1 /* $NetBSD: lparser.c,v 1.3 2015/02/02 14:03:05 lneto Exp $ */
4 ** Id: lparser.c,v 2.147 2014/12/27 20:31:43 roberto Exp
6 ** See Copyright Notice in lua.h
36 /* maximum number of local variables per function (must be smaller
37 than 250, due to the bytecode format) */
41 #define hasmultret(k) ((k) == VCALL || (k) == VVARARG)
44 /* because all strings are unified by the scanner, the parser
45 can use pointer equality for string equality */
46 #define eqstr(a,b) ((a) == (b))
50 ** nodes for block list (list of active blocks)
52 typedef struct BlockCnt
{
53 struct BlockCnt
*previous
; /* chain */
54 int firstlabel
; /* index of first label in this block */
55 int firstgoto
; /* index of first pending goto in this block */
56 lu_byte nactvar
; /* # active locals outside the block */
57 lu_byte upval
; /* true if some variable in the block is an upvalue */
58 lu_byte isloop
; /* true if 'block' is a loop */
64 ** prototypes for recursive non-terminal functions
66 static void statement (LexState
*ls
);
67 static void expr (LexState
*ls
, expdesc
*v
);
71 static l_noret
semerror (LexState
*ls
, const char *msg
) {
72 ls
->t
.token
= 0; /* remove "near <token>" from final message */
73 luaX_syntaxerror(ls
, msg
);
77 static l_noret
error_expected (LexState
*ls
, int token
) {
79 luaO_pushfstring(ls
->L
, "%s expected", luaX_token2str(ls
, token
)));
83 static l_noret
errorlimit (FuncState
*fs
, int limit
, const char *what
) {
84 lua_State
*L
= fs
->ls
->L
;
86 int line
= fs
->f
->linedefined
;
87 const char *where
= (line
== 0)
89 : luaO_pushfstring(L
, "function at line %d", line
);
90 msg
= luaO_pushfstring(L
, "too many %s (limit is %d) in %s",
92 luaX_syntaxerror(fs
->ls
, msg
);
96 static void checklimit (FuncState
*fs
, int v
, int l
, const char *what
) {
97 if (v
> l
) errorlimit(fs
, l
, what
);
101 static int testnext (LexState
*ls
, int c
) {
102 if (ls
->t
.token
== c
) {
110 static void check (LexState
*ls
, int c
) {
111 if (ls
->t
.token
!= c
)
112 error_expected(ls
, c
);
116 static void checknext (LexState
*ls
, int c
) {
122 #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); }
126 static void check_match (LexState
*ls
, int what
, int who
, int where
) {
127 if (!testnext(ls
, what
)) {
128 if (where
== ls
->linenumber
)
129 error_expected(ls
, what
);
131 luaX_syntaxerror(ls
, luaO_pushfstring(ls
->L
,
132 "%s expected (to close %s at line %d)",
133 luaX_token2str(ls
, what
), luaX_token2str(ls
, who
), where
));
139 static TString
*str_checkname (LexState
*ls
) {
142 ts
= ls
->t
.seminfo
.ts
;
148 static void init_exp (expdesc
*e
, expkind k
, int i
) {
149 e
->f
= e
->t
= NO_JUMP
;
155 static void codestring (LexState
*ls
, expdesc
*e
, TString
*s
) {
156 init_exp(e
, VK
, luaK_stringK(ls
->fs
, s
));
160 static void checkname (LexState
*ls
, expdesc
*e
) {
161 codestring(ls
, e
, str_checkname(ls
));
165 static int registerlocalvar (LexState
*ls
, TString
*varname
) {
166 FuncState
*fs
= ls
->fs
;
168 int oldsize
= f
->sizelocvars
;
169 luaM_growvector(ls
->L
, f
->locvars
, fs
->nlocvars
, f
->sizelocvars
,
170 LocVar
, SHRT_MAX
, "local variables");
171 while (oldsize
< f
->sizelocvars
) f
->locvars
[oldsize
++].varname
= NULL
;
172 f
->locvars
[fs
->nlocvars
].varname
= varname
;
173 luaC_objbarrier(ls
->L
, f
, varname
);
174 return fs
->nlocvars
++;
178 static void new_localvar (LexState
*ls
, TString
*name
) {
179 FuncState
*fs
= ls
->fs
;
180 Dyndata
*dyd
= ls
->dyd
;
181 int reg
= registerlocalvar(ls
, name
);
182 checklimit(fs
, dyd
->actvar
.n
+ 1 - fs
->firstlocal
,
183 MAXVARS
, "local variables");
184 luaM_growvector(ls
->L
, dyd
->actvar
.arr
, dyd
->actvar
.n
+ 1,
185 dyd
->actvar
.size
, Vardesc
, MAX_INT
, "local variables");
186 dyd
->actvar
.arr
[dyd
->actvar
.n
++].idx
= cast(short, reg
);
190 static void new_localvarliteral_ (LexState
*ls
, const char *name
, size_t sz
) {
191 new_localvar(ls
, luaX_newstring(ls
, name
, sz
));
194 #define new_localvarliteral(ls,v) \
195 new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1)
198 static LocVar
*getlocvar (FuncState
*fs
, int i
) {
199 int idx
= fs
->ls
->dyd
->actvar
.arr
[fs
->firstlocal
+ i
].idx
;
200 lua_assert(idx
< fs
->nlocvars
);
201 return &fs
->f
->locvars
[idx
];
205 static void adjustlocalvars (LexState
*ls
, int nvars
) {
206 FuncState
*fs
= ls
->fs
;
207 fs
->nactvar
= cast_byte(fs
->nactvar
+ nvars
);
208 for (; nvars
; nvars
--) {
209 getlocvar(fs
, fs
->nactvar
- nvars
)->startpc
= fs
->pc
;
214 static void removevars (FuncState
*fs
, int tolevel
) {
215 fs
->ls
->dyd
->actvar
.n
-= (fs
->nactvar
- tolevel
);
216 while (fs
->nactvar
> tolevel
)
217 getlocvar(fs
, --fs
->nactvar
)->endpc
= fs
->pc
;
221 static int searchupvalue (FuncState
*fs
, TString
*name
) {
223 Upvaldesc
*up
= fs
->f
->upvalues
;
224 for (i
= 0; i
< fs
->nups
; i
++) {
225 if (eqstr(up
[i
].name
, name
)) return i
;
227 return -1; /* not found */
231 static int newupvalue (FuncState
*fs
, TString
*name
, expdesc
*v
) {
233 int oldsize
= f
->sizeupvalues
;
234 checklimit(fs
, fs
->nups
+ 1, MAXUPVAL
, "upvalues");
235 luaM_growvector(fs
->ls
->L
, f
->upvalues
, fs
->nups
, f
->sizeupvalues
,
236 Upvaldesc
, MAXUPVAL
, "upvalues");
237 while (oldsize
< f
->sizeupvalues
) f
->upvalues
[oldsize
++].name
= NULL
;
238 f
->upvalues
[fs
->nups
].instack
= (v
->k
== VLOCAL
);
239 f
->upvalues
[fs
->nups
].idx
= cast_byte(v
->u
.info
);
240 f
->upvalues
[fs
->nups
].name
= name
;
241 luaC_objbarrier(fs
->ls
->L
, f
, name
);
246 static int searchvar (FuncState
*fs
, TString
*n
) {
248 for (i
= cast_int(fs
->nactvar
) - 1; i
>= 0; i
--) {
249 if (eqstr(n
, getlocvar(fs
, i
)->varname
))
252 return -1; /* not found */
257 Mark block where variable at given level was defined
258 (to emit close instructions later).
260 static void markupval (FuncState
*fs
, int level
) {
261 BlockCnt
*bl
= fs
->bl
;
262 while (bl
->nactvar
> level
) bl
= bl
->previous
;
268 Find variable with given name 'n'. If it is an upvalue, add this
269 upvalue into all intermediate functions.
271 static int singlevaraux (FuncState
*fs
, TString
*n
, expdesc
*var
, int base
) {
272 if (fs
== NULL
) /* no more levels? */
273 return VVOID
; /* default is global */
275 int v
= searchvar(fs
, n
); /* look up locals at current level */
276 if (v
>= 0) { /* found? */
277 init_exp(var
, VLOCAL
, v
); /* variable is local */
279 markupval(fs
, v
); /* local will be used as an upval */
282 else { /* not found as local at current level; try upvalues */
283 int idx
= searchupvalue(fs
, n
); /* try existing upvalues */
284 if (idx
< 0) { /* not found? */
285 if (singlevaraux(fs
->prev
, n
, var
, 0) == VVOID
) /* try upper levels */
286 return VVOID
; /* not found; is a global */
287 /* else was LOCAL or UPVAL */
288 idx
= newupvalue(fs
, n
, var
); /* will be a new upvalue */
290 init_exp(var
, VUPVAL
, idx
);
297 static void singlevar (LexState
*ls
, expdesc
*var
) {
298 TString
*varname
= str_checkname(ls
);
299 FuncState
*fs
= ls
->fs
;
300 if (singlevaraux(fs
, varname
, var
, 1) == VVOID
) { /* global name? */
302 singlevaraux(fs
, ls
->envn
, var
, 1); /* get environment variable */
303 lua_assert(var
->k
== VLOCAL
|| var
->k
== VUPVAL
);
304 codestring(ls
, &key
, varname
); /* key is variable name */
305 luaK_indexed(fs
, var
, &key
); /* env[varname] */
310 static void adjust_assign (LexState
*ls
, int nvars
, int nexps
, expdesc
*e
) {
311 FuncState
*fs
= ls
->fs
;
312 int extra
= nvars
- nexps
;
313 if (hasmultret(e
->k
)) {
314 extra
++; /* includes call itself */
315 if (extra
< 0) extra
= 0;
316 luaK_setreturns(fs
, e
, extra
); /* last exp. provides the difference */
317 if (extra
> 1) luaK_reserveregs(fs
, extra
-1);
320 if (e
->k
!= VVOID
) luaK_exp2nextreg(fs
, e
); /* close last expression */
322 int reg
= fs
->freereg
;
323 luaK_reserveregs(fs
, extra
);
324 luaK_nil(fs
, reg
, extra
);
330 static void enterlevel (LexState
*ls
) {
331 lua_State
*L
= ls
->L
;
333 checklimit(ls
->fs
, L
->nCcalls
, LUAI_MAXCCALLS
, "C levels");
337 #define leavelevel(ls) ((ls)->L->nCcalls--)
340 static void closegoto (LexState
*ls
, int g
, Labeldesc
*label
) {
342 FuncState
*fs
= ls
->fs
;
343 Labellist
*gl
= &ls
->dyd
->gt
;
344 Labeldesc
*gt
= &gl
->arr
[g
];
345 lua_assert(eqstr(gt
->name
, label
->name
));
346 if (gt
->nactvar
< label
->nactvar
) {
347 TString
*vname
= getlocvar(fs
, gt
->nactvar
)->varname
;
348 const char *msg
= luaO_pushfstring(ls
->L
,
349 "<goto %s> at line %d jumps into the scope of local '%s'",
350 getstr(gt
->name
), gt
->line
, getstr(vname
));
353 luaK_patchlist(fs
, gt
->pc
, label
->pc
);
354 /* remove goto from pending list */
355 for (i
= g
; i
< gl
->n
- 1; i
++)
356 gl
->arr
[i
] = gl
->arr
[i
+ 1];
362 ** try to close a goto with existing labels; this solves backward jumps
364 static int findlabel (LexState
*ls
, int g
) {
366 BlockCnt
*bl
= ls
->fs
->bl
;
367 Dyndata
*dyd
= ls
->dyd
;
368 Labeldesc
*gt
= &dyd
->gt
.arr
[g
];
369 /* check labels in current block for a match */
370 for (i
= bl
->firstlabel
; i
< dyd
->label
.n
; i
++) {
371 Labeldesc
*lb
= &dyd
->label
.arr
[i
];
372 if (eqstr(lb
->name
, gt
->name
)) { /* correct label? */
373 if (gt
->nactvar
> lb
->nactvar
&&
374 (bl
->upval
|| dyd
->label
.n
> bl
->firstlabel
))
375 luaK_patchclose(ls
->fs
, gt
->pc
, lb
->nactvar
);
376 closegoto(ls
, g
, lb
); /* close it */
380 return 0; /* label not found; cannot close goto */
384 static int newlabelentry (LexState
*ls
, Labellist
*l
, TString
*name
,
387 luaM_growvector(ls
->L
, l
->arr
, n
, l
->size
,
388 Labeldesc
, SHRT_MAX
, "labels/gotos");
389 l
->arr
[n
].name
= name
;
390 l
->arr
[n
].line
= line
;
391 l
->arr
[n
].nactvar
= ls
->fs
->nactvar
;
399 ** check whether new label 'lb' matches any pending gotos in current
400 ** block; solves forward jumps
402 static void findgotos (LexState
*ls
, Labeldesc
*lb
) {
403 Labellist
*gl
= &ls
->dyd
->gt
;
404 int i
= ls
->fs
->bl
->firstgoto
;
406 if (eqstr(gl
->arr
[i
].name
, lb
->name
))
407 closegoto(ls
, i
, lb
);
415 ** export pending gotos to outer level, to check them against
416 ** outer labels; if the block being exited has upvalues, and
417 ** the goto exits the scope of any variable (which can be the
418 ** upvalue), close those variables being exited.
420 static void movegotosout (FuncState
*fs
, BlockCnt
*bl
) {
421 int i
= bl
->firstgoto
;
422 Labellist
*gl
= &fs
->ls
->dyd
->gt
;
423 /* correct pending gotos to current block and try to close it
424 with visible labels */
426 Labeldesc
*gt
= &gl
->arr
[i
];
427 if (gt
->nactvar
> bl
->nactvar
) {
429 luaK_patchclose(fs
, gt
->pc
, bl
->nactvar
);
430 gt
->nactvar
= bl
->nactvar
;
432 if (!findlabel(fs
->ls
, i
))
433 i
++; /* move to next one */
438 static void enterblock (FuncState
*fs
, BlockCnt
*bl
, lu_byte isloop
) {
440 bl
->nactvar
= fs
->nactvar
;
441 bl
->firstlabel
= fs
->ls
->dyd
->label
.n
;
442 bl
->firstgoto
= fs
->ls
->dyd
->gt
.n
;
444 bl
->previous
= fs
->bl
;
446 lua_assert(fs
->freereg
== fs
->nactvar
);
451 ** create a label named 'break' to resolve break statements
453 static void breaklabel (LexState
*ls
) {
454 TString
*n
= luaS_new(ls
->L
, "break");
455 int l
= newlabelentry(ls
, &ls
->dyd
->label
, n
, 0, ls
->fs
->pc
);
456 findgotos(ls
, &ls
->dyd
->label
.arr
[l
]);
460 ** generates an error for an undefined 'goto'; choose appropriate
461 ** message when label name is a reserved word (which can only be 'break')
463 static l_noret
undefgoto (LexState
*ls
, Labeldesc
*gt
) {
464 const char *msg
= isreserved(gt
->name
)
465 ? "<%s> at line %d not inside a loop"
466 : "no visible label '%s' for <goto> at line %d";
467 msg
= luaO_pushfstring(ls
->L
, msg
, getstr(gt
->name
), gt
->line
);
472 static void leaveblock (FuncState
*fs
) {
473 BlockCnt
*bl
= fs
->bl
;
474 LexState
*ls
= fs
->ls
;
475 if (bl
->previous
&& bl
->upval
) {
476 /* create a 'jump to here' to close upvalues */
477 int j
= luaK_jump(fs
);
478 luaK_patchclose(fs
, j
, bl
->nactvar
);
479 luaK_patchtohere(fs
, j
);
482 breaklabel(ls
); /* close pending breaks */
483 fs
->bl
= bl
->previous
;
484 removevars(fs
, bl
->nactvar
);
485 lua_assert(bl
->nactvar
== fs
->nactvar
);
486 fs
->freereg
= fs
->nactvar
; /* free registers */
487 ls
->dyd
->label
.n
= bl
->firstlabel
; /* remove local labels */
488 if (bl
->previous
) /* inner block? */
489 movegotosout(fs
, bl
); /* update pending gotos to outer block */
490 else if (bl
->firstgoto
< ls
->dyd
->gt
.n
) /* pending gotos in outer block? */
491 undefgoto(ls
, &ls
->dyd
->gt
.arr
[bl
->firstgoto
]); /* error */
496 ** adds a new prototype into list of prototypes
498 static Proto
*addprototype (LexState
*ls
) {
500 lua_State
*L
= ls
->L
;
501 FuncState
*fs
= ls
->fs
;
502 Proto
*f
= fs
->f
; /* prototype of current function */
503 if (fs
->np
>= f
->sizep
) {
504 int oldsize
= f
->sizep
;
505 luaM_growvector(L
, f
->p
, fs
->np
, f
->sizep
, Proto
*, MAXARG_Bx
, "functions");
506 while (oldsize
< f
->sizep
) 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 -> '...' */
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
) {
935 init_exp(v
, VKFLT
, 0);
936 v
->u
.nval
= ls
->t
.seminfo
.r
;
941 init_exp(v
, VKINT
, 0);
942 v
->u
.ival
= ls
->t
.seminfo
.i
;
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 '...' 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_BNOT
;
991 case '#': return OPR_LEN
;
992 default: return OPR_NOUNOPR
;
997 static BinOpr
getbinopr (int op
) {
999 case '+': return OPR_ADD
;
1000 case '-': return OPR_SUB
;
1001 case '*': return OPR_MUL
;
1002 case '%': return OPR_MOD
;
1004 case '^': return OPR_POW
;
1005 case '/': return OPR_DIV
;
1007 case '/': return OPR_IDIV
;
1009 case TK_IDIV
: return OPR_IDIV
;
1010 case '&': return OPR_BAND
;
1011 case '|': return OPR_BOR
;
1012 case '~': return OPR_BXOR
;
1013 case TK_SHL
: return OPR_SHL
;
1014 case TK_SHR
: return OPR_SHR
;
1015 case TK_CONCAT
: return OPR_CONCAT
;
1016 case TK_NE
: return OPR_NE
;
1017 case TK_EQ
: return OPR_EQ
;
1018 case '<': return OPR_LT
;
1019 case TK_LE
: return OPR_LE
;
1020 case '>': return OPR_GT
;
1021 case TK_GE
: return OPR_GE
;
1022 case TK_AND
: return OPR_AND
;
1023 case TK_OR
: return OPR_OR
;
1024 default: return OPR_NOBINOPR
;
1029 static const struct {
1030 lu_byte left
; /* left priority for each binary operator */
1031 lu_byte right
; /* right priority */
1032 } priority
[] = { /* ORDER OPR */
1033 {10, 10}, {10, 10}, /* '+' '-' */
1034 {11, 11}, {11, 11}, /* '*' '%' */
1035 {14, 13}, /* '^' (right associative) */
1036 {11, 11}, {11, 11}, /* '/' '//' */
1037 {6, 6}, {4, 4}, {5, 5}, /* '&' '|' '~' */
1038 {7, 7}, {7, 7}, /* '<<' '>>' */
1039 {9, 8}, /* '..' (right associative) */
1040 {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */
1041 {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */
1042 {2, 2}, {1, 1} /* and, or */
1045 #define UNARY_PRIORITY 12 /* priority for unary operators */
1049 ** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
1050 ** where 'binop' is any binary operator with a priority higher than 'limit'
1052 static BinOpr
subexpr (LexState
*ls
, expdesc
*v
, int limit
) {
1056 uop
= getunopr(ls
->t
.token
);
1057 if (uop
!= OPR_NOUNOPR
) {
1058 int line
= ls
->linenumber
;
1060 subexpr(ls
, v
, UNARY_PRIORITY
);
1061 luaK_prefix(ls
->fs
, uop
, v
, line
);
1063 else simpleexp(ls
, v
);
1064 /* expand while operators have priorities higher than 'limit' */
1065 op
= getbinopr(ls
->t
.token
);
1066 while (op
!= OPR_NOBINOPR
&& priority
[op
].left
> limit
) {
1069 int line
= ls
->linenumber
;
1071 luaK_infix(ls
->fs
, op
, v
);
1072 /* read sub-expression with higher priority */
1073 nextop
= subexpr(ls
, &v2
, priority
[op
].right
);
1074 luaK_posfix(ls
->fs
, op
, v
, &v2
, line
);
1078 return op
; /* return first untreated operator */
1082 static void expr (LexState
*ls
, expdesc
*v
) {
1086 /* }==================================================================== */
1091 ** {======================================================================
1092 ** Rules for Statements
1093 ** =======================================================================
1097 static void block (LexState
*ls
) {
1098 /* block -> statlist */
1099 FuncState
*fs
= ls
->fs
;
1101 enterblock(fs
, &bl
, 0);
1108 ** structure to chain all variables in the left-hand side of an
1112 struct LHS_assign
*prev
;
1113 expdesc v
; /* variable (global, local, upvalue, or indexed) */
1118 ** check whether, in an assignment to an upvalue/local variable, the
1119 ** upvalue/local variable is begin used in a previous assignment to a
1120 ** table. If so, save original upvalue/local value in a safe place and
1121 ** use this safe copy in the previous assignment.
1123 static void check_conflict (LexState
*ls
, struct LHS_assign
*lh
, expdesc
*v
) {
1124 FuncState
*fs
= ls
->fs
;
1125 int extra
= fs
->freereg
; /* eventual position to save local variable */
1127 for (; lh
; lh
= lh
->prev
) { /* check all previous assignments */
1128 if (lh
->v
.k
== VINDEXED
) { /* assigning to a table? */
1129 /* table is the upvalue/local being assigned now? */
1130 if (lh
->v
.u
.ind
.vt
== v
->k
&& lh
->v
.u
.ind
.t
== v
->u
.info
) {
1132 lh
->v
.u
.ind
.vt
= VLOCAL
;
1133 lh
->v
.u
.ind
.t
= extra
; /* previous assignment will use safe copy */
1135 /* index is the local being assigned? (index cannot be upvalue) */
1136 if (v
->k
== VLOCAL
&& lh
->v
.u
.ind
.idx
== v
->u
.info
) {
1138 lh
->v
.u
.ind
.idx
= extra
; /* previous assignment will use safe copy */
1143 /* copy upvalue/local value to a temporary (in position 'extra') */
1144 OpCode op
= (v
->k
== VLOCAL
) ? OP_MOVE
: OP_GETUPVAL
;
1145 luaK_codeABC(fs
, op
, extra
, v
->u
.info
, 0);
1146 luaK_reserveregs(fs
, 1);
1151 static void assignment (LexState
*ls
, struct LHS_assign
*lh
, int nvars
) {
1153 check_condition(ls
, vkisvar(lh
->v
.k
), "syntax error");
1154 if (testnext(ls
, ',')) { /* assignment -> ',' suffixedexp assignment */
1155 struct LHS_assign nv
;
1157 suffixedexp(ls
, &nv
.v
);
1158 if (nv
.v
.k
!= VINDEXED
)
1159 check_conflict(ls
, lh
, &nv
.v
);
1160 checklimit(ls
->fs
, nvars
+ ls
->L
->nCcalls
, LUAI_MAXCCALLS
,
1162 assignment(ls
, &nv
, nvars
+1);
1164 else { /* assignment -> '=' explist */
1167 nexps
= explist(ls
, &e
);
1168 if (nexps
!= nvars
) {
1169 adjust_assign(ls
, nvars
, nexps
, &e
);
1171 ls
->fs
->freereg
-= nexps
- nvars
; /* remove extra values */
1174 luaK_setoneret(ls
->fs
, &e
); /* close last expression */
1175 luaK_storevar(ls
->fs
, &lh
->v
, &e
);
1176 return; /* avoid default */
1179 init_exp(&e
, VNONRELOC
, ls
->fs
->freereg
-1); /* default assignment */
1180 luaK_storevar(ls
->fs
, &lh
->v
, &e
);
1184 static int cond (LexState
*ls
) {
1187 expr(ls
, &v
); /* read condition */
1188 if (v
.k
== VNIL
) v
.k
= VFALSE
; /* 'falses' are all equal here */
1189 luaK_goiftrue(ls
->fs
, &v
);
1194 static void gotostat (LexState
*ls
, int pc
) {
1195 int line
= ls
->linenumber
;
1198 if (testnext(ls
, TK_GOTO
))
1199 label
= str_checkname(ls
);
1201 luaX_next(ls
); /* skip break */
1202 label
= luaS_new(ls
->L
, "break");
1204 g
= newlabelentry(ls
, &ls
->dyd
->gt
, label
, line
, pc
);
1205 findlabel(ls
, g
); /* close it if label already defined */
1209 /* check for repeated labels on the same block */
1210 static void checkrepeated (FuncState
*fs
, Labellist
*ll
, TString
*label
) {
1212 for (i
= fs
->bl
->firstlabel
; i
< ll
->n
; i
++) {
1213 if (eqstr(label
, ll
->arr
[i
].name
)) {
1214 const char *msg
= luaO_pushfstring(fs
->ls
->L
,
1215 "label '%s' already defined on line %d",
1216 getstr(label
), ll
->arr
[i
].line
);
1217 semerror(fs
->ls
, msg
);
1223 /* skip no-op statements */
1224 static void skipnoopstat (LexState
*ls
) {
1225 while (ls
->t
.token
== ';' || ls
->t
.token
== TK_DBCOLON
)
1230 static void labelstat (LexState
*ls
, TString
*label
, int line
) {
1231 /* label -> '::' NAME '::' */
1232 FuncState
*fs
= ls
->fs
;
1233 Labellist
*ll
= &ls
->dyd
->label
;
1234 int l
; /* index of new label being created */
1235 checkrepeated(fs
, ll
, label
); /* check for repeated labels */
1236 checknext(ls
, TK_DBCOLON
); /* skip double colon */
1237 /* create new entry for this label */
1238 l
= newlabelentry(ls
, ll
, label
, line
, fs
->pc
);
1239 skipnoopstat(ls
); /* skip other no-op statements */
1240 if (block_follow(ls
, 0)) { /* label is last no-op statement in the block? */
1241 /* assume that locals are already out of scope */
1242 ll
->arr
[l
].nactvar
= fs
->bl
->nactvar
;
1244 findgotos(ls
, &ll
->arr
[l
]);
1248 static void whilestat (LexState
*ls
, int line
) {
1249 /* whilestat -> WHILE cond DO block END */
1250 FuncState
*fs
= ls
->fs
;
1254 luaX_next(ls
); /* skip WHILE */
1255 whileinit
= luaK_getlabel(fs
);
1256 condexit
= cond(ls
);
1257 enterblock(fs
, &bl
, 1);
1258 checknext(ls
, TK_DO
);
1260 luaK_jumpto(fs
, whileinit
);
1261 check_match(ls
, TK_END
, TK_WHILE
, line
);
1263 luaK_patchtohere(fs
, condexit
); /* false conditions finish the loop */
1267 static void repeatstat (LexState
*ls
, int line
) {
1268 /* repeatstat -> REPEAT block UNTIL cond */
1270 FuncState
*fs
= ls
->fs
;
1271 int repeat_init
= luaK_getlabel(fs
);
1273 enterblock(fs
, &bl1
, 1); /* loop block */
1274 enterblock(fs
, &bl2
, 0); /* scope block */
1275 luaX_next(ls
); /* skip REPEAT */
1277 check_match(ls
, TK_UNTIL
, TK_REPEAT
, line
);
1278 condexit
= cond(ls
); /* read condition (inside scope block) */
1279 if (bl2
.upval
) /* upvalues? */
1280 luaK_patchclose(fs
, condexit
, bl2
.nactvar
);
1281 leaveblock(fs
); /* finish scope */
1282 luaK_patchlist(fs
, condexit
, repeat_init
); /* close the loop */
1283 leaveblock(fs
); /* finish loop */
1287 static int exp1 (LexState
*ls
) {
1291 luaK_exp2nextreg(ls
->fs
, &e
);
1292 lua_assert(e
.k
== VNONRELOC
);
1298 static void forbody (LexState
*ls
, int base
, int line
, int nvars
, int isnum
) {
1299 /* forbody -> DO block */
1301 FuncState
*fs
= ls
->fs
;
1303 adjustlocalvars(ls
, 3); /* control variables */
1304 checknext(ls
, TK_DO
);
1305 prep
= isnum
? luaK_codeAsBx(fs
, OP_FORPREP
, base
, NO_JUMP
) : luaK_jump(fs
);
1306 enterblock(fs
, &bl
, 0); /* scope for declared variables */
1307 adjustlocalvars(ls
, nvars
);
1308 luaK_reserveregs(fs
, nvars
);
1310 leaveblock(fs
); /* end of scope for declared variables */
1311 luaK_patchtohere(fs
, prep
);
1312 if (isnum
) /* numeric for? */
1313 endfor
= luaK_codeAsBx(fs
, OP_FORLOOP
, base
, NO_JUMP
);
1314 else { /* generic for */
1315 luaK_codeABC(fs
, OP_TFORCALL
, base
, 0, nvars
);
1316 luaK_fixline(fs
, line
);
1317 endfor
= luaK_codeAsBx(fs
, OP_TFORLOOP
, base
+ 2, NO_JUMP
);
1319 luaK_patchlist(fs
, endfor
, prep
+ 1);
1320 luaK_fixline(fs
, line
);
1324 static void fornum (LexState
*ls
, TString
*varname
, int line
) {
1325 /* fornum -> NAME = exp1,exp1[,exp1] forbody */
1326 FuncState
*fs
= ls
->fs
;
1327 int base
= fs
->freereg
;
1328 new_localvarliteral(ls
, "(for index)");
1329 new_localvarliteral(ls
, "(for limit)");
1330 new_localvarliteral(ls
, "(for step)");
1331 new_localvar(ls
, varname
);
1333 exp1(ls
); /* initial value */
1335 exp1(ls
); /* limit */
1336 if (testnext(ls
, ','))
1337 exp1(ls
); /* optional step */
1338 else { /* default step = 1 */
1339 luaK_codek(fs
, fs
->freereg
, luaK_intK(fs
, 1));
1340 luaK_reserveregs(fs
, 1);
1342 forbody(ls
, base
, line
, 1, 1);
1346 static void forlist (LexState
*ls
, TString
*indexname
) {
1347 /* forlist -> NAME {,NAME} IN explist forbody */
1348 FuncState
*fs
= ls
->fs
;
1350 int nvars
= 4; /* gen, state, control, plus at least one declared var */
1352 int base
= fs
->freereg
;
1353 /* create control variables */
1354 new_localvarliteral(ls
, "(for generator)");
1355 new_localvarliteral(ls
, "(for state)");
1356 new_localvarliteral(ls
, "(for control)");
1357 /* create declared variables */
1358 new_localvar(ls
, indexname
);
1359 while (testnext(ls
, ',')) {
1360 new_localvar(ls
, str_checkname(ls
));
1363 checknext(ls
, TK_IN
);
1364 line
= ls
->linenumber
;
1365 adjust_assign(ls
, 3, explist(ls
, &e
), &e
);
1366 luaK_checkstack(fs
, 3); /* extra space to call generator */
1367 forbody(ls
, base
, line
, nvars
- 3, 0);
1371 static void forstat (LexState
*ls
, int line
) {
1372 /* forstat -> FOR (fornum | forlist) END */
1373 FuncState
*fs
= ls
->fs
;
1376 enterblock(fs
, &bl
, 1); /* scope for loop and control variables */
1377 luaX_next(ls
); /* skip 'for' */
1378 varname
= str_checkname(ls
); /* first variable name */
1379 switch (ls
->t
.token
) {
1380 case '=': fornum(ls
, varname
, line
); break;
1381 case ',': case TK_IN
: forlist(ls
, varname
); break;
1382 default: luaX_syntaxerror(ls
, "'=' or 'in' expected");
1384 check_match(ls
, TK_END
, TK_FOR
, line
);
1385 leaveblock(fs
); /* loop scope ('break' jumps to this point) */
1389 static void test_then_block (LexState
*ls
, int *escapelist
) {
1390 /* test_then_block -> [IF | ELSEIF] cond THEN block */
1392 FuncState
*fs
= ls
->fs
;
1394 int jf
; /* instruction to skip 'then' code (if condition is false) */
1395 luaX_next(ls
); /* skip IF or ELSEIF */
1396 expr(ls
, &v
); /* read condition */
1397 checknext(ls
, TK_THEN
);
1398 if (ls
->t
.token
== TK_GOTO
|| ls
->t
.token
== TK_BREAK
) {
1399 luaK_goiffalse(ls
->fs
, &v
); /* will jump to label if condition is true */
1400 enterblock(fs
, &bl
, 0); /* must enter block before 'goto' */
1401 gotostat(ls
, v
.t
); /* handle goto/break */
1402 skipnoopstat(ls
); /* skip other no-op statements */
1403 if (block_follow(ls
, 0)) { /* 'goto' is the entire block? */
1405 return; /* and that is it */
1407 else /* must skip over 'then' part if condition is false */
1410 else { /* regular case (not goto/break) */
1411 luaK_goiftrue(ls
->fs
, &v
); /* skip over block if condition is false */
1412 enterblock(fs
, &bl
, 0);
1415 statlist(ls
); /* 'then' part */
1417 if (ls
->t
.token
== TK_ELSE
||
1418 ls
->t
.token
== TK_ELSEIF
) /* followed by 'else'/'elseif'? */
1419 luaK_concat(fs
, escapelist
, luaK_jump(fs
)); /* must jump over it */
1420 luaK_patchtohere(fs
, jf
);
1424 static void ifstat (LexState
*ls
, int line
) {
1425 /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
1426 FuncState
*fs
= ls
->fs
;
1427 int escapelist
= NO_JUMP
; /* exit list for finished parts */
1428 test_then_block(ls
, &escapelist
); /* IF cond THEN block */
1429 while (ls
->t
.token
== TK_ELSEIF
)
1430 test_then_block(ls
, &escapelist
); /* ELSEIF cond THEN block */
1431 if (testnext(ls
, TK_ELSE
))
1432 block(ls
); /* 'else' part */
1433 check_match(ls
, TK_END
, TK_IF
, line
);
1434 luaK_patchtohere(fs
, escapelist
); /* patch escape list to 'if' end */
1438 static void localfunc (LexState
*ls
) {
1440 FuncState
*fs
= ls
->fs
;
1441 new_localvar(ls
, str_checkname(ls
)); /* new local variable */
1442 adjustlocalvars(ls
, 1); /* enter its scope */
1443 body(ls
, &b
, 0, ls
->linenumber
); /* function created in next register */
1444 /* debug information will only see the variable after this point! */
1445 getlocvar(fs
, b
.u
.info
)->startpc
= fs
->pc
;
1449 static void localstat (LexState
*ls
) {
1450 /* stat -> LOCAL NAME {',' NAME} ['=' explist] */
1455 new_localvar(ls
, str_checkname(ls
));
1457 } while (testnext(ls
, ','));
1458 if (testnext(ls
, '='))
1459 nexps
= explist(ls
, &e
);
1464 adjust_assign(ls
, nvars
, nexps
, &e
);
1465 adjustlocalvars(ls
, nvars
);
1469 static int funcname (LexState
*ls
, expdesc
*v
) {
1470 /* funcname -> NAME {fieldsel} [':' NAME] */
1473 while (ls
->t
.token
== '.')
1475 if (ls
->t
.token
== ':') {
1483 static void funcstat (LexState
*ls
, int line
) {
1484 /* funcstat -> FUNCTION funcname body */
1487 luaX_next(ls
); /* skip FUNCTION */
1488 ismethod
= funcname(ls
, &v
);
1489 body(ls
, &b
, ismethod
, line
);
1490 luaK_storevar(ls
->fs
, &v
, &b
);
1491 luaK_fixline(ls
->fs
, line
); /* definition "happens" in the first line */
1495 static void exprstat (LexState
*ls
) {
1496 /* stat -> func | assignment */
1497 FuncState
*fs
= ls
->fs
;
1498 struct LHS_assign v
;
1499 suffixedexp(ls
, &v
.v
);
1500 if (ls
->t
.token
== '=' || ls
->t
.token
== ',') { /* stat -> assignment ? */
1502 assignment(ls
, &v
, 1);
1504 else { /* stat -> func */
1505 check_condition(ls
, v
.v
.k
== VCALL
, "syntax error");
1506 SETARG_C(getcode(fs
, &v
.v
), 1); /* call statement uses no results */
1511 static void retstat (LexState
*ls
) {
1512 /* stat -> RETURN [explist] [';'] */
1513 FuncState
*fs
= ls
->fs
;
1515 int first
, nret
; /* registers with returned values */
1516 if (block_follow(ls
, 1) || ls
->t
.token
== ';')
1517 first
= nret
= 0; /* return no values */
1519 nret
= explist(ls
, &e
); /* optional return values */
1520 if (hasmultret(e
.k
)) {
1521 luaK_setmultret(fs
, &e
);
1522 if (e
.k
== VCALL
&& nret
== 1) { /* tail call? */
1523 SET_OPCODE(getcode(fs
,&e
), OP_TAILCALL
);
1524 lua_assert(GETARG_A(getcode(fs
,&e
)) == fs
->nactvar
);
1526 first
= fs
->nactvar
;
1527 nret
= LUA_MULTRET
; /* return all values */
1530 if (nret
== 1) /* only one single value? */
1531 first
= luaK_exp2anyreg(fs
, &e
);
1533 luaK_exp2nextreg(fs
, &e
); /* values must go to the stack */
1534 first
= fs
->nactvar
; /* return all active values */
1535 lua_assert(nret
== fs
->freereg
- first
);
1539 luaK_ret(fs
, first
, nret
);
1540 testnext(ls
, ';'); /* skip optional semicolon */
1544 static void statement (LexState
*ls
) {
1545 int line
= ls
->linenumber
; /* may be needed for error messages */
1547 switch (ls
->t
.token
) {
1548 case ';': { /* stat -> ';' (empty statement) */
1549 luaX_next(ls
); /* skip ';' */
1552 case TK_IF
: { /* stat -> ifstat */
1556 case TK_WHILE
: { /* stat -> whilestat */
1557 whilestat(ls
, line
);
1560 case TK_DO
: { /* stat -> DO block END */
1561 luaX_next(ls
); /* skip DO */
1563 check_match(ls
, TK_END
, TK_DO
, line
);
1566 case TK_FOR
: { /* stat -> forstat */
1570 case TK_REPEAT
: { /* stat -> repeatstat */
1571 repeatstat(ls
, line
);
1574 case TK_FUNCTION
: { /* stat -> funcstat */
1578 case TK_LOCAL
: { /* stat -> localstat */
1579 luaX_next(ls
); /* skip LOCAL */
1580 if (testnext(ls
, TK_FUNCTION
)) /* local function? */
1586 case TK_DBCOLON
: { /* stat -> label */
1587 luaX_next(ls
); /* skip double colon */
1588 labelstat(ls
, str_checkname(ls
), line
);
1591 case TK_RETURN
: { /* stat -> retstat */
1592 luaX_next(ls
); /* skip RETURN */
1596 case TK_BREAK
: /* stat -> breakstat */
1597 case TK_GOTO
: { /* stat -> 'goto' NAME */
1598 gotostat(ls
, luaK_jump(ls
->fs
));
1601 default: { /* stat -> func | assignment */
1606 lua_assert(ls
->fs
->f
->maxstacksize
>= ls
->fs
->freereg
&&
1607 ls
->fs
->freereg
>= ls
->fs
->nactvar
);
1608 ls
->fs
->freereg
= ls
->fs
->nactvar
; /* free registers */
1612 /* }====================================================================== */
1616 ** compiles the main function, which is a regular vararg function with an
1617 ** upvalue named LUA_ENV
1619 static void mainfunc (LexState
*ls
, FuncState
*fs
) {
1622 open_func(ls
, fs
, &bl
);
1623 fs
->f
->is_vararg
= 1; /* main function is always vararg */
1624 init_exp(&v
, VLOCAL
, 0); /* create and... */
1625 newupvalue(fs
, ls
->envn
, &v
); /* ...set environment upvalue */
1626 luaX_next(ls
); /* read first token */
1627 statlist(ls
); /* parse main body */
1633 LClosure
*luaY_parser (lua_State
*L
, ZIO
*z
, Mbuffer
*buff
,
1634 Dyndata
*dyd
, const char *name
, int firstchar
) {
1636 FuncState funcstate
;
1637 LClosure
*cl
= luaF_newLclosure(L
, 1); /* create main closure */
1638 setclLvalue(L
, L
->top
, cl
); /* anchor it (to avoid being collected) */
1640 lexstate
.h
= luaH_new(L
); /* create table for scanner */
1641 sethvalue(L
, L
->top
, lexstate
.h
); /* anchor it */
1643 funcstate
.f
= cl
->p
= luaF_newproto(L
);
1644 funcstate
.f
->source
= luaS_new(L
, name
); /* create and anchor TString */
1645 lua_assert(iswhite(funcstate
.f
)); /* do not need barrier here */
1646 lexstate
.buff
= buff
;
1648 dyd
->actvar
.n
= dyd
->gt
.n
= dyd
->label
.n
= 0;
1649 luaX_setinput(L
, &lexstate
, z
, funcstate
.f
->source
, firstchar
);
1650 mainfunc(&lexstate
, &funcstate
);
1651 lua_assert(!funcstate
.prev
&& funcstate
.nups
== 1 && !lexstate
.fs
);
1652 /* all scopes should be correctly finished */
1653 lua_assert(dyd
->actvar
.n
== 0 && dyd
->gt
.n
== 0 && dyd
->label
.n
== 0);
1654 L
->top
--; /* remove scanner's table */
1655 return cl
; /* closure is on the stack, too */