1 files changed, 1638 insertions, 0 deletions

diff --git a/lparser.c b/lparser.c
new file mode 100644
index 00000000..d8f5b4ff
--- /dev/null
+++ b/lparser.c
@@ -0,0 +1,1638 @@
+/*
+** $Id: lparser.c,v 2.130 2013/02/06 13:37:39 roberto Exp $
+** Lua Parser
+** See Copyright Notice in lua.h
+*/
+
+
+#include <string.h>
+
+#define lparser_c
+#define LUA_CORE
+
+#include "lua.h"
+
+#include "lcode.h"
+#include "ldebug.h"
+#include "ldo.h"
+#include "lfunc.h"
+#include "llex.h"
+#include "lmem.h"
+#include "lobject.h"
+#include "lopcodes.h"
+#include "lparser.h"
+#include "lstate.h"
+#include "lstring.h"
+#include "ltable.h"
+
+
+
+/* maximum number of local variables per function (must be smaller
+   than 250, due to the bytecode format) */
+#define MAXVARS         200
+
+
+#define hasmultret(k)           ((k) == VCALL || (k) == VVARARG)
+
+
+
+/*
+** nodes for block list (list of active blocks)
+*/
+typedef struct BlockCnt {
+  struct BlockCnt *previous;  /* chain */
+  short firstlabel;  /* index of first label in this block */
+  short firstgoto;  /* index of first pending goto in this block */
+  lu_byte nactvar;  /* # active locals outside the block */
+  lu_byte upval;  /* true if some variable in the block is an upvalue */
+  lu_byte isloop;  /* true if `block' is a loop */
+} BlockCnt;
+
+
+
+/*
+** prototypes for recursive non-terminal functions
+*/
+static void statement (LexState *ls);
+static void expr (LexState *ls, expdesc *v);
+
+
+static void anchor_token (LexState *ls) {
+  /* last token from outer function must be EOS */
+  lua_assert(ls->fs != NULL || ls->t.token == TK_EOS);
+  if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) {
+    TString *ts = ls->t.seminfo.ts;
+    luaX_newstring(ls, getstr(ts), ts->tsv.len);
+  }
+}
+
+
+/* semantic error */
+static l_noret semerror (LexState *ls, const char *msg) {
+  ls->t.token = 0;  /* remove 'near to' from final message */
+  luaX_syntaxerror(ls, msg);
+}
+
+
+static l_noret error_expected (LexState *ls, int token) {
+  luaX_syntaxerror(ls,
+      luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token)));
+}
+
+
+static l_noret errorlimit (FuncState *fs, int limit, const char *what) {
+  lua_State *L = fs->ls->L;
+  const char *msg;
+  int line = fs->f->linedefined;
+  const char *where = (line == 0)
+                      ? "main function"
+                      : luaO_pushfstring(L, "function at line %d", line);
+  msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s",
+                             what, limit, where);
+  luaX_syntaxerror(fs->ls, msg);
+}
+
+
+static void checklimit (FuncState *fs, int v, int l, const char *what) {
+  if (v > l) errorlimit(fs, l, what);
+}
+
+
+static int testnext (LexState *ls, int c) {
+  if (ls->t.token == c) {
+    luaX_next(ls);
+    return 1;
+  }
+  else return 0;
+}
+
+
+static void check (LexState *ls, int c) {
+  if (ls->t.token != c)
+    error_expected(ls, c);
+}
+
+
+static void checknext (LexState *ls, int c) {
+  check(ls, c);
+  luaX_next(ls);
+}
+
+
+#define check_condition(ls,c,msg)       { if (!(c)) luaX_syntaxerror(ls, msg); }
+
+
+
+static void check_match (LexState *ls, int what, int who, int where) {
+  if (!testnext(ls, what)) {
+    if (where == ls->linenumber)
+      error_expected(ls, what);
+    else {
+      luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
+             "%s expected (to close %s at line %d)",
+              luaX_token2str(ls, what), luaX_token2str(ls, who), where));
+    }
+  }
+}
+
+
+static TString *str_checkname (LexState *ls) {
+  TString *ts;
+  check(ls, TK_NAME);
+  ts = ls->t.seminfo.ts;
+  luaX_next(ls);
+  return ts;
+}
+
+
+static void init_exp (expdesc *e, expkind k, int i) {
+  e->f = e->t = NO_JUMP;
+  e->k = k;
+  e->u.info = i;
+}
+
+
+static void codestring (LexState *ls, expdesc *e, TString *s) {
+  init_exp(e, VK, luaK_stringK(ls->fs, s));
+}
+
+
+static void checkname (LexState *ls, expdesc *e) {
+  codestring(ls, e, str_checkname(ls));
+}
+
+
+static int registerlocalvar (LexState *ls, TString *varname) {
+  FuncState *fs = ls->fs;
+  Proto *f = fs->f;
+  int oldsize = f->sizelocvars;
+  luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
+                  LocVar, SHRT_MAX, "local variables");
+  while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL;
+  f->locvars[fs->nlocvars].varname = varname;
+  luaC_objbarrier(ls->L, f, varname);
+  return fs->nlocvars++;
+}
+
+
+static void new_localvar (LexState *ls, TString *name) {
+  FuncState *fs = ls->fs;
+  Dyndata *dyd = ls->dyd;
+  int reg = registerlocalvar(ls, name);
+  checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal,
+                  MAXVARS, "local variables");
+  luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1,
+                  dyd->actvar.size, Vardesc, MAX_INT, "local variables");
+  dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg);
+}
+
+
+static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) {
+  new_localvar(ls, luaX_newstring(ls, name, sz));
+}
+
+#define new_localvarliteral(ls,v) \
+        new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1)
+
+
+static LocVar *getlocvar (FuncState *fs, int i) {
+  int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx;
+  lua_assert(idx < fs->nlocvars);
+  return &fs->f->locvars[idx];
+}
+
+
+static void adjustlocalvars (LexState *ls, int nvars) {
+  FuncState *fs = ls->fs;
+  fs->nactvar = cast_byte(fs->nactvar + nvars);
+  for (; nvars; nvars--) {
+    getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc;
+  }
+}
+
+
+static void removevars (FuncState *fs, int tolevel) {
+  fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel);
+  while (fs->nactvar > tolevel)
+    getlocvar(fs, --fs->nactvar)->endpc = fs->pc;
+}
+
+
+static int searchupvalue (FuncState *fs, TString *name) {
+  int i;
+  Upvaldesc *up = fs->f->upvalues;
+  for (i = 0; i < fs->nups; i++) {
+    if (luaS_eqstr(up[i].name, name)) return i;
+  }
+  return -1;  /* not found */
+}
+
+
+static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
+  Proto *f = fs->f;
+  int oldsize = f->sizeupvalues;
+  checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues");
+  luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues,
+                  Upvaldesc, MAXUPVAL, "upvalues");
+  while (oldsize < f->sizeupvalues) f->upvalues[oldsize++].name = NULL;
+  f->upvalues[fs->nups].instack = (v->k == VLOCAL);
+  f->upvalues[fs->nups].idx = cast_byte(v->u.info);
+  f->upvalues[fs->nups].name = name;
+  luaC_objbarrier(fs->ls->L, f, name);
+  return fs->nups++;
+}
+
+
+static int searchvar (FuncState *fs, TString *n) {
+  int i;
+  for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) {
+    if (luaS_eqstr(n, getlocvar(fs, i)->varname))
+      return i;
+  }
+  return -1;  /* not found */
+}
+
+
+/*
+  Mark block where variable at given level was defined
+  (to emit close instructions later).
+*/
+static void markupval (FuncState *fs, int level) {
+  BlockCnt *bl = fs->bl;
+  while (bl->nactvar > level) bl = bl->previous;
+  bl->upval = 1;
+}
+
+
+/*
+  Find variable with given name 'n'. If it is an upvalue, add this
+  upvalue into all intermediate functions.
+*/
+static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
+  if (fs == NULL)  /* no more levels? */
+    return VVOID;  /* default is global */
+  else {
+    int v = searchvar(fs, n);  /* look up locals at current level */
+    if (v >= 0) {  /* found? */
+      init_exp(var, VLOCAL, v);  /* variable is local */
+      if (!base)
+        markupval(fs, v);  /* local will be used as an upval */
+      return VLOCAL;
+    }
+    else {  /* not found as local at current level; try upvalues */
+      int idx = searchupvalue(fs, n);  /* try existing upvalues */
+      if (idx < 0) {  /* not found? */
+        if (singlevaraux(fs->prev, n, var, 0) == VVOID) /* try upper levels */
+          return VVOID;  /* not found; is a global */
+        /* else was LOCAL or UPVAL */
+        idx  = newupvalue(fs, n, var);  /* will be a new upvalue */
+      }
+      init_exp(var, VUPVAL, idx);
+      return VUPVAL;
+    }
+  }
+}
+
+
+static void singlevar (LexState *ls, expdesc *var) {
+  TString *varname = str_checkname(ls);
+  FuncState *fs = ls->fs;
+  if (singlevaraux(fs, varname, var, 1) == VVOID) {  /* global name? */
+    expdesc key;
+    singlevaraux(fs, ls->envn, var, 1);  /* get environment variable */
+    lua_assert(var->k == VLOCAL || var->k == VUPVAL);
+    codestring(ls, &key, varname);  /* key is variable name */
+    luaK_indexed(fs, var, &key);  /* env[varname] */
+  }
+}
+
+
+static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
+  FuncState *fs = ls->fs;
+  int extra = nvars - nexps;
+  if (hasmultret(e->k)) {
+    extra++;  /* includes call itself */
+    if (extra < 0) extra = 0;
+    luaK_setreturns(fs, e, extra);  /* last exp. provides the difference */
+    if (extra > 1) luaK_reserveregs(fs, extra-1);
+  }
+  else {
+    if (e->k != VVOID) luaK_exp2nextreg(fs, e);  /* close last expression */
+    if (extra > 0) {
+      int reg = fs->freereg;
+      luaK_reserveregs(fs, extra);
+      luaK_nil(fs, reg, extra);
+    }
+  }
+}
+
+
+static void enterlevel (LexState *ls) {
+  lua_State *L = ls->L;
+  ++L->nCcalls;
+  checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "C levels");
+}
+
+
+#define leavelevel(ls)  ((ls)->L->nCcalls--)
+
+
+static void closegoto (LexState *ls, int g, Labeldesc *label) {
+  int i;
+  FuncState *fs = ls->fs;
+  Labellist *gl = &ls->dyd->gt;
+  Labeldesc *gt = &gl->arr[g];
+  lua_assert(luaS_eqstr(gt->name, label->name));
+  if (gt->nactvar < label->nactvar) {
+    TString *vname = getlocvar(fs, gt->nactvar)->varname;
+    const char *msg = luaO_pushfstring(ls->L,
+      "<goto %s> at line %d jumps into the scope of local " LUA_QS,
+      getstr(gt->name), gt->line, getstr(vname));
+    semerror(ls, msg);
+  }
+  luaK_patchlist(fs, gt->pc, label->pc);
+  /* remove goto from pending list */
+  for (i = g; i < gl->n - 1; i++)
+    gl->arr[i] = gl->arr[i + 1];
+  gl->n--;
+}
+
+
+/*
+** try to close a goto with existing labels; this solves backward jumps
+*/
+static int findlabel (LexState *ls, int g) {
+  int i;
+  BlockCnt *bl = ls->fs->bl;
+  Dyndata *dyd = ls->dyd;
+  Labeldesc *gt = &dyd->gt.arr[g];
+  /* check labels in current block for a match */
+  for (i = bl->firstlabel; i < dyd->label.n; i++) {
+    Labeldesc *lb = &dyd->label.arr[i];
+    if (luaS_eqstr(lb->name, gt->name)) {  /* correct label? */
+      if (gt->nactvar > lb->nactvar &&
+          (bl->upval || dyd->label.n > bl->firstlabel))
+        luaK_patchclose(ls->fs, gt->pc, lb->nactvar);
+      closegoto(ls, g, lb);  /* close it */
+      return 1;
+    }
+  }
+  return 0;  /* label not found; cannot close goto */
+}
+
+
+static int newlabelentry (LexState *ls, Labellist *l, TString *name,
+                          int line, int pc) {
+  int n = l->n;
+  luaM_growvector(ls->L, l->arr, n, l->size,
+                  Labeldesc, SHRT_MAX, "labels/gotos");
+  l->arr[n].name = name;
+  l->arr[n].line = line;
+  l->arr[n].nactvar = ls->fs->nactvar;
+  l->arr[n].pc = pc;
+  l->n++;
+  return n;
+}
+
+
+/*
+** check whether new label 'lb' matches any pending gotos in current
+** block; solves forward jumps
+*/
+static void findgotos (LexState *ls, Labeldesc *lb) {
+  Labellist *gl = &ls->dyd->gt;
+  int i = ls->fs->bl->firstgoto;
+  while (i < gl->n) {
+    if (luaS_eqstr(gl->arr[i].name, lb->name))
+      closegoto(ls, i, lb);
+    else
+      i++;
+  }
+}
+
+
+/*
+** "export" pending gotos to outer level, to check them against
+** outer labels; if the block being exited has upvalues, and
+** the goto exits the scope of any variable (which can be the
+** upvalue), close those variables being exited.
+*/
+static void movegotosout (FuncState *fs, BlockCnt *bl) {
+  int i = bl->firstgoto;
+  Labellist *gl = &fs->ls->dyd->gt;
+  /* correct pending gotos to current block and try to close it
+     with visible labels */
+  while (i < gl->n) {
+    Labeldesc *gt = &gl->arr[i];
+    if (gt->nactvar > bl->nactvar) {
+      if (bl->upval)
+        luaK_patchclose(fs, gt->pc, bl->nactvar);
+      gt->nactvar = bl->nactvar;
+    }
+    if (!findlabel(fs->ls, i))
+      i++;  /* move to next one */
+  }
+}
+
+
+static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) {
+  bl->isloop = isloop;
+  bl->nactvar = fs->nactvar;
+  bl->firstlabel = fs->ls->dyd->label.n;
+  bl->firstgoto = fs->ls->dyd->gt.n;
+  bl->upval = 0;
+  bl->previous = fs->bl;
+  fs->bl = bl;
+  lua_assert(fs->freereg == fs->nactvar);
+}
+
+
+/*
+** create a label named "break" to resolve break statements
+*/
+static void breaklabel (LexState *ls) {
+  TString *n = luaS_new(ls->L, "break");
+  int l = newlabelentry(ls, &ls->dyd->label, n, 0, ls->fs->pc);
+  findgotos(ls, &ls->dyd->label.arr[l]);
+}
+
+/*
+** generates an error for an undefined 'goto'; choose appropriate
+** message when label name is a reserved word (which can only be 'break')
+*/
+static l_noret undefgoto (LexState *ls, Labeldesc *gt) {
+  const char *msg = isreserved(gt->name)
+                    ? "<%s> at line %d not inside a loop"
+                    : "no visible label " LUA_QS " for <goto> at line %d";
+  msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line);
+  semerror(ls, msg);
+}
+
+
+static void leaveblock (FuncState *fs) {
+  BlockCnt *bl = fs->bl;
+  LexState *ls = fs->ls;
+  if (bl->previous && bl->upval) {
+    /* create a 'jump to here' to close upvalues */
+    int j = luaK_jump(fs);
+    luaK_patchclose(fs, j, bl->nactvar);
+    luaK_patchtohere(fs, j);
+  }
+  if (bl->isloop)
+    breaklabel(ls);  /* close pending breaks */
+  fs->bl = bl->previous;
+  removevars(fs, bl->nactvar);
+  lua_assert(bl->nactvar == fs->nactvar);
+  fs->freereg = fs->nactvar;  /* free registers */
+  ls->dyd->label.n = bl->firstlabel;  /* remove local labels */
+  if (bl->previous)  /* inner block? */
+    movegotosout(fs, bl);  /* update pending gotos to outer block */
+  else if (bl->firstgoto < ls->dyd->gt.n)  /* pending gotos in outer block? */
+    undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]);  /* error */
+}
+
+
+/*
+** adds a new prototype into list of prototypes
+*/
+static Proto *addprototype (LexState *ls) {
+  Proto *clp;
+  lua_State *L = ls->L;
+  FuncState *fs = ls->fs;
+  Proto *f = fs->f;  /* prototype of current function */
+  if (fs->np >= f->sizep) {
+    int oldsize = f->sizep;
+    luaM_growvector(L, f->p, fs->np, f->sizep, Proto *, MAXARG_Bx, "functions");
+    while (oldsize < f->sizep) f->p[oldsize++] = NULL;
+  }
+  f->p[fs->np++] = clp = luaF_newproto(L);
+  luaC_objbarrier(L, f, clp);
+  return clp;
+}
+
+
+/*
+** codes instruction to create new closure in parent function.
+** The OP_CLOSURE instruction must use the last available register,
+** so that, if it invokes the GC, the GC knows which registers
+** are in use at that time.
+*/
+static void codeclosure (LexState *ls, expdesc *v) {
+  FuncState *fs = ls->fs->prev;
+  init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1));
+  luaK_exp2nextreg(fs, v);  /* fix it at the last register */
+}
+
+
+static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
+  lua_State *L = ls->L;
+  Proto *f;
+  fs->prev = ls->fs;  /* linked list of funcstates */
+  fs->ls = ls;
+  ls->fs = fs;
+  fs->pc = 0;
+  fs->lasttarget = 0;
+  fs->jpc = NO_JUMP;
+  fs->freereg = 0;
+  fs->nk = 0;
+  fs->np = 0;
+  fs->nups = 0;
+  fs->nlocvars = 0;
+  fs->nactvar = 0;
+  fs->firstlocal = ls->dyd->actvar.n;
+  fs->bl = NULL;
+  f = fs->f;
+  f->source = ls->source;
+  f->maxstacksize = 2;  /* registers 0/1 are always valid */
+  fs->h = luaH_new(L);
+  /* anchor table of constants (to avoid being collected) */
+  sethvalue2s(L, L->top, fs->h);
+  incr_top(L);
+  enterblock(fs, bl, 0);
+}
+
+
+static void close_func (LexState *ls) {
+  lua_State *L = ls->L;
+  FuncState *fs = ls->fs;
+  Proto *f = fs->f;
+  luaK_ret(fs, 0, 0);  /* final return */
+  leaveblock(fs);
+  luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
+  f->sizecode = fs->pc;
+  luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
+  f->sizelineinfo = fs->pc;
+  luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
+  f->sizek = fs->nk;
+  luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
+  f->sizep = fs->np;
+  luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
+  f->sizelocvars = fs->nlocvars;
+  luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc);
+  f->sizeupvalues = fs->nups;
+  lua_assert(fs->bl == NULL);
+  ls->fs = fs->prev;
+  /* last token read was anchored in defunct function; must re-anchor it */
+  anchor_token(ls);
+  L->top--;  /* pop table of constants */
+  luaC_checkGC(L);
+}
+
+
+
+/*============================================================*/
+/* GRAMMAR RULES */
+/*============================================================*/
+
+
+/*
+** check whether current token is in the follow set of a block.
+** 'until' closes syntactical blocks, but do not close scope,
+** so it handled in separate.
+*/
+static int block_follow (LexState *ls, int withuntil) {
+  switch (ls->t.token) {
+    case TK_ELSE: case TK_ELSEIF:
+    case TK_END: case TK_EOS:
+      return 1;
+    case TK_UNTIL: return withuntil;
+    default: return 0;
+  }
+}
+
+
+static void statlist (LexState *ls) {
+  /* statlist -> { stat [`;'] } */
+  while (!block_follow(ls, 1)) {
+    if (ls->t.token == TK_RETURN) {
+      statement(ls);
+      return;  /* 'return' must be last statement */
+    }
+    statement(ls);
+  }
+}
+
+
+static void fieldsel (LexState *ls, expdesc *v) {
+  /* fieldsel -> ['.' | ':'] NAME */
+  FuncState *fs = ls->fs;
+  expdesc key;
+  luaK_exp2anyregup(fs, v);
+  luaX_next(ls);  /* skip the dot or colon */
+  checkname(ls, &key);
+  luaK_indexed(fs, v, &key);
+}
+
+
+static void yindex (LexState *ls, expdesc *v) {
+  /* index -> '[' expr ']' */
+  luaX_next(ls);  /* skip the '[' */
+  expr(ls, v);
+  luaK_exp2val(ls->fs, v);
+  checknext(ls, ']');
+}
+
+
+/*
+** {======================================================================
+** Rules for Constructors
+** =======================================================================
+*/
+
+
+struct ConsControl {
+  expdesc v;  /* last list item read */
+  expdesc *t;  /* table descriptor */
+  int nh;  /* total number of `record' elements */
+  int na;  /* total number of array elements */
+  int tostore;  /* number of array elements pending to be stored */
+};
+
+
+static void recfield (LexState *ls, struct ConsControl *cc) {
+  /* recfield -> (NAME | `['exp1`]') = exp1 */
+  FuncState *fs = ls->fs;
+  int reg = ls->fs->freereg;
+  expdesc key, val;
+  int rkkey;
+  if (ls->t.token == TK_NAME) {
+    checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
+    checkname(ls, &key);
+  }
+  else  /* ls->t.token == '[' */
+    yindex(ls, &key);
+  cc->nh++;
+  checknext(ls, '=');
+  rkkey = luaK_exp2RK(fs, &key);
+  expr(ls, &val);
+  luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val));
+  fs->freereg = reg;  /* free registers */
+}
+
+
+static void closelistfield (FuncState *fs, struct ConsControl *cc) {
+  if (cc->v.k == VVOID) return;  /* there is no list item */
+  luaK_exp2nextreg(fs, &cc->v);
+  cc->v.k = VVOID;
+  if (cc->tostore == LFIELDS_PER_FLUSH) {
+    luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);  /* flush */
+    cc->tostore = 0;  /* no more items pending */
+  }
+}
+
+
+static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
+  if (cc->tostore == 0) return;
+  if (hasmultret(cc->v.k)) {
+    luaK_setmultret(fs, &cc->v);
+    luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET);
+    cc->na--;  /* do not count last expression (unknown number of elements) */
+  }
+  else {
+    if (cc->v.k != VVOID)
+      luaK_exp2nextreg(fs, &cc->v);
+    luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);
+  }
+}
+
+
+static void listfield (LexState *ls, struct ConsControl *cc) {
+  /* listfield -> exp */
+  expr(ls, &cc->v);
+  checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
+  cc->na++;
+  cc->tostore++;
+}
+
+
+static void field (LexState *ls, struct ConsControl *cc) {
+  /* field -> listfield | recfield */
+  switch(ls->t.token) {
+    case TK_NAME: {  /* may be 'listfield' or 'recfield' */
+      if (luaX_lookahead(ls) != '=')  /* expression? */
+        listfield(ls, cc);
+      else
+        recfield(ls, cc);
+      break;
+    }
+    case '[': {
+      recfield(ls, cc);
+      break;
+    }
+    default: {
+      listfield(ls, cc);
+      break;
+    }
+  }
+}
+
+
+static void constructor (LexState *ls, expdesc *t) {
+  /* constructor -> '{' [ field { sep field } [sep] ] '}'
+     sep -> ',' | ';' */
+  FuncState *fs = ls->fs;
+  int line = ls->linenumber;
+  int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
+  struct ConsControl cc;
+  cc.na = cc.nh = cc.tostore = 0;
+  cc.t = t;
+  init_exp(t, VRELOCABLE, pc);
+  init_exp(&cc.v, VVOID, 0);  /* no value (yet) */
+  luaK_exp2nextreg(ls->fs, t);  /* fix it at stack top */
+  checknext(ls, '{');
+  do {
+    lua_assert(cc.v.k == VVOID || cc.tostore > 0);
+    if (ls->t.token == '}') break;
+    closelistfield(fs, &cc);
+    field(ls, &cc);
+  } while (testnext(ls, ',') || testnext(ls, ';'));
+  check_match(ls, '}', '{', line);
+  lastlistfield(fs, &cc);
+  SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
+  SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh));  /* set initial table size */
+}
+
+/* }====================================================================== */
+
+
+
+static void parlist (LexState *ls) {
+  /* parlist -> [ param { `,' param } ] */
+  FuncState *fs = ls->fs;
+  Proto *f = fs->f;
+  int nparams = 0;
+  f->is_vararg = 0;
+  if (ls->t.token != ')') {  /* is `parlist' not empty? */
+    do {
+      switch (ls->t.token) {
+        case TK_NAME: {  /* param -> NAME */
+          new_localvar(ls, str_checkname(ls));
+          nparams++;
+          break;
+        }
+        case TK_DOTS: {  /* param -> `...' */
+          luaX_next(ls);
+          f->is_vararg = 1;
+          break;
+        }
+        default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected");
+      }
+    } while (!f->is_vararg && testnext(ls, ','));
+  }
+  adjustlocalvars(ls, nparams);
+  f->numparams = cast_byte(fs->nactvar);
+  luaK_reserveregs(fs, fs->nactvar);  /* reserve register for parameters */
+}
+
+
+static void body (LexState *ls, expdesc *e, int ismethod, int line) {
+  /* body ->  `(' parlist `)' block END */
+  FuncState new_fs;
+  BlockCnt bl;
+  new_fs.f = addprototype(ls);
+  new_fs.f->linedefined = line;
+  open_func(ls, &new_fs, &bl);
+  checknext(ls, '(');
+  if (ismethod) {
+    new_localvarliteral(ls, "self");  /* create 'self' parameter */
+    adjustlocalvars(ls, 1);
+  }
+  parlist(ls);
+  checknext(ls, ')');
+  statlist(ls);
+  new_fs.f->lastlinedefined = ls->linenumber;
+  check_match(ls, TK_END, TK_FUNCTION, line);
+  codeclosure(ls, e);
+  close_func(ls);
+}
+
+
+static int explist (LexState *ls, expdesc *v) {
+  /* explist -> expr { `,' expr } */
+  int n = 1;  /* at least one expression */
+  expr(ls, v);
+  while (testnext(ls, ',')) {
+    luaK_exp2nextreg(ls->fs, v);
+    expr(ls, v);
+    n++;
+  }
+  return n;
+}
+
+
+static void funcargs (LexState *ls, expdesc *f, int line) {
+  FuncState *fs = ls->fs;
+  expdesc args;
+  int base, nparams;
+  switch (ls->t.token) {
+    case '(': {  /* funcargs -> `(' [ explist ] `)' */
+      luaX_next(ls);
+      if (ls->t.token == ')')  /* arg list is empty? */
+        args.k = VVOID;
+      else {
+        explist(ls, &args);
+        luaK_setmultret(fs, &args);
+      }
+      check_match(ls, ')', '(', line);
+      break;
+    }
+    case '{': {  /* funcargs -> constructor */
+      constructor(ls, &args);
+      break;
+    }
+    case TK_STRING: {  /* funcargs -> STRING */
+      codestring(ls, &args, ls->t.seminfo.ts);
+      luaX_next(ls);  /* must use `seminfo' before `next' */
+      break;
+    }
+    default: {
+      luaX_syntaxerror(ls, "function arguments expected");
+    }
+  }
+  lua_assert(f->k == VNONRELOC);
+  base = f->u.info;  /* base register for call */
+  if (hasmultret(args.k))
+    nparams = LUA_MULTRET;  /* open call */
+  else {
+    if (args.k != VVOID)
+      luaK_exp2nextreg(fs, &args);  /* close last argument */
+    nparams = fs->freereg - (base+1);
+  }
+  init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
+  luaK_fixline(fs, line);
+  fs->freereg = base+1;  /* call remove function and arguments and leaves
+                            (unless changed) one result */
+}
+
+
+
+
+/*
+** {======================================================================
+** Expression parsing
+** =======================================================================
+*/
+
+
+static void primaryexp (LexState *ls, expdesc *v) {
+  /* primaryexp -> NAME | '(' expr ')' */
+  switch (ls->t.token) {
+    case '(': {
+      int line = ls->linenumber;
+      luaX_next(ls);
+      expr(ls, v);
+      check_match(ls, ')', '(', line);
+      luaK_dischargevars(ls->fs, v);
+      return;
+    }
+    case TK_NAME: {
+      singlevar(ls, v);
+      return;
+    }
+    default: {
+      luaX_syntaxerror(ls, "unexpected symbol");
+    }
+  }
+}
+
+
+static void suffixedexp (LexState *ls, expdesc *v) {
+  /* suffixedexp ->
+       primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */
+  FuncState *fs = ls->fs;
+  int line = ls->linenumber;
+  primaryexp(ls, v);
+  for (;;) {
+    switch (ls->t.token) {
+      case '.': {  /* fieldsel */
+        fieldsel(ls, v);
+        break;
+      }
+      case '[': {  /* `[' exp1 `]' */
+        expdesc key;
+        luaK_exp2anyregup(fs, v);
+        yindex(ls, &key);
+        luaK_indexed(fs, v, &key);
+        break;
+      }
+      case ':': {  /* `:' NAME funcargs */
+        expdesc key;
+        luaX_next(ls);
+        checkname(ls, &key);
+        luaK_self(fs, v, &key);
+        funcargs(ls, v, line);
+        break;
+      }
+      case '(': case TK_STRING: case '{': {  /* funcargs */
+        luaK_exp2nextreg(fs, v);
+        funcargs(ls, v, line);
+        break;
+      }
+      default: return;
+    }
+  }
+}
+
+
+static void simpleexp (LexState *ls, expdesc *v) {
+  /* simpleexp -> NUMBER | STRING | NIL | TRUE | FALSE | ... |
+                  constructor | FUNCTION body | suffixedexp */
+  switch (ls->t.token) {
+    case TK_NUMBER: {
+      init_exp(v, VKNUM, 0);
+      v->u.nval = ls->t.seminfo.r;
+      break;
+    }
+    case TK_STRING: {
+      codestring(ls, v, ls->t.seminfo.ts);
+      break;
+    }
+    case TK_NIL: {
+      init_exp(v, VNIL, 0);
+      break;
+    }
+    case TK_TRUE: {
+      init_exp(v, VTRUE, 0);
+      break;
+    }
+    case TK_FALSE: {
+      init_exp(v, VFALSE, 0);
+      break;
+    }
+    case TK_DOTS: {  /* vararg */
+      FuncState *fs = ls->fs;
+      check_condition(ls, fs->f->is_vararg,
+                      "cannot use " LUA_QL("...") " outside a vararg function");
+      init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
+      break;
+    }
+    case '{': {  /* constructor */
+      constructor(ls, v);
+      return;
+    }
+    case TK_FUNCTION: {
+      luaX_next(ls);
+      body(ls, v, 0, ls->linenumber);
+      return;
+    }
+    default: {
+      suffixedexp(ls, v);
+      return;
+    }
+  }
+  luaX_next(ls);
+}
+
+
+static UnOpr getunopr (int op) {
+  switch (op) {
+    case TK_NOT: return OPR_NOT;
+    case '-': return OPR_MINUS;
+    case '#': return OPR_LEN;
+    default: return OPR_NOUNOPR;
+  }
+}
+
+
+static BinOpr getbinopr (int op) {
+  switch (op) {
+    case '+': return OPR_ADD;
+    case '-': return OPR_SUB;
+    case '*': return OPR_MUL;
+    case '/': return OPR_DIV;
+    case '%': return OPR_MOD;
+    case '^': return OPR_POW;
+    case TK_CONCAT: return OPR_CONCAT;
+    case TK_NE: return OPR_NE;
+    case TK_EQ: return OPR_EQ;
+    case '<': return OPR_LT;
+    case TK_LE: return OPR_LE;
+    case '>': return OPR_GT;
+    case TK_GE: return OPR_GE;
+    case TK_AND: return OPR_AND;
+    case TK_OR: return OPR_OR;
+    default: return OPR_NOBINOPR;
+  }
+}
+
+
+static const struct {
+  lu_byte left;  /* left priority for each binary operator */
+  lu_byte right; /* right priority */
+} priority[] = {  /* ORDER OPR */
+   {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7},  /* `+' `-' `*' `/' `%' */
+   {10, 9}, {5, 4},                 /* ^, .. (right associative) */
+   {3, 3}, {3, 3}, {3, 3},          /* ==, <, <= */
+   {3, 3}, {3, 3}, {3, 3},          /* ~=, >, >= */
+   {2, 2}, {1, 1}                   /* and, or */
+};
+
+#define UNARY_PRIORITY  8  /* priority for unary operators */
+
+
+/*
+** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
+** where `binop' is any binary operator with a priority higher than `limit'
+*/
+static BinOpr subexpr (LexState *ls, expdesc *v, int limit) {
+  BinOpr op;
+  UnOpr uop;
+  enterlevel(ls);
+  uop = getunopr(ls->t.token);
+  if (uop != OPR_NOUNOPR) {
+    int line = ls->linenumber;
+    luaX_next(ls);
+    subexpr(ls, v, UNARY_PRIORITY);
+    luaK_prefix(ls->fs, uop, v, line);
+  }
+  else simpleexp(ls, v);
+  /* expand while operators have priorities higher than `limit' */
+  op = getbinopr(ls->t.token);
+  while (op != OPR_NOBINOPR && priority[op].left > limit) {
+    expdesc v2;
+    BinOpr nextop;
+    int line = ls->linenumber;
+    luaX_next(ls);
+    luaK_infix(ls->fs, op, v);
+    /* read sub-expression with higher priority */
+    nextop = subexpr(ls, &v2, priority[op].right);
+    luaK_posfix(ls->fs, op, v, &v2, line);
+    op = nextop;
+  }
+  leavelevel(ls);
+  return op;  /* return first untreated operator */
+}
+
+
+static void expr (LexState *ls, expdesc *v) {
+  subexpr(ls, v, 0);
+}
+
+/* }==================================================================== */
+
+
+
+/*
+** {======================================================================
+** Rules for Statements
+** =======================================================================
+*/
+
+
+static void block (LexState *ls) {
+  /* block -> statlist */
+  FuncState *fs = ls->fs;
+  BlockCnt bl;
+  enterblock(fs, &bl, 0);
+  statlist(ls);
+  leaveblock(fs);
+}
+
+
+/*
+** structure to chain all variables in the left-hand side of an
+** assignment
+*/
+struct LHS_assign {
+  struct LHS_assign *prev;
+  expdesc v;  /* variable (global, local, upvalue, or indexed) */
+};
+
+
+/*
+** check whether, in an assignment to an upvalue/local variable, the
+** upvalue/local variable is begin used in a previous assignment to a
+** table. If so, save original upvalue/local value in a safe place and
+** use this safe copy in the previous assignment.
+*/
+static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
+  FuncState *fs = ls->fs;
+  int extra = fs->freereg;  /* eventual position to save local variable */
+  int conflict = 0;
+  for (; lh; lh = lh->prev) {  /* check all previous assignments */
+    if (lh->v.k == VINDEXED) {  /* assigning to a table? */
+      /* table is the upvalue/local being assigned now? */
+      if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) {
+        conflict = 1;
+        lh->v.u.ind.vt = VLOCAL;
+        lh->v.u.ind.t = extra;  /* previous assignment will use safe copy */
+      }
+      /* index is the local being assigned? (index cannot be upvalue) */
+      if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) {
+        conflict = 1;
+        lh->v.u.ind.idx = extra;  /* previous assignment will use safe copy */
+      }
+    }
+  }
+  if (conflict) {
+    /* copy upvalue/local value to a temporary (in position 'extra') */
+    OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
+    luaK_codeABC(fs, op, extra, v->u.info, 0);
+    luaK_reserveregs(fs, 1);
+  }
+}
+
+
+static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
+  expdesc e;
+  check_condition(ls, vkisvar(lh->v.k), "syntax error");
+  if (testnext(ls, ',')) {  /* assignment -> ',' suffixedexp assignment */
+    struct LHS_assign nv;
+    nv.prev = lh;
+    suffixedexp(ls, &nv.v);
+    if (nv.v.k != VINDEXED)
+      check_conflict(ls, lh, &nv.v);
+    checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS,
+                    "C levels");
+    assignment(ls, &nv, nvars+1);
+  }
+  else {  /* assignment -> `=' explist */
+    int nexps;
+    checknext(ls, '=');
+    nexps = explist(ls, &e);
+    if (nexps != nvars) {
+      adjust_assign(ls, nvars, nexps, &e);
+      if (nexps > nvars)
+        ls->fs->freereg -= nexps - nvars;  /* remove extra values */
+    }
+    else {
+      luaK_setoneret(ls->fs, &e);  /* close last expression */
+      luaK_storevar(ls->fs, &lh->v, &e);
+      return;  /* avoid default */
+    }
+  }
+  init_exp(&e, VNONRELOC, ls->fs->freereg-1);  /* default assignment */
+  luaK_storevar(ls->fs, &lh->v, &e);
+}
+
+
+static int cond (LexState *ls) {
+  /* cond -> exp */
+  expdesc v;
+  expr(ls, &v);  /* read condition */
+  if (v.k == VNIL) v.k = VFALSE;  /* `falses' are all equal here */
+  luaK_goiftrue(ls->fs, &v);
+  return v.f;
+}
+
+
+static void gotostat (LexState *ls, int pc) {
+  int line = ls->linenumber;
+  TString *label;
+  int g;
+  if (testnext(ls, TK_GOTO))
+    label = str_checkname(ls);
+  else {
+    luaX_next(ls);  /* skip break */
+    label = luaS_new(ls->L, "break");
+  }
+  g = newlabelentry(ls, &ls->dyd->gt, label, line, pc);
+  findlabel(ls, g);  /* close it if label already defined */
+}
+
+
+/* check for repeated labels on the same block */
+static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) {
+  int i;
+  for (i = fs->bl->firstlabel; i < ll->n; i++) {
+    if (luaS_eqstr(label, ll->arr[i].name)) {
+      const char *msg = luaO_pushfstring(fs->ls->L,
+                          "label " LUA_QS " already defined on line %d",
+                          getstr(label), ll->arr[i].line);
+      semerror(fs->ls, msg);
+    }
+  }
+}
+
+
+/* skip no-op statements */
+static void skipnoopstat (LexState *ls) {
+  while (ls->t.token == ';' || ls->t.token == TK_DBCOLON)
+    statement(ls);
+}
+
+
+static void labelstat (LexState *ls, TString *label, int line) {
+  /* label -> '::' NAME '::' */
+  FuncState *fs = ls->fs;
+  Labellist *ll = &ls->dyd->label;
+  int l;  /* index of new label being created */
+  checkrepeated(fs, ll, label);  /* check for repeated labels */
+  checknext(ls, TK_DBCOLON);  /* skip double colon */
+  /* create new entry for this label */
+  l = newlabelentry(ls, ll, label, line, fs->pc);
+  skipnoopstat(ls);  /* skip other no-op statements */
+  if (block_follow(ls, 0)) {  /* label is last no-op statement in the block? */
+    /* assume that locals are already out of scope */
+    ll->arr[l].nactvar = fs->bl->nactvar;
+  }
+  findgotos(ls, &ll->arr[l]);
+}
+
+
+static void whilestat (LexState *ls, int line) {
+  /* whilestat -> WHILE cond DO block END */
+  FuncState *fs = ls->fs;
+  int whileinit;
+  int condexit;
+  BlockCnt bl;
+  luaX_next(ls);  /* skip WHILE */
+  whileinit = luaK_getlabel(fs);
+  condexit = cond(ls);
+  enterblock(fs, &bl, 1);
+  checknext(ls, TK_DO);
+  block(ls);
+  luaK_jumpto(fs, whileinit);
+  check_match(ls, TK_END, TK_WHILE, line);
+  leaveblock(fs);
+  luaK_patchtohere(fs, condexit);  /* false conditions finish the loop */
+}
+
+
+static void repeatstat (LexState *ls, int line) {
+  /* repeatstat -> REPEAT block UNTIL cond */
+  int condexit;
+  FuncState *fs = ls->fs;
+  int repeat_init = luaK_getlabel(fs);
+  BlockCnt bl1, bl2;
+  enterblock(fs, &bl1, 1);  /* loop block */
+  enterblock(fs, &bl2, 0);  /* scope block */
+  luaX_next(ls);  /* skip REPEAT */
+  statlist(ls);
+  check_match(ls, TK_UNTIL, TK_REPEAT, line);
+  condexit = cond(ls);  /* read condition (inside scope block) */
+  if (bl2.upval)  /* upvalues? */
+    luaK_patchclose(fs, condexit, bl2.nactvar);
+  leaveblock(fs);  /* finish scope */
+  luaK_patchlist(fs, condexit, repeat_init);  /* close the loop */
+  leaveblock(fs);  /* finish loop */
+}
+
+
+static int exp1 (LexState *ls) {
+  expdesc e;
+  int reg;
+  expr(ls, &e);
+  luaK_exp2nextreg(ls->fs, &e);
+  lua_assert(e.k == VNONRELOC);
+  reg = e.u.info;
+  return reg;
+}
+
+
+static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
+  /* forbody -> DO block */
+  BlockCnt bl;
+  FuncState *fs = ls->fs;
+  int prep, endfor;
+  adjustlocalvars(ls, 3);  /* control variables */
+  checknext(ls, TK_DO);
+  prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
+  enterblock(fs, &bl, 0);  /* scope for declared variables */
+  adjustlocalvars(ls, nvars);
+  luaK_reserveregs(fs, nvars);
+  block(ls);
+  leaveblock(fs);  /* end of scope for declared variables */
+  luaK_patchtohere(fs, prep);
+  if (isnum)  /* numeric for? */
+    endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP);
+  else {  /* generic for */
+    luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
+    luaK_fixline(fs, line);
+    endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP);
+  }
+  luaK_patchlist(fs, endfor, prep + 1);
+  luaK_fixline(fs, line);
+}
+
+
+static void fornum (LexState *ls, TString *varname, int line) {
+  /* fornum -> NAME = exp1,exp1[,exp1] forbody */
+  FuncState *fs = ls->fs;
+  int base = fs->freereg;
+  new_localvarliteral(ls, "(for index)");
+  new_localvarliteral(ls, "(for limit)");
+  new_localvarliteral(ls, "(for step)");
+  new_localvar(ls, varname);
+  checknext(ls, '=');
+  exp1(ls);  /* initial value */
+  checknext(ls, ',');
+  exp1(ls);  /* limit */
+  if (testnext(ls, ','))
+    exp1(ls);  /* optional step */
+  else {  /* default step = 1 */
+    luaK_codek(fs, fs->freereg, luaK_numberK(fs, 1));
+    luaK_reserveregs(fs, 1);
+  }
+  forbody(ls, base, line, 1, 1);
+}
+
+
+static void forlist (LexState *ls, TString *indexname) {
+  /* forlist -> NAME {,NAME} IN explist forbody */
+  FuncState *fs = ls->fs;
+  expdesc e;
+  int nvars = 4;  /* gen, state, control, plus at least one declared var */
+  int line;
+  int base = fs->freereg;
+  /* create control variables */
+  new_localvarliteral(ls, "(for generator)");
+  new_localvarliteral(ls, "(for state)");
+  new_localvarliteral(ls, "(for control)");
+  /* create declared variables */
+  new_localvar(ls, indexname);
+  while (testnext(ls, ',')) {
+    new_localvar(ls, str_checkname(ls));
+    nvars++;
+  }
+  checknext(ls, TK_IN);
+  line = ls->linenumber;
+  adjust_assign(ls, 3, explist(ls, &e), &e);
+  luaK_checkstack(fs, 3);  /* extra space to call generator */
+  forbody(ls, base, line, nvars - 3, 0);
+}
+
+
+static void forstat (LexState *ls, int line) {
+  /* forstat -> FOR (fornum | forlist) END */
+  FuncState *fs = ls->fs;
+  TString *varname;
+  BlockCnt bl;
+  enterblock(fs, &bl, 1);  /* scope for loop and control variables */
+  luaX_next(ls);  /* skip `for' */
+  varname = str_checkname(ls);  /* first variable name */
+  switch (ls->t.token) {
+    case '=': fornum(ls, varname, line); break;
+    case ',': case TK_IN: forlist(ls, varname); break;
+    default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected");
+  }
+  check_match(ls, TK_END, TK_FOR, line);
+  leaveblock(fs);  /* loop scope (`break' jumps to this point) */
+}
+
+
+static void test_then_block (LexState *ls, int *escapelist) {
+  /* test_then_block -> [IF | ELSEIF] cond THEN block */
+  BlockCnt bl;
+  FuncState *fs = ls->fs;
+  expdesc v;
+  int jf;  /* instruction to skip 'then' code (if condition is false) */
+  luaX_next(ls);  /* skip IF or ELSEIF */
+  expr(ls, &v);  /* read condition */
+  checknext(ls, TK_THEN);
+  if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) {
+    luaK_goiffalse(ls->fs, &v);  /* will jump to label if condition is true */
+    enterblock(fs, &bl, 0);  /* must enter block before 'goto' */
+    gotostat(ls, v.t);  /* handle goto/break */
+    skipnoopstat(ls);  /* skip other no-op statements */
+    if (block_follow(ls, 0)) {  /* 'goto' is the entire block? */
+      leaveblock(fs);
+      return;  /* and that is it */
+    }
+    else  /* must skip over 'then' part if condition is false */
+      jf = luaK_jump(fs);
+  }
+  else {  /* regular case (not goto/break) */
+    luaK_goiftrue(ls->fs, &v);  /* skip over block if condition is false */
+    enterblock(fs, &bl, 0);
+    jf = v.f;
+  }
+  statlist(ls);  /* `then' part */
+  leaveblock(fs);
+  if (ls->t.token == TK_ELSE ||
+      ls->t.token == TK_ELSEIF)  /* followed by 'else'/'elseif'? */
+    luaK_concat(fs, escapelist, luaK_jump(fs));  /* must jump over it */
+  luaK_patchtohere(fs, jf);
+}
+
+
+static void ifstat (LexState *ls, int line) {
+  /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
+  FuncState *fs = ls->fs;
+  int escapelist = NO_JUMP;  /* exit list for finished parts */
+  test_then_block(ls, &escapelist);  /* IF cond THEN block */
+  while (ls->t.token == TK_ELSEIF)
+    test_then_block(ls, &escapelist);  /* ELSEIF cond THEN block */
+  if (testnext(ls, TK_ELSE))
+    block(ls);  /* `else' part */
+  check_match(ls, TK_END, TK_IF, line);
+  luaK_patchtohere(fs, escapelist);  /* patch escape list to 'if' end */
+}
+
+
+static void localfunc (LexState *ls) {
+  expdesc b;
+  FuncState *fs = ls->fs;
+  new_localvar(ls, str_checkname(ls));  /* new local variable */
+  adjustlocalvars(ls, 1);  /* enter its scope */
+  body(ls, &b, 0, ls->linenumber);  /* function created in next register */
+  /* debug information will only see the variable after this point! */
+  getlocvar(fs, b.u.info)->startpc = fs->pc;
+}
+
+
+static void localstat (LexState *ls) {
+  /* stat -> LOCAL NAME {`,' NAME} [`=' explist] */
+  int nvars = 0;
+  int nexps;
+  expdesc e;
+  do {
+    new_localvar(ls, str_checkname(ls));
+    nvars++;
+  } while (testnext(ls, ','));
+  if (testnext(ls, '='))
+    nexps = explist(ls, &e);
+  else {
+    e.k = VVOID;
+    nexps = 0;
+  }
+  adjust_assign(ls, nvars, nexps, &e);
+  adjustlocalvars(ls, nvars);
+}
+
+
+static int funcname (LexState *ls, expdesc *v) {
+  /* funcname -> NAME {fieldsel} [`:' NAME] */
+  int ismethod = 0;
+  singlevar(ls, v);
+  while (ls->t.token == '.')
+    fieldsel(ls, v);
+  if (ls->t.token == ':') {
+    ismethod = 1;
+    fieldsel(ls, v);
+  }
+  return ismethod;
+}
+
+
+static void funcstat (LexState *ls, int line) {
+  /* funcstat -> FUNCTION funcname body */
+  int ismethod;
+  expdesc v, b;
+  luaX_next(ls);  /* skip FUNCTION */
+  ismethod = funcname(ls, &v);
+  body(ls, &b, ismethod, line);
+  luaK_storevar(ls->fs, &v, &b);
+  luaK_fixline(ls->fs, line);  /* definition `happens' in the first line */
+}
+
+
+static void exprstat (LexState *ls) {
+  /* stat -> func | assignment */
+  FuncState *fs = ls->fs;
+  struct LHS_assign v;
+  suffixedexp(ls, &v.v);
+  if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */
+    v.prev = NULL;
+    assignment(ls, &v, 1);
+  }
+  else {  /* stat -> func */
+    check_condition(ls, v.v.k == VCALL, "syntax error");
+    SETARG_C(getcode(fs, &v.v), 1);  /* call statement uses no results */
+  }
+}
+
+
+static void retstat (LexState *ls) {
+  /* stat -> RETURN [explist] [';'] */
+  FuncState *fs = ls->fs;
+  expdesc e;
+  int first, nret;  /* registers with returned values */
+  if (block_follow(ls, 1) || ls->t.token == ';')
+    first = nret = 0;  /* return no values */
+  else {
+    nret = explist(ls, &e);  /* optional return values */
+    if (hasmultret(e.k)) {
+      luaK_setmultret(fs, &e);
+      if (e.k == VCALL && nret == 1) {  /* tail call? */
+        SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
+        lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
+      }
+      first = fs->nactvar;
+      nret = LUA_MULTRET;  /* return all values */
+    }
+    else {
+      if (nret == 1)  /* only one single value? */
+        first = luaK_exp2anyreg(fs, &e);
+      else {
+        luaK_exp2nextreg(fs, &e);  /* values must go to the `stack' */
+        first = fs->nactvar;  /* return all `active' values */
+        lua_assert(nret == fs->freereg - first);
+      }
+    }
+  }
+  luaK_ret(fs, first, nret);
+  testnext(ls, ';');  /* skip optional semicolon */
+}
+
+
+static void statement (LexState *ls) {
+  int line = ls->linenumber;  /* may be needed for error messages */
+  enterlevel(ls);
+  switch (ls->t.token) {
+    case ';': {  /* stat -> ';' (empty statement) */
+      luaX_next(ls);  /* skip ';' */
+      break;
+    }
+    case TK_IF: {  /* stat -> ifstat */
+      ifstat(ls, line);
+      break;
+    }
+    case TK_WHILE: {  /* stat -> whilestat */
+      whilestat(ls, line);
+      break;
+    }
+    case TK_DO: {  /* stat -> DO block END */
+      luaX_next(ls);  /* skip DO */
+      block(ls);
+      check_match(ls, TK_END, TK_DO, line);
+      break;
+    }
+    case TK_FOR: {  /* stat -> forstat */
+      forstat(ls, line);
+      break;
+    }
+    case TK_REPEAT: {  /* stat -> repeatstat */
+      repeatstat(ls, line);
+      break;
+    }
+    case TK_FUNCTION: {  /* stat -> funcstat */
+      funcstat(ls, line);
+      break;
+    }
+    case TK_LOCAL: {  /* stat -> localstat */
+      luaX_next(ls);  /* skip LOCAL */
+      if (testnext(ls, TK_FUNCTION))  /* local function? */
+        localfunc(ls);
+      else
+        localstat(ls);
+      break;
+    }
+    case TK_DBCOLON: {  /* stat -> label */
+      luaX_next(ls);  /* skip double colon */
+      labelstat(ls, str_checkname(ls), line);
+      break;
+    }
+    case TK_RETURN: {  /* stat -> retstat */
+      luaX_next(ls);  /* skip RETURN */
+      retstat(ls);
+      break;
+    }
+    case TK_BREAK:   /* stat -> breakstat */
+    case TK_GOTO: {  /* stat -> 'goto' NAME */
+      gotostat(ls, luaK_jump(ls->fs));
+      break;
+    }
+    default: {  /* stat -> func | assignment */
+      exprstat(ls);
+      break;
+    }
+  }
+  lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
+             ls->fs->freereg >= ls->fs->nactvar);
+  ls->fs->freereg = ls->fs->nactvar;  /* free registers */
+  leavelevel(ls);
+}
+
+/* }====================================================================== */
+
+
+/*
+** compiles the main function, which is a regular vararg function with an
+** upvalue named LUA_ENV
+*/
+static void mainfunc (LexState *ls, FuncState *fs) {
+  BlockCnt bl;
+  expdesc v;
+  open_func(ls, fs, &bl);
+  fs->f->is_vararg = 1;  /* main function is always vararg */
+  init_exp(&v, VLOCAL, 0);  /* create and... */
+  newupvalue(fs, ls->envn, &v);  /* ...set environment upvalue */
+  luaX_next(ls);  /* read first token */
+  statlist(ls);  /* parse main body */
+  check(ls, TK_EOS);
+  close_func(ls);
+}
+
+
+Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
+                      Dyndata *dyd, const char *name, int firstchar) {
+  LexState lexstate;
+  FuncState funcstate;
+  Closure *cl = luaF_newLclosure(L, 1);  /* create main closure */
+  /* anchor closure (to avoid being collected) */
+  setclLvalue(L, L->top, cl);
+  incr_top(L);
+  funcstate.f = cl->l.p = luaF_newproto(L);
+  funcstate.f->source = luaS_new(L, name);  /* create and anchor TString */
+  lexstate.buff = buff;
+  lexstate.dyd = dyd;
+  dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
+  luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar);
+  mainfunc(&lexstate, &funcstate);
+  lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
+  /* all scopes should be correctly finished */
+  lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0);
+  return cl;  /* it's on the stack too */
+}
+