From 7a1ea510a9fc43ccbc257601b149a90920332e13 Mon Sep 17 00:00:00 2001 From: Alex Auvolat Date: Fri, 15 Jul 2016 22:39:04 +0200 Subject: Add Lua source, not compiled yet as libc/libm functions remain unimplemented --- src/lib/lua/lparser.c | 1652 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1652 insertions(+) create mode 100644 src/lib/lua/lparser.c (limited to 'src/lib/lua/lparser.c') diff --git a/src/lib/lua/lparser.c b/src/lib/lua/lparser.c new file mode 100644 index 0000000..22530a5 --- /dev/null +++ b/src/lib/lua/lparser.c @@ -0,0 +1,1652 @@ +/* +** $Id: lparser.c,v 2.153 2016/05/13 19:10:16 roberto Exp $ +** Lua Parser +** See Copyright Notice in lua.h +*/ + +#define lparser_c +#define LUA_CORE + +#include "lprefix.h" + + +#include + +#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) + + +/* because all strings are unified by the scanner, the parser + can use pointer equality for string equality */ +#define eqstr(a,b) ((a) == (b)) + + +/* +** nodes for block list (list of active blocks) +*/ +typedef struct BlockCnt { + struct BlockCnt *previous; /* chain */ + int firstlabel; /* index of first label in this block */ + int 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); + + +/* semantic error */ +static l_noret semerror (LexState *ls, const char *msg) { + ls->t.token = 0; /* remove "near " 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 (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 (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 void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { + if (fs == NULL) /* no more levels? */ + init_exp(var, VVOID, 0); /* 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 */ + } + else { /* not found as local at current level; try upvalues */ + int idx = searchupvalue(fs, n); /* try existing upvalues */ + if (idx < 0) { /* not found? */ + singlevaraux(fs->prev, n, var, 0); /* try upper levels */ + if (var->k == VVOID) /* not found? */ + return; /* it is a global */ + /* else was LOCAL or UPVAL */ + idx = newupvalue(fs, n, var); /* will be a new upvalue */ + } + init_exp(var, VUPVAL, idx); /* new or old upvalue */ + } + } +} + + +static void singlevar (LexState *ls, expdesc *var) { + TString *varname = str_checkname(ls); + FuncState *fs = ls->fs; + singlevaraux(fs, varname, var, 1); + if (var->k == VVOID) { /* global name? */ + expdesc key; + singlevaraux(fs, ls->envn, var, 1); /* get environment variable */ + lua_assert(var->k != VVOID); /* this one must exist */ + 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(eqstr(gt->name, label->name)); + if (gt->nactvar < label->nactvar) { + TString *vname = getlocvar(fs, gt->nactvar)->varname; + const char *msg = luaO_pushfstring(ls->L, + " at line %d jumps into the scope of local '%s'", + 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 (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 = n + 1; + 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 (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 '%s' for 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) { + 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 */ + 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; + 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 is 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 = 2; /* declared vararg */ + break; + } + default: luaX_syntaxerror(ls, " or '...' 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 -> FLT | INT | STRING | NIL | TRUE | FALSE | ... | + constructor | FUNCTION body | suffixedexp */ + switch (ls->t.token) { + case TK_FLT: { + init_exp(v, VKFLT, 0); + v->u.nval = ls->t.seminfo.r; + break; + } + case TK_INT: { + init_exp(v, VKINT, 0); + v->u.ival = ls->t.seminfo.i; + 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 '...' outside a vararg function"); + fs->f->is_vararg = 1; /* function actually uses vararg */ + 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_BNOT; + 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_MOD; + case '^': return OPR_POW; + case '/': return OPR_DIV; + case TK_IDIV: return OPR_IDIV; + case '&': return OPR_BAND; + case '|': return OPR_BOR; + case '~': return OPR_BXOR; + case TK_SHL: return OPR_SHL; + case TK_SHR: return OPR_SHR; + 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 */ + {10, 10}, {10, 10}, /* '+' '-' */ + {11, 11}, {11, 11}, /* '*' '%' */ + {14, 13}, /* '^' (right associative) */ + {11, 11}, {11, 11}, /* '/' '//' */ + {6, 6}, {4, 4}, {5, 5}, /* '&' '|' '~' */ + {7, 7}, {7, 7}, /* '<<' '>>' */ + {9, 8}, /* '..' (right associative) */ + {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */ + {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */ + {2, 2}, {1, 1} /* and, or */ +}; + +#define UNARY_PRIORITY 12 /* 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 (eqstr(label, ll->arr[i].name)) { + const char *msg = luaO_pushfstring(fs->ls->L, + "label '%s' 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, luaK_getlabel(fs)); + 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_intK(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, "'=' or '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(getinstruction(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(getinstruction(fs,&e), OP_TAILCALL); + lua_assert(GETARG_A(getinstruction(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 = 2; /* main function is always declared 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); +} + + +LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, + Dyndata *dyd, const char *name, int firstchar) { + LexState lexstate; + FuncState funcstate; + LClosure *cl = luaF_newLclosure(L, 1); /* create main closure */ + setclLvalue(L, L->top, cl); /* anchor it (to avoid being collected) */ + luaD_inctop(L); + lexstate.h = luaH_new(L); /* create table for scanner */ + sethvalue(L, L->top, lexstate.h); /* anchor it */ + luaD_inctop(L); + funcstate.f = cl->p = luaF_newproto(L); + funcstate.f->source = luaS_new(L, name); /* create and anchor TString */ + lua_assert(iswhite(funcstate.f)); /* do not need barrier here */ + 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); + L->top--; /* remove scanner's table */ + return cl; /* closure is on the stack, too */ +} + -- cgit v1.2.3