2 ** $Id: lparser.c,v 2.153 2016/05/13 19:10:16 roberto Exp $
4 ** See Copyright Notice in lua.h
32 /* maximum number of local variables per function (must be smaller
33 than 250, due to the bytecode format) */
37 #define hasmultret(k) ((k) == VCALL || (k) == VVARARG)
40 /* because all strings are unified by the scanner, the parser
41 can use pointer equality for string equality */
42 #define eqstr(a,b) ((a) == (b))
46 ** nodes for block list (list of active blocks)
48 typedef struct BlockCnt {
49 struct BlockCnt *previous; /* chain */
50 int firstlabel; /* index of first label in this block */
51 int firstgoto; /* index of first pending goto in this block */
52 lu_byte nactvar; /* # active locals outside the block */
53 lu_byte upval; /* true if some variable in the block is an upvalue */
54 lu_byte isloop; /* true if 'block' is a loop */
60 ** prototypes for recursive non-terminal functions
62 static void statement (LexState *ls);
63 static void expr (LexState *ls, expdesc *v);
67 static l_noret semerror (LexState *ls, const char *msg) {
68 ls->t.token = 0; /* remove "near <token>" from final message */
69 luaX_syntaxerror(ls, msg);
73 static l_noret error_expected (LexState *ls, int token) {
75 luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token)));
79 static l_noret errorlimit (FuncState *fs, int limit, const char *what) {
80 lua_State *L = fs->ls->L;
82 int line = fs->f->linedefined;
83 const char *where = (line == 0)
85 : luaO_pushfstring(L, "function at line %d", line);
86 msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s",
88 luaX_syntaxerror(fs->ls, msg);
92 static void checklimit (FuncState *fs, int v, int l, const char *what) {
93 if (v > l) errorlimit(fs, l, what);
97 static int testnext (LexState *ls, int c) {
98 if (ls->t.token == c) {
106 static void check (LexState *ls, int c) {
107 if (ls->t.token != c)
108 error_expected(ls, c);
112 static void checknext (LexState *ls, int c) {
118 #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); }
122 static void check_match (LexState *ls, int what, int who, int where) {
123 if (!testnext(ls, what)) {
124 if (where == ls->linenumber)
125 error_expected(ls, what);
127 luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
128 "%s expected (to close %s at line %d)",
129 luaX_token2str(ls, what), luaX_token2str(ls, who), where));
135 static TString *str_checkname (LexState *ls) {
138 ts = ls->t.seminfo.ts;
144 static void init_exp (expdesc *e, expkind k, int i) {
145 e->f = e->t = NO_JUMP;
151 static void codestring (LexState *ls, expdesc *e, TString *s) {
152 init_exp(e, VK, luaK_stringK(ls->fs, s));
156 static void checkname (LexState *ls, expdesc *e) {
157 codestring(ls, e, str_checkname(ls));
161 static int registerlocalvar (LexState *ls, TString *varname) {
162 FuncState *fs = ls->fs;
164 int oldsize = f->sizelocvars;
165 luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
166 LocVar, SHRT_MAX, "local variables");
167 while (oldsize < f->sizelocvars)
168 f->locvars[oldsize++].varname = NULL;
169 f->locvars[fs->nlocvars].varname = varname;
170 luaC_objbarrier(ls->L, f, varname);
171 return fs->nlocvars++;
175 static void new_localvar (LexState *ls, TString *name) {
176 FuncState *fs = ls->fs;
177 Dyndata *dyd = ls->dyd;
178 int reg = registerlocalvar(ls, name);
179 checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal,
180 MAXVARS, "local variables");
181 luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1,
182 dyd->actvar.size, Vardesc, MAX_INT, "local variables");
183 dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg);
187 static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) {
188 new_localvar(ls, luaX_newstring(ls, name, sz));
191 #define new_localvarliteral(ls,v) \
192 new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1)
195 static LocVar *getlocvar (FuncState *fs, int i) {
196 int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx;
197 lua_assert(idx < fs->nlocvars);
198 return &fs->f->locvars[idx];
202 static void adjustlocalvars (LexState *ls, int nvars) {
203 FuncState *fs = ls->fs;
204 fs->nactvar = cast_byte(fs->nactvar + nvars);
205 for (; nvars; nvars--) {
206 getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc;
211 static void removevars (FuncState *fs, int tolevel) {
212 fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel);
213 while (fs->nactvar > tolevel)
214 getlocvar(fs, --fs->nactvar)->endpc = fs->pc;
218 static int searchupvalue (FuncState *fs, TString *name) {
220 Upvaldesc *up = fs->f->upvalues;
221 for (i = 0; i < fs->nups; i++) {
222 if (eqstr(up[i].name, name)) return i;
224 return -1; /* not found */
228 static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
230 int oldsize = f->sizeupvalues;
231 checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues");
232 luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues,
233 Upvaldesc, MAXUPVAL, "upvalues");
234 while (oldsize < f->sizeupvalues)
235 f->upvalues[oldsize++].name = NULL;
236 f->upvalues[fs->nups].instack = (v->k == VLOCAL);
237 f->upvalues[fs->nups].idx = cast_byte(v->u.info);
238 f->upvalues[fs->nups].name = name;
239 luaC_objbarrier(fs->ls->L, f, name);
244 static int searchvar (FuncState *fs, TString *n) {
246 for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) {
247 if (eqstr(n, getlocvar(fs, i)->varname))
250 return -1; /* not found */
255 Mark block where variable at given level was defined
256 (to emit close instructions later).
258 static void markupval (FuncState *fs, int level) {
259 BlockCnt *bl = fs->bl;
260 while (bl->nactvar > level)
267 Find variable with given name 'n'. If it is an upvalue, add this
268 upvalue into all intermediate functions.
270 static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
271 if (fs == NULL) /* no more levels? */
272 init_exp(var, VVOID, 0); /* default is global */
274 int v = searchvar(fs, n); /* look up locals at current level */
275 if (v >= 0) { /* found? */
276 init_exp(var, VLOCAL, v); /* variable is local */
278 markupval(fs, v); /* local will be used as an upval */
280 else { /* not found as local at current level; try upvalues */
281 int idx = searchupvalue(fs, n); /* try existing upvalues */
282 if (idx < 0) { /* not found? */
283 singlevaraux(fs->prev, n, var, 0); /* try upper levels */
284 if (var->k == VVOID) /* not found? */
285 return; /* it is a global */
286 /* else was LOCAL or UPVAL */
287 idx = newupvalue(fs, n, var); /* will be a new upvalue */
289 init_exp(var, VUPVAL, idx); /* new or old upvalue */
295 static void singlevar (LexState *ls, expdesc *var) {
296 TString *varname = str_checkname(ls);
297 FuncState *fs = ls->fs;
298 singlevaraux(fs, varname, var, 1);
299 if (var->k == VVOID) { /* global name? */
301 singlevaraux(fs, ls->envn, var, 1); /* get environment variable */
302 lua_assert(var->k != VVOID); /* this one must exist */
303 codestring(ls, &key, varname); /* key is variable name */
304 luaK_indexed(fs, var, &key); /* env[varname] */
309 static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
310 FuncState *fs = ls->fs;
311 int extra = nvars - nexps;
312 if (hasmultret(e->k)) {
313 extra++; /* includes call itself */
314 if (extra < 0) extra = 0;
315 luaK_setreturns(fs, e, extra); /* last exp. provides the difference */
316 if (extra > 1) luaK_reserveregs(fs, extra-1);
319 if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */
321 int reg = fs->freereg;
322 luaK_reserveregs(fs, extra);
323 luaK_nil(fs, reg, extra);
329 static void enterlevel (LexState *ls) {
330 lua_State *L = ls->L;
332 checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "C levels");
336 #define leavelevel(ls) ((ls)->L->nCcalls--)
339 static void closegoto (LexState *ls, int g, Labeldesc *label) {
341 FuncState *fs = ls->fs;
342 Labellist *gl = &ls->dyd->gt;
343 Labeldesc *gt = &gl->arr[g];
344 lua_assert(eqstr(gt->name, label->name));
345 if (gt->nactvar < label->nactvar) {
346 TString *vname = getlocvar(fs, gt->nactvar)->varname;
347 const char *msg = luaO_pushfstring(ls->L,
348 "<goto %s> at line %d jumps into the scope of local '%s'",
349 getstr(gt->name), gt->line, getstr(vname));
352 luaK_patchlist(fs, gt->pc, label->pc);
353 /* remove goto from pending list */
354 for (i = g; i < gl->n - 1; i++)
355 gl->arr[i] = gl->arr[i + 1];
361 ** try to close a goto with existing labels; this solves backward jumps
363 static int findlabel (LexState *ls, int g) {
365 BlockCnt *bl = ls->fs->bl;
366 Dyndata *dyd = ls->dyd;
367 Labeldesc *gt = &dyd->gt.arr[g];
368 /* check labels in current block for a match */
369 for (i = bl->firstlabel; i < dyd->label.n; i++) {
370 Labeldesc *lb = &dyd->label.arr[i];
371 if (eqstr(lb->name, gt->name)) { /* correct label? */
372 if (gt->nactvar > lb->nactvar &&
373 (bl->upval || dyd->label.n > bl->firstlabel))
374 luaK_patchclose(ls->fs, gt->pc, lb->nactvar);
375 closegoto(ls, g, lb); /* close it */
379 return 0; /* label not found; cannot close goto */
383 static int newlabelentry (LexState *ls, Labellist *l, TString *name,
386 luaM_growvector(ls->L, l->arr, n, l->size,
387 Labeldesc, SHRT_MAX, "labels/gotos");
388 l->arr[n].name = name;
389 l->arr[n].line = line;
390 l->arr[n].nactvar = ls->fs->nactvar;
398 ** check whether new label 'lb' matches any pending gotos in current
399 ** block; solves forward jumps
401 static void findgotos (LexState *ls, Labeldesc *lb) {
402 Labellist *gl = &ls->dyd->gt;
403 int i = ls->fs->bl->firstgoto;
405 if (eqstr(gl->arr[i].name, lb->name))
406 closegoto(ls, i, lb);
414 ** export pending gotos to outer level, to check them against
415 ** outer labels; if the block being exited has upvalues, and
416 ** the goto exits the scope of any variable (which can be the
417 ** upvalue), close those variables being exited.
419 static void movegotosout (FuncState *fs, BlockCnt *bl) {
420 int i = bl->firstgoto;
421 Labellist *gl = &fs->ls->dyd->gt;
422 /* correct pending gotos to current block and try to close it
423 with visible labels */
425 Labeldesc *gt = &gl->arr[i];
426 if (gt->nactvar > bl->nactvar) {
428 luaK_patchclose(fs, gt->pc, bl->nactvar);
429 gt->nactvar = bl->nactvar;
431 if (!findlabel(fs->ls, i))
432 i++; /* move to next one */
437 static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) {
439 bl->nactvar = fs->nactvar;
440 bl->firstlabel = fs->ls->dyd->label.n;
441 bl->firstgoto = fs->ls->dyd->gt.n;
443 bl->previous = fs->bl;
445 lua_assert(fs->freereg == fs->nactvar);
450 ** create a label named 'break' to resolve break statements
452 static void breaklabel (LexState *ls) {
453 TString *n = luaS_new(ls->L, "break");
454 int l = newlabelentry(ls, &ls->dyd->label, n, 0, ls->fs->pc);
455 findgotos(ls, &ls->dyd->label.arr[l]);
459 ** generates an error for an undefined 'goto'; choose appropriate
460 ** message when label name is a reserved word (which can only be 'break')
462 static l_noret undefgoto (LexState *ls, Labeldesc *gt) {
463 const char *msg = isreserved(gt->name)
464 ? "<%s> at line %d not inside a loop"
465 : "no visible label '%s' for <goto> at line %d";
466 msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line);
471 static void leaveblock (FuncState *fs) {
472 BlockCnt *bl = fs->bl;
473 LexState *ls = fs->ls;
474 if (bl->previous && bl->upval) {
475 /* create a 'jump to here' to close upvalues */
476 int j = luaK_jump(fs);
477 luaK_patchclose(fs, j, bl->nactvar);
478 luaK_patchtohere(fs, j);
481 breaklabel(ls); /* close pending breaks */
482 fs->bl = bl->previous;
483 removevars(fs, bl->nactvar);
484 lua_assert(bl->nactvar == fs->nactvar);
485 fs->freereg = fs->nactvar; /* free registers */
486 ls->dyd->label.n = bl->firstlabel; /* remove local labels */
487 if (bl->previous) /* inner block? */
488 movegotosout(fs, bl); /* update pending gotos to outer block */
489 else if (bl->firstgoto < ls->dyd->gt.n) /* pending gotos in outer block? */
490 undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]); /* error */
495 ** adds a new prototype into list of prototypes
497 static Proto *addprototype (LexState *ls) {
499 lua_State *L = ls->L;
500 FuncState *fs = ls->fs;
501 Proto *f = fs->f; /* prototype of current function */
502 if (fs->np >= f->sizep) {
503 int oldsize = f->sizep;
504 luaM_growvector(L, f->p, fs->np, f->sizep, Proto *, MAXARG_Bx, "functions");
505 while (oldsize < f->sizep)
506 f->p[oldsize++] = NULL;
508 f->p[fs->np++] = clp = luaF_newproto(L);
509 luaC_objbarrier(L, f, clp);
515 ** codes instruction to create new closure in parent function.
516 ** The OP_CLOSURE instruction must use the last available register,
517 ** so that, if it invokes the GC, the GC knows which registers
518 ** are in use at that time.
520 static void codeclosure (LexState *ls, expdesc *v) {
521 FuncState *fs = ls->fs->prev;
522 init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1));
523 luaK_exp2nextreg(fs, v); /* fix it at the last register */
527 static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
529 fs->prev = ls->fs; /* linked list of funcstates */
541 fs->firstlocal = ls->dyd->actvar.n;
544 f->source = ls->source;
545 f->maxstacksize = 2; /* registers 0/1 are always valid */
546 enterblock(fs, bl, 0);
550 static void close_func (LexState *ls) {
551 lua_State *L = ls->L;
552 FuncState *fs = ls->fs;
554 luaK_ret(fs, 0, 0); /* final return */
556 luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
557 f->sizecode = fs->pc;
558 luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
559 f->sizelineinfo = fs->pc;
560 luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
562 luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
564 luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
565 f->sizelocvars = fs->nlocvars;
566 luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc);
567 f->sizeupvalues = fs->nups;
568 lua_assert(fs->bl == NULL);
575 /*============================================================*/
577 /*============================================================*/
581 ** check whether current token is in the follow set of a block.
582 ** 'until' closes syntactical blocks, but do not close scope,
583 ** so it is handled in separate.
585 static int block_follow (LexState *ls, int withuntil) {
586 switch (ls->t.token) {
587 case TK_ELSE: case TK_ELSEIF:
588 case TK_END: case TK_EOS:
590 case TK_UNTIL: return withuntil;
596 static void statlist (LexState *ls) {
597 /* statlist -> { stat [';'] } */
598 while (!block_follow(ls, 1)) {
599 if (ls->t.token == TK_RETURN) {
601 return; /* 'return' must be last statement */
608 static void fieldsel (LexState *ls, expdesc *v) {
609 /* fieldsel -> ['.' | ':'] NAME */
610 FuncState *fs = ls->fs;
612 luaK_exp2anyregup(fs, v);
613 luaX_next(ls); /* skip the dot or colon */
615 luaK_indexed(fs, v, &key);
619 static void yindex (LexState *ls, expdesc *v) {
620 /* index -> '[' expr ']' */
621 luaX_next(ls); /* skip the '[' */
623 luaK_exp2val(ls->fs, v);
629 ** {======================================================================
630 ** Rules for Constructors
631 ** =======================================================================
636 expdesc v; /* last list item read */
637 expdesc *t; /* table descriptor */
638 int nh; /* total number of 'record' elements */
639 int na; /* total number of array elements */
640 int tostore; /* number of array elements pending to be stored */
644 static void recfield (LexState *ls, struct ConsControl *cc) {
645 /* recfield -> (NAME | '['exp1']') = exp1 */
646 FuncState *fs = ls->fs;
647 int reg = ls->fs->freereg;
650 if (ls->t.token == TK_NAME) {
651 checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
654 else /* ls->t.token == '[' */
658 rkkey = luaK_exp2RK(fs, &key);
660 luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val));
661 fs->freereg = reg; /* free registers */
665 static void closelistfield (FuncState *fs, struct ConsControl *cc) {
666 if (cc->v.k == VVOID) return; /* there is no list item */
667 luaK_exp2nextreg(fs, &cc->v);
669 if (cc->tostore == LFIELDS_PER_FLUSH) {
670 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); /* flush */
671 cc->tostore = 0; /* no more items pending */
676 static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
677 if (cc->tostore == 0) return;
678 if (hasmultret(cc->v.k)) {
679 luaK_setmultret(fs, &cc->v);
680 luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET);
681 cc->na--; /* do not count last expression (unknown number of elements) */
684 if (cc->v.k != VVOID)
685 luaK_exp2nextreg(fs, &cc->v);
686 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);
691 static void listfield (LexState *ls, struct ConsControl *cc) {
692 /* listfield -> exp */
694 checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
700 static void field (LexState *ls, struct ConsControl *cc) {
701 /* field -> listfield | recfield */
702 switch(ls->t.token) {
703 case TK_NAME: { /* may be 'listfield' or 'recfield' */
704 if (luaX_lookahead(ls) != '=') /* expression? */
722 static void constructor (LexState *ls, expdesc *t) {
723 /* constructor -> '{' [ field { sep field } [sep] ] '}'
725 FuncState *fs = ls->fs;
726 int line = ls->linenumber;
727 int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
728 struct ConsControl cc;
729 cc.na = cc.nh = cc.tostore = 0;
731 init_exp(t, VRELOCABLE, pc);
732 init_exp(&cc.v, VVOID, 0); /* no value (yet) */
733 luaK_exp2nextreg(ls->fs, t); /* fix it at stack top */
736 lua_assert(cc.v.k == VVOID || cc.tostore > 0);
737 if (ls->t.token == '}') break;
738 closelistfield(fs, &cc);
740 } while (testnext(ls, ',') || testnext(ls, ';'));
741 check_match(ls, '}', '{', line);
742 lastlistfield(fs, &cc);
743 SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
744 SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */
747 /* }====================================================================== */
751 static void parlist (LexState *ls) {
752 /* parlist -> [ param { ',' param } ] */
753 FuncState *fs = ls->fs;
757 if (ls->t.token != ')') { /* is 'parlist' not empty? */
759 switch (ls->t.token) {
760 case TK_NAME: { /* param -> NAME */
761 new_localvar(ls, str_checkname(ls));
765 case TK_DOTS: { /* param -> '...' */
767 f->is_vararg = 2; /* declared vararg */
770 default: luaX_syntaxerror(ls, "<name> or '...' expected");
772 } while (!f->is_vararg && testnext(ls, ','));
774 adjustlocalvars(ls, nparams);
775 f->numparams = cast_byte(fs->nactvar);
776 luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */
780 static void body (LexState *ls, expdesc *e, int ismethod, int line) {
781 /* body -> '(' parlist ')' block END */
784 new_fs.f = addprototype(ls);
785 new_fs.f->linedefined = line;
786 open_func(ls, &new_fs, &bl);
789 new_localvarliteral(ls, "self"); /* create 'self' parameter */
790 adjustlocalvars(ls, 1);
795 new_fs.f->lastlinedefined = ls->linenumber;
796 check_match(ls, TK_END, TK_FUNCTION, line);
802 static int explist (LexState *ls, expdesc *v) {
803 /* explist -> expr { ',' expr } */
804 int n = 1; /* at least one expression */
806 while (testnext(ls, ',')) {
807 luaK_exp2nextreg(ls->fs, v);
815 static void funcargs (LexState *ls, expdesc *f, int line) {
816 FuncState *fs = ls->fs;
819 switch (ls->t.token) {
820 case '(': { /* funcargs -> '(' [ explist ] ')' */
822 if (ls->t.token == ')') /* arg list is empty? */
826 luaK_setmultret(fs, &args);
828 check_match(ls, ')', '(', line);
831 case '{': { /* funcargs -> constructor */
832 constructor(ls, &args);
835 case TK_STRING: { /* funcargs -> STRING */
836 codestring(ls, &args, ls->t.seminfo.ts);
837 luaX_next(ls); /* must use 'seminfo' before 'next' */
841 luaX_syntaxerror(ls, "function arguments expected");
844 lua_assert(f->k == VNONRELOC);
845 base = f->u.info; /* base register for call */
846 if (hasmultret(args.k))
847 nparams = LUA_MULTRET; /* open call */
850 luaK_exp2nextreg(fs, &args); /* close last argument */
851 nparams = fs->freereg - (base+1);
853 init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
854 luaK_fixline(fs, line);
855 fs->freereg = base+1; /* call remove function and arguments and leaves
856 (unless changed) one result */
863 ** {======================================================================
864 ** Expression parsing
865 ** =======================================================================
869 static void primaryexp (LexState *ls, expdesc *v) {
870 /* primaryexp -> NAME | '(' expr ')' */
871 switch (ls->t.token) {
873 int line = ls->linenumber;
876 check_match(ls, ')', '(', line);
877 luaK_dischargevars(ls->fs, v);
885 luaX_syntaxerror(ls, "unexpected symbol");
891 static void suffixedexp (LexState *ls, expdesc *v) {
893 primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */
894 FuncState *fs = ls->fs;
895 int line = ls->linenumber;
898 switch (ls->t.token) {
899 case '.': { /* fieldsel */
903 case '[': { /* '[' exp1 ']' */
905 luaK_exp2anyregup(fs, v);
907 luaK_indexed(fs, v, &key);
910 case ':': { /* ':' NAME funcargs */
914 luaK_self(fs, v, &key);
915 funcargs(ls, v, line);
918 case '(': case TK_STRING: case '{': { /* funcargs */
919 luaK_exp2nextreg(fs, v);
920 funcargs(ls, v, line);
929 static void simpleexp (LexState *ls, expdesc *v) {
930 /* simpleexp -> FLT | INT | STRING | NIL | TRUE | FALSE | ... |
931 constructor | FUNCTION body | suffixedexp */
932 switch (ls->t.token) {
934 init_exp(v, VKFLT, 0);
935 v->u.nval = ls->t.seminfo.r;
939 init_exp(v, VKINT, 0);
940 v->u.ival = ls->t.seminfo.i;
944 codestring(ls, v, ls->t.seminfo.ts);
948 init_exp(v, VNIL, 0);
952 init_exp(v, VTRUE, 0);
956 init_exp(v, VFALSE, 0);
959 case TK_DOTS: { /* vararg */
960 FuncState *fs = ls->fs;
961 check_condition(ls, fs->f->is_vararg,
962 "cannot use '...' outside a vararg function");
963 fs->f->is_vararg = 1; /* function actually uses vararg */
964 init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
967 case '{': { /* constructor */
973 body(ls, v, 0, ls->linenumber);
985 static UnOpr getunopr (int op) {
987 case TK_NOT: return OPR_NOT;
988 case '-': return OPR_MINUS;
989 case '~': return OPR_BNOT;
990 case '#': return OPR_LEN;
991 default: return OPR_NOUNOPR;
996 static BinOpr getbinopr (int op) {
998 case '+': return OPR_ADD;
999 case '-': return OPR_SUB;
1000 case '*': return OPR_MUL;
1001 case '%': return OPR_MOD;
1002 case '^': return OPR_POW;
1003 case '/': return OPR_DIV;
1004 case TK_IDIV: return OPR_IDIV;
1005 case '&': return OPR_BAND;
1006 case '|': return OPR_BOR;
1007 case '~': return OPR_BXOR;
1008 case TK_SHL: return OPR_SHL;
1009 case TK_SHR: return OPR_SHR;
1010 case TK_CONCAT: return OPR_CONCAT;
1011 case TK_NE: return OPR_NE;
1012 case TK_EQ: return OPR_EQ;
1013 case '<': return OPR_LT;
1014 case TK_LE: return OPR_LE;
1015 case '>': return OPR_GT;
1016 case TK_GE: return OPR_GE;
1017 case TK_AND: return OPR_AND;
1018 case TK_OR: return OPR_OR;
1019 default: return OPR_NOBINOPR;
1024 static const struct {
1025 lu_byte left; /* left priority for each binary operator */
1026 lu_byte right; /* right priority */
1027 } priority[] = { /* ORDER OPR */
1028 {10, 10}, {10, 10}, /* '+' '-' */
1029 {11, 11}, {11, 11}, /* '*' '%' */
1030 {14, 13}, /* '^' (right associative) */
1031 {11, 11}, {11, 11}, /* '/' '//' */
1032 {6, 6}, {4, 4}, {5, 5}, /* '&' '|' '~' */
1033 {7, 7}, {7, 7}, /* '<<' '>>' */
1034 {9, 8}, /* '..' (right associative) */
1035 {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */
1036 {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */
1037 {2, 2}, {1, 1} /* and, or */
1040 #define UNARY_PRIORITY 12 /* priority for unary operators */
1044 ** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
1045 ** where 'binop' is any binary operator with a priority higher than 'limit'
1047 static BinOpr subexpr (LexState *ls, expdesc *v, int limit) {
1051 uop = getunopr(ls->t.token);
1052 if (uop != OPR_NOUNOPR) {
1053 int line = ls->linenumber;
1055 subexpr(ls, v, UNARY_PRIORITY);
1056 luaK_prefix(ls->fs, uop, v, line);
1058 else simpleexp(ls, v);
1059 /* expand while operators have priorities higher than 'limit' */
1060 op = getbinopr(ls->t.token);
1061 while (op != OPR_NOBINOPR && priority[op].left > limit) {
1064 int line = ls->linenumber;
1066 luaK_infix(ls->fs, op, v);
1067 /* read sub-expression with higher priority */
1068 nextop = subexpr(ls, &v2, priority[op].right);
1069 luaK_posfix(ls->fs, op, v, &v2, line);
1073 return op; /* return first untreated operator */
1077 static void expr (LexState *ls, expdesc *v) {
1081 /* }==================================================================== */
1086 ** {======================================================================
1087 ** Rules for Statements
1088 ** =======================================================================
1092 static void block (LexState *ls) {
1093 /* block -> statlist */
1094 FuncState *fs = ls->fs;
1096 enterblock(fs, &bl, 0);
1103 ** structure to chain all variables in the left-hand side of an
1107 struct LHS_assign *prev;
1108 expdesc v; /* variable (global, local, upvalue, or indexed) */
1113 ** check whether, in an assignment to an upvalue/local variable, the
1114 ** upvalue/local variable is begin used in a previous assignment to a
1115 ** table. If so, save original upvalue/local value in a safe place and
1116 ** use this safe copy in the previous assignment.
1118 static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
1119 FuncState *fs = ls->fs;
1120 int extra = fs->freereg; /* eventual position to save local variable */
1122 for (; lh; lh = lh->prev) { /* check all previous assignments */
1123 if (lh->v.k == VINDEXED) { /* assigning to a table? */
1124 /* table is the upvalue/local being assigned now? */
1125 if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) {
1127 lh->v.u.ind.vt = VLOCAL;
1128 lh->v.u.ind.t = extra; /* previous assignment will use safe copy */
1130 /* index is the local being assigned? (index cannot be upvalue) */
1131 if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) {
1133 lh->v.u.ind.idx = extra; /* previous assignment will use safe copy */
1138 /* copy upvalue/local value to a temporary (in position 'extra') */
1139 OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
1140 luaK_codeABC(fs, op, extra, v->u.info, 0);
1141 luaK_reserveregs(fs, 1);
1146 static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
1148 check_condition(ls, vkisvar(lh->v.k), "syntax error");
1149 if (testnext(ls, ',')) { /* assignment -> ',' suffixedexp assignment */
1150 struct LHS_assign nv;
1152 suffixedexp(ls, &nv.v);
1153 if (nv.v.k != VINDEXED)
1154 check_conflict(ls, lh, &nv.v);
1155 checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS,
1157 assignment(ls, &nv, nvars+1);
1159 else { /* assignment -> '=' explist */
1162 nexps = explist(ls, &e);
1163 if (nexps != nvars) {
1164 adjust_assign(ls, nvars, nexps, &e);
1166 ls->fs->freereg -= nexps - nvars; /* remove extra values */
1169 luaK_setoneret(ls->fs, &e); /* close last expression */
1170 luaK_storevar(ls->fs, &lh->v, &e);
1171 return; /* avoid default */
1174 init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */
1175 luaK_storevar(ls->fs, &lh->v, &e);
1179 static int cond (LexState *ls) {
1182 expr(ls, &v); /* read condition */
1183 if (v.k == VNIL) v.k = VFALSE; /* 'falses' are all equal here */
1184 luaK_goiftrue(ls->fs, &v);
1189 static void gotostat (LexState *ls, int pc) {
1190 int line = ls->linenumber;
1193 if (testnext(ls, TK_GOTO))
1194 label = str_checkname(ls);
1196 luaX_next(ls); /* skip break */
1197 label = luaS_new(ls->L, "break");
1199 g = newlabelentry(ls, &ls->dyd->gt, label, line, pc);
1200 findlabel(ls, g); /* close it if label already defined */
1204 /* check for repeated labels on the same block */
1205 static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) {
1207 for (i = fs->bl->firstlabel; i < ll->n; i++) {
1208 if (eqstr(label, ll->arr[i].name)) {
1209 const char *msg = luaO_pushfstring(fs->ls->L,
1210 "label '%s' already defined on line %d",
1211 getstr(label), ll->arr[i].line);
1212 semerror(fs->ls, msg);
1218 /* skip no-op statements */
1219 static void skipnoopstat (LexState *ls) {
1220 while (ls->t.token == ';' || ls->t.token == TK_DBCOLON)
1225 static void labelstat (LexState *ls, TString *label, int line) {
1226 /* label -> '::' NAME '::' */
1227 FuncState *fs = ls->fs;
1228 Labellist *ll = &ls->dyd->label;
1229 int l; /* index of new label being created */
1230 checkrepeated(fs, ll, label); /* check for repeated labels */
1231 checknext(ls, TK_DBCOLON); /* skip double colon */
1232 /* create new entry for this label */
1233 l = newlabelentry(ls, ll, label, line, luaK_getlabel(fs));
1234 skipnoopstat(ls); /* skip other no-op statements */
1235 if (block_follow(ls, 0)) { /* label is last no-op statement in the block? */
1236 /* assume that locals are already out of scope */
1237 ll->arr[l].nactvar = fs->bl->nactvar;
1239 findgotos(ls, &ll->arr[l]);
1243 static void whilestat (LexState *ls, int line) {
1244 /* whilestat -> WHILE cond DO block END */
1245 FuncState *fs = ls->fs;
1249 luaX_next(ls); /* skip WHILE */
1250 whileinit = luaK_getlabel(fs);
1251 condexit = cond(ls);
1252 enterblock(fs, &bl, 1);
1253 checknext(ls, TK_DO);
1255 luaK_jumpto(fs, whileinit);
1256 check_match(ls, TK_END, TK_WHILE, line);
1258 luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
1262 static void repeatstat (LexState *ls, int line) {
1263 /* repeatstat -> REPEAT block UNTIL cond */
1265 FuncState *fs = ls->fs;
1266 int repeat_init = luaK_getlabel(fs);
1268 enterblock(fs, &bl1, 1); /* loop block */
1269 enterblock(fs, &bl2, 0); /* scope block */
1270 luaX_next(ls); /* skip REPEAT */
1272 check_match(ls, TK_UNTIL, TK_REPEAT, line);
1273 condexit = cond(ls); /* read condition (inside scope block) */
1274 if (bl2.upval) /* upvalues? */
1275 luaK_patchclose(fs, condexit, bl2.nactvar);
1276 leaveblock(fs); /* finish scope */
1277 luaK_patchlist(fs, condexit, repeat_init); /* close the loop */
1278 leaveblock(fs); /* finish loop */
1282 static int exp1 (LexState *ls) {
1286 luaK_exp2nextreg(ls->fs, &e);
1287 lua_assert(e.k == VNONRELOC);
1293 static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
1294 /* forbody -> DO block */
1296 FuncState *fs = ls->fs;
1298 adjustlocalvars(ls, 3); /* control variables */
1299 checknext(ls, TK_DO);
1300 prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
1301 enterblock(fs, &bl, 0); /* scope for declared variables */
1302 adjustlocalvars(ls, nvars);
1303 luaK_reserveregs(fs, nvars);
1305 leaveblock(fs); /* end of scope for declared variables */
1306 luaK_patchtohere(fs, prep);
1307 if (isnum) /* numeric for? */
1308 endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP);
1309 else { /* generic for */
1310 luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
1311 luaK_fixline(fs, line);
1312 endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP);
1314 luaK_patchlist(fs, endfor, prep + 1);
1315 luaK_fixline(fs, line);
1319 static void fornum (LexState *ls, TString *varname, int line) {
1320 /* fornum -> NAME = exp1,exp1[,exp1] forbody */
1321 FuncState *fs = ls->fs;
1322 int base = fs->freereg;
1323 new_localvarliteral(ls, "(for index)");
1324 new_localvarliteral(ls, "(for limit)");
1325 new_localvarliteral(ls, "(for step)");
1326 new_localvar(ls, varname);
1328 exp1(ls); /* initial value */
1330 exp1(ls); /* limit */
1331 if (testnext(ls, ','))
1332 exp1(ls); /* optional step */
1333 else { /* default step = 1 */
1334 luaK_codek(fs, fs->freereg, luaK_intK(fs, 1));
1335 luaK_reserveregs(fs, 1);
1337 forbody(ls, base, line, 1, 1);
1341 static void forlist (LexState *ls, TString *indexname) {
1342 /* forlist -> NAME {,NAME} IN explist forbody */
1343 FuncState *fs = ls->fs;
1345 int nvars = 4; /* gen, state, control, plus at least one declared var */
1347 int base = fs->freereg;
1348 /* create control variables */
1349 new_localvarliteral(ls, "(for generator)");
1350 new_localvarliteral(ls, "(for state)");
1351 new_localvarliteral(ls, "(for control)");
1352 /* create declared variables */
1353 new_localvar(ls, indexname);
1354 while (testnext(ls, ',')) {
1355 new_localvar(ls, str_checkname(ls));
1358 checknext(ls, TK_IN);
1359 line = ls->linenumber;
1360 adjust_assign(ls, 3, explist(ls, &e), &e);
1361 luaK_checkstack(fs, 3); /* extra space to call generator */
1362 forbody(ls, base, line, nvars - 3, 0);
1366 static void forstat (LexState *ls, int line) {
1367 /* forstat -> FOR (fornum | forlist) END */
1368 FuncState *fs = ls->fs;
1371 enterblock(fs, &bl, 1); /* scope for loop and control variables */
1372 luaX_next(ls); /* skip 'for' */
1373 varname = str_checkname(ls); /* first variable name */
1374 switch (ls->t.token) {
1375 case '=': fornum(ls, varname, line); break;
1376 case ',': case TK_IN: forlist(ls, varname); break;
1377 default: luaX_syntaxerror(ls, "'=' or 'in' expected");
1379 check_match(ls, TK_END, TK_FOR, line);
1380 leaveblock(fs); /* loop scope ('break' jumps to this point) */
1384 static void test_then_block (LexState *ls, int *escapelist) {
1385 /* test_then_block -> [IF | ELSEIF] cond THEN block */
1387 FuncState *fs = ls->fs;
1389 int jf; /* instruction to skip 'then' code (if condition is false) */
1390 luaX_next(ls); /* skip IF or ELSEIF */
1391 expr(ls, &v); /* read condition */
1392 checknext(ls, TK_THEN);
1393 if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) {
1394 luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */
1395 enterblock(fs, &bl, 0); /* must enter block before 'goto' */
1396 gotostat(ls, v.t); /* handle goto/break */
1397 skipnoopstat(ls); /* skip other no-op statements */
1398 if (block_follow(ls, 0)) { /* 'goto' is the entire block? */
1400 return; /* and that is it */
1402 else /* must skip over 'then' part if condition is false */
1405 else { /* regular case (not goto/break) */
1406 luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */
1407 enterblock(fs, &bl, 0);
1410 statlist(ls); /* 'then' part */
1412 if (ls->t.token == TK_ELSE ||
1413 ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */
1414 luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */
1415 luaK_patchtohere(fs, jf);
1419 static void ifstat (LexState *ls, int line) {
1420 /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
1421 FuncState *fs = ls->fs;
1422 int escapelist = NO_JUMP; /* exit list for finished parts */
1423 test_then_block(ls, &escapelist); /* IF cond THEN block */
1424 while (ls->t.token == TK_ELSEIF)
1425 test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */
1426 if (testnext(ls, TK_ELSE))
1427 block(ls); /* 'else' part */
1428 check_match(ls, TK_END, TK_IF, line);
1429 luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */
1433 static void localfunc (LexState *ls) {
1435 FuncState *fs = ls->fs;
1436 new_localvar(ls, str_checkname(ls)); /* new local variable */
1437 adjustlocalvars(ls, 1); /* enter its scope */
1438 body(ls, &b, 0, ls->linenumber); /* function created in next register */
1439 /* debug information will only see the variable after this point! */
1440 getlocvar(fs, b.u.info)->startpc = fs->pc;
1444 static void localstat (LexState *ls) {
1445 /* stat -> LOCAL NAME {',' NAME} ['=' explist] */
1450 new_localvar(ls, str_checkname(ls));
1452 } while (testnext(ls, ','));
1453 if (testnext(ls, '='))
1454 nexps = explist(ls, &e);
1459 adjust_assign(ls, nvars, nexps, &e);
1460 adjustlocalvars(ls, nvars);
1464 static int funcname (LexState *ls, expdesc *v) {
1465 /* funcname -> NAME {fieldsel} [':' NAME] */
1468 while (ls->t.token == '.')
1470 if (ls->t.token == ':') {
1478 static void funcstat (LexState *ls, int line) {
1479 /* funcstat -> FUNCTION funcname body */
1482 luaX_next(ls); /* skip FUNCTION */
1483 ismethod = funcname(ls, &v);
1484 body(ls, &b, ismethod, line);
1485 luaK_storevar(ls->fs, &v, &b);
1486 luaK_fixline(ls->fs, line); /* definition "happens" in the first line */
1490 static void exprstat (LexState *ls) {
1491 /* stat -> func | assignment */
1492 FuncState *fs = ls->fs;
1493 struct LHS_assign v;
1494 suffixedexp(ls, &v.v);
1495 if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */
1497 assignment(ls, &v, 1);
1499 else { /* stat -> func */
1500 check_condition(ls, v.v.k == VCALL, "syntax error");
1501 SETARG_C(getinstruction(fs, &v.v), 1); /* call statement uses no results */
1506 static void retstat (LexState *ls) {
1507 /* stat -> RETURN [explist] [';'] */
1508 FuncState *fs = ls->fs;
1510 int first, nret; /* registers with returned values */
1511 if (block_follow(ls, 1) || ls->t.token == ';')
1512 first = nret = 0; /* return no values */
1514 nret = explist(ls, &e); /* optional return values */
1515 if (hasmultret(e.k)) {
1516 luaK_setmultret(fs, &e);
1517 if (e.k == VCALL && nret == 1) { /* tail call? */
1518 SET_OPCODE(getinstruction(fs,&e), OP_TAILCALL);
1519 lua_assert(GETARG_A(getinstruction(fs,&e)) == fs->nactvar);
1521 first = fs->nactvar;
1522 nret = LUA_MULTRET; /* return all values */
1525 if (nret == 1) /* only one single value? */
1526 first = luaK_exp2anyreg(fs, &e);
1528 luaK_exp2nextreg(fs, &e); /* values must go to the stack */
1529 first = fs->nactvar; /* return all active values */
1530 lua_assert(nret == fs->freereg - first);
1534 luaK_ret(fs, first, nret);
1535 testnext(ls, ';'); /* skip optional semicolon */
1539 static void statement (LexState *ls) {
1540 int line = ls->linenumber; /* may be needed for error messages */
1542 switch (ls->t.token) {
1543 case ';': { /* stat -> ';' (empty statement) */
1544 luaX_next(ls); /* skip ';' */
1547 case TK_IF: { /* stat -> ifstat */
1551 case TK_WHILE: { /* stat -> whilestat */
1552 whilestat(ls, line);
1555 case TK_DO: { /* stat -> DO block END */
1556 luaX_next(ls); /* skip DO */
1558 check_match(ls, TK_END, TK_DO, line);
1561 case TK_FOR: { /* stat -> forstat */
1565 case TK_REPEAT: { /* stat -> repeatstat */
1566 repeatstat(ls, line);
1569 case TK_FUNCTION: { /* stat -> funcstat */
1573 case TK_LOCAL: { /* stat -> localstat */
1574 luaX_next(ls); /* skip LOCAL */
1575 if (testnext(ls, TK_FUNCTION)) /* local function? */
1581 case TK_DBCOLON: { /* stat -> label */
1582 luaX_next(ls); /* skip double colon */
1583 labelstat(ls, str_checkname(ls), line);
1586 case TK_RETURN: { /* stat -> retstat */
1587 luaX_next(ls); /* skip RETURN */
1591 case TK_BREAK: /* stat -> breakstat */
1592 case TK_GOTO: { /* stat -> 'goto' NAME */
1593 gotostat(ls, luaK_jump(ls->fs));
1596 default: { /* stat -> func | assignment */
1601 lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
1602 ls->fs->freereg >= ls->fs->nactvar);
1603 ls->fs->freereg = ls->fs->nactvar; /* free registers */
1607 /* }====================================================================== */
1611 ** compiles the main function, which is a regular vararg function with an
1612 ** upvalue named LUA_ENV
1614 static void mainfunc (LexState *ls, FuncState *fs) {
1617 open_func(ls, fs, &bl);
1618 fs->f->is_vararg = 2; /* main function is always declared vararg */
1619 init_exp(&v, VLOCAL, 0); /* create and... */
1620 newupvalue(fs, ls->envn, &v); /* ...set environment upvalue */
1621 luaX_next(ls); /* read first token */
1622 statlist(ls); /* parse main body */
1628 LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
1629 Dyndata *dyd, const char *name, int firstchar) {
1631 FuncState funcstate;
1632 LClosure *cl = luaF_newLclosure(L, 1); /* create main closure */
1633 setclLvalue(L, L->top, cl); /* anchor it (to avoid being collected) */
1635 lexstate.h = luaH_new(L); /* create table for scanner */
1636 sethvalue(L, L->top, lexstate.h); /* anchor it */
1638 funcstate.f = cl->p = luaF_newproto(L);
1639 funcstate.f->source = luaS_new(L, name); /* create and anchor TString */
1640 lua_assert(iswhite(funcstate.f)); /* do not need barrier here */
1641 lexstate.buff = buff;
1643 dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
1644 luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar);
1645 mainfunc(&lexstate, &funcstate);
1646 lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
1647 /* all scopes should be correctly finished */
1648 lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0);
1649 L->top--; /* remove scanner's table */
1650 return cl; /* closure is on the stack, too */