rlm@1: /*
rlm@1: ** $Id: lparser.c,v 2.42.1.3 2007/12/28 15:32:23 roberto Exp $
rlm@1: ** Lua Parser
rlm@1: ** See Copyright Notice in lua.h
rlm@1: */
rlm@1: 
rlm@1: 
rlm@1: #include <string.h>
rlm@1: 
rlm@1: #define lparser_c
rlm@1: #define LUA_CORE
rlm@1: 
rlm@1: #include "lua.h"
rlm@1: 
rlm@1: #include "lcode.h"
rlm@1: #include "ldebug.h"
rlm@1: #include "ldo.h"
rlm@1: #include "lfunc.h"
rlm@1: #include "llex.h"
rlm@1: #include "lmem.h"
rlm@1: #include "lobject.h"
rlm@1: #include "lopcodes.h"
rlm@1: #include "lparser.h"
rlm@1: #include "lstate.h"
rlm@1: #include "lstring.h"
rlm@1: #include "ltable.h"
rlm@1: 
rlm@1: 
rlm@1: 
rlm@1: #define hasmultret(k)		((k) == VCALL || (k) == VVARARG)
rlm@1: 
rlm@1: #define getlocvar(fs, i)	((fs)->f->locvars[(fs)->actvar[i]])
rlm@1: 
rlm@1: #define luaY_checklimit(fs,v,l,m)	if ((v)>(l)) errorlimit(fs,l,m)
rlm@1: 
rlm@1: 
rlm@1: /*
rlm@1: ** nodes for block list (list of active blocks)
rlm@1: */
rlm@1: typedef struct BlockCnt {
rlm@1:   struct BlockCnt *previous;  /* chain */
rlm@1:   int breaklist;  /* list of jumps out of this loop */
rlm@1:   lu_byte nactvar;  /* # active locals outside the breakable structure */
rlm@1:   lu_byte upval;  /* true if some variable in the block is an upvalue */
rlm@1:   lu_byte isbreakable;  /* true if `block' is a loop */
rlm@1: } BlockCnt;
rlm@1: 
rlm@1: 
rlm@1: 
rlm@1: /*
rlm@1: ** prototypes for recursive non-terminal functions
rlm@1: */
rlm@1: static void chunk (LexState *ls);
rlm@1: static void expr (LexState *ls, expdesc *v);
rlm@1: 
rlm@1: 
rlm@1: static void anchor_token (LexState *ls) {
rlm@1:   if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) {
rlm@1:     TString *ts = ls->t.seminfo.ts;
rlm@1:     luaX_newstring(ls, getstr(ts), ts->tsv.len);
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void error_expected (LexState *ls, int token) {
rlm@1:   luaX_syntaxerror(ls,
rlm@1:       luaO_pushfstring(ls->L, LUA_QS " expected", luaX_token2str(ls, token)));
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void errorlimit (FuncState *fs, int limit, const char *what) {
rlm@1:   const char *msg = (fs->f->linedefined == 0) ?
rlm@1:     luaO_pushfstring(fs->L, "main function has more than %d %s", limit, what) :
rlm@1:     luaO_pushfstring(fs->L, "function at line %d has more than %d %s",
rlm@1:                             fs->f->linedefined, limit, what);
rlm@1:   luaX_lexerror(fs->ls, msg, 0);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int testnext (LexState *ls, int c) {
rlm@1:   if (ls->t.token == c) {
rlm@1:     luaX_next(ls);
rlm@1:     return 1;
rlm@1:   }
rlm@1:   else return 0;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void check (LexState *ls, int c) {
rlm@1:   if (ls->t.token != c)
rlm@1:     error_expected(ls, c);
rlm@1: }
rlm@1: 
rlm@1: static void checknext (LexState *ls, int c) {
rlm@1:   check(ls, c);
rlm@1:   luaX_next(ls);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: #define check_condition(ls,c,msg)	{ if (!(c)) luaX_syntaxerror(ls, msg); }
rlm@1: 
rlm@1: 
rlm@1: 
rlm@1: static void check_match (LexState *ls, int what, int who, int where) {
rlm@1:   if (!testnext(ls, what)) {
rlm@1:     if (where == ls->linenumber)
rlm@1:       error_expected(ls, what);
rlm@1:     else {
rlm@1:       luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
rlm@1:              LUA_QS " expected (to close " LUA_QS " at line %d)",
rlm@1:               luaX_token2str(ls, what), luaX_token2str(ls, who), where));
rlm@1:     }
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static TString *str_checkname (LexState *ls) {
rlm@1:   TString *ts;
rlm@1:   check(ls, TK_NAME);
rlm@1:   ts = ls->t.seminfo.ts;
rlm@1:   luaX_next(ls);
rlm@1:   return ts;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void init_exp (expdesc *e, expkind k, int i) {
rlm@1:   e->f = e->t = NO_JUMP;
rlm@1:   e->k = k;
rlm@1:   e->u.s.info = i;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void codestring (LexState *ls, expdesc *e, TString *s) {
rlm@1:   init_exp(e, VK, luaK_stringK(ls->fs, s));
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void checkname(LexState *ls, expdesc *e) {
rlm@1:   codestring(ls, e, str_checkname(ls));
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int registerlocalvar (LexState *ls, TString *varname) {
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   Proto *f = fs->f;
rlm@1:   int oldsize = f->sizelocvars;
rlm@1:   luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
rlm@1:                   LocVar, SHRT_MAX, "too many local variables");
rlm@1:   while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL;
rlm@1:   f->locvars[fs->nlocvars].varname = varname;
rlm@1:   luaC_objbarrier(ls->L, f, varname);
rlm@1:   return fs->nlocvars++;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: #define new_localvarliteral(ls,v,n) \
rlm@1:   new_localvar(ls, luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char))-1), n)
rlm@1: 
rlm@1: 
rlm@1: static void new_localvar (LexState *ls, TString *name, int n) {
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   luaY_checklimit(fs, fs->nactvar+n+1, LUAI_MAXVARS, "local variables");
rlm@1:   fs->actvar[fs->nactvar+n] = cast(unsigned short, registerlocalvar(ls, name));
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void adjustlocalvars (LexState *ls, int nvars) {
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   fs->nactvar = cast_byte(fs->nactvar + nvars);
rlm@1:   for (; nvars; nvars--) {
rlm@1:     getlocvar(fs, fs->nactvar - nvars).startpc = fs->pc;
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void removevars (LexState *ls, int tolevel) {
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   while (fs->nactvar > tolevel)
rlm@1:     getlocvar(fs, --fs->nactvar).endpc = fs->pc;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int indexupvalue (FuncState *fs, TString *name, expdesc *v) {
rlm@1:   int i;
rlm@1:   Proto *f = fs->f;
rlm@1:   int oldsize = f->sizeupvalues;
rlm@1:   for (i=0; i<f->nups; i++) {
rlm@1:     if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->u.s.info) {
rlm@1:       lua_assert(f->upvalues[i] == name);
rlm@1:       return i;
rlm@1:     }
rlm@1:   }
rlm@1:   /* new one */
rlm@1:   luaY_checklimit(fs, f->nups + 1, LUAI_MAXUPVALUES, "upvalues");
rlm@1:   luaM_growvector(fs->L, f->upvalues, f->nups, f->sizeupvalues,
rlm@1:                   TString *, MAX_INT, "");
rlm@1:   while (oldsize < f->sizeupvalues) f->upvalues[oldsize++] = NULL;
rlm@1:   f->upvalues[f->nups] = name;
rlm@1:   luaC_objbarrier(fs->L, f, name);
rlm@1:   lua_assert(v->k == VLOCAL || v->k == VUPVAL);
rlm@1:   fs->upvalues[f->nups].k = cast_byte(v->k);
rlm@1:   fs->upvalues[f->nups].info = cast_byte(v->u.s.info);
rlm@1:   return f->nups++;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int searchvar (FuncState *fs, TString *n) {
rlm@1:   int i;
rlm@1:   for (i=fs->nactvar-1; i >= 0; i--) {
rlm@1:     if (n == getlocvar(fs, i).varname)
rlm@1:       return i;
rlm@1:   }
rlm@1:   return -1;  /* not found */
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void markupval (FuncState *fs, int level) {
rlm@1:   BlockCnt *bl = fs->bl;
rlm@1:   while (bl && bl->nactvar > level) bl = bl->previous;
rlm@1:   if (bl) bl->upval = 1;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
rlm@1:   if (fs == NULL) {  /* no more levels? */
rlm@1:     init_exp(var, VGLOBAL, NO_REG);  /* default is global variable */
rlm@1:     return VGLOBAL;
rlm@1:   }
rlm@1:   else {
rlm@1:     int v = searchvar(fs, n);  /* look up at current level */
rlm@1:     if (v >= 0) {
rlm@1:       init_exp(var, VLOCAL, v);
rlm@1:       if (!base)
rlm@1:         markupval(fs, v);  /* local will be used as an upval */
rlm@1:       return VLOCAL;
rlm@1:     }
rlm@1:     else {  /* not found at current level; try upper one */
rlm@1:       if (singlevaraux(fs->prev, n, var, 0) == VGLOBAL)
rlm@1:         return VGLOBAL;
rlm@1:       var->u.s.info = indexupvalue(fs, n, var);  /* else was LOCAL or UPVAL */
rlm@1:       var->k = VUPVAL;  /* upvalue in this level */
rlm@1:       return VUPVAL;
rlm@1:     }
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void singlevar (LexState *ls, expdesc *var) {
rlm@1:   TString *varname = str_checkname(ls);
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   if (singlevaraux(fs, varname, var, 1) == VGLOBAL)
rlm@1:     var->u.s.info = luaK_stringK(fs, varname);  /* info points to global name */
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   int extra = nvars - nexps;
rlm@1:   if (hasmultret(e->k)) {
rlm@1:     extra++;  /* includes call itself */
rlm@1:     if (extra < 0) extra = 0;
rlm@1:     luaK_setreturns(fs, e, extra);  /* last exp. provides the difference */
rlm@1:     if (extra > 1) luaK_reserveregs(fs, extra-1);
rlm@1:   }
rlm@1:   else {
rlm@1:     if (e->k != VVOID) luaK_exp2nextreg(fs, e);  /* close last expression */
rlm@1:     if (extra > 0) {
rlm@1:       int reg = fs->freereg;
rlm@1:       luaK_reserveregs(fs, extra);
rlm@1:       luaK_nil(fs, reg, extra);
rlm@1:     }
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void enterlevel (LexState *ls) {
rlm@1:   if (++ls->L->nCcalls > LUAI_MAXCCALLS)
rlm@1: 	luaX_lexerror(ls, "chunk has too many syntax levels", 0);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: #define leavelevel(ls)	((ls)->L->nCcalls--)
rlm@1: 
rlm@1: 
rlm@1: static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isbreakable) {
rlm@1:   bl->breaklist = NO_JUMP;
rlm@1:   bl->isbreakable = isbreakable;
rlm@1:   bl->nactvar = fs->nactvar;
rlm@1:   bl->upval = 0;
rlm@1:   bl->previous = fs->bl;
rlm@1:   fs->bl = bl;
rlm@1:   lua_assert(fs->freereg == fs->nactvar);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void leaveblock (FuncState *fs) {
rlm@1:   BlockCnt *bl = fs->bl;
rlm@1:   fs->bl = bl->previous;
rlm@1:   removevars(fs->ls, bl->nactvar);
rlm@1:   if (bl->upval)
rlm@1:     luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
rlm@1:   /* a block either controls scope or breaks (never both) */
rlm@1:   lua_assert(!bl->isbreakable || !bl->upval);
rlm@1:   lua_assert(bl->nactvar == fs->nactvar);
rlm@1:   fs->freereg = fs->nactvar;  /* free registers */
rlm@1:   luaK_patchtohere(fs, bl->breaklist);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void pushclosure (LexState *ls, FuncState *func, expdesc *v) {
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   Proto *f = fs->f;
rlm@1:   int oldsize = f->sizep;
rlm@1:   int i;
rlm@1:   luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *,
rlm@1:                   MAXARG_Bx, "constant table overflow");
rlm@1:   while (oldsize < f->sizep) f->p[oldsize++] = NULL;
rlm@1:   f->p[fs->np++] = func->f;
rlm@1:   luaC_objbarrier(ls->L, f, func->f);
rlm@1:   init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np-1));
rlm@1:   for (i=0; i<func->f->nups; i++) {
rlm@1:     OpCode o = (func->upvalues[i].k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
rlm@1:     luaK_codeABC(fs, o, 0, func->upvalues[i].info, 0);
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void open_func (LexState *ls, FuncState *fs) {
rlm@1:   lua_State *L = ls->L;
rlm@1:   Proto *f = luaF_newproto(L);
rlm@1:   fs->f = f;
rlm@1:   fs->prev = ls->fs;  /* linked list of funcstates */
rlm@1:   fs->ls = ls;
rlm@1:   fs->L = L;
rlm@1:   ls->fs = fs;
rlm@1:   fs->pc = 0;
rlm@1:   fs->lasttarget = -1;
rlm@1:   fs->jpc = NO_JUMP;
rlm@1:   fs->freereg = 0;
rlm@1:   fs->nk = 0;
rlm@1:   fs->np = 0;
rlm@1:   fs->nlocvars = 0;
rlm@1:   fs->nactvar = 0;
rlm@1:   fs->bl = NULL;
rlm@1:   f->source = ls->source;
rlm@1:   f->maxstacksize = 2;  /* registers 0/1 are always valid */
rlm@1:   fs->h = luaH_new(L, 0, 0);
rlm@1:   /* anchor table of constants and prototype (to avoid being collected) */
rlm@1:   sethvalue2s(L, L->top, fs->h);
rlm@1:   incr_top(L);
rlm@1:   setptvalue2s(L, L->top, f);
rlm@1:   incr_top(L);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void close_func (LexState *ls) {
rlm@1:   lua_State *L = ls->L;
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   Proto *f = fs->f;
rlm@1:   removevars(ls, 0);
rlm@1:   luaK_ret(fs, 0, 0);  /* final return */
rlm@1:   luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
rlm@1:   f->sizecode = fs->pc;
rlm@1:   luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
rlm@1:   f->sizelineinfo = fs->pc;
rlm@1:   luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
rlm@1:   f->sizek = fs->nk;
rlm@1:   luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
rlm@1:   f->sizep = fs->np;
rlm@1:   luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
rlm@1:   f->sizelocvars = fs->nlocvars;
rlm@1:   luaM_reallocvector(L, f->upvalues, f->sizeupvalues, f->nups, TString *);
rlm@1:   f->sizeupvalues = f->nups;
rlm@1:   lua_assert(luaG_checkcode(f));
rlm@1:   lua_assert(fs->bl == NULL);
rlm@1:   ls->fs = fs->prev;
rlm@1:   L->top -= 2;  /* remove table and prototype from the stack */
rlm@1:   /* last token read was anchored in defunct function; must reanchor it */
rlm@1:   if (fs) anchor_token(ls);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
rlm@1:   struct LexState lexstate;
rlm@1:   struct FuncState funcstate;
rlm@1:   lexstate.buff = buff;
rlm@1:   luaX_setinput(L, &lexstate, z, luaS_new(L, name));
rlm@1:   open_func(&lexstate, &funcstate);
rlm@1:   funcstate.f->is_vararg = VARARG_ISVARARG;  /* main func. is always vararg */
rlm@1:   luaX_next(&lexstate);  /* read first token */
rlm@1:   chunk(&lexstate);
rlm@1:   check(&lexstate, TK_EOS);
rlm@1:   close_func(&lexstate);
rlm@1:   lua_assert(funcstate.prev == NULL);
rlm@1:   lua_assert(funcstate.f->nups == 0);
rlm@1:   lua_assert(lexstate.fs == NULL);
rlm@1:   return funcstate.f;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: 
rlm@1: /*============================================================*/
rlm@1: /* GRAMMAR RULES */
rlm@1: /*============================================================*/
rlm@1: 
rlm@1: 
rlm@1: static void field (LexState *ls, expdesc *v) {
rlm@1:   /* field -> ['.' | ':'] NAME */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   expdesc key;
rlm@1:   luaK_exp2anyreg(fs, v);
rlm@1:   luaX_next(ls);  /* skip the dot or colon */
rlm@1:   checkname(ls, &key);
rlm@1:   luaK_indexed(fs, v, &key);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void yindex (LexState *ls, expdesc *v) {
rlm@1:   /* index -> '[' expr ']' */
rlm@1:   luaX_next(ls);  /* skip the '[' */
rlm@1:   expr(ls, v);
rlm@1:   luaK_exp2val(ls->fs, v);
rlm@1:   checknext(ls, ']');
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: /*
rlm@1: ** {======================================================================
rlm@1: ** Rules for Constructors
rlm@1: ** =======================================================================
rlm@1: */
rlm@1: 
rlm@1: 
rlm@1: struct ConsControl {
rlm@1:   expdesc v;  /* last list item read */
rlm@1:   expdesc *t;  /* table descriptor */
rlm@1:   int nh;  /* total number of `record' elements */
rlm@1:   int na;  /* total number of array elements */
rlm@1:   int tostore;  /* number of array elements pending to be stored */
rlm@1: };
rlm@1: 
rlm@1: 
rlm@1: static void recfield (LexState *ls, struct ConsControl *cc) {
rlm@1:   /* recfield -> (NAME | `['exp1`]') = exp1 */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   int reg = ls->fs->freereg;
rlm@1:   expdesc key, val;
rlm@1:   int rkkey;
rlm@1:   if (ls->t.token == TK_NAME) {
rlm@1:     luaY_checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
rlm@1:     checkname(ls, &key);
rlm@1:   }
rlm@1:   else  /* ls->t.token == '[' */
rlm@1:     yindex(ls, &key);
rlm@1:   cc->nh++;
rlm@1:   checknext(ls, '=');
rlm@1:   rkkey = luaK_exp2RK(fs, &key);
rlm@1:   expr(ls, &val);
rlm@1:   luaK_codeABC(fs, OP_SETTABLE, cc->t->u.s.info, rkkey, luaK_exp2RK(fs, &val));
rlm@1:   fs->freereg = reg;  /* free registers */
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void closelistfield (FuncState *fs, struct ConsControl *cc) {
rlm@1:   if (cc->v.k == VVOID) return;  /* there is no list item */
rlm@1:   luaK_exp2nextreg(fs, &cc->v);
rlm@1:   cc->v.k = VVOID;
rlm@1:   if (cc->tostore == LFIELDS_PER_FLUSH) {
rlm@1:     luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore);  /* flush */
rlm@1:     cc->tostore = 0;  /* no more items pending */
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
rlm@1:   if (cc->tostore == 0) return;
rlm@1:   if (hasmultret(cc->v.k)) {
rlm@1:     luaK_setmultret(fs, &cc->v);
rlm@1:     luaK_setlist(fs, cc->t->u.s.info, cc->na, LUA_MULTRET);
rlm@1:     cc->na--;  /* do not count last expression (unknown number of elements) */
rlm@1:   }
rlm@1:   else {
rlm@1:     if (cc->v.k != VVOID)
rlm@1:       luaK_exp2nextreg(fs, &cc->v);
rlm@1:     luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore);
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void listfield (LexState *ls, struct ConsControl *cc) {
rlm@1:   expr(ls, &cc->v);
rlm@1:   luaY_checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
rlm@1:   cc->na++;
rlm@1:   cc->tostore++;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void constructor (LexState *ls, expdesc *t) {
rlm@1:   /* constructor -> ?? */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   int line = ls->linenumber;
rlm@1:   int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
rlm@1:   struct ConsControl cc;
rlm@1:   cc.na = cc.nh = cc.tostore = 0;
rlm@1:   cc.t = t;
rlm@1:   init_exp(t, VRELOCABLE, pc);
rlm@1:   init_exp(&cc.v, VVOID, 0);  /* no value (yet) */
rlm@1:   luaK_exp2nextreg(ls->fs, t);  /* fix it at stack top (for gc) */
rlm@1:   checknext(ls, '{');
rlm@1:   do {
rlm@1:     lua_assert(cc.v.k == VVOID || cc.tostore > 0);
rlm@1:     if (ls->t.token == '}') break;
rlm@1:     closelistfield(fs, &cc);
rlm@1:     switch(ls->t.token) {
rlm@1:       case TK_NAME: {  /* may be listfields or recfields */
rlm@1:         luaX_lookahead(ls);
rlm@1:         if (ls->lookahead.token != '=')  /* expression? */
rlm@1:           listfield(ls, &cc);
rlm@1:         else
rlm@1:           recfield(ls, &cc);
rlm@1:         break;
rlm@1:       }
rlm@1:       case '[': {  /* constructor_item -> recfield */
rlm@1:         recfield(ls, &cc);
rlm@1:         break;
rlm@1:       }
rlm@1:       default: {  /* constructor_part -> listfield */
rlm@1:         listfield(ls, &cc);
rlm@1:         break;
rlm@1:       }
rlm@1:     }
rlm@1:   } while (testnext(ls, ',') || testnext(ls, ';'));
rlm@1:   check_match(ls, '}', '{', line);
rlm@1:   lastlistfield(fs, &cc);
rlm@1:   SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
rlm@1:   SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh));  /* set initial table size */
rlm@1: }
rlm@1: 
rlm@1: /* }====================================================================== */
rlm@1: 
rlm@1: 
rlm@1: 
rlm@1: static void parlist (LexState *ls) {
rlm@1:   /* parlist -> [ param { `,' param } ] */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   Proto *f = fs->f;
rlm@1:   int nparams = 0;
rlm@1:   f->is_vararg = 0;
rlm@1:   if (ls->t.token != ')') {  /* is `parlist' not empty? */
rlm@1:     do {
rlm@1:       switch (ls->t.token) {
rlm@1:         case TK_NAME: {  /* param -> NAME */
rlm@1:           new_localvar(ls, str_checkname(ls), nparams++);
rlm@1:           break;
rlm@1:         }
rlm@1:         case TK_DOTS: {  /* param -> `...' */
rlm@1:           luaX_next(ls);
rlm@1: #if defined(LUA_COMPAT_VARARG)
rlm@1:           /* use `arg' as default name */
rlm@1:           new_localvarliteral(ls, "arg", nparams++);
rlm@1:           f->is_vararg = VARARG_HASARG | VARARG_NEEDSARG;
rlm@1: #endif
rlm@1:           f->is_vararg |= VARARG_ISVARARG;
rlm@1:           break;
rlm@1:         }
rlm@1:         default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected");
rlm@1:       }
rlm@1:     } while (!f->is_vararg && testnext(ls, ','));
rlm@1:   }
rlm@1:   adjustlocalvars(ls, nparams);
rlm@1:   f->numparams = cast_byte(fs->nactvar - (f->is_vararg & VARARG_HASARG));
rlm@1:   luaK_reserveregs(fs, fs->nactvar);  /* reserve register for parameters */
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void body (LexState *ls, expdesc *e, int needself, int line) {
rlm@1:   /* body ->  `(' parlist `)' chunk END */
rlm@1:   FuncState new_fs;
rlm@1:   open_func(ls, &new_fs);
rlm@1:   new_fs.f->linedefined = line;
rlm@1:   checknext(ls, '(');
rlm@1:   if (needself) {
rlm@1:     new_localvarliteral(ls, "self", 0);
rlm@1:     adjustlocalvars(ls, 1);
rlm@1:   }
rlm@1:   parlist(ls);
rlm@1:   checknext(ls, ')');
rlm@1:   chunk(ls);
rlm@1:   new_fs.f->lastlinedefined = ls->linenumber;
rlm@1:   check_match(ls, TK_END, TK_FUNCTION, line);
rlm@1:   close_func(ls);
rlm@1:   pushclosure(ls, &new_fs, e);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int explist1 (LexState *ls, expdesc *v) {
rlm@1:   /* explist1 -> expr { `,' expr } */
rlm@1:   int n = 1;  /* at least one expression */
rlm@1:   expr(ls, v);
rlm@1:   while (testnext(ls, ',')) {
rlm@1:     luaK_exp2nextreg(ls->fs, v);
rlm@1:     expr(ls, v);
rlm@1:     n++;
rlm@1:   }
rlm@1:   return n;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void funcargs (LexState *ls, expdesc *f) {
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   expdesc args;
rlm@1:   int base, nparams;
rlm@1:   int line = ls->linenumber;
rlm@1:   switch (ls->t.token) {
rlm@1:     case '(': {  /* funcargs -> `(' [ explist1 ] `)' */
rlm@1:       if (line != ls->lastline)
rlm@1:         luaX_syntaxerror(ls,"ambiguous syntax (function call x new statement)");
rlm@1:       luaX_next(ls);
rlm@1:       if (ls->t.token == ')')  /* arg list is empty? */
rlm@1:         args.k = VVOID;
rlm@1:       else {
rlm@1:         explist1(ls, &args);
rlm@1:         luaK_setmultret(fs, &args);
rlm@1:       }
rlm@1:       check_match(ls, ')', '(', line);
rlm@1:       break;
rlm@1:     }
rlm@1:     case '{': {  /* funcargs -> constructor */
rlm@1:       constructor(ls, &args);
rlm@1:       break;
rlm@1:     }
rlm@1:     case TK_STRING: {  /* funcargs -> STRING */
rlm@1:       codestring(ls, &args, ls->t.seminfo.ts);
rlm@1:       luaX_next(ls);  /* must use `seminfo' before `next' */
rlm@1:       break;
rlm@1:     }
rlm@1:     default: {
rlm@1:       luaX_syntaxerror(ls, "function arguments expected");
rlm@1:       return;
rlm@1:     }
rlm@1:   }
rlm@1:   lua_assert(f->k == VNONRELOC);
rlm@1:   base = f->u.s.info;  /* base register for call */
rlm@1:   if (hasmultret(args.k))
rlm@1:     nparams = LUA_MULTRET;  /* open call */
rlm@1:   else {
rlm@1:     if (args.k != VVOID)
rlm@1:       luaK_exp2nextreg(fs, &args);  /* close last argument */
rlm@1:     nparams = fs->freereg - (base+1);
rlm@1:   }
rlm@1:   init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
rlm@1:   luaK_fixline(fs, line);
rlm@1:   fs->freereg = base+1;  /* call remove function and arguments and leaves
rlm@1:                             (unless changed) one result */
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: 
rlm@1: 
rlm@1: /*
rlm@1: ** {======================================================================
rlm@1: ** Expression parsing
rlm@1: ** =======================================================================
rlm@1: */
rlm@1: 
rlm@1: 
rlm@1: static void prefixexp (LexState *ls, expdesc *v) {
rlm@1:   /* prefixexp -> NAME | '(' expr ')' */
rlm@1:   switch (ls->t.token) {
rlm@1:     case '(': {
rlm@1:       int line = ls->linenumber;
rlm@1:       luaX_next(ls);
rlm@1:       expr(ls, v);
rlm@1:       check_match(ls, ')', '(', line);
rlm@1:       luaK_dischargevars(ls->fs, v);
rlm@1:       return;
rlm@1:     }
rlm@1:     case TK_NAME: {
rlm@1:       singlevar(ls, v);
rlm@1:       return;
rlm@1:     }
rlm@1:     default: {
rlm@1:       luaX_syntaxerror(ls, "unexpected symbol");
rlm@1:       return;
rlm@1:     }
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void primaryexp (LexState *ls, expdesc *v) {
rlm@1:   /* primaryexp ->
rlm@1:         prefixexp { `.' NAME | `[' exp `]' | `:' NAME funcargs | funcargs } */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   prefixexp(ls, v);
rlm@1:   for (;;) {
rlm@1:     switch (ls->t.token) {
rlm@1:       case '.': {  /* field */
rlm@1:         field(ls, v);
rlm@1:         break;
rlm@1:       }
rlm@1:       case '[': {  /* `[' exp1 `]' */
rlm@1:         expdesc key;
rlm@1:         luaK_exp2anyreg(fs, v);
rlm@1:         yindex(ls, &key);
rlm@1:         luaK_indexed(fs, v, &key);
rlm@1:         break;
rlm@1:       }
rlm@1:       case ':': {  /* `:' NAME funcargs */
rlm@1:         expdesc key;
rlm@1:         luaX_next(ls);
rlm@1:         checkname(ls, &key);
rlm@1:         luaK_self(fs, v, &key);
rlm@1:         funcargs(ls, v);
rlm@1:         break;
rlm@1:       }
rlm@1:       case '(': case TK_STRING: case '{': {  /* funcargs */
rlm@1:         luaK_exp2nextreg(fs, v);
rlm@1:         funcargs(ls, v);
rlm@1:         break;
rlm@1:       }
rlm@1:       default: return;
rlm@1:     }
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void simpleexp (LexState *ls, expdesc *v) {
rlm@1:   /* simpleexp -> NUMBER | STRING | NIL | true | false | ... |
rlm@1:                   constructor | FUNCTION body | primaryexp */
rlm@1:   switch (ls->t.token) {
rlm@1:     case TK_NUMBER: {
rlm@1:       init_exp(v, VKNUM, 0);
rlm@1:       v->u.nval = ls->t.seminfo.r;
rlm@1:       break;
rlm@1:     }
rlm@1:     case TK_STRING: {
rlm@1:       codestring(ls, v, ls->t.seminfo.ts);
rlm@1:       break;
rlm@1:     }
rlm@1:     case TK_NIL: {
rlm@1:       init_exp(v, VNIL, 0);
rlm@1:       break;
rlm@1:     }
rlm@1:     case TK_TRUE: {
rlm@1:       init_exp(v, VTRUE, 0);
rlm@1:       break;
rlm@1:     }
rlm@1:     case TK_FALSE: {
rlm@1:       init_exp(v, VFALSE, 0);
rlm@1:       break;
rlm@1:     }
rlm@1:     case TK_DOTS: {  /* vararg */
rlm@1:       FuncState *fs = ls->fs;
rlm@1:       check_condition(ls, fs->f->is_vararg,
rlm@1:                       "cannot use " LUA_QL("...") " outside a vararg function");
rlm@1:       fs->f->is_vararg &= ~VARARG_NEEDSARG;  /* don't need 'arg' */
rlm@1:       init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
rlm@1:       break;
rlm@1:     }
rlm@1:     case '{': {  /* constructor */
rlm@1:       constructor(ls, v);
rlm@1:       return;
rlm@1:     }
rlm@1:     case TK_FUNCTION: {
rlm@1:       luaX_next(ls);
rlm@1:       body(ls, v, 0, ls->linenumber);
rlm@1:       return;
rlm@1:     }
rlm@1:     default: {
rlm@1:       primaryexp(ls, v);
rlm@1:       return;
rlm@1:     }
rlm@1:   }
rlm@1:   luaX_next(ls);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static UnOpr getunopr (int op) {
rlm@1:   switch (op) {
rlm@1:     case TK_NOT: return OPR_NOT;
rlm@1:     case '-': return OPR_MINUS;
rlm@1:     case '#': return OPR_LEN;
rlm@1:     default: return OPR_NOUNOPR;
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static BinOpr getbinopr (int op) {
rlm@1:   switch (op) {
rlm@1:     case '+': return OPR_ADD;
rlm@1:     case '-': return OPR_SUB;
rlm@1:     case '*': return OPR_MUL;
rlm@1:     case '/': return OPR_DIV;
rlm@1:     case '%': return OPR_MOD;
rlm@1:     case '^': return OPR_POW;
rlm@1:     case TK_CONCAT: return OPR_CONCAT;
rlm@1:     case TK_NE: return OPR_NE;
rlm@1:     case TK_EQ: return OPR_EQ;
rlm@1:     case '<': return OPR_LT;
rlm@1:     case TK_LE: return OPR_LE;
rlm@1:     case '>': return OPR_GT;
rlm@1:     case TK_GE: return OPR_GE;
rlm@1:     case TK_AND: return OPR_AND;
rlm@1:     case TK_OR: return OPR_OR;
rlm@1:     default: return OPR_NOBINOPR;
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static const struct {
rlm@1:   lu_byte left;  /* left priority for each binary operator */
rlm@1:   lu_byte right; /* right priority */
rlm@1: } priority[] = {  /* ORDER OPR */
rlm@1:    {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7},  /* `+' `-' `/' `%' */
rlm@1:    {10, 9}, {5, 4},                 /* power and concat (right associative) */
rlm@1:    {3, 3}, {3, 3},                  /* equality and inequality */
rlm@1:    {3, 3}, {3, 3}, {3, 3}, {3, 3},  /* order */
rlm@1:    {2, 2}, {1, 1}                   /* logical (and/or) */
rlm@1: };
rlm@1: 
rlm@1: #define UNARY_PRIORITY	8  /* priority for unary operators */
rlm@1: 
rlm@1: 
rlm@1: /*
rlm@1: ** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
rlm@1: ** where `binop' is any binary operator with a priority higher than `limit'
rlm@1: */
rlm@1: static BinOpr subexpr (LexState *ls, expdesc *v, unsigned int limit) {
rlm@1:   BinOpr op;
rlm@1:   UnOpr uop;
rlm@1:   enterlevel(ls);
rlm@1:   uop = getunopr(ls->t.token);
rlm@1:   if (uop != OPR_NOUNOPR) {
rlm@1:     luaX_next(ls);
rlm@1:     subexpr(ls, v, UNARY_PRIORITY);
rlm@1:     luaK_prefix(ls->fs, uop, v);
rlm@1:   }
rlm@1:   else simpleexp(ls, v);
rlm@1:   /* expand while operators have priorities higher than `limit' */
rlm@1:   op = getbinopr(ls->t.token);
rlm@1:   while (op != OPR_NOBINOPR && priority[op].left > limit) {
rlm@1:     expdesc v2;
rlm@1:     BinOpr nextop;
rlm@1:     luaX_next(ls);
rlm@1:     luaK_infix(ls->fs, op, v);
rlm@1:     /* read sub-expression with higher priority */
rlm@1:     nextop = subexpr(ls, &v2, priority[op].right);
rlm@1:     luaK_posfix(ls->fs, op, v, &v2);
rlm@1:     op = nextop;
rlm@1:   }
rlm@1:   leavelevel(ls);
rlm@1:   return op;  /* return first untreated operator */
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void expr (LexState *ls, expdesc *v) {
rlm@1:   subexpr(ls, v, 0);
rlm@1: }
rlm@1: 
rlm@1: /* }==================================================================== */
rlm@1: 
rlm@1: 
rlm@1: 
rlm@1: /*
rlm@1: ** {======================================================================
rlm@1: ** Rules for Statements
rlm@1: ** =======================================================================
rlm@1: */
rlm@1: 
rlm@1: 
rlm@1: static int block_follow (int token) {
rlm@1:   switch (token) {
rlm@1:     case TK_ELSE: case TK_ELSEIF: case TK_END:
rlm@1:     case TK_UNTIL: case TK_EOS:
rlm@1:       return 1;
rlm@1:     default: return 0;
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void block (LexState *ls) {
rlm@1:   /* block -> chunk */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   BlockCnt bl;
rlm@1:   enterblock(fs, &bl, 0);
rlm@1:   chunk(ls);
rlm@1:   lua_assert(bl.breaklist == NO_JUMP);
rlm@1:   leaveblock(fs);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: /*
rlm@1: ** structure to chain all variables in the left-hand side of an
rlm@1: ** assignment
rlm@1: */
rlm@1: struct LHS_assign {
rlm@1:   struct LHS_assign *prev;
rlm@1:   expdesc v;  /* variable (global, local, upvalue, or indexed) */
rlm@1: };
rlm@1: 
rlm@1: 
rlm@1: /*
rlm@1: ** check whether, in an assignment to a local variable, the local variable
rlm@1: ** is needed in a previous assignment (to a table). If so, save original
rlm@1: ** local value in a safe place and use this safe copy in the previous
rlm@1: ** assignment.
rlm@1: */
rlm@1: static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   int extra = fs->freereg;  /* eventual position to save local variable */
rlm@1:   int conflict = 0;
rlm@1:   for (; lh; lh = lh->prev) {
rlm@1:     if (lh->v.k == VINDEXED) {
rlm@1:       if (lh->v.u.s.info == v->u.s.info) {  /* conflict? */
rlm@1:         conflict = 1;
rlm@1:         lh->v.u.s.info = extra;  /* previous assignment will use safe copy */
rlm@1:       }
rlm@1:       if (lh->v.u.s.aux == v->u.s.info) {  /* conflict? */
rlm@1:         conflict = 1;
rlm@1:         lh->v.u.s.aux = extra;  /* previous assignment will use safe copy */
rlm@1:       }
rlm@1:     }
rlm@1:   }
rlm@1:   if (conflict) {
rlm@1:     luaK_codeABC(fs, OP_MOVE, fs->freereg, v->u.s.info, 0);  /* make copy */
rlm@1:     luaK_reserveregs(fs, 1);
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
rlm@1:   expdesc e;
rlm@1:   check_condition(ls, VLOCAL <= lh->v.k && lh->v.k <= VINDEXED,
rlm@1:                       "syntax error");
rlm@1:   if (testnext(ls, ',')) {  /* assignment -> `,' primaryexp assignment */
rlm@1:     struct LHS_assign nv;
rlm@1:     nv.prev = lh;
rlm@1:     primaryexp(ls, &nv.v);
rlm@1:     if (nv.v.k == VLOCAL)
rlm@1:       check_conflict(ls, lh, &nv.v);
rlm@1:     luaY_checklimit(ls->fs, nvars, LUAI_MAXCCALLS - ls->L->nCcalls,
rlm@1:                     "variables in assignment");
rlm@1:     assignment(ls, &nv, nvars+1);
rlm@1:   }
rlm@1:   else {  /* assignment -> `=' explist1 */
rlm@1:     int nexps;
rlm@1:     checknext(ls, '=');
rlm@1:     nexps = explist1(ls, &e);
rlm@1:     if (nexps != nvars) {
rlm@1:       adjust_assign(ls, nvars, nexps, &e);
rlm@1:       if (nexps > nvars)
rlm@1:         ls->fs->freereg -= nexps - nvars;  /* remove extra values */
rlm@1:     }
rlm@1:     else {
rlm@1:       luaK_setoneret(ls->fs, &e);  /* close last expression */
rlm@1:       luaK_storevar(ls->fs, &lh->v, &e);
rlm@1:       return;  /* avoid default */
rlm@1:     }
rlm@1:   }
rlm@1:   init_exp(&e, VNONRELOC, ls->fs->freereg-1);  /* default assignment */
rlm@1:   luaK_storevar(ls->fs, &lh->v, &e);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int cond (LexState *ls) {
rlm@1:   /* cond -> exp */
rlm@1:   expdesc v;
rlm@1:   expr(ls, &v);  /* read condition */
rlm@1:   if (v.k == VNIL) v.k = VFALSE;  /* `falses' are all equal here */
rlm@1:   luaK_goiftrue(ls->fs, &v);
rlm@1:   return v.f;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void breakstat (LexState *ls) {
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   BlockCnt *bl = fs->bl;
rlm@1:   int upval = 0;
rlm@1:   while (bl && !bl->isbreakable) {
rlm@1:     upval |= bl->upval;
rlm@1:     bl = bl->previous;
rlm@1:   }
rlm@1:   if (!bl)
rlm@1:     luaX_syntaxerror(ls, "no loop to break");
rlm@1:   if (upval)
rlm@1:     luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
rlm@1:   luaK_concat(fs, &bl->breaklist, luaK_jump(fs));
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void whilestat (LexState *ls, int line) {
rlm@1:   /* whilestat -> WHILE cond DO block END */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   int whileinit;
rlm@1:   int condexit;
rlm@1:   BlockCnt bl;
rlm@1:   luaX_next(ls);  /* skip WHILE */
rlm@1:   whileinit = luaK_getlabel(fs);
rlm@1:   condexit = cond(ls);
rlm@1:   enterblock(fs, &bl, 1);
rlm@1:   checknext(ls, TK_DO);
rlm@1:   block(ls);
rlm@1:   luaK_patchlist(fs, luaK_jump(fs), whileinit);
rlm@1:   check_match(ls, TK_END, TK_WHILE, line);
rlm@1:   leaveblock(fs);
rlm@1:   luaK_patchtohere(fs, condexit);  /* false conditions finish the loop */
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void repeatstat (LexState *ls, int line) {
rlm@1:   /* repeatstat -> REPEAT block UNTIL cond */
rlm@1:   int condexit;
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   int repeat_init = luaK_getlabel(fs);
rlm@1:   BlockCnt bl1, bl2;
rlm@1:   enterblock(fs, &bl1, 1);  /* loop block */
rlm@1:   enterblock(fs, &bl2, 0);  /* scope block */
rlm@1:   luaX_next(ls);  /* skip REPEAT */
rlm@1:   chunk(ls);
rlm@1:   check_match(ls, TK_UNTIL, TK_REPEAT, line);
rlm@1:   condexit = cond(ls);  /* read condition (inside scope block) */
rlm@1:   if (!bl2.upval) {  /* no upvalues? */
rlm@1:     leaveblock(fs);  /* finish scope */
rlm@1:     luaK_patchlist(ls->fs, condexit, repeat_init);  /* close the loop */
rlm@1:   }
rlm@1:   else {  /* complete semantics when there are upvalues */
rlm@1:     breakstat(ls);  /* if condition then break */
rlm@1:     luaK_patchtohere(ls->fs, condexit);  /* else... */
rlm@1:     leaveblock(fs);  /* finish scope... */
rlm@1:     luaK_patchlist(ls->fs, luaK_jump(fs), repeat_init);  /* and repeat */
rlm@1:   }
rlm@1:   leaveblock(fs);  /* finish loop */
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int exp1 (LexState *ls) {
rlm@1:   expdesc e;
rlm@1:   int k;
rlm@1:   expr(ls, &e);
rlm@1:   k = e.k;
rlm@1:   luaK_exp2nextreg(ls->fs, &e);
rlm@1:   return k;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
rlm@1:   /* forbody -> DO block */
rlm@1:   BlockCnt bl;
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   int prep, endfor;
rlm@1:   adjustlocalvars(ls, 3);  /* control variables */
rlm@1:   checknext(ls, TK_DO);
rlm@1:   prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
rlm@1:   enterblock(fs, &bl, 0);  /* scope for declared variables */
rlm@1:   adjustlocalvars(ls, nvars);
rlm@1:   luaK_reserveregs(fs, nvars);
rlm@1:   block(ls);
rlm@1:   leaveblock(fs);  /* end of scope for declared variables */
rlm@1:   luaK_patchtohere(fs, prep);
rlm@1:   endfor = (isnum) ? luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP) :
rlm@1:                      luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars);
rlm@1:   luaK_fixline(fs, line);  /* pretend that `OP_FOR' starts the loop */
rlm@1:   luaK_patchlist(fs, (isnum ? endfor : luaK_jump(fs)), prep + 1);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void fornum (LexState *ls, TString *varname, int line) {
rlm@1:   /* fornum -> NAME = exp1,exp1[,exp1] forbody */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   int base = fs->freereg;
rlm@1:   new_localvarliteral(ls, "(for index)", 0);
rlm@1:   new_localvarliteral(ls, "(for limit)", 1);
rlm@1:   new_localvarliteral(ls, "(for step)", 2);
rlm@1:   new_localvar(ls, varname, 3);
rlm@1:   checknext(ls, '=');
rlm@1:   exp1(ls);  /* initial value */
rlm@1:   checknext(ls, ',');
rlm@1:   exp1(ls);  /* limit */
rlm@1:   if (testnext(ls, ','))
rlm@1:     exp1(ls);  /* optional step */
rlm@1:   else {  /* default step = 1 */
rlm@1:     luaK_codeABx(fs, OP_LOADK, fs->freereg, luaK_numberK(fs, 1));
rlm@1:     luaK_reserveregs(fs, 1);
rlm@1:   }
rlm@1:   forbody(ls, base, line, 1, 1);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void forlist (LexState *ls, TString *indexname) {
rlm@1:   /* forlist -> NAME {,NAME} IN explist1 forbody */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   expdesc e;
rlm@1:   int nvars = 0;
rlm@1:   int line;
rlm@1:   int base = fs->freereg;
rlm@1:   /* create control variables */
rlm@1:   new_localvarliteral(ls, "(for generator)", nvars++);
rlm@1:   new_localvarliteral(ls, "(for state)", nvars++);
rlm@1:   new_localvarliteral(ls, "(for control)", nvars++);
rlm@1:   /* create declared variables */
rlm@1:   new_localvar(ls, indexname, nvars++);
rlm@1:   while (testnext(ls, ','))
rlm@1:     new_localvar(ls, str_checkname(ls), nvars++);
rlm@1:   checknext(ls, TK_IN);
rlm@1:   line = ls->linenumber;
rlm@1:   adjust_assign(ls, 3, explist1(ls, &e), &e);
rlm@1:   luaK_checkstack(fs, 3);  /* extra space to call generator */
rlm@1:   forbody(ls, base, line, nvars - 3, 0);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void forstat (LexState *ls, int line) {
rlm@1:   /* forstat -> FOR (fornum | forlist) END */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   TString *varname;
rlm@1:   BlockCnt bl;
rlm@1:   enterblock(fs, &bl, 1);  /* scope for loop and control variables */
rlm@1:   luaX_next(ls);  /* skip `for' */
rlm@1:   varname = str_checkname(ls);  /* first variable name */
rlm@1:   switch (ls->t.token) {
rlm@1:     case '=': fornum(ls, varname, line); break;
rlm@1:     case ',': case TK_IN: forlist(ls, varname); break;
rlm@1:     default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected");
rlm@1:   }
rlm@1:   check_match(ls, TK_END, TK_FOR, line);
rlm@1:   leaveblock(fs);  /* loop scope (`break' jumps to this point) */
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int test_then_block (LexState *ls) {
rlm@1:   /* test_then_block -> [IF | ELSEIF] cond THEN block */
rlm@1:   int condexit;
rlm@1:   luaX_next(ls);  /* skip IF or ELSEIF */
rlm@1:   condexit = cond(ls);
rlm@1:   checknext(ls, TK_THEN);
rlm@1:   block(ls);  /* `then' part */
rlm@1:   return condexit;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void ifstat (LexState *ls, int line) {
rlm@1:   /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   int flist;
rlm@1:   int escapelist = NO_JUMP;
rlm@1:   flist = test_then_block(ls);  /* IF cond THEN block */
rlm@1:   while (ls->t.token == TK_ELSEIF) {
rlm@1:     luaK_concat(fs, &escapelist, luaK_jump(fs));
rlm@1:     luaK_patchtohere(fs, flist);
rlm@1:     flist = test_then_block(ls);  /* ELSEIF cond THEN block */
rlm@1:   }
rlm@1:   if (ls->t.token == TK_ELSE) {
rlm@1:     luaK_concat(fs, &escapelist, luaK_jump(fs));
rlm@1:     luaK_patchtohere(fs, flist);
rlm@1:     luaX_next(ls);  /* skip ELSE (after patch, for correct line info) */
rlm@1:     block(ls);  /* `else' part */
rlm@1:   }
rlm@1:   else
rlm@1:     luaK_concat(fs, &escapelist, flist);
rlm@1:   luaK_patchtohere(fs, escapelist);
rlm@1:   check_match(ls, TK_END, TK_IF, line);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void localfunc (LexState *ls) {
rlm@1:   expdesc v, b;
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   new_localvar(ls, str_checkname(ls), 0);
rlm@1:   init_exp(&v, VLOCAL, fs->freereg);
rlm@1:   luaK_reserveregs(fs, 1);
rlm@1:   adjustlocalvars(ls, 1);
rlm@1:   body(ls, &b, 0, ls->linenumber);
rlm@1:   luaK_storevar(fs, &v, &b);
rlm@1:   /* debug information will only see the variable after this point! */
rlm@1:   getlocvar(fs, fs->nactvar - 1).startpc = fs->pc;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void localstat (LexState *ls) {
rlm@1:   /* stat -> LOCAL NAME {`,' NAME} [`=' explist1] */
rlm@1:   int nvars = 0;
rlm@1:   int nexps;
rlm@1:   expdesc e;
rlm@1:   do {
rlm@1:     new_localvar(ls, str_checkname(ls), nvars++);
rlm@1:   } while (testnext(ls, ','));
rlm@1:   if (testnext(ls, '='))
rlm@1:     nexps = explist1(ls, &e);
rlm@1:   else {
rlm@1:     e.k = VVOID;
rlm@1:     nexps = 0;
rlm@1:   }
rlm@1:   adjust_assign(ls, nvars, nexps, &e);
rlm@1:   adjustlocalvars(ls, nvars);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int funcname (LexState *ls, expdesc *v) {
rlm@1:   /* funcname -> NAME {field} [`:' NAME] */
rlm@1:   int needself = 0;
rlm@1:   singlevar(ls, v);
rlm@1:   while (ls->t.token == '.')
rlm@1:     field(ls, v);
rlm@1:   if (ls->t.token == ':') {
rlm@1:     needself = 1;
rlm@1:     field(ls, v);
rlm@1:   }
rlm@1:   return needself;
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void funcstat (LexState *ls, int line) {
rlm@1:   /* funcstat -> FUNCTION funcname body */
rlm@1:   int needself;
rlm@1:   expdesc v, b;
rlm@1:   luaX_next(ls);  /* skip FUNCTION */
rlm@1:   needself = funcname(ls, &v);
rlm@1:   body(ls, &b, needself, line);
rlm@1:   luaK_storevar(ls->fs, &v, &b);
rlm@1:   luaK_fixline(ls->fs, line);  /* definition `happens' in the first line */
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void exprstat (LexState *ls) {
rlm@1:   /* stat -> func | assignment */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   struct LHS_assign v;
rlm@1:   primaryexp(ls, &v.v);
rlm@1:   if (v.v.k == VCALL)  /* stat -> func */
rlm@1:     SETARG_C(getcode(fs, &v.v), 1);  /* call statement uses no results */
rlm@1:   else {  /* stat -> assignment */
rlm@1:     v.prev = NULL;
rlm@1:     assignment(ls, &v, 1);
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void retstat (LexState *ls) {
rlm@1:   /* stat -> RETURN explist */
rlm@1:   FuncState *fs = ls->fs;
rlm@1:   expdesc e;
rlm@1:   int first, nret;  /* registers with returned values */
rlm@1:   luaX_next(ls);  /* skip RETURN */
rlm@1:   if (block_follow(ls->t.token) || ls->t.token == ';')
rlm@1:     first = nret = 0;  /* return no values */
rlm@1:   else {
rlm@1:     nret = explist1(ls, &e);  /* optional return values */
rlm@1:     if (hasmultret(e.k)) {
rlm@1:       luaK_setmultret(fs, &e);
rlm@1:       if (e.k == VCALL && nret == 1) {  /* tail call? */
rlm@1:         SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
rlm@1:         lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
rlm@1:       }
rlm@1:       first = fs->nactvar;
rlm@1:       nret = LUA_MULTRET;  /* return all values */
rlm@1:     }
rlm@1:     else {
rlm@1:       if (nret == 1)  /* only one single value? */
rlm@1:         first = luaK_exp2anyreg(fs, &e);
rlm@1:       else {
rlm@1:         luaK_exp2nextreg(fs, &e);  /* values must go to the `stack' */
rlm@1:         first = fs->nactvar;  /* return all `active' values */
rlm@1:         lua_assert(nret == fs->freereg - first);
rlm@1:       }
rlm@1:     }
rlm@1:   }
rlm@1:   luaK_ret(fs, first, nret);
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static int statement (LexState *ls) {
rlm@1:   int line = ls->linenumber;  /* may be needed for error messages */
rlm@1:   switch (ls->t.token) {
rlm@1:     case TK_IF: {  /* stat -> ifstat */
rlm@1:       ifstat(ls, line);
rlm@1:       return 0;
rlm@1:     }
rlm@1:     case TK_WHILE: {  /* stat -> whilestat */
rlm@1:       whilestat(ls, line);
rlm@1:       return 0;
rlm@1:     }
rlm@1:     case TK_DO: {  /* stat -> DO block END */
rlm@1:       luaX_next(ls);  /* skip DO */
rlm@1:       block(ls);
rlm@1:       check_match(ls, TK_END, TK_DO, line);
rlm@1:       return 0;
rlm@1:     }
rlm@1:     case TK_FOR: {  /* stat -> forstat */
rlm@1:       forstat(ls, line);
rlm@1:       return 0;
rlm@1:     }
rlm@1:     case TK_REPEAT: {  /* stat -> repeatstat */
rlm@1:       repeatstat(ls, line);
rlm@1:       return 0;
rlm@1:     }
rlm@1:     case TK_FUNCTION: {
rlm@1:       funcstat(ls, line);  /* stat -> funcstat */
rlm@1:       return 0;
rlm@1:     }
rlm@1:     case TK_LOCAL: {  /* stat -> localstat */
rlm@1:       luaX_next(ls);  /* skip LOCAL */
rlm@1:       if (testnext(ls, TK_FUNCTION))  /* local function? */
rlm@1:         localfunc(ls);
rlm@1:       else
rlm@1:         localstat(ls);
rlm@1:       return 0;
rlm@1:     }
rlm@1:     case TK_RETURN: {  /* stat -> retstat */
rlm@1:       retstat(ls);
rlm@1:       return 1;  /* must be last statement */
rlm@1:     }
rlm@1:     case TK_BREAK: {  /* stat -> breakstat */
rlm@1:       luaX_next(ls);  /* skip BREAK */
rlm@1:       breakstat(ls);
rlm@1:       return 1;  /* must be last statement */
rlm@1:     }
rlm@1:     default: {
rlm@1:       exprstat(ls);
rlm@1:       return 0;  /* to avoid warnings */
rlm@1:     }
rlm@1:   }
rlm@1: }
rlm@1: 
rlm@1: 
rlm@1: static void chunk (LexState *ls) {
rlm@1:   /* chunk -> { stat [`;'] } */
rlm@1:   int islast = 0;
rlm@1:   enterlevel(ls);
rlm@1:   while (!islast && !block_follow(ls->t.token)) {
rlm@1:     islast = statement(ls);
rlm@1:     testnext(ls, ';');
rlm@1:     lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
rlm@1:                ls->fs->freereg >= ls->fs->nactvar);
rlm@1:     ls->fs->freereg = ls->fs->nactvar;  /* free registers */
rlm@1:   }
rlm@1:   leavelevel(ls);
rlm@1: }
rlm@1: 
rlm@1: /* }====================================================================== */