12  /* priority for unary operators */
1046
1047
1048 /*
1049 ** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
1050 ** where 'binop' is any binary operator with a priority higher than 'limit'
1051 */
1052 static BinOpr subexpr (LexState *ls, expdesc *v, int limit) {
1053   BinOpr op;
1054   UnOpr uop;
1055   enterlevel(ls);
1056   uop = getunopr(ls->t.token);
1057   if (uop != OPR_NOUNOPR) {
1058     int line = ls->linenumber;
1059     luaX_next(ls);
1060     subexpr(ls, v, UNARY_PRIORITY);
1061     luaK_prefix(ls->fs, uop, v, line);
1062   }
1063   else simpleexp(ls, v);
1064   /* expand while operators have priorities higher than 'limit' */
1065   op = getbinopr(ls->t.token);
1066   while (op != OPR_NOBINOPR && priority[op].left > limit) {
1067     expdesc v2;
1068     BinOpr nextop;
1069     int line = ls->linenumber;
1070     luaX_next(ls);
1071     luaK_infix(ls->fs, op, v);
1072     /* read sub-expression with higher priority */
1073     nextop = subexpr(ls, &v2, priority[op].right);
1074     luaK_posfix(ls->fs, op, v, &v2, line);
1075     op = nextop;
1076   }
1077   leavelevel(ls);
1078   return op;  /* return first untreated operator */
1079 }
1080
1081
1082 static void expr (LexState *ls, expdesc *v) {
1083   subexpr(ls, v, 0);
1084 }
1085
1086 /* }==================================================================== */
1087
1088
1089
1090 /*
1091 ** {======================================================================
1092 ** Rules for Statements
1093 ** =======================================================================
1094 */
1095
1096
1097 static void block (LexState *ls) {
1098   /* block -> statlist */
1099   FuncState *fs = ls->fs;
1100   BlockCnt bl;
1101   enterblock(fs, &bl, 0);
1102   statlist(ls);
1103   leaveblock(fs);
1104 }
1105
1106
1107 /*
1108 ** structure to chain all variables in the left-hand side of an
1109 ** assignment
1110 */
1111 struct LHS_assign {
1112   struct LHS_assign *prev;
1113   expdesc v;  /* variable (global, local, upvalue, or indexed) */
1114 };
1115
1116
1117 /*
1118 ** check whether, in an assignment to an upvalue/local variable, the
1119 ** upvalue/local variable is begin used in a previous assignment to a
1120 ** table. If so, save original upvalue/local value in a safe place and
1121 ** use this safe copy in the previous assignment.
1122 */
1123 static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
1124   FuncState *fs = ls->fs;
1125   int extra = fs->freereg;  /* eventual position to save local variable */
1126   int conflict = 0;
1127   for (; lh; lh = lh->prev) {  /* check all previous assignments */
1128     if (lh->v.k == VINDEXED) {  /* assigning to a table? */
1129       /* table is the upvalue/local being assigned now? */
1130       if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) {
1131         conflict = 1;
1132         lh->v.u.ind.vt = VLOCAL;
1133         lh->v.u.ind.t = extra;  /* previous assignment will use safe copy */
1134       }
1135       /* index is the local being assigned? (index cannot be upvalue) */
1136       if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) {
1137         conflict = 1;
1138         lh->v.u.ind.idx = extra;  /* previous assignment will use safe copy */
1139       }
1140     }
1141   }
1142   if (conflict) {
1143     /* copy upvalue/local value to a temporary (in position 'extra') */
1144     OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
1145     luaK_codeABC(fs, op, extra, v->u.info, 0);
1146     luaK_reserveregs(fs, 1);
1147   }
1148 }
1149
1150
1151 static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
1152   expdesc e;
1153   check_condition(ls, vkisvar(lh->v.k), "syntax error");
1154   if (testnext(ls, ',')) {  /* assignment -> ',' suffixedexp assignment */
1155     struct LHS_assign nv;
1156     nv.prev = lh;
1157     suffixedexp(ls, &nv.v);
1158     if (nv.v.k != VINDEXED)
1159       check_conflict(ls, lh, &nv.v);
1160     checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS,
1161                     "C levels");
1162     assignment(ls, &nv, nvars+1);
1163   }
1164   else {  /* assignment -> '=' explist */
1165     int nexps;
1166     checknext(ls, '=');
1167     nexps = explist(ls, &e);
1168     if (nexps != nvars) {
1169       adjust_assign(ls, nvars, nexps, &e);
1170       if (nexps > nvars)
1171         ls->fs->freereg -= nexps - nvars;  /* remove extra values */
1172     }
1173     else {
1174       luaK_setoneret(ls->fs, &e);  /* close last expression */
1175       luaK_storevar(ls->fs, &lh->v, &e);
1176       return;  /* avoid default */
1177     }
1178   }
1179   init_exp(&e, VNONRELOC, ls->fs->freereg-1);  /* default assignment */
1180   luaK_storevar(ls->fs, &lh->v, &e);
1181 }
1182
1183
1184 static int cond (LexState *ls) {
1185   /* cond -> exp */
1186   expdesc v;
1187   expr(ls, &v);  /* read condition */
1188   if (v.k == VNIL) v.k = VFALSE;  /* 'falses' are all equal here */
1189   luaK_goiftrue(ls->fs, &v);
1190   return v.f;
1191 }
1192
1193
1194 static void gotostat (LexState *ls, int pc) {
1195   int line = ls->linenumber;
1196   TString *label;
1197   int g;
1198   if (testnext(ls, TK_GOTO))
1199     label = str_checkname(ls);
1200   else {
1201     luaX_next(ls);  /* skip break */
1202     label = luaS_new(ls->L, "break");
1203   }
1204   g = newlabelentry(ls, &ls->dyd->gt, label, line, pc);
1205   findlabel(ls, g);  /* close it if label already defined */
1206 }
1207
1208
1209 /* check for repeated labels on the same block */
1210 static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) {
1211   int i;
1212   for (i = fs->bl->firstlabel; i < ll->n; i++) {
1213     if (eqstr(label, ll->arr[i].name)) {
1214       const char *msg = luaO_pushfstring(fs->ls->L,
1215                           "label '%s' already defined on line %d",
1216                           getstr(label), ll->arr[i].line);
1217       semerror(fs->ls, msg);
1218     }
1219   }
1220 }
1221
1222
1223 /* skip no-op statements */
1224 static void skipnoopstat (LexState *ls) {
1225   while (ls->t.token == ';' || ls->t.token == TK_DBCOLON)
1226     statement(ls);
1227 }
1228
1229
1230 static void labelstat (LexState *ls, TString *label, int line) {
1231   /* label -> '::' NAME '::' */
1232   FuncState *fs = ls->fs;
1233   Labellist *ll = &ls->dyd->label;
1234   int l;  /* index of new label being created */
1235   checkrepeated(fs, ll, label);  /* check for repeated labels */
1236   checknext(ls, TK_DBCOLON);  /* skip double colon */
1237   /* create new entry for this label */
1238   l = newlabelentry(ls, ll, label, line, fs->pc);
1239   skipnoopstat(ls);  /* skip other no-op statements */
1240   if (block_follow(ls, 0)) {  /* label is last no-op statement in the block? */
1241     /* assume that locals are already out of scope */
1242     ll->arr[l].nactvar = fs->bl->nactvar;
1243   }
1244   findgotos(ls, &ll->arr[l]);
1245 }
1246
1247
1248 static void whilestat (LexState *ls, int line) {
1249   /* whilestat -> WHILE cond DO block END */
1250   FuncState *fs = ls->fs;
1251   int whileinit;
1252   int condexit;
1253   BlockCnt bl;
1254   luaX_next(ls);  /* skip WHILE */
1255   whileinit = luaK_getlabel(fs);
1256   condexit = cond(ls);
1257   enterblock(fs, &bl, 1);
1258   checknext(ls, TK_DO);
1259   block(ls);
1260   luaK_jumpto(fs, whileinit);
1261   check_match(ls, TK_END, TK_WHILE, line);
1262   leaveblock(fs);
1263   luaK_patchtohere(fs, condexit);  /* false conditions finish the loop */
1264 }
1265
1266
1267 static void repeatstat (LexState *ls, int line) {
1268   /* repeatstat -> REPEAT block UNTIL cond */
1269   int condexit;
1270   FuncState *fs = ls->fs;
1271   int repeat_init = luaK_getlabel(fs);
1272   BlockCnt bl1, bl2;
1273   enterblock(fs, &bl1, 1);  /* loop block */
1274   enterblock(fs, &bl2, 0);  /* scope block */
1275   luaX_next(ls);  /* skip REPEAT */
1276   statlist(ls);
1277   check_match(ls, TK_UNTIL, TK_REPEAT, line);
1278   condexit = cond(ls);  /* read condition (inside scope block) */
1279   if (bl2.upval)  /* upvalues? */
1280     luaK_patchclose(fs, condexit, bl2.nactvar);
1281   leaveblock(fs);  /* finish scope */
1282   luaK_patchlist(fs, condexit, repeat_init);  /* close the loop */
1283   leaveblock(fs);  /* finish loop */
1284 }
1285
1286
1287 static int exp1 (LexState *ls) {
1288   expdesc e;
1289   int reg;
1290   expr(ls, &e);
1291   luaK_exp2nextreg(ls->fs, &e);
1292   lua_assert(e.k == VNONRELOC);
1293   reg = e.u.info;
1294   return reg;
1295 }
1296
1297
1298 static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
1299   /* forbody -> DO block */
1300   BlockCnt bl;
1301   FuncState *fs = ls->fs;
1302   int prep, endfor;
1303   adjustlocalvars(ls, 3);  /* control variables */
1304   checknext(ls, TK_DO);
1305   prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
1306   enterblock(fs, &bl, 0);  /* scope for declared variables */
1307   adjustlocalvars(ls, nvars);
1308   luaK_reserveregs(fs, nvars);
1309   block(ls);
1310   leaveblock(fs);  /* end of scope for declared variables */
1311   luaK_patchtohere(fs, prep);
1312   if (isnum)  /* numeric for? */
1313     endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP);
1314   else {  /* generic for */
1315     luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
1316     luaK_fixline(fs, line);
1317     endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP);
1318   }
1319   luaK_patchlist(fs, endfor, prep + 1);
1320   luaK_fixline(fs, line);
1321 }
1322
1323
1324 static void fornum (LexState *ls, TString *varname, int line) {
1325   /* fornum -> NAME = exp1,exp1[,exp1] forbody */
1326   FuncState *fs = ls->fs;
1327   int base = fs->freereg;
1328   new_localvarliteral(ls, "(for index)");
1329   new_localvarliteral(ls, "(for limit)");
1330   new_localvarliteral(ls, "(for step)");
1331   new_localvar(ls, varname);
1332   checknext(ls, '=');
1333   exp1(ls);  /* initial value */
1334   checknext(ls, ',');
1335   exp1(ls);  /* limit */
1336   if (testnext(ls, ','))
1337     exp1(ls);  /* optional step */
1338   else {  /* default step = 1 */
1339     luaK_codek(fs, fs->freereg, luaK_intK(fs, 1));
1340     luaK_reserveregs(fs, 1);
1341   }
1342   forbody(ls, base, line, 1, 1);
1343 }
1344
1345
1346 static void forlist (LexState *ls, TString *indexname) {
1347   /* forlist -> NAME {,NAME} IN explist forbody */
1348   FuncState *fs = ls->fs;
1349   expdesc e;
1350   int nvars = 4;  /* gen, state, control, plus at least one declared var */
1351   int line;
1352   int base = fs->freereg;
1353   /* create control variables */
1354   new_localvarliteral(ls, "(for generator)");
1355   new_localvarliteral(ls, "(for state)");
1356   new_localvarliteral(ls, "(for control)");
1357   /* create declared variables */
1358   new_localvar(ls, indexname);
1359   while (testnext(ls, ',')) {
1360     new_localvar(ls, str_checkname(ls));
1361     nvars++;
1362   }
1363   checknext(ls, TK_IN);
1364   line = ls->linenumber;
1365   adjust_assign(ls, 3, explist(ls, &e), &e);
1366   luaK_checkstack(fs, 3);  /* extra space to call generator */
1367   forbody(ls, base, line, nvars - 3, 0);
1368 }
1369
1370
1371 static void forstat (LexState *ls, int line) {
1372   /* forstat -> FOR (fornum | forlist) END */
1373   FuncState *fs = ls->fs;
1374   TString *varname;
1375   BlockCnt bl;
1376   enterblock(fs, &bl, 1);  /* scope for loop and control variables */
1377   luaX_next(ls);  /* skip 'for' */
1378   varname = str_checkname(ls);  /* first variable name */
1379   switch (ls->t.token) {
1380     case '=': fornum(ls, varname, line); break;
1381     case ',': case TK_IN: forlist(ls, varname); break;
1382     default: luaX_syntaxerror(ls, "'=' or 'in' expected");
1383   }
1384   check_match(ls, TK_END, TK_FOR, line);
1385   leaveblock(fs);  /* loop scope ('break' jumps to this point) */
1386 }
1387
1388
1389 static void test_then_block (LexState *ls, int *escapelist) {
1390   /* test_then_block -> [IF | ELSEIF] cond THEN block */
1391   BlockCnt bl;
1392   FuncState *fs = ls->fs;
1393   expdesc v;
1394   int jf;  /* instruction to skip 'then' code (if condition is false) */
1395   luaX_next(ls);  /* skip IF or ELSEIF */
1396   expr(ls, &v);  /* read condition */
1397   checknext(ls, TK_THEN);
1398   if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) {
1399     luaK_goiffalse(ls->fs, &v);  /* will jump to label if condition is true */
1400     enterblock(fs, &bl, 0);  /* must enter block before 'goto' */
1401     gotostat(ls, v.t);  /* handle goto/break */
1402     skipnoopstat(ls);  /* skip other no-op statements */
1403     if (block_follow(ls, 0)) {  /* 'goto' is the entire block? */
1404       leaveblock(fs);
1405       return;  /* and that is it */
1406     }
1407     else  /* must skip over 'then' part if condition is false */
1408       jf = luaK_jump(fs);
1409   }
1410   else {  /* regular case (not goto/break) */
1411     luaK_goiftrue(ls->fs, &v);  /* skip over block if condition is false */
1412     enterblock(fs, &bl, 0);
1413     jf = v.f;
1414   }
1415   statlist(ls);  /* 'then' part */
1416   leaveblock(fs);
1417   if (ls->t.token == TK_ELSE ||
1418       ls->t.token == TK_ELSEIF)  /* followed by 'else'/'elseif'? */
1419     luaK_concat(fs, escapelist, luaK_jump(fs));  /* must jump over it */
1420   luaK_patchtohere(fs, jf);
1421 }
1422
1423
1424 static void ifstat (LexState *ls, int line) {
1425   /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
1426   FuncState *fs = ls->fs;
1427   int escapelist = NO_JUMP;  /* exit list for finished parts */
1428   test_then_block(ls, &escapelist);  /* IF cond THEN block */
1429   while (ls->t.token == TK_ELSEIF)
1430     test_then_block(ls, &escapelist);  /* ELSEIF cond THEN block */
1431   if (testnext(ls, TK_ELSE))
1432     block(ls);  /* 'else' part */
1433   check_match(ls, TK_END, TK_IF, line);
1434   luaK_patchtohere(fs, escapelist);  /* patch escape list to 'if' end */
1435 }
1436
1437
1438 static void localfunc (LexState *ls) {
1439   expdesc b;
1440   FuncState *fs = ls->fs;
1441   new_localvar(ls, str_checkname(ls));  /* new local variable */
1442   adjustlocalvars(ls, 1);  /* enter its scope */
1443   body(ls, &b, 0, ls->linenumber);  /* function created in next register */
1444   /* debug information will only see the variable after this point! */
1445   getlocvar(fs, b.u.info)->startpc = fs->pc;
1446 }
1447
1448
1449 static void localstat (LexState *ls) {
1450   /* stat -> LOCAL NAME {',' NAME} ['=' explist] */
1451   int nvars = 0;
1452   int nexps;
1453   expdesc e;
1454   do {
1455     new_localvar(ls, str_checkname(ls));
1456     nvars++;
1457   } while (testnext(ls, ','));
1458   if (testnext(ls, '='))
1459     nexps = explist(ls, &e);
1460   else {
1461     e.k = VVOID;
1462     nexps = 0;
1463   }
1464   adjust_assign(ls, nvars, nexps, &e);
1465   adjustlocalvars(ls, nvars);
1466 }
1467
1468
1469 static int funcname (LexState *ls, expdesc *v) {
1470   /* funcname -> NAME {fieldsel} [':' NAME] */
1471   int ismethod = 0;
1472   singlevar(ls, v);
1473   while (ls->t.token == '.')
1474     fieldsel(ls, v);
1475   if (ls->t.token == ':') {
1476     ismethod = 1;
1477     fieldsel(ls, v);
1478   }
1479   return ismethod;
1480 }
1481
1482
1483 static void funcstat (LexState *ls, int line) {
1484   /* funcstat -> FUNCTION funcname body */
1485   int ismethod;
1486   expdesc v, b;
1487   luaX_next(ls);  /* skip FUNCTION */
1488   ismethod = funcname(ls, &v);
1489   body(ls, &b, ismethod, line);
1490   luaK_storevar(ls->fs, &v, &b);
1491   luaK_fixline(ls->fs, line);  /* definition "happens" in the first line */
1492 }
1493
1494
1495 static void exprstat (LexState *ls) {
1496   /* stat -> func | assignment */
1497   FuncState *fs = ls->fs;
1498   struct LHS_assign v;
1499   suffixedexp(ls, &v.v);
1500   if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */
1501     v.prev = NULL;
1502     assignment(ls, &v, 1);
1503   }
1504   else {  /* stat -> func */
1505     check_condition(ls, v.v.k == VCALL, "syntax error");
1506     SETARG_C(getcode(fs, &v.v), 1);  /* call statement uses no results */
1507   }
1508 }
1509
1510
1511 static void retstat (LexState *ls) {
1512   /* stat -> RETURN [explist] [';'] */
1513   FuncState *fs = ls->fs;
1514   expdesc e;
1515   int first, nret;  /* registers with returned values */
1516   if (block_follow(ls, 1) || ls->t.token == ';')
1517     first = nret = 0;  /* return no values */
1518   else {
1519     nret = explist(ls, &e);  /* optional return values */
1520     if (hasmultret(e.k)) {
1521       luaK_setmultret(fs, &e);
1522       if (e.k == VCALL && nret == 1) {  /* tail call? */
1523         SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
1524         lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
1525       }
1526       first = fs->nactvar;
1527       nret = LUA_MULTRET;  /* return all values */
1528     }
1529     else {
1530       if (nret == 1)  /* only one single value? */
1531         first = luaK_exp2anyreg(fs, &e);
1532       else {
1533         luaK_exp2nextreg(fs, &e);  /* values must go to the stack */
1534         first = fs->nactvar;  /* return all active values */
1535         lua_assert(nret == fs->freereg - first);
1536       }
1537     }
1538   }
1539   luaK_ret(fs, first, nret);
1540   testnext(ls, ';');  /* skip optional semicolon */
1541 }
1542
1543
1544 static void statement (LexState *ls) {
1545   int line = ls->linenumber;  /* may be needed for error messages */
1546   enterlevel(ls);
1547   switch (ls->t.token) {
1548     case ';': {  /* stat -> ';' (empty statement) */
1549       luaX_next(ls);  /* skip ';' */
1550       break;
1551     }
1552     case TK_IF: {  /* stat -> ifstat */
1553       ifstat(ls, line);
1554       break;
1555     }
1556     case TK_WHILE: {  /* stat -> whilestat */
1557       whilestat(ls, line);
1558       break;
1559     }
1560     case TK_DO: {  /* stat -> DO block END */
1561       luaX_next(ls);  /* skip DO */
1562       block(ls);
1563       check_match(ls, TK_END, TK_DO, line);
1564       break;
1565     }
1566     case TK_FOR: {  /* stat -> forstat */
1567       forstat(ls, line);
1568       break;
1569     }
1570     case TK_REPEAT: {  /* stat -> repeatstat */
1571       repeatstat(ls, line);
1572       break;
1573     }
1574     case TK_FUNCTION: {  /* stat -> funcstat */
1575       funcstat(ls, line);
1576       break;
1577     }
1578     case TK_LOCAL: {  /* stat -> localstat */
1579       luaX_next(ls);  /* skip LOCAL */
1580       if (testnext(ls, TK_FUNCTION))  /* local function? */
1581         localfunc(ls);
1582       else
1583         localstat(ls);
1584       break;
1585     }
1586     case TK_DBCOLON: {  /* stat -> label */
1587       luaX_next(ls);  /* skip double colon */
1588       labelstat(ls, str_checkname(ls), line);
1589       break;
1590     }
1591     case TK_RETURN: {  /* stat -> retstat */
1592       luaX_next(ls);  /* skip RETURN */
1593       retstat(ls);
1594       break;
1595     }
1596     case TK_BREAK:   /* stat -> breakstat */
1597     case TK_GOTO: {  /* stat -> 'goto' NAME */
1598       gotostat(ls, luaK_jump(ls->fs));
1599       break;
1600     }
1601     default: {  /* stat -> func | assignment */
1602       exprstat(ls);
1603       break;
1604     }
1605   }
1606   lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
1607              ls->fs->freereg >= ls->fs->nactvar);
1608   ls->fs->freereg = ls->fs->nactvar;  /* free registers */
1609   leavelevel(ls);
1610 }
1611
1612 /* }====================================================================== */
1613
1614
1615 /*
1616 ** compiles the main function, which is a regular vararg function with an
1617 ** upvalue named LUA_ENV
1618 */
1619 static void mainfunc (LexState *ls, FuncState *fs) {
1620   BlockCnt bl;
1621   expdesc v;
1622   open_func(ls, fs, &bl);
1623   fs->f->is_vararg = 1;  /* main function is always vararg */
1624   init_exp(&v, VLOCAL, 0);  /* create and... */
1625   newupvalue(fs, ls->envn, &v);  /* ...set environment upvalue */
1626   luaX_next(ls);  /* read first token */
1627   statlist(ls);  /* parse main body */
1628   check(ls, TK_EOS);
1629   close_func(ls);
1630 }
1631
1632
1633 LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
1634                        Dyndata *dyd, const char *name, int firstchar) {
1635   LexState lexstate;
1636   FuncState funcstate;
1637   LClosure *cl = luaF_newLclosure(L, 1);  /* create main closure */
1638   setclLvalue(L, L->top, cl);  /* anchor it (to avoid being collected) */
1639   incr_top(L);
1640   lexstate.h = luaH_new(L);  /* create table for scanner */
1641   sethvalue(L, L->top, lexstate.h);  /* anchor it */
1642   incr_top(L);
1643   funcstate.f = cl->p = luaF_newproto(L);
1644   funcstate.f->source = luaS_new(L, name);  /* create and anchor TString */
1645   lua_assert(iswhite(funcstate.f));  /* do not need barrier here */
1646   lexstate.buff = buff;
1647   lexstate.dyd = dyd;
1648   dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
1649   luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar);
1650   mainfunc(&lexstate, &funcstate);
1651   lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
1652   /* all scopes should be correctly finished */
1653   lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0);
1654   L->top--;  /* remove scanner's table */
1655   return cl;  /* closure is on the stack, too */
1656 }
1657