2 ** $Id: lparser.c,v 2.130.1.1 2013/04/12 18:48:47 roberto Exp $
4 ** See Copyright Notice in lua.h
7 #include <sys/zfs_context.h>
29 /* maximum number of local variables per function (must be smaller
30 than 250, due to the bytecode format) */
34 #define hasmultret(k) ((k) == VCALL || (k) == VVARARG)
39 ** nodes for block list (list of active blocks)
41 typedef struct BlockCnt {
42 struct BlockCnt *previous; /* chain */
43 short firstlabel; /* index of first label in this block */
44 short firstgoto; /* index of first pending goto in this block */
45 lu_byte nactvar; /* # active locals outside the block */
46 lu_byte upval; /* true if some variable in the block is an upvalue */
47 lu_byte isloop; /* true if `block' is a loop */
53 ** prototypes for recursive non-terminal functions
55 static void statement (LexState *ls);
56 static void expr (LexState *ls, expdesc *v);
59 static void anchor_token (LexState *ls) {
60 /* last token from outer function must be EOS */
61 lua_assert(ls->fs != NULL || ls->t.token == TK_EOS);
62 if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) {
63 TString *ts = ls->t.seminfo.ts;
64 luaX_newstring(ls, getstr(ts), ts->tsv.len);
70 static l_noret semerror (LexState *ls, const char *msg) {
71 ls->t.token = 0; /* remove 'near to' from final message */
72 luaX_syntaxerror(ls, msg);
76 static l_noret error_expected (LexState *ls, int token) {
78 luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token)));
82 static l_noret errorlimit (FuncState *fs, int limit, const char *what) {
83 lua_State *L = fs->ls->L;
85 int line = fs->f->linedefined;
86 const char *where = (line == 0)
88 : luaO_pushfstring(L, "function at line %d", line);
89 msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s",
91 luaX_syntaxerror(fs->ls, msg);
95 static void checklimit (FuncState *fs, int v, int l, const char *what) {
96 if (v > l) errorlimit(fs, l, what);
100 static int testnext (LexState *ls, int c) {
101 if (ls->t.token == c) {
109 static void check (LexState *ls, int c) {
110 if (ls->t.token != c)
111 error_expected(ls, c);
115 static void checknext (LexState *ls, int c) {
121 #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); }
125 static void check_match (LexState *ls, int what, int who, int where) {
126 if (!testnext(ls, what)) {
127 if (where == ls->linenumber)
128 error_expected(ls, what);
130 luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
131 "%s expected (to close %s at line %d)",
132 luaX_token2str(ls, what), luaX_token2str(ls, who), where));
138 static TString *str_checkname (LexState *ls) {
141 ts = ls->t.seminfo.ts;
147 static void init_exp (expdesc *e, expkind k, int i) {
148 e->f = e->t = NO_JUMP;
154 static void codestring (LexState *ls, expdesc *e, TString *s) {
155 init_exp(e, VK, luaK_stringK(ls->fs, s));
159 static void checkname (LexState *ls, expdesc *e) {
160 codestring(ls, e, str_checkname(ls));
164 static int registerlocalvar (LexState *ls, TString *varname) {
165 FuncState *fs = ls->fs;
167 int oldsize = f->sizelocvars;
168 luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
169 LocVar, SHRT_MAX, "local variables");
170 while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL;
171 f->locvars[fs->nlocvars].varname = varname;
172 luaC_objbarrier(ls->L, f, varname);
173 return fs->nlocvars++;
177 static void new_localvar (LexState *ls, TString *name) {
178 FuncState *fs = ls->fs;
179 Dyndata *dyd = ls->dyd;
180 int reg = registerlocalvar(ls, name);
181 checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal,
182 MAXVARS, "local variables");
183 luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1,
184 dyd->actvar.size, Vardesc, MAX_INT, "local variables");
185 dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg);
189 static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) {
190 new_localvar(ls, luaX_newstring(ls, name, sz));
193 #define new_localvarliteral(ls,v) \
194 new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1)
197 static LocVar *getlocvar (FuncState *fs, int i) {
198 int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx;
199 lua_assert(idx < fs->nlocvars);
200 return &fs->f->locvars[idx];
204 static void adjustlocalvars (LexState *ls, int nvars) {
205 FuncState *fs = ls->fs;
206 fs->nactvar = cast_byte(fs->nactvar + nvars);
207 for (; nvars; nvars--) {
208 getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc;
213 static void removevars (FuncState *fs, int tolevel) {
214 fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel);
215 while (fs->nactvar > tolevel)
216 getlocvar(fs, --fs->nactvar)->endpc = fs->pc;
220 static int searchupvalue (FuncState *fs, TString *name) {
222 Upvaldesc *up = fs->f->upvalues;
223 for (i = 0; i < fs->nups; i++) {
224 if (luaS_eqstr(up[i].name, name)) return i;
226 return -1; /* not found */
230 static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
232 int oldsize = f->sizeupvalues;
233 checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues");
234 luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues,
235 Upvaldesc, MAXUPVAL, "upvalues");
236 while (oldsize < f->sizeupvalues) f->upvalues[oldsize++].name = NULL;
237 f->upvalues[fs->nups].instack = (v->k == VLOCAL);
238 f->upvalues[fs->nups].idx = cast_byte(v->u.info);
239 f->upvalues[fs->nups].name = name;
240 luaC_objbarrier(fs->ls->L, f, name);
245 static int searchvar (FuncState *fs, TString *n) {
247 for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) {
248 if (luaS_eqstr(n, getlocvar(fs, i)->varname))
251 return -1; /* not found */
256 Mark block where variable at given level was defined
257 (to emit close instructions later).
259 static void markupval (FuncState *fs, int level) {
260 BlockCnt *bl = fs->bl;
261 while (bl->nactvar > level) bl = bl->previous;
267 Find variable with given name 'n'. If it is an upvalue, add this
268 upvalue into all intermediate functions.
270 static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
271 if (fs == NULL) /* no more levels? */
272 return VVOID; /* default is global */
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 */
281 else { /* not found as local at current level; try upvalues */
282 int idx = searchupvalue(fs, n); /* try existing upvalues */
283 if (idx < 0) { /* not found? */
284 if (singlevaraux(fs->prev, n, var, 0) == VVOID) /* try upper levels */
285 return VVOID; /* not found; is a global */
286 /* else was LOCAL or UPVAL */
287 idx = newupvalue(fs, n, var); /* will be a new upvalue */
289 init_exp(var, VUPVAL, idx);
296 static void singlevar (LexState *ls, expdesc *var) {
297 TString *varname = str_checkname(ls);
298 FuncState *fs = ls->fs;
299 if (singlevaraux(fs, varname, var, 1) == VVOID) { /* global name? */
301 singlevaraux(fs, ls->envn, var, 1); /* get environment variable */
302 lua_assert(var->k == VLOCAL || var->k == VUPVAL);
303 codestring(ls, &key, varname); /* key is variable name */
304 luaK_indexed(fs, var, &key); /* env[varname] */
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(luaS_eqstr(gt->name, label->name));
345 if (gt->nactvar < label->nactvar) {
346 TString *vname = getlocvar(fs, gt->nactvar)->varname;
347 const char *msg = luaO_pushfstring(ls->L,
348 "<goto %s> at line %d jumps into the scope of local " LUA_QS,
349 getstr(gt->name), gt->line, getstr(vname));
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 (luaS_eqstr(lb->name, gt->name)) { /* correct label? */
372 if (gt->nactvar > lb->nactvar &&
373 (bl->upval || dyd->label.n > bl->firstlabel))
374 luaK_patchclose(ls->fs, gt->pc, lb->nactvar);
375 closegoto(ls, g, lb); /* close it */
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 (luaS_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 " LUA_QS " 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) f->p[oldsize++] = NULL;
507 f->p[fs->np++] = clp = luaF_newproto(L);
508 luaC_objbarrier(L, f, clp);
514 ** codes instruction to create new closure in parent function.
515 ** The OP_CLOSURE instruction must use the last available register,
516 ** so that, if it invokes the GC, the GC knows which registers
517 ** are in use at that time.
519 static void codeclosure (LexState *ls, expdesc *v) {
520 FuncState *fs = ls->fs->prev;
521 init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1));
522 luaK_exp2nextreg(fs, v); /* fix it at the last register */
526 static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
527 lua_State *L = ls->L;
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 */
547 /* anchor table of constants (to avoid being collected) */
548 sethvalue2s(L, L->top, fs->h);
550 enterblock(fs, bl, 0);
554 static void close_func (LexState *ls) {
555 lua_State *L = ls->L;
556 FuncState *fs = ls->fs;
558 luaK_ret(fs, 0, 0); /* final return */
560 luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
561 f->sizecode = fs->pc;
562 luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
563 f->sizelineinfo = fs->pc;
564 luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
566 luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
568 luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
569 f->sizelocvars = fs->nlocvars;
570 luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc);
571 f->sizeupvalues = fs->nups;
572 lua_assert(fs->bl == NULL);
574 /* last token read was anchored in defunct function; must re-anchor it */
576 L->top--; /* pop table of constants */
582 /*============================================================*/
584 /*============================================================*/
588 ** check whether current token is in the follow set of a block.
589 ** 'until' closes syntactical blocks, but do not close scope,
590 ** so it handled in separate.
592 static int block_follow (LexState *ls, int withuntil) {
593 switch (ls->t.token) {
594 case TK_ELSE: case TK_ELSEIF:
595 case TK_END: case TK_EOS:
597 case TK_UNTIL: return withuntil;
603 static void statlist (LexState *ls) {
604 /* statlist -> { stat [`;'] } */
605 while (!block_follow(ls, 1)) {
606 if (ls->t.token == TK_RETURN) {
608 return; /* 'return' must be last statement */
615 static void fieldsel (LexState *ls, expdesc *v) {
616 /* fieldsel -> ['.' | ':'] NAME */
617 FuncState *fs = ls->fs;
619 luaK_exp2anyregup(fs, v);
620 luaX_next(ls); /* skip the dot or colon */
622 luaK_indexed(fs, v, &key);
626 static void yindex (LexState *ls, expdesc *v) {
627 /* index -> '[' expr ']' */
628 luaX_next(ls); /* skip the '[' */
630 luaK_exp2val(ls->fs, v);
636 ** {======================================================================
637 ** Rules for Constructors
638 ** =======================================================================
643 expdesc v; /* last list item read */
644 expdesc *t; /* table descriptor */
645 int nh; /* total number of `record' elements */
646 int na; /* total number of array elements */
647 int tostore; /* number of array elements pending to be stored */
651 static void recfield (LexState *ls, struct ConsControl *cc) {
652 /* recfield -> (NAME | `['exp1`]') = exp1 */
653 FuncState *fs = ls->fs;
654 int reg = ls->fs->freereg;
657 if (ls->t.token == TK_NAME) {
658 checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
661 else /* ls->t.token == '[' */
665 rkkey = luaK_exp2RK(fs, &key);
667 luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val));
668 fs->freereg = reg; /* free registers */
672 static void closelistfield (FuncState *fs, struct ConsControl *cc) {
673 if (cc->v.k == VVOID) return; /* there is no list item */
674 luaK_exp2nextreg(fs, &cc->v);
676 if (cc->tostore == LFIELDS_PER_FLUSH) {
677 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); /* flush */
678 cc->tostore = 0; /* no more items pending */
683 static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
684 if (cc->tostore == 0) return;
685 if (hasmultret(cc->v.k)) {
686 luaK_setmultret(fs, &cc->v);
687 luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET);
688 cc->na--; /* do not count last expression (unknown number of elements) */
691 if (cc->v.k != VVOID)
692 luaK_exp2nextreg(fs, &cc->v);
693 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);
698 static void listfield (LexState *ls, struct ConsControl *cc) {
699 /* listfield -> exp */
701 checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
707 static void field (LexState *ls, struct ConsControl *cc) {
708 /* field -> listfield | recfield */
709 switch(ls->t.token) {
710 case TK_NAME: { /* may be 'listfield' or 'recfield' */
711 if (luaX_lookahead(ls) != '=') /* expression? */
729 static void constructor (LexState *ls, expdesc *t) {
730 /* constructor -> '{' [ field { sep field } [sep] ] '}'
732 FuncState *fs = ls->fs;
733 int line = ls->linenumber;
734 int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
735 struct ConsControl cc;
736 cc.na = cc.nh = cc.tostore = 0;
738 init_exp(t, VRELOCABLE, pc);
739 init_exp(&cc.v, VVOID, 0); /* no value (yet) */
740 luaK_exp2nextreg(ls->fs, t); /* fix it at stack top */
743 lua_assert(cc.v.k == VVOID || cc.tostore > 0);
744 if (ls->t.token == '}') break;
745 closelistfield(fs, &cc);
747 } while (testnext(ls, ',') || testnext(ls, ';'));
748 check_match(ls, '}', '{', line);
749 lastlistfield(fs, &cc);
750 SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
751 SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */
754 /* }====================================================================== */
758 static void parlist (LexState *ls) {
759 /* parlist -> [ param { `,' param } ] */
760 FuncState *fs = ls->fs;
764 if (ls->t.token != ')') { /* is `parlist' not empty? */
766 switch (ls->t.token) {
767 case TK_NAME: { /* param -> NAME */
768 new_localvar(ls, str_checkname(ls));
772 case TK_DOTS: { /* param -> `...' */
777 default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected");
779 } while (!f->is_vararg && testnext(ls, ','));
781 adjustlocalvars(ls, nparams);
782 f->numparams = cast_byte(fs->nactvar);
783 luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */
787 static void body (LexState *ls, expdesc *e, int ismethod, int line) {
788 /* body -> `(' parlist `)' block END */
791 new_fs.f = addprototype(ls);
792 new_fs.f->linedefined = line;
793 open_func(ls, &new_fs, &bl);
796 new_localvarliteral(ls, "self"); /* create 'self' parameter */
797 adjustlocalvars(ls, 1);
802 new_fs.f->lastlinedefined = ls->linenumber;
803 check_match(ls, TK_END, TK_FUNCTION, line);
809 static int explist (LexState *ls, expdesc *v) {
810 /* explist -> expr { `,' expr } */
811 int n = 1; /* at least one expression */
813 while (testnext(ls, ',')) {
814 luaK_exp2nextreg(ls->fs, v);
822 static void funcargs (LexState *ls, expdesc *f, int line) {
823 FuncState *fs = ls->fs;
826 switch (ls->t.token) {
827 case '(': { /* funcargs -> `(' [ explist ] `)' */
829 if (ls->t.token == ')') /* arg list is empty? */
833 luaK_setmultret(fs, &args);
835 check_match(ls, ')', '(', line);
838 case '{': { /* funcargs -> constructor */
839 constructor(ls, &args);
842 case TK_STRING: { /* funcargs -> STRING */
843 codestring(ls, &args, ls->t.seminfo.ts);
844 luaX_next(ls); /* must use `seminfo' before `next' */
848 luaX_syntaxerror(ls, "function arguments expected");
851 lua_assert(f->k == VNONRELOC);
852 base = f->u.info; /* base register for call */
853 if (hasmultret(args.k))
854 nparams = LUA_MULTRET; /* open call */
857 luaK_exp2nextreg(fs, &args); /* close last argument */
858 nparams = fs->freereg - (base+1);
860 init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
861 luaK_fixline(fs, line);
862 fs->freereg = base+1; /* call remove function and arguments and leaves
863 (unless changed) one result */
870 ** {======================================================================
871 ** Expression parsing
872 ** =======================================================================
876 static void primaryexp (LexState *ls, expdesc *v) {
877 /* primaryexp -> NAME | '(' expr ')' */
878 switch (ls->t.token) {
880 int line = ls->linenumber;
883 check_match(ls, ')', '(', line);
884 luaK_dischargevars(ls->fs, v);
892 luaX_syntaxerror(ls, "unexpected symbol");
898 static void suffixedexp (LexState *ls, expdesc *v) {
900 primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */
901 FuncState *fs = ls->fs;
902 int line = ls->linenumber;
905 switch (ls->t.token) {
906 case '.': { /* fieldsel */
910 case '[': { /* `[' exp1 `]' */
912 luaK_exp2anyregup(fs, v);
914 luaK_indexed(fs, v, &key);
917 case ':': { /* `:' NAME funcargs */
921 luaK_self(fs, v, &key);
922 funcargs(ls, v, line);
925 case '(': case TK_STRING: case '{': { /* funcargs */
926 luaK_exp2nextreg(fs, v);
927 funcargs(ls, v, line);
936 static void simpleexp (LexState *ls, expdesc *v) {
937 /* simpleexp -> NUMBER | STRING | NIL | TRUE | FALSE | ... |
938 constructor | FUNCTION body | suffixedexp */
939 switch (ls->t.token) {
941 init_exp(v, VKNUM, 0);
942 v->u.nval = ls->t.seminfo.r;
946 codestring(ls, v, ls->t.seminfo.ts);
950 init_exp(v, VNIL, 0);
954 init_exp(v, VTRUE, 0);
958 init_exp(v, VFALSE, 0);
961 case TK_DOTS: { /* vararg */
962 FuncState *fs = ls->fs;
963 check_condition(ls, fs->f->is_vararg,
964 "cannot use " LUA_QL("...") " outside a vararg function");
965 init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
968 case '{': { /* constructor */
974 body(ls, v, 0, ls->linenumber);
986 static UnOpr getunopr (int op) {
988 case TK_NOT: return OPR_NOT;
989 case '-': return OPR_MINUS;
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_DIV;
1002 case '%': return OPR_MOD;
1003 case '^': return OPR_POW;
1004 case TK_CONCAT: return OPR_CONCAT;
1005 case TK_NE: return OPR_NE;
1006 case TK_EQ: return OPR_EQ;
1007 case '<': return OPR_LT;
1008 case TK_LE: return OPR_LE;
1009 case '>': return OPR_GT;
1010 case TK_GE: return OPR_GE;
1011 case TK_AND: return OPR_AND;
1012 case TK_OR: return OPR_OR;
1013 default: return OPR_NOBINOPR;
1018 static const struct {
1019 lu_byte left; /* left priority for each binary operator */
1020 lu_byte right; /* right priority */
1021 } priority[] = { /* ORDER OPR */
1022 {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `*' `/' `%' */
1023 {10, 9}, {5, 4}, /* ^, .. (right associative) */
1024 {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */
1025 {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */
1026 {2, 2}, {1, 1} /* and, or */
1029 #define UNARY_PRIORITY 8 /* priority for unary operators */
1033 ** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
1034 ** where `binop' is any binary operator with a priority higher than `limit'
1036 static BinOpr subexpr (LexState *ls, expdesc *v, int limit) {
1040 uop = getunopr(ls->t.token);
1041 if (uop != OPR_NOUNOPR) {
1042 int line = ls->linenumber;
1044 subexpr(ls, v, UNARY_PRIORITY);
1045 luaK_prefix(ls->fs, uop, v, line);
1047 else simpleexp(ls, v);
1048 /* expand while operators have priorities higher than `limit' */
1049 op = getbinopr(ls->t.token);
1050 while (op != OPR_NOBINOPR && priority[op].left > limit) {
1053 int line = ls->linenumber;
1055 luaK_infix(ls->fs, op, v);
1056 /* read sub-expression with higher priority */
1057 nextop = subexpr(ls, &v2, priority[op].right);
1058 luaK_posfix(ls->fs, op, v, &v2, line);
1062 return op; /* return first untreated operator */
1066 static void expr (LexState *ls, expdesc *v) {
1070 /* }==================================================================== */
1075 ** {======================================================================
1076 ** Rules for Statements
1077 ** =======================================================================
1081 static void block (LexState *ls) {
1082 /* block -> statlist */
1083 FuncState *fs = ls->fs;
1085 enterblock(fs, &bl, 0);
1092 ** structure to chain all variables in the left-hand side of an
1096 struct LHS_assign *prev;
1097 expdesc v; /* variable (global, local, upvalue, or indexed) */
1102 ** check whether, in an assignment to an upvalue/local variable, the
1103 ** upvalue/local variable is begin used in a previous assignment to a
1104 ** table. If so, save original upvalue/local value in a safe place and
1105 ** use this safe copy in the previous assignment.
1107 static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
1108 FuncState *fs = ls->fs;
1109 int extra = fs->freereg; /* eventual position to save local variable */
1111 for (; lh; lh = lh->prev) { /* check all previous assignments */
1112 if (lh->v.k == VINDEXED) { /* assigning to a table? */
1113 /* table is the upvalue/local being assigned now? */
1114 if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) {
1116 lh->v.u.ind.vt = VLOCAL;
1117 lh->v.u.ind.t = extra; /* previous assignment will use safe copy */
1119 /* index is the local being assigned? (index cannot be upvalue) */
1120 if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) {
1122 lh->v.u.ind.idx = extra; /* previous assignment will use safe copy */
1127 /* copy upvalue/local value to a temporary (in position 'extra') */
1128 OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
1129 luaK_codeABC(fs, op, extra, v->u.info, 0);
1130 luaK_reserveregs(fs, 1);
1135 static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
1137 check_condition(ls, vkisvar(lh->v.k), "syntax error");
1138 if (testnext(ls, ',')) { /* assignment -> ',' suffixedexp assignment */
1139 struct LHS_assign nv;
1141 suffixedexp(ls, &nv.v);
1142 if (nv.v.k != VINDEXED)
1143 check_conflict(ls, lh, &nv.v);
1144 checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS,
1146 assignment(ls, &nv, nvars+1);
1148 else { /* assignment -> `=' explist */
1151 nexps = explist(ls, &e);
1152 if (nexps != nvars) {
1153 adjust_assign(ls, nvars, nexps, &e);
1155 ls->fs->freereg -= nexps - nvars; /* remove extra values */
1158 luaK_setoneret(ls->fs, &e); /* close last expression */
1159 luaK_storevar(ls->fs, &lh->v, &e);
1160 return; /* avoid default */
1163 init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */
1164 luaK_storevar(ls->fs, &lh->v, &e);
1168 static int cond (LexState *ls) {
1171 expr(ls, &v); /* read condition */
1172 if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */
1173 luaK_goiftrue(ls->fs, &v);
1178 static void gotostat (LexState *ls, int pc) {
1179 int line = ls->linenumber;
1182 if (testnext(ls, TK_GOTO))
1183 label = str_checkname(ls);
1185 luaX_next(ls); /* skip break */
1186 label = luaS_new(ls->L, "break");
1188 g = newlabelentry(ls, &ls->dyd->gt, label, line, pc);
1189 findlabel(ls, g); /* close it if label already defined */
1193 /* check for repeated labels on the same block */
1194 static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) {
1196 for (i = fs->bl->firstlabel; i < ll->n; i++) {
1197 if (luaS_eqstr(label, ll->arr[i].name)) {
1198 const char *msg = luaO_pushfstring(fs->ls->L,
1199 "label " LUA_QS " already defined on line %d",
1200 getstr(label), ll->arr[i].line);
1201 semerror(fs->ls, msg);
1207 /* skip no-op statements */
1208 static void skipnoopstat (LexState *ls) {
1209 while (ls->t.token == ';' || ls->t.token == TK_DBCOLON)
1214 static void labelstat (LexState *ls, TString *label, int line) {
1215 /* label -> '::' NAME '::' */
1216 FuncState *fs = ls->fs;
1217 Labellist *ll = &ls->dyd->label;
1218 int l; /* index of new label being created */
1219 checkrepeated(fs, ll, label); /* check for repeated labels */
1220 checknext(ls, TK_DBCOLON); /* skip double colon */
1221 /* create new entry for this label */
1222 l = newlabelentry(ls, ll, label, line, fs->pc);
1223 skipnoopstat(ls); /* skip other no-op statements */
1224 if (block_follow(ls, 0)) { /* label is last no-op statement in the block? */
1225 /* assume that locals are already out of scope */
1226 ll->arr[l].nactvar = fs->bl->nactvar;
1228 findgotos(ls, &ll->arr[l]);
1232 static void whilestat (LexState *ls, int line) {
1233 /* whilestat -> WHILE cond DO block END */
1234 FuncState *fs = ls->fs;
1238 luaX_next(ls); /* skip WHILE */
1239 whileinit = luaK_getlabel(fs);
1240 condexit = cond(ls);
1241 enterblock(fs, &bl, 1);
1242 checknext(ls, TK_DO);
1244 luaK_jumpto(fs, whileinit);
1245 check_match(ls, TK_END, TK_WHILE, line);
1247 luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
1251 static void repeatstat (LexState *ls, int line) {
1252 /* repeatstat -> REPEAT block UNTIL cond */
1254 FuncState *fs = ls->fs;
1255 int repeat_init = luaK_getlabel(fs);
1257 enterblock(fs, &bl1, 1); /* loop block */
1258 enterblock(fs, &bl2, 0); /* scope block */
1259 luaX_next(ls); /* skip REPEAT */
1261 check_match(ls, TK_UNTIL, TK_REPEAT, line);
1262 condexit = cond(ls); /* read condition (inside scope block) */
1263 if (bl2.upval) /* upvalues? */
1264 luaK_patchclose(fs, condexit, bl2.nactvar);
1265 leaveblock(fs); /* finish scope */
1266 luaK_patchlist(fs, condexit, repeat_init); /* close the loop */
1267 leaveblock(fs); /* finish loop */
1271 static int exp1 (LexState *ls) {
1275 luaK_exp2nextreg(ls->fs, &e);
1276 lua_assert(e.k == VNONRELOC);
1282 static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
1283 /* forbody -> DO block */
1285 FuncState *fs = ls->fs;
1287 adjustlocalvars(ls, 3); /* control variables */
1288 checknext(ls, TK_DO);
1289 prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
1290 enterblock(fs, &bl, 0); /* scope for declared variables */
1291 adjustlocalvars(ls, nvars);
1292 luaK_reserveregs(fs, nvars);
1294 leaveblock(fs); /* end of scope for declared variables */
1295 luaK_patchtohere(fs, prep);
1296 if (isnum) /* numeric for? */
1297 endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP);
1298 else { /* generic for */
1299 luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
1300 luaK_fixline(fs, line);
1301 endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP);
1303 luaK_patchlist(fs, endfor, prep + 1);
1304 luaK_fixline(fs, line);
1308 static void fornum (LexState *ls, TString *varname, int line) {
1309 /* fornum -> NAME = exp1,exp1[,exp1] forbody */
1310 FuncState *fs = ls->fs;
1311 int base = fs->freereg;
1312 new_localvarliteral(ls, "(for index)");
1313 new_localvarliteral(ls, "(for limit)");
1314 new_localvarliteral(ls, "(for step)");
1315 new_localvar(ls, varname);
1317 exp1(ls); /* initial value */
1319 exp1(ls); /* limit */
1320 if (testnext(ls, ','))
1321 exp1(ls); /* optional step */
1322 else { /* default step = 1 */
1323 luaK_codek(fs, fs->freereg, luaK_numberK(fs, 1));
1324 luaK_reserveregs(fs, 1);
1326 forbody(ls, base, line, 1, 1);
1330 static void forlist (LexState *ls, TString *indexname) {
1331 /* forlist -> NAME {,NAME} IN explist forbody */
1332 FuncState *fs = ls->fs;
1334 int nvars = 4; /* gen, state, control, plus at least one declared var */
1336 int base = fs->freereg;
1337 /* create control variables */
1338 new_localvarliteral(ls, "(for generator)");
1339 new_localvarliteral(ls, "(for state)");
1340 new_localvarliteral(ls, "(for control)");
1341 /* create declared variables */
1342 new_localvar(ls, indexname);
1343 while (testnext(ls, ',')) {
1344 new_localvar(ls, str_checkname(ls));
1347 checknext(ls, TK_IN);
1348 line = ls->linenumber;
1349 adjust_assign(ls, 3, explist(ls, &e), &e);
1350 luaK_checkstack(fs, 3); /* extra space to call generator */
1351 forbody(ls, base, line, nvars - 3, 0);
1355 static void forstat (LexState *ls, int line) {
1356 /* forstat -> FOR (fornum | forlist) END */
1357 FuncState *fs = ls->fs;
1360 enterblock(fs, &bl, 1); /* scope for loop and control variables */
1361 luaX_next(ls); /* skip `for' */
1362 varname = str_checkname(ls); /* first variable name */
1363 switch (ls->t.token) {
1364 case '=': fornum(ls, varname, line); break;
1365 case ',': case TK_IN: forlist(ls, varname); break;
1366 default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected");
1368 check_match(ls, TK_END, TK_FOR, line);
1369 leaveblock(fs); /* loop scope (`break' jumps to this point) */
1373 static void test_then_block (LexState *ls, int *escapelist) {
1374 /* test_then_block -> [IF | ELSEIF] cond THEN block */
1376 FuncState *fs = ls->fs;
1378 int jf; /* instruction to skip 'then' code (if condition is false) */
1379 luaX_next(ls); /* skip IF or ELSEIF */
1380 expr(ls, &v); /* read condition */
1381 checknext(ls, TK_THEN);
1382 if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) {
1383 luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */
1384 enterblock(fs, &bl, 0); /* must enter block before 'goto' */
1385 gotostat(ls, v.t); /* handle goto/break */
1386 skipnoopstat(ls); /* skip other no-op statements */
1387 if (block_follow(ls, 0)) { /* 'goto' is the entire block? */
1389 return; /* and that is it */
1391 else /* must skip over 'then' part if condition is false */
1394 else { /* regular case (not goto/break) */
1395 luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */
1396 enterblock(fs, &bl, 0);
1399 statlist(ls); /* `then' part */
1401 if (ls->t.token == TK_ELSE ||
1402 ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */
1403 luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */
1404 luaK_patchtohere(fs, jf);
1408 static void ifstat (LexState *ls, int line) {
1409 /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
1410 FuncState *fs = ls->fs;
1411 int escapelist = NO_JUMP; /* exit list for finished parts */
1412 test_then_block(ls, &escapelist); /* IF cond THEN block */
1413 while (ls->t.token == TK_ELSEIF)
1414 test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */
1415 if (testnext(ls, TK_ELSE))
1416 block(ls); /* `else' part */
1417 check_match(ls, TK_END, TK_IF, line);
1418 luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */
1422 static void localfunc (LexState *ls) {
1424 FuncState *fs = ls->fs;
1425 new_localvar(ls, str_checkname(ls)); /* new local variable */
1426 adjustlocalvars(ls, 1); /* enter its scope */
1427 body(ls, &b, 0, ls->linenumber); /* function created in next register */
1428 /* debug information will only see the variable after this point! */
1429 getlocvar(fs, b.u.info)->startpc = fs->pc;
1433 static void localstat (LexState *ls) {
1434 /* stat -> LOCAL NAME {`,' NAME} [`=' explist] */
1439 new_localvar(ls, str_checkname(ls));
1441 } while (testnext(ls, ','));
1442 if (testnext(ls, '='))
1443 nexps = explist(ls, &e);
1448 adjust_assign(ls, nvars, nexps, &e);
1449 adjustlocalvars(ls, nvars);
1453 static int funcname (LexState *ls, expdesc *v) {
1454 /* funcname -> NAME {fieldsel} [`:' NAME] */
1457 while (ls->t.token == '.')
1459 if (ls->t.token == ':') {
1467 static void funcstat (LexState *ls, int line) {
1468 /* funcstat -> FUNCTION funcname body */
1471 luaX_next(ls); /* skip FUNCTION */
1472 ismethod = funcname(ls, &v);
1473 body(ls, &b, ismethod, line);
1474 luaK_storevar(ls->fs, &v, &b);
1475 luaK_fixline(ls->fs, line); /* definition `happens' in the first line */
1479 static void exprstat (LexState *ls) {
1480 /* stat -> func | assignment */
1481 FuncState *fs = ls->fs;
1482 struct LHS_assign v;
1483 suffixedexp(ls, &v.v);
1484 if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */
1486 assignment(ls, &v, 1);
1488 else { /* stat -> func */
1489 check_condition(ls, v.v.k == VCALL, "syntax error");
1490 SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */
1495 static void retstat (LexState *ls) {
1496 /* stat -> RETURN [explist] [';'] */
1497 FuncState *fs = ls->fs;
1499 int first, nret; /* registers with returned values */
1500 if (block_follow(ls, 1) || ls->t.token == ';')
1501 first = nret = 0; /* return no values */
1503 nret = explist(ls, &e); /* optional return values */
1504 if (hasmultret(e.k)) {
1505 luaK_setmultret(fs, &e);
1506 if (e.k == VCALL && nret == 1) { /* tail call? */
1507 SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
1508 lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
1510 first = fs->nactvar;
1511 nret = LUA_MULTRET; /* return all values */
1514 if (nret == 1) /* only one single value? */
1515 first = luaK_exp2anyreg(fs, &e);
1517 luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */
1518 first = fs->nactvar; /* return all `active' values */
1519 lua_assert(nret == fs->freereg - first);
1523 luaK_ret(fs, first, nret);
1524 testnext(ls, ';'); /* skip optional semicolon */
1528 static void statement (LexState *ls) {
1529 int line = ls->linenumber; /* may be needed for error messages */
1531 switch (ls->t.token) {
1532 case ';': { /* stat -> ';' (empty statement) */
1533 luaX_next(ls); /* skip ';' */
1536 case TK_IF: { /* stat -> ifstat */
1540 case TK_WHILE: { /* stat -> whilestat */
1541 whilestat(ls, line);
1544 case TK_DO: { /* stat -> DO block END */
1545 luaX_next(ls); /* skip DO */
1547 check_match(ls, TK_END, TK_DO, line);
1550 case TK_FOR: { /* stat -> forstat */
1554 case TK_REPEAT: { /* stat -> repeatstat */
1555 repeatstat(ls, line);
1558 case TK_FUNCTION: { /* stat -> funcstat */
1562 case TK_LOCAL: { /* stat -> localstat */
1563 luaX_next(ls); /* skip LOCAL */
1564 if (testnext(ls, TK_FUNCTION)) /* local function? */
1570 case TK_DBCOLON: { /* stat -> label */
1571 luaX_next(ls); /* skip double colon */
1572 labelstat(ls, str_checkname(ls), line);
1575 case TK_RETURN: { /* stat -> retstat */
1576 luaX_next(ls); /* skip RETURN */
1580 case TK_BREAK: /* stat -> breakstat */
1581 case TK_GOTO: { /* stat -> 'goto' NAME */
1582 gotostat(ls, luaK_jump(ls->fs));
1585 default: { /* stat -> func | assignment */
1590 lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
1591 ls->fs->freereg >= ls->fs->nactvar);
1592 ls->fs->freereg = ls->fs->nactvar; /* free registers */
1596 /* }====================================================================== */
1600 ** compiles the main function, which is a regular vararg function with an
1601 ** upvalue named LUA_ENV
1603 static void mainfunc (LexState *ls, FuncState *fs) {
1606 open_func(ls, fs, &bl);
1607 fs->f->is_vararg = 1; /* main function is always vararg */
1608 init_exp(&v, VLOCAL, 0); /* create and... */
1609 newupvalue(fs, ls->envn, &v); /* ...set environment upvalue */
1610 luaX_next(ls); /* read first token */
1611 statlist(ls); /* parse main body */
1617 Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
1618 Dyndata *dyd, const char *name, int firstchar) {
1620 FuncState funcstate;
1621 Closure *cl = luaF_newLclosure(L, 1); /* create main closure */
1622 /* anchor closure (to avoid being collected) */
1623 setclLvalue(L, L->top, cl);
1625 funcstate.f = cl->l.p = luaF_newproto(L);
1626 funcstate.f->source = luaS_new(L, name); /* create and anchor TString */
1627 lexstate.buff = buff;
1629 dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
1630 luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar);
1631 mainfunc(&lexstate, &funcstate);
1632 lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
1633 /* all scopes should be correctly finished */
1634 lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0);
1635 return cl; /* it's on the stack too */