kernel/fs/zfs/lua/lparser.c

   1 /*
   2 ** $Id: lparser.c,v 2.130.1.1 2013/04/12 18:48:47 roberto Exp $
   3 ** Lua Parser
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #include <sys/zfs_context.h>
   8
   9 #define lparser_c
  10 #define LUA_CORE
  11
  12 #include "lua.h"
  13
  14 #include "lcode.h"
  15 #include "ldebug.h"
  16 #include "ldo.h"
  17 #include "lfunc.h"
  18 #include "llex.h"
  19 #include "lmem.h"
  20 #include "lobject.h"
  21 #include "lopcodes.h"
  22 #include "lparser.h"
  23 #include "lstate.h"
  24 #include "lstring.h"
  25 #include "ltable.h"
  26
  27
  28
  29 /* maximum number of local variables per function (must be smaller
  30    than 250, due to the bytecode format) */
  31 #define MAXVARS         200
  32
  33
  34 #define hasmultret(k)           ((k) == VCALL || (k) == VVARARG)
  35
  36
  37
  38 /*
  39 ** nodes for block list (list of active blocks)
  40 */
  41 typedef struct BlockCnt {
  42   struct BlockCnt *previous;  /* chain */
  43   short firstlabel;  /* index of first label in this block */
  44   short firstgoto;  /* index of first pending goto in this block */
  45   lu_byte nactvar;  /* # active locals outside the block */
  46   lu_byte upval;  /* true if some variable in the block is an upvalue */
  47   lu_byte isloop;  /* true if `block' is a loop */
  48 } BlockCnt;
  49
  50
  51
  52 /*
  53 ** prototypes for recursive non-terminal functions
  54 */
  55 static void statement (LexState *ls);
  56 static void expr (LexState *ls, expdesc *v);
  57
  58
  59 static void anchor_token (LexState *ls) {
  60   /* last token from outer function must be EOS */
  61   lua_assert(ls->fs != NULL || ls->t.token == TK_EOS);
  62   if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) {
  63     TString *ts = ls->t.seminfo.ts;
  64     luaX_newstring(ls, getstr(ts), ts->tsv.len);
  65   }
  66 }
  67
  68
  69 /* semantic error */
  70 static l_noret semerror (LexState *ls, const char *msg) {
  71   ls->t.token = 0;  /* remove 'near to' from final message */
  72   luaX_syntaxerror(ls, msg);
  73 }
  74
  75
  76 static l_noret error_expected (LexState *ls, int token) {
  77   luaX_syntaxerror(ls,
  78       luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token)));
  79 }
  80
  81
  82 static l_noret errorlimit (FuncState *fs, int limit, const char *what) {
  83   lua_State *L = fs->ls->L;
  84   const char *msg;
  85   int line = fs->f->linedefined;
  86   const char *where = (line == 0)
  87                       ? "main function"
  88                       : luaO_pushfstring(L, "function at line %d", line);
  89   msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s",
  90                              what, limit, where);
  91   luaX_syntaxerror(fs->ls, msg);
  92 }
  93
  94
  95 static void checklimit (FuncState *fs, int v, int l, const char *what) {
  96   if (v > l) errorlimit(fs, l, what);
  97 }
  98
  99
 100 static int testnext (LexState *ls, int c) {
 101   if (ls->t.token == c) {
 102     luaX_next(ls);
 103     return 1;
 104   }
 105   else return 0;
 106 }
 107
 108
 109 static void check (LexState *ls, int c) {
 110   if (ls->t.token != c)
 111     error_expected(ls, c);
 112 }
 113
 114
 115 static void checknext (LexState *ls, int c) {
 116   check(ls, c);
 117   luaX_next(ls);
 118 }
 119
 120
 121 #define check_condition(ls,c,msg)       { if (!(c)) luaX_syntaxerror(ls, msg); }
 122
 123
 124
 125 static void check_match (LexState *ls, int what, int who, int where) {
 126   if (!testnext(ls, what)) {
 127     if (where == ls->linenumber)
 128       error_expected(ls, what);
 129     else {
 130       luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
 131              "%s expected (to close %s at line %d)",
 132               luaX_token2str(ls, what), luaX_token2str(ls, who), where));
 133     }
 134   }
 135 }
 136
 137
 138 static TString *str_checkname (LexState *ls) {
 139   TString *ts;
 140   check(ls, TK_NAME);
 141   ts = ls->t.seminfo.ts;
 142   luaX_next(ls);
 143   return ts;
 144 }
 145
 146
 147 static void init_exp (expdesc *e, expkind k, int i) {
 148   e->f = e->t = NO_JUMP;
 149   e->k = k;
 150   e->u.info = i;
 151 }
 152
 153
 154 static void codestring (LexState *ls, expdesc *e, TString *s) {
 155   init_exp(e, VK, luaK_stringK(ls->fs, s));
 156 }
 157
 158
 159 static void checkname (LexState *ls, expdesc *e) {
 160   codestring(ls, e, str_checkname(ls));
 161 }
 162
 163
 164 static int registerlocalvar (LexState *ls, TString *varname) {
 165   FuncState *fs = ls->fs;
 166   Proto *f = fs->f;
 167   int oldsize = f->sizelocvars;
 168   luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
 169                   LocVar, SHRT_MAX, "local variables");
 170   while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL;
 171   f->locvars[fs->nlocvars].varname = varname;
 172   luaC_objbarrier(ls->L, f, varname);
 173   return fs->nlocvars++;
 174 }
 175
 176
 177 static void new_localvar (LexState *ls, TString *name) {
 178   FuncState *fs = ls->fs;
 179   Dyndata *dyd = ls->dyd;
 180   int reg = registerlocalvar(ls, name);
 181   checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal,
 182                   MAXVARS, "local variables");
 183   luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1,
 184                   dyd->actvar.size, Vardesc, MAX_INT, "local variables");
 185   dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg);
 186 }
 187
 188
 189 static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) {
 190   new_localvar(ls, luaX_newstring(ls, name, sz));
 191 }
 192
 193 #define new_localvarliteral(ls,v) \
 194         new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1)
 195
 196
 197 static LocVar *getlocvar (FuncState *fs, int i) {
 198   int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx;
 199   lua_assert(idx < fs->nlocvars);
 200   return &fs->f->locvars[idx];
 201 }
 202
 203
 204 static void adjustlocalvars (LexState *ls, int nvars) {
 205   FuncState *fs = ls->fs;
 206   fs->nactvar = cast_byte(fs->nactvar + nvars);
 207   for (; nvars; nvars--) {
 208     getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc;
 209   }
 210 }
 211
 212
 213 static void removevars (FuncState *fs, int tolevel) {
 214   fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel);
 215   while (fs->nactvar > tolevel)
 216     getlocvar(fs, --fs->nactvar)->endpc = fs->pc;
 217 }
 218
 219
 220 static int searchupvalue (FuncState *fs, TString *name) {
 221   int i;
 222   Upvaldesc *up = fs->f->upvalues;
 223   for (i = 0; i < fs->nups; i++) {
 224     if (luaS_eqstr(up[i].name, name)) return i;
 225   }
 226   return -1;  /* not found */
 227 }
 228
 229
 230 static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
 231   Proto *f = fs->f;
 232   int oldsize = f->sizeupvalues;
 233   checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues");
 234   luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues,
 235                   Upvaldesc, MAXUPVAL, "upvalues");
 236   while (oldsize < f->sizeupvalues) f->upvalues[oldsize++].name = NULL;
 237   f->upvalues[fs->nups].instack = (v->k == VLOCAL);
 238   f->upvalues[fs->nups].idx = cast_byte(v->u.info);
 239   f->upvalues[fs->nups].name = name;
 240   luaC_objbarrier(fs->ls->L, f, name);
 241   return fs->nups++;
 242 }
 243
 244
 245 static int searchvar (FuncState *fs, TString *n) {
 246   int i;
 247   for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) {
 248     if (luaS_eqstr(n, getlocvar(fs, i)->varname))
 249       return i;
 250   }
 251   return -1;  /* not found */
 252 }
 253
 254
 255 /*
 256   Mark block where variable at given level was defined
 257   (to emit close instructions later).
 258 */
 259 static void markupval (FuncState *fs, int level) {
 260   BlockCnt *bl = fs->bl;
 261   while (bl->nactvar > level) bl = bl->previous;
 262   bl->upval = 1;
 263 }
 264
 265
 266 /*
 267   Find variable with given name 'n'. If it is an upvalue, add this
 268   upvalue into all intermediate functions.
 269 */
 270 static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
 271   if (fs == NULL)  /* no more levels? */
 272     return VVOID;  /* default is global */
 273   else {
 274     int v = searchvar(fs, n);  /* look up locals at current level */
 275     if (v >= 0) {  /* found? */
 276       init_exp(var, VLOCAL, v);  /* variable is local */
 277       if (!base)
 278         markupval(fs, v);  /* local will be used as an upval */
 279       return VLOCAL;
 280     }
 281     else {  /* not found as local at current level; try upvalues */
 282       int idx = searchupvalue(fs, n);  /* try existing upvalues */
 283       if (idx < 0) {  /* not found? */
 284         if (singlevaraux(fs->prev, n, var, 0) == VVOID) /* try upper levels */
 285           return VVOID;  /* not found; is a global */
 286         /* else was LOCAL or UPVAL */
 287         idx  = newupvalue(fs, n, var);  /* will be a new upvalue */
 288       }
 289       init_exp(var, VUPVAL, idx);
 290       return VUPVAL;
 291     }
 292   }
 293 }
 294
 295
 296 static void singlevar (LexState *ls, expdesc *var) {
 297   TString *varname = str_checkname(ls);
 298   FuncState *fs = ls->fs;
 299   if (singlevaraux(fs, varname, var, 1) == VVOID) {  /* global name? */
 300     expdesc key;
 301     singlevaraux(fs, ls->envn, var, 1);  /* get environment variable */
 302     lua_assert(var->k == VLOCAL || var->k == VUPVAL);
 303     codestring(ls, &key, varname);  /* key is variable name */
 304     luaK_indexed(fs, var, &key);  /* env[varname] */
 305   }
 306 }
 307
 308
 309 static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
 310   FuncState *fs = ls->fs;
 311   int extra = nvars - nexps;
 312   if (hasmultret(e->k)) {
 313     extra++;  /* includes call itself */
 314     if (extra < 0) extra = 0;
 315     luaK_setreturns(fs, e, extra);  /* last exp. provides the difference */
 316     if (extra > 1) luaK_reserveregs(fs, extra-1);
 317   }
 318   else {
 319     if (e->k != VVOID) luaK_exp2nextreg(fs, e);  /* close last expression */
 320     if (extra > 0) {
 321       int reg = fs->freereg;
 322       luaK_reserveregs(fs, extra);
 323       luaK_nil(fs, reg, extra);
 324     }
 325   }
 326 }
 327
 328
 329 static void enterlevel (LexState *ls) {
 330   lua_State *L = ls->L;
 331   ++L->nCcalls;
 332   checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "C levels");
 333 }
 334
 335
 336 #define leavelevel(ls)  ((ls)->L->nCcalls--)
 337
 338
 339 static void closegoto (LexState *ls, int g, Labeldesc *label) {
 340   int i;
 341   FuncState *fs = ls->fs;
 342   Labellist *gl = &ls->dyd->gt;
 343   Labeldesc *gt = &gl->arr[g];
 344   lua_assert(luaS_eqstr(gt->name, label->name));
 345   if (gt->nactvar < label->nactvar) {
 346     TString *vname = getlocvar(fs, gt->nactvar)->varname;
 347     const char *msg = luaO_pushfstring(ls->L,
 348       "<goto %s> at line %d jumps into the scope of local " LUA_QS,
 349       getstr(gt->name), gt->line, getstr(vname));
 350     semerror(ls, msg);
 351   }
 352   luaK_patchlist(fs, gt->pc, label->pc);
 353   /* remove goto from pending list */
 354   for (i = g; i < gl->n - 1; i++)
 355     gl->arr[i] = gl->arr[i + 1];
 356   gl->n--;
 357 }
 358
 359
 360 /*
 361 ** try to close a goto with existing labels; this solves backward jumps
 362 */
 363 static int findlabel (LexState *ls, int g) {
 364   int i;
 365   BlockCnt *bl = ls->fs->bl;
 366   Dyndata *dyd = ls->dyd;
 367   Labeldesc *gt = &dyd->gt.arr[g];
 368   /* check labels in current block for a match */
 369   for (i = bl->firstlabel; i < dyd->label.n; i++) {
 370     Labeldesc *lb = &dyd->label.arr[i];
 371     if (luaS_eqstr(lb->name, gt->name)) {  /* correct label? */
 372       if (gt->nactvar > lb->nactvar &&
 373           (bl->upval || dyd->label.n > bl->firstlabel))
 374         luaK_patchclose(ls->fs, gt->pc, lb->nactvar);
 375       closegoto(ls, g, lb);  /* close it */
 376       return 1;
 377     }
 378   }
 379   return 0;  /* label not found; cannot close goto */
 380 }
 381
 382
 383 static int newlabelentry (LexState *ls, Labellist *l, TString *name,
 384                           int line, int pc) {
 385   int n = l->n;
 386   luaM_growvector(ls->L, l->arr, n, l->size,
 387                   Labeldesc, SHRT_MAX, "labels/gotos");
 388   l->arr[n].name = name;
 389   l->arr[n].line = line;
 390   l->arr[n].nactvar = ls->fs->nactvar;
 391   l->arr[n].pc = pc;
 392   l->n++;
 393   return n;
 394 }
 395
 396
 397 /*
 398 ** check whether new label 'lb' matches any pending gotos in current
 399 ** block; solves forward jumps
 400 */
 401 static void findgotos (LexState *ls, Labeldesc *lb) {
 402   Labellist *gl = &ls->dyd->gt;
 403   int i = ls->fs->bl->firstgoto;
 404   while (i < gl->n) {
 405     if (luaS_eqstr(gl->arr[i].name, lb->name))
 406       closegoto(ls, i, lb);
 407     else
 408       i++;
 409   }
 410 }
 411
 412
 413 /*
 414 ** "export" pending gotos to outer level, to check them against
 415 ** outer labels; if the block being exited has upvalues, and
 416 ** the goto exits the scope of any variable (which can be the
 417 ** upvalue), close those variables being exited.
 418 */
 419 static void movegotosout (FuncState *fs, BlockCnt *bl) {
 420   int i = bl->firstgoto;
 421   Labellist *gl = &fs->ls->dyd->gt;
 422   /* correct pending gotos to current block and try to close it
 423      with visible labels */
 424   while (i < gl->n) {
 425     Labeldesc *gt = &gl->arr[i];
 426     if (gt->nactvar > bl->nactvar) {
 427       if (bl->upval)
 428         luaK_patchclose(fs, gt->pc, bl->nactvar);
 429       gt->nactvar = bl->nactvar;
 430     }
 431     if (!findlabel(fs->ls, i))
 432       i++;  /* move to next one */
 433   }
 434 }
 435
 436
 437 static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) {
 438   bl->isloop = isloop;
 439   bl->nactvar = fs->nactvar;
 440   bl->firstlabel = fs->ls->dyd->label.n;
 441   bl->firstgoto = fs->ls->dyd->gt.n;
 442   bl->upval = 0;
 443   bl->previous = fs->bl;
 444   fs->bl = bl;
 445   lua_assert(fs->freereg == fs->nactvar);
 446 }
 447
 448
 449 /*
 450 ** create a label named "break" to resolve break statements
 451 */
 452 static void breaklabel (LexState *ls) {
 453   TString *n = luaS_new(ls->L, "break");
 454   int l = newlabelentry(ls, &ls->dyd->label, n, 0, ls->fs->pc);
 455   findgotos(ls, &ls->dyd->label.arr[l]);
 456 }
 457
 458 /*
 459 ** generates an error for an undefined 'goto'; choose appropriate
 460 ** message when label name is a reserved word (which can only be 'break')
 461 */
 462 static l_noret undefgoto (LexState *ls, Labeldesc *gt) {
 463   const char *msg = isreserved(gt->name)
 464                     ? "<%s> at line %d not inside a loop"
 465                     : "no visible label " LUA_QS " for <goto> at line %d";
 466   msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line);
 467   semerror(ls, msg);
 468 }
 469
 470
 471 static void leaveblock (FuncState *fs) {
 472   BlockCnt *bl = fs->bl;
 473   LexState *ls = fs->ls;
 474   if (bl->previous && bl->upval) {
 475     /* create a 'jump to here' to close upvalues */
 476     int j = luaK_jump(fs);
 477     luaK_patchclose(fs, j, bl->nactvar);
 478     luaK_patchtohere(fs, j);
 479   }
 480   if (bl->isloop)
 481     breaklabel(ls);  /* close pending breaks */
 482   fs->bl = bl->previous;
 483   removevars(fs, bl->nactvar);
 484   lua_assert(bl->nactvar == fs->nactvar);
 485   fs->freereg = fs->nactvar;  /* free registers */
 486   ls->dyd->label.n = bl->firstlabel;  /* remove local labels */
 487   if (bl->previous)  /* inner block? */
 488     movegotosout(fs, bl);  /* update pending gotos to outer block */
 489   else if (bl->firstgoto < ls->dyd->gt.n)  /* pending gotos in outer block? */
 490     undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]);  /* error */
 491 }
 492
 493
 494 /*
 495 ** adds a new prototype into list of prototypes
 496 */
 497 static Proto *addprototype (LexState *ls) {
 498   Proto *clp;
 499   lua_State *L = ls->L;
 500   FuncState *fs = ls->fs;
 501   Proto *f = fs->f;  /* prototype of current function */
 502   if (fs->np >= f->sizep) {
 503     int oldsize = f->sizep;
 504     luaM_growvector(L, f->p, fs->np, f->sizep, Proto *, MAXARG_Bx, "functions");
 505     while (oldsize < f->sizep) f->p[oldsize++] = NULL;
 506   }
 507   f->p[fs->np++] = clp = luaF_newproto(L);
 508   luaC_objbarrier(L, f, clp);
 509   return clp;
 510 }
 511
 512
 513 /*
 514 ** codes instruction to create new closure in parent function.
 515 ** The OP_CLOSURE instruction must use the last available register,
 516 ** so that, if it invokes the GC, the GC knows which registers
 517 ** are in use at that time.
 518 */
 519 static void codeclosure (LexState *ls, expdesc *v) {
 520   FuncState *fs = ls->fs->prev;
 521   init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1));
 522   luaK_exp2nextreg(fs, v);  /* fix it at the last register */
 523 }
 524
 525
 526 static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
 527   lua_State *L = ls->L;
 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   fs->h = luaH_new(L);
 547   /* anchor table of constants (to avoid being collected) */
 548   sethvalue2s(L, L->top, fs->h);
 549   incr_top(L);
 550   enterblock(fs, bl, 0);
 551 }
 552
 553
 554 static void close_func (LexState *ls) {
 555   lua_State *L = ls->L;
 556   FuncState *fs = ls->fs;
 557   Proto *f = fs->f;
 558   luaK_ret(fs, 0, 0);  /* final return */
 559   leaveblock(fs);
 560   luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
 561   f->sizecode = fs->pc;
 562   luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
 563   f->sizelineinfo = fs->pc;
 564   luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
 565   f->sizek = fs->nk;
 566   luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
 567   f->sizep = fs->np;
 568   luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
 569   f->sizelocvars = fs->nlocvars;
 570   luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc);
 571   f->sizeupvalues = fs->nups;
 572   lua_assert(fs->bl == NULL);
 573   ls->fs = fs->prev;
 574   /* last token read was anchored in defunct function; must re-anchor it */
 575   anchor_token(ls);
 576   L->top--;  /* pop table of constants */
 577   luaC_checkGC(L);
 578 }
 579
 580
 581
 582 /*============================================================*/
 583 /* GRAMMAR RULES */
 584 /*============================================================*/
 585
 586
 587 /*
 588 ** check whether current token is in the follow set of a block.
 589 ** 'until' closes syntactical blocks, but do not close scope,
 590 ** so it handled in separate.
 591 */
 592 static int block_follow (LexState *ls, int withuntil) {
 593   switch (ls->t.token) {
 594     case TK_ELSE: case TK_ELSEIF:
 595     case TK_END: case TK_EOS:
 596       return 1;
 597     case TK_UNTIL: return withuntil;
 598     default: return 0;
 599   }
 600 }
 601
 602
 603 static void statlist (LexState *ls) {
 604   /* statlist -> { stat [`;'] } */
 605   while (!block_follow(ls, 1)) {
 606     if (ls->t.token == TK_RETURN) {
 607       statement(ls);
 608       return;  /* 'return' must be last statement */
 609     }
 610     statement(ls);
 611   }
 612 }
 613
 614
 615 static void fieldsel (LexState *ls, expdesc *v) {
 616   /* fieldsel -> ['.' | ':'] NAME */
 617   FuncState *fs = ls->fs;
 618   expdesc key;
 619   luaK_exp2anyregup(fs, v);
 620   luaX_next(ls);  /* skip the dot or colon */
 621   checkname(ls, &key);
 622   luaK_indexed(fs, v, &key);
 623 }
 624
 625
 626 static void yindex (LexState *ls, expdesc *v) {
 627   /* index -> '[' expr ']' */
 628   luaX_next(ls);  /* skip the '[' */
 629   expr(ls, v);
 630   luaK_exp2val(ls->fs, v);
 631   checknext(ls, ']');
 632 }
 633
 634
 635 /*
 636 ** {======================================================================
 637 ** Rules for Constructors
 638 ** =======================================================================
 639 */
 640
 641
 642 struct ConsControl {
 643   expdesc v;  /* last list item read */
 644   expdesc *t;  /* table descriptor */
 645   int nh;  /* total number of `record' elements */
 646   int na;  /* total number of array elements */
 647   int tostore;  /* number of array elements pending to be stored */
 648 };
 649
 650
 651 static void recfield (LexState *ls, struct ConsControl *cc) {
 652   /* recfield -> (NAME | `['exp1`]') = exp1 */
 653   FuncState *fs = ls->fs;
 654   int reg = ls->fs->freereg;
 655   expdesc key, val;
 656   int rkkey;
 657   if (ls->t.token == TK_NAME) {
 658     checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
 659     checkname(ls, &key);
 660   }
 661   else  /* ls->t.token == '[' */
 662     yindex(ls, &key);
 663   cc->nh++;
 664   checknext(ls, '=');
 665   rkkey = luaK_exp2RK(fs, &key);
 666   expr(ls, &val);
 667   luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val));
 668   fs->freereg = reg;  /* free registers */
 669 }
 670
 671
 672 static void closelistfield (FuncState *fs, struct ConsControl *cc) {
 673   if (cc->v.k == VVOID) return;  /* there is no list item */
 674   luaK_exp2nextreg(fs, &cc->v);
 675   cc->v.k = VVOID;
 676   if (cc->tostore == LFIELDS_PER_FLUSH) {
 677     luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);  /* flush */
 678     cc->tostore = 0;  /* no more items pending */
 679   }
 680 }
 681
 682
 683 static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
 684   if (cc->tostore == 0) return;
 685   if (hasmultret(cc->v.k)) {
 686     luaK_setmultret(fs, &cc->v);
 687     luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET);
 688     cc->na--;  /* do not count last expression (unknown number of elements) */
 689   }
 690   else {
 691     if (cc->v.k != VVOID)
 692       luaK_exp2nextreg(fs, &cc->v);
 693     luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);
 694   }
 695 }
 696
 697
 698 static void listfield (LexState *ls, struct ConsControl *cc) {
 699   /* listfield -> exp */
 700   expr(ls, &cc->v);
 701   checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
 702   cc->na++;
 703   cc->tostore++;
 704 }
 705
 706
 707 static void field (LexState *ls, struct ConsControl *cc) {
 708   /* field -> listfield | recfield */
 709   switch(ls->t.token) {
 710     case TK_NAME: {  /* may be 'listfield' or 'recfield' */
 711       if (luaX_lookahead(ls) != '=')  /* expression? */
 712         listfield(ls, cc);
 713       else
 714         recfield(ls, cc);
 715       break;
 716     }
 717     case '[': {
 718       recfield(ls, cc);
 719       break;
 720     }
 721     default: {
 722       listfield(ls, cc);
 723       break;
 724     }
 725   }
 726 }
 727
 728
 729 static void constructor (LexState *ls, expdesc *t) {
 730   /* constructor -> '{' [ field { sep field } [sep] ] '}'
 731      sep -> ',' | ';' */
 732   FuncState *fs = ls->fs;
 733   int line = ls->linenumber;
 734   int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
 735   struct ConsControl cc;
 736   cc.na = cc.nh = cc.tostore = 0;
 737   cc.t = t;
 738   init_exp(t, VRELOCABLE, pc);
 739   init_exp(&cc.v, VVOID, 0);  /* no value (yet) */
 740   luaK_exp2nextreg(ls->fs, t);  /* fix it at stack top */
 741   checknext(ls, '{');
 742   do {
 743     lua_assert(cc.v.k == VVOID || cc.tostore > 0);
 744     if (ls->t.token == '}') break;
 745     closelistfield(fs, &cc);
 746     field(ls, &cc);
 747   } while (testnext(ls, ',') || testnext(ls, ';'));
 748   check_match(ls, '}', '{', line);
 749   lastlistfield(fs, &cc);
 750   SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
 751   SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh));  /* set initial table size */
 752 }
 753
 754 /* }====================================================================== */
 755
 756
 757
 758 static void parlist (LexState *ls) {
 759   /* parlist -> [ param { `,' param } ] */
 760   FuncState *fs = ls->fs;
 761   Proto *f = fs->f;
 762   int nparams = 0;
 763   f->is_vararg = 0;
 764   if (ls->t.token != ')') {  /* is `parlist' not empty? */
 765     do {
 766       switch (ls->t.token) {
 767         case TK_NAME: {  /* param -> NAME */
 768           new_localvar(ls, str_checkname(ls));
 769           nparams++;
 770           break;
 771         }
 772         case TK_DOTS: {  /* param -> `...' */
 773           luaX_next(ls);
 774           f->is_vararg = 1;
 775           break;
 776         }
 777         default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected");
 778       }
 779     } while (!f->is_vararg && testnext(ls, ','));
 780   }
 781   adjustlocalvars(ls, nparams);
 782   f->numparams = cast_byte(fs->nactvar);
 783   luaK_reserveregs(fs, fs->nactvar);  /* reserve register for parameters */
 784 }
 785
 786
 787 static void body (LexState *ls, expdesc *e, int ismethod, int line) {
 788   /* body ->  `(' parlist `)' block END */
 789   FuncState new_fs;
 790   BlockCnt bl;
 791   new_fs.f = addprototype(ls);
 792   new_fs.f->linedefined = line;
 793   open_func(ls, &new_fs, &bl);
 794   checknext(ls, '(');
 795   if (ismethod) {
 796     new_localvarliteral(ls, "self");  /* create 'self' parameter */
 797     adjustlocalvars(ls, 1);
 798   }
 799   parlist(ls);
 800   checknext(ls, ')');
 801   statlist(ls);
 802   new_fs.f->lastlinedefined = ls->linenumber;
 803   check_match(ls, TK_END, TK_FUNCTION, line);
 804   codeclosure(ls, e);
 805   close_func(ls);
 806 }
 807
 808
 809 static int explist (LexState *ls, expdesc *v) {
 810   /* explist -> expr { `,' expr } */
 811   int n = 1;  /* at least one expression */
 812   expr(ls, v);
 813   while (testnext(ls, ',')) {
 814     luaK_exp2nextreg(ls->fs, v);
 815     expr(ls, v);
 816     n++;
 817   }
 818   return n;
 819 }
 820
 821
 822 static void funcargs (LexState *ls, expdesc *f, int line) {
 823   FuncState *fs = ls->fs;
 824   expdesc args;
 825   int base, nparams;
 826   switch (ls->t.token) {
 827     case '(': {  /* funcargs -> `(' [ explist ] `)' */
 828       luaX_next(ls);
 829       if (ls->t.token == ')')  /* arg list is empty? */
 830         args.k = VVOID;
 831       else {
 832         explist(ls, &args);
 833         luaK_setmultret(fs, &args);
 834       }
 835       check_match(ls, ')', '(', line);
 836       break;
 837     }
 838     case '{': {  /* funcargs -> constructor */
 839       constructor(ls, &args);
 840       break;
 841     }
 842     case TK_STRING: {  /* funcargs -> STRING */
 843       codestring(ls, &args, ls->t.seminfo.ts);
 844       luaX_next(ls);  /* must use `seminfo' before `next' */
 845       break;
 846     }
 847     default: {
 848       luaX_syntaxerror(ls, "function arguments expected");
 849     }
 850   }
 851   lua_assert(f->k == VNONRELOC);
 852   base = f->u.info;  /* base register for call */
 853   if (hasmultret(args.k))
 854     nparams = LUA_MULTRET;  /* open call */
 855   else {
 856     if (args.k != VVOID)
 857       luaK_exp2nextreg(fs, &args);  /* close last argument */
 858     nparams = fs->freereg - (base+1);
 859   }
 860   init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
 861   luaK_fixline(fs, line);
 862   fs->freereg = base+1;  /* call remove function and arguments and leaves
 863                             (unless changed) one result */
 864 }
 865
 866
 867
 868
 869 /*
 870 ** {======================================================================
 871 ** Expression parsing
 872 ** =======================================================================
 873 */
 874
 875
 876 static void primaryexp (LexState *ls, expdesc *v) {
 877   /* primaryexp -> NAME | '(' expr ')' */
 878   switch (ls->t.token) {
 879     case '(': {
 880       int line = ls->linenumber;
 881       luaX_next(ls);
 882       expr(ls, v);
 883       check_match(ls, ')', '(', line);
 884       luaK_dischargevars(ls->fs, v);
 885       return;
 886     }
 887     case TK_NAME: {
 888       singlevar(ls, v);
 889       return;
 890     }
 891     default: {
 892       luaX_syntaxerror(ls, "unexpected symbol");
 893     }
 894   }
 895 }
 896
 897
 898 static void suffixedexp (LexState *ls, expdesc *v) {
 899   /* suffixedexp ->
 900        primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */
 901   FuncState *fs = ls->fs;
 902   int line = ls->linenumber;
 903   primaryexp(ls, v);
 904   for (;;) {
 905     switch (ls->t.token) {
 906       case '.': {  /* fieldsel */
 907         fieldsel(ls, v);
 908         break;
 909       }
 910       case '[': {  /* `[' exp1 `]' */
 911         expdesc key;
 912         luaK_exp2anyregup(fs, v);
 913         yindex(ls, &key);
 914         luaK_indexed(fs, v, &key);
 915         break;
 916       }
 917       case ':': {  /* `:' NAME funcargs */
 918         expdesc key;
 919         luaX_next(ls);
 920         checkname(ls, &key);
 921         luaK_self(fs, v, &key);
 922         funcargs(ls, v, line);
 923         break;
 924       }
 925       case '(': case TK_STRING: case '{': {  /* funcargs */
 926         luaK_exp2nextreg(fs, v);
 927         funcargs(ls, v, line);
 928         break;
 929       }
 930       default: return;
 931     }
 932   }
 933 }
 934
 935
 936 static void simpleexp (LexState *ls, expdesc *v) {
 937   /* simpleexp -> NUMBER | STRING | NIL | TRUE | FALSE | ... |
 938                   constructor | FUNCTION body | suffixedexp */
 939   switch (ls->t.token) {
 940     case TK_NUMBER: {
 941       init_exp(v, VKNUM, 0);
 942       v->u.nval = ls->t.seminfo.r;
 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 " LUA_QL("...") " 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_LEN;
 991     default: return OPR_NOUNOPR;
 992   }
 993 }
 994
 995
 996 static BinOpr getbinopr (int op) {
 997   switch (op) {
 998     case '+': return OPR_ADD;
 999     case '-': return OPR_SUB;
1000     case '*': return OPR_MUL;
1001     case '/': return OPR_DIV;
1002     case '%': return OPR_MOD;
1003     case '^': return OPR_POW;
1004     case TK_CONCAT: return OPR_CONCAT;
1005     case TK_NE: return OPR_NE;
1006     case TK_EQ: return OPR_EQ;
1007     case '<': return OPR_LT;
1008     case TK_LE: return OPR_LE;
1009     case '>': return OPR_GT;
1010     case TK_GE: return OPR_GE;
1011     case TK_AND: return OPR_AND;
1012     case TK_OR: return OPR_OR;
1013     default: return OPR_NOBINOPR;
1014   }
1015 }
1016
1017
1018 static const struct {
1019   lu_byte left;  /* left priority for each binary operator */
1020   lu_byte right; /* right priority */
1021 } priority[] = {  /* ORDER OPR */
1022    {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7},  /* `+' `-' `*' `/' `%' */
1023    {10, 9}, {5, 4},                 /* ^, .. (right associative) */
1024    {3, 3}, {3, 3}, {3, 3},          /* ==, <, <= */
1025    {3, 3}, {3, 3}, {3, 3},          /* ~=, >, >= */
1026    {2, 2}, {1, 1}                   /* and, or */
1027 };
1028
1029 #define UNARY_PRIORITY  8  /* priority for unary operators */
1030
1031
1032 /*
1033 ** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
1034 ** where `binop' is any binary operator with a priority higher than `limit'
1035 */
1036 static BinOpr subexpr (LexState *ls, expdesc *v, int limit) {
1037   BinOpr op;
1038   UnOpr uop;
1039   enterlevel(ls);
1040   uop = getunopr(ls->t.token);
1041   if (uop != OPR_NOUNOPR) {
1042     int line = ls->linenumber;
1043     luaX_next(ls);
1044     subexpr(ls, v, UNARY_PRIORITY);
1045     luaK_prefix(ls->fs, uop, v, line);
1046   }
1047   else simpleexp(ls, v);
1048   /* expand while operators have priorities higher than `limit' */
1049   op = getbinopr(ls->t.token);
1050   while (op != OPR_NOBINOPR && priority[op].left > limit) {
1051     expdesc v2;
1052     BinOpr nextop;
1053     int line = ls->linenumber;
1054     luaX_next(ls);
1055     luaK_infix(ls->fs, op, v);
1056     /* read sub-expression with higher priority */
1057     nextop = subexpr(ls, &v2, priority[op].right);
1058     luaK_posfix(ls->fs, op, v, &v2, line);
1059     op = nextop;
1060   }
1061   leavelevel(ls);
1062   return op;  /* return first untreated operator */
1063 }
1064
1065
1066 static void expr (LexState *ls, expdesc *v) {
1067   subexpr(ls, v, 0);
1068 }
1069
1070 /* }==================================================================== */
1071
1072
1073
1074 /*
1075 ** {======================================================================
1076 ** Rules for Statements
1077 ** =======================================================================
1078 */
1079
1080
1081 static void block (LexState *ls) {
1082   /* block -> statlist */
1083   FuncState *fs = ls->fs;
1084   BlockCnt bl;
1085   enterblock(fs, &bl, 0);
1086   statlist(ls);
1087   leaveblock(fs);
1088 }
1089
1090
1091 /*
1092 ** structure to chain all variables in the left-hand side of an
1093 ** assignment
1094 */
1095 struct LHS_assign {
1096   struct LHS_assign *prev;
1097   expdesc v;  /* variable (global, local, upvalue, or indexed) */
1098 };
1099
1100
1101 /*
1102 ** check whether, in an assignment to an upvalue/local variable, the
1103 ** upvalue/local variable is begin used in a previous assignment to a
1104 ** table. If so, save original upvalue/local value in a safe place and
1105 ** use this safe copy in the previous assignment.
1106 */
1107 static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
1108   FuncState *fs = ls->fs;
1109   int extra = fs->freereg;  /* eventual position to save local variable */
1110   int conflict = 0;
1111   for (; lh; lh = lh->prev) {  /* check all previous assignments */
1112     if (lh->v.k == VINDEXED) {  /* assigning to a table? */
1113       /* table is the upvalue/local being assigned now? */
1114       if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) {
1115         conflict = 1;
1116         lh->v.u.ind.vt = VLOCAL;
1117         lh->v.u.ind.t = extra;  /* previous assignment will use safe copy */
1118       }
1119       /* index is the local being assigned? (index cannot be upvalue) */
1120       if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) {
1121         conflict = 1;
1122         lh->v.u.ind.idx = extra;  /* previous assignment will use safe copy */
1123       }
1124     }
1125   }
1126   if (conflict) {
1127     /* copy upvalue/local value to a temporary (in position 'extra') */
1128     OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
1129     luaK_codeABC(fs, op, extra, v->u.info, 0);
1130     luaK_reserveregs(fs, 1);
1131   }
1132 }
1133
1134
1135 static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
1136   expdesc e;
1137   check_condition(ls, vkisvar(lh->v.k), "syntax error");
1138   if (testnext(ls, ',')) {  /* assignment -> ',' suffixedexp assignment */
1139     struct LHS_assign nv;
1140     nv.prev = lh;
1141     suffixedexp(ls, &nv.v);
1142     if (nv.v.k != VINDEXED)
1143       check_conflict(ls, lh, &nv.v);
1144     checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS,
1145                     "C levels");
1146     assignment(ls, &nv, nvars+1);
1147   }
1148   else {  /* assignment -> `=' explist */
1149     int nexps;
1150     checknext(ls, '=');
1151     nexps = explist(ls, &e);
1152     if (nexps != nvars) {
1153       adjust_assign(ls, nvars, nexps, &e);
1154       if (nexps > nvars)
1155         ls->fs->freereg -= nexps - nvars;  /* remove extra values */
1156     }
1157     else {
1158       luaK_setoneret(ls->fs, &e);  /* close last expression */
1159       luaK_storevar(ls->fs, &lh->v, &e);
1160       return;  /* avoid default */
1161     }
1162   }
1163   init_exp(&e, VNONRELOC, ls->fs->freereg-1);  /* default assignment */
1164   luaK_storevar(ls->fs, &lh->v, &e);
1165 }
1166
1167
1168 static int cond (LexState *ls) {
1169   /* cond -> exp */
1170   expdesc v;
1171   expr(ls, &v);  /* read condition */
1172   if (v.k == VNIL) v.k = VFALSE;  /* `falses' are all equal here */
1173   luaK_goiftrue(ls->fs, &v);
1174   return v.f;
1175 }
1176
1177
1178 static void gotostat (LexState *ls, int pc) {
1179   int line = ls->linenumber;
1180   TString *label;
1181   int g;
1182   if (testnext(ls, TK_GOTO))
1183     label = str_checkname(ls);
1184   else {
1185     luaX_next(ls);  /* skip break */
1186     label = luaS_new(ls->L, "break");
1187   }
1188   g = newlabelentry(ls, &ls->dyd->gt, label, line, pc);
1189   findlabel(ls, g);  /* close it if label already defined */
1190 }
1191
1192
1193 /* check for repeated labels on the same block */
1194 static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) {
1195   int i;
1196   for (i = fs->bl->firstlabel; i < ll->n; i++) {
1197     if (luaS_eqstr(label, ll->arr[i].name)) {
1198       const char *msg = luaO_pushfstring(fs->ls->L,
1199                           "label " LUA_QS " already defined on line %d",
1200                           getstr(label), ll->arr[i].line);
1201       semerror(fs->ls, msg);
1202     }
1203   }
1204 }
1205
1206
1207 /* skip no-op statements */
1208 static void skipnoopstat (LexState *ls) {
1209   while (ls->t.token == ';' || ls->t.token == TK_DBCOLON)
1210     statement(ls);
1211 }
1212
1213
1214 static void labelstat (LexState *ls, TString *label, int line) {
1215   /* label -> '::' NAME '::' */
1216   FuncState *fs = ls->fs;
1217   Labellist *ll = &ls->dyd->label;
1218   int l;  /* index of new label being created */
1219   checkrepeated(fs, ll, label);  /* check for repeated labels */
1220   checknext(ls, TK_DBCOLON);  /* skip double colon */
1221   /* create new entry for this label */
1222   l = newlabelentry(ls, ll, label, line, fs->pc);
1223   skipnoopstat(ls);  /* skip other no-op statements */
1224   if (block_follow(ls, 0)) {  /* label is last no-op statement in the block? */
1225     /* assume that locals are already out of scope */
1226     ll->arr[l].nactvar = fs->bl->nactvar;
1227   }
1228   findgotos(ls, &ll->arr[l]);
1229 }
1230
1231
1232 static void whilestat (LexState *ls, int line) {
1233   /* whilestat -> WHILE cond DO block END */
1234   FuncState *fs = ls->fs;
1235   int whileinit;
1236   int condexit;
1237   BlockCnt bl;
1238   luaX_next(ls);  /* skip WHILE */
1239   whileinit = luaK_getlabel(fs);
1240   condexit = cond(ls);
1241   enterblock(fs, &bl, 1);
1242   checknext(ls, TK_DO);
1243   block(ls);
1244   luaK_jumpto(fs, whileinit);
1245   check_match(ls, TK_END, TK_WHILE, line);
1246   leaveblock(fs);
1247   luaK_patchtohere(fs, condexit);  /* false conditions finish the loop */
1248 }
1249
1250
1251 static void repeatstat (LexState *ls, int line) {
1252   /* repeatstat -> REPEAT block UNTIL cond */
1253   int condexit;
1254   FuncState *fs = ls->fs;
1255   int repeat_init = luaK_getlabel(fs);
1256   BlockCnt bl1, bl2;
1257   enterblock(fs, &bl1, 1);  /* loop block */
1258   enterblock(fs, &bl2, 0);  /* scope block */
1259   luaX_next(ls);  /* skip REPEAT */
1260   statlist(ls);
1261   check_match(ls, TK_UNTIL, TK_REPEAT, line);
1262   condexit = cond(ls);  /* read condition (inside scope block) */
1263   if (bl2.upval)  /* upvalues? */
1264     luaK_patchclose(fs, condexit, bl2.nactvar);
1265   leaveblock(fs);  /* finish scope */
1266   luaK_patchlist(fs, condexit, repeat_init);  /* close the loop */
1267   leaveblock(fs);  /* finish loop */
1268 }
1269
1270
1271 static int exp1 (LexState *ls) {
1272   expdesc e;
1273   int reg;
1274   expr(ls, &e);
1275   luaK_exp2nextreg(ls->fs, &e);
1276   lua_assert(e.k == VNONRELOC);
1277   reg = e.u.info;
1278   return reg;
1279 }
1280
1281
1282 static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
1283   /* forbody -> DO block */
1284   BlockCnt bl;
1285   FuncState *fs = ls->fs;
1286   int prep, endfor;
1287   adjustlocalvars(ls, 3);  /* control variables */
1288   checknext(ls, TK_DO);
1289   prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
1290   enterblock(fs, &bl, 0);  /* scope for declared variables */
1291   adjustlocalvars(ls, nvars);
1292   luaK_reserveregs(fs, nvars);
1293   block(ls);
1294   leaveblock(fs);  /* end of scope for declared variables */
1295   luaK_patchtohere(fs, prep);
1296   if (isnum)  /* numeric for? */
1297     endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP);
1298   else {  /* generic for */
1299     luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
1300     luaK_fixline(fs, line);
1301     endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP);
1302   }
1303   luaK_patchlist(fs, endfor, prep + 1);
1304   luaK_fixline(fs, line);
1305 }
1306
1307
1308 static void fornum (LexState *ls, TString *varname, int line) {
1309   /* fornum -> NAME = exp1,exp1[,exp1] forbody */
1310   FuncState *fs = ls->fs;
1311   int base = fs->freereg;
1312   new_localvarliteral(ls, "(for index)");
1313   new_localvarliteral(ls, "(for limit)");
1314   new_localvarliteral(ls, "(for step)");
1315   new_localvar(ls, varname);
1316   checknext(ls, '=');
1317   exp1(ls);  /* initial value */
1318   checknext(ls, ',');
1319   exp1(ls);  /* limit */
1320   if (testnext(ls, ','))
1321     exp1(ls);  /* optional step */
1322   else {  /* default step = 1 */
1323     luaK_codek(fs, fs->freereg, luaK_numberK(fs, 1));
1324     luaK_reserveregs(fs, 1);
1325   }
1326   forbody(ls, base, line, 1, 1);
1327 }
1328
1329
1330 static void forlist (LexState *ls, TString *indexname) {
1331   /* forlist -> NAME {,NAME} IN explist forbody */
1332   FuncState *fs = ls->fs;
1333   expdesc e;
1334   int nvars = 4;  /* gen, state, control, plus at least one declared var */
1335   int line;
1336   int base = fs->freereg;
1337   /* create control variables */
1338   new_localvarliteral(ls, "(for generator)");
1339   new_localvarliteral(ls, "(for state)");
1340   new_localvarliteral(ls, "(for control)");
1341   /* create declared variables */
1342   new_localvar(ls, indexname);
1343   while (testnext(ls, ',')) {
1344     new_localvar(ls, str_checkname(ls));
1345     nvars++;
1346   }
1347   checknext(ls, TK_IN);
1348   line = ls->linenumber;
1349   adjust_assign(ls, 3, explist(ls, &e), &e);
1350   luaK_checkstack(fs, 3);  /* extra space to call generator */
1351   forbody(ls, base, line, nvars - 3, 0);
1352 }
1353
1354
1355 static void forstat (LexState *ls, int line) {
1356   /* forstat -> FOR (fornum | forlist) END */
1357   FuncState *fs = ls->fs;
1358   TString *varname;
1359   BlockCnt bl;
1360   enterblock(fs, &bl, 1);  /* scope for loop and control variables */
1361   luaX_next(ls);  /* skip `for' */
1362   varname = str_checkname(ls);  /* first variable name */
1363   switch (ls->t.token) {
1364     case '=': fornum(ls, varname, line); break;
1365     case ',': case TK_IN: forlist(ls, varname); break;
1366     default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected");
1367   }
1368   check_match(ls, TK_END, TK_FOR, line);
1369   leaveblock(fs);  /* loop scope (`break' jumps to this point) */
1370 }
1371
1372
1373 static void test_then_block (LexState *ls, int *escapelist) {
1374   /* test_then_block -> [IF | ELSEIF] cond THEN block */
1375   BlockCnt bl;
1376   FuncState *fs = ls->fs;
1377   expdesc v;
1378   int jf;  /* instruction to skip 'then' code (if condition is false) */
1379   luaX_next(ls);  /* skip IF or ELSEIF */
1380   expr(ls, &v);  /* read condition */
1381   checknext(ls, TK_THEN);
1382   if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) {
1383     luaK_goiffalse(ls->fs, &v);  /* will jump to label if condition is true */
1384     enterblock(fs, &bl, 0);  /* must enter block before 'goto' */
1385     gotostat(ls, v.t);  /* handle goto/break */
1386     skipnoopstat(ls);  /* skip other no-op statements */
1387     if (block_follow(ls, 0)) {  /* 'goto' is the entire block? */
1388       leaveblock(fs);
1389       return;  /* and that is it */
1390     }
1391     else  /* must skip over 'then' part if condition is false */
1392       jf = luaK_jump(fs);
1393   }
1394   else {  /* regular case (not goto/break) */
1395     luaK_goiftrue(ls->fs, &v);  /* skip over block if condition is false */
1396     enterblock(fs, &bl, 0);
1397     jf = v.f;
1398   }
1399   statlist(ls);  /* `then' part */
1400   leaveblock(fs);
1401   if (ls->t.token == TK_ELSE ||
1402       ls->t.token == TK_ELSEIF)  /* followed by 'else'/'elseif'? */
1403     luaK_concat(fs, escapelist, luaK_jump(fs));  /* must jump over it */
1404   luaK_patchtohere(fs, jf);
1405 }
1406
1407
1408 static void ifstat (LexState *ls, int line) {
1409   /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
1410   FuncState *fs = ls->fs;
1411   int escapelist = NO_JUMP;  /* exit list for finished parts */
1412   test_then_block(ls, &escapelist);  /* IF cond THEN block */
1413   while (ls->t.token == TK_ELSEIF)
1414     test_then_block(ls, &escapelist);  /* ELSEIF cond THEN block */
1415   if (testnext(ls, TK_ELSE))
1416     block(ls);  /* `else' part */
1417   check_match(ls, TK_END, TK_IF, line);
1418   luaK_patchtohere(fs, escapelist);  /* patch escape list to 'if' end */
1419 }
1420
1421
1422 static void localfunc (LexState *ls) {
1423   expdesc b;
1424   FuncState *fs = ls->fs;
1425   new_localvar(ls, str_checkname(ls));  /* new local variable */
1426   adjustlocalvars(ls, 1);  /* enter its scope */
1427   body(ls, &b, 0, ls->linenumber);  /* function created in next register */
1428   /* debug information will only see the variable after this point! */
1429   getlocvar(fs, b.u.info)->startpc = fs->pc;
1430 }
1431
1432
1433 static void localstat (LexState *ls) {
1434   /* stat -> LOCAL NAME {`,' NAME} [`=' explist] */
1435   int nvars = 0;
1436   int nexps;
1437   expdesc e;
1438   do {
1439     new_localvar(ls, str_checkname(ls));
1440     nvars++;
1441   } while (testnext(ls, ','));
1442   if (testnext(ls, '='))
1443     nexps = explist(ls, &e);
1444   else {
1445     e.k = VVOID;
1446     nexps = 0;
1447   }
1448   adjust_assign(ls, nvars, nexps, &e);
1449   adjustlocalvars(ls, nvars);
1450 }
1451
1452
1453 static int funcname (LexState *ls, expdesc *v) {
1454   /* funcname -> NAME {fieldsel} [`:' NAME] */
1455   int ismethod = 0;
1456   singlevar(ls, v);
1457   while (ls->t.token == '.')
1458     fieldsel(ls, v);
1459   if (ls->t.token == ':') {
1460     ismethod = 1;
1461     fieldsel(ls, v);
1462   }
1463   return ismethod;
1464 }
1465
1466
1467 static void funcstat (LexState *ls, int line) {
1468   /* funcstat -> FUNCTION funcname body */
1469   int ismethod;
1470   expdesc v, b;
1471   luaX_next(ls);  /* skip FUNCTION */
1472   ismethod = funcname(ls, &v);
1473   body(ls, &b, ismethod, line);
1474   luaK_storevar(ls->fs, &v, &b);
1475   luaK_fixline(ls->fs, line);  /* definition `happens' in the first line */
1476 }
1477
1478
1479 static void exprstat (LexState *ls) {
1480   /* stat -> func | assignment */
1481   FuncState *fs = ls->fs;
1482   struct LHS_assign v;
1483   suffixedexp(ls, &v.v);
1484   if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */
1485     v.prev = NULL;
1486     assignment(ls, &v, 1);
1487   }
1488   else {  /* stat -> func */
1489     check_condition(ls, v.v.k == VCALL, "syntax error");
1490     SETARG_C(getcode(fs, &v.v), 1);  /* call statement uses no results */
1491   }
1492 }
1493
1494
1495 static void retstat (LexState *ls) {
1496   /* stat -> RETURN [explist] [';'] */
1497   FuncState *fs = ls->fs;
1498   expdesc e;
1499   int first, nret;  /* registers with returned values */
1500   if (block_follow(ls, 1) || ls->t.token == ';')
1501     first = nret = 0;  /* return no values */
1502   else {
1503     nret = explist(ls, &e);  /* optional return values */
1504     if (hasmultret(e.k)) {
1505       luaK_setmultret(fs, &e);
1506       if (e.k == VCALL && nret == 1) {  /* tail call? */
1507         SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
1508         lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
1509       }
1510       first = fs->nactvar;
1511       nret = LUA_MULTRET;  /* return all values */
1512     }
1513     else {
1514       if (nret == 1)  /* only one single value? */
1515         first = luaK_exp2anyreg(fs, &e);
1516       else {
1517         luaK_exp2nextreg(fs, &e);  /* values must go to the `stack' */
1518         first = fs->nactvar;  /* return all `active' values */
1519         lua_assert(nret == fs->freereg - first);
1520       }
1521     }
1522   }
1523   luaK_ret(fs, first, nret);
1524   testnext(ls, ';');  /* skip optional semicolon */
1525 }
1526
1527
1528 static void statement (LexState *ls) {
1529   int line = ls->linenumber;  /* may be needed for error messages */
1530   enterlevel(ls);
1531   switch (ls->t.token) {
1532     case ';': {  /* stat -> ';' (empty statement) */
1533       luaX_next(ls);  /* skip ';' */
1534       break;
1535     }
1536     case TK_IF: {  /* stat -> ifstat */
1537       ifstat(ls, line);
1538       break;
1539     }
1540     case TK_WHILE: {  /* stat -> whilestat */
1541       whilestat(ls, line);
1542       break;
1543     }
1544     case TK_DO: {  /* stat -> DO block END */
1545       luaX_next(ls);  /* skip DO */
1546       block(ls);
1547       check_match(ls, TK_END, TK_DO, line);
1548       break;
1549     }
1550     case TK_FOR: {  /* stat -> forstat */
1551       forstat(ls, line);
1552       break;
1553     }
1554     case TK_REPEAT: {  /* stat -> repeatstat */
1555       repeatstat(ls, line);
1556       break;
1557     }
1558     case TK_FUNCTION: {  /* stat -> funcstat */
1559       funcstat(ls, line);
1560       break;
1561     }
1562     case TK_LOCAL: {  /* stat -> localstat */
1563       luaX_next(ls);  /* skip LOCAL */
1564       if (testnext(ls, TK_FUNCTION))  /* local function? */
1565         localfunc(ls);
1566       else
1567         localstat(ls);
1568       break;
1569     }
1570     case TK_DBCOLON: {  /* stat -> label */
1571       luaX_next(ls);  /* skip double colon */
1572       labelstat(ls, str_checkname(ls), line);
1573       break;
1574     }
1575     case TK_RETURN: {  /* stat -> retstat */
1576       luaX_next(ls);  /* skip RETURN */
1577       retstat(ls);
1578       break;
1579     }
1580     case TK_BREAK:   /* stat -> breakstat */
1581     case TK_GOTO: {  /* stat -> 'goto' NAME */
1582       gotostat(ls, luaK_jump(ls->fs));
1583       break;
1584     }
1585     default: {  /* stat -> func | assignment */
1586       exprstat(ls);
1587       break;
1588     }
1589   }
1590   lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
1591              ls->fs->freereg >= ls->fs->nactvar);
1592   ls->fs->freereg = ls->fs->nactvar;  /* free registers */
1593   leavelevel(ls);
1594 }
1595
1596 /* }====================================================================== */
1597
1598
1599 /*
1600 ** compiles the main function, which is a regular vararg function with an
1601 ** upvalue named LUA_ENV
1602 */
1603 static void mainfunc (LexState *ls, FuncState *fs) {
1604   BlockCnt bl;
1605   expdesc v;
1606   open_func(ls, fs, &bl);
1607   fs->f->is_vararg = 1;  /* main function is always vararg */
1608   init_exp(&v, VLOCAL, 0);  /* create and... */
1609   newupvalue(fs, ls->envn, &v);  /* ...set environment upvalue */
1610   luaX_next(ls);  /* read first token */
1611   statlist(ls);  /* parse main body */
1612   check(ls, TK_EOS);
1613   close_func(ls);
1614 }
1615
1616
1617 Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
1618                       Dyndata *dyd, const char *name, int firstchar) {
1619   LexState lexstate;
1620   FuncState funcstate;
1621   Closure *cl = luaF_newLclosure(L, 1);  /* create main closure */
1622   /* anchor closure (to avoid being collected) */
1623   setclLvalue(L, L->top, cl);
1624   incr_top(L);
1625   funcstate.f = cl->l.p = luaF_newproto(L);
1626   funcstate.f->source = luaS_new(L, name);  /* create and anchor TString */
1627   lexstate.buff = buff;
1628   lexstate.dyd = dyd;
1629   dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
1630   luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar);
1631   mainfunc(&lexstate, &funcstate);
1632   lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
1633   /* all scopes should be correctly finished */
1634   lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0);
1635   return cl;  /* it's on the stack too */
1636 }
1637