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comparison luabuild/lua-5.2.1/src/lparser.c @ 1087:07b68c71b89c

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<GreyKnight> (cd luabuild; tar -xvf lua-5.2.1.tar.gz)
author HackBot
date Fri, 14 Dec 2012 20:33:11 +0000
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1086:64bb613b689c 1087:07b68c71b89c
1 /*
2 ** $Id: lparser.c,v 2.128 2012/05/20 14:51:23 roberto Exp $
3 ** Lua Parser
4 ** See Copyright Notice in lua.h
5 */
6
7
8 #include <string.h>
9
10 #define lparser_c
11 #define LUA_CORE
12
13 #include "lua.h"
14
15 #include "lcode.h"
16 #include "ldebug.h"
17 #include "ldo.h"
18 #include "lfunc.h"
19 #include "llex.h"
20 #include "lmem.h"
21 #include "lobject.h"
22 #include "lopcodes.h"
23 #include "lparser.h"
24 #include "lstate.h"
25 #include "lstring.h"
26 #include "ltable.h"
27
28
29
30 /* maximum number of local variables per function (must be smaller
31 than 250, due to the bytecode format) */
32 #define MAXVARS 200
33
34
35 #define hasmultret(k) ((k) == VCALL || (k) == VVARARG)
36
37
38
39 /*
40 ** nodes for block list (list of active blocks)
41 */
42 typedef struct BlockCnt {
43 struct BlockCnt *previous; /* chain */
44 short firstlabel; /* index of first label in this block */
45 short firstgoto; /* index of first pending goto in this block */
46 lu_byte nactvar; /* # active locals outside the block */
47 lu_byte upval; /* true if some variable in the block is an upvalue */
48 lu_byte isloop; /* true if `block' is a loop */
49 } BlockCnt;
50
51
52
53 /*
54 ** prototypes for recursive non-terminal functions
55 */
56 static void statement (LexState *ls);
57 static void expr (LexState *ls, expdesc *v);
58
59
60 static void anchor_token (LexState *ls) {
61 /* last token from outer function must be EOS */
62 lua_assert(ls->fs != NULL || ls->t.token == TK_EOS);
63 if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) {
64 TString *ts = ls->t.seminfo.ts;
65 luaX_newstring(ls, getstr(ts), ts->tsv.len);
66 }
67 }
68
69
70 /* semantic error */
71 static l_noret semerror (LexState *ls, const char *msg) {
72 ls->t.token = 0; /* remove 'near to' from final message */
73 luaX_syntaxerror(ls, msg);
74 }
75
76
77 static l_noret error_expected (LexState *ls, int token) {
78 luaX_syntaxerror(ls,
79 luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token)));
80 }
81
82
83 static l_noret errorlimit (FuncState *fs, int limit, const char *what) {
84 lua_State *L = fs->ls->L;
85 const char *msg;
86 int line = fs->f->linedefined;
87 const char *where = (line == 0)
88 ? "main function"
89 : luaO_pushfstring(L, "function at line %d", line);
90 msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s",
91 what, limit, where);
92 luaX_syntaxerror(fs->ls, msg);
93 }
94
95
96 static void checklimit (FuncState *fs, int v, int l, const char *what) {
97 if (v > l) errorlimit(fs, l, what);
98 }
99
100
101 static int testnext (LexState *ls, int c) {
102 if (ls->t.token == c) {
103 luaX_next(ls);
104 return 1;
105 }
106 else return 0;
107 }
108
109
110 static void check (LexState *ls, int c) {
111 if (ls->t.token != c)
112 error_expected(ls, c);
113 }
114
115
116 static void checknext (LexState *ls, int c) {
117 check(ls, c);
118 luaX_next(ls);
119 }
120
121
122 #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); }
123
124
125
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);
130 else {
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));
134 }
135 }
136 }
137
138
139 static TString *str_checkname (LexState *ls) {
140 TString *ts;
141 check(ls, TK_NAME);
142 ts = ls->t.seminfo.ts;
143 luaX_next(ls);
144 return ts;
145 }
146
147
148 static void init_exp (expdesc *e, expkind k, int i) {
149 e->f = e->t = NO_JUMP;
150 e->k = k;
151 e->u.info = i;
152 }
153
154
155 static void codestring (LexState *ls, expdesc *e, TString *s) {
156 init_exp(e, VK, luaK_stringK(ls->fs, s));
157 }
158
159
160 static void checkname (LexState *ls, expdesc *e) {
161 codestring(ls, e, str_checkname(ls));
162 }
163
164
165 static int registerlocalvar (LexState *ls, TString *varname) {
166 FuncState *fs = ls->fs;
167 Proto *f = fs->f;
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++;
175 }
176
177
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);
187 }
188
189
190 static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) {
191 new_localvar(ls, luaX_newstring(ls, name, sz));
192 }
193
194 #define new_localvarliteral(ls,v) \
195 new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1)
196
197
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];
202 }
203
204
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;
210 }
211 }
212
213
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;
218 }
219
220
221 static int searchupvalue (FuncState *fs, TString *name) {
222 int i;
223 Upvaldesc *up = fs->f->upvalues;
224 for (i = 0; i < fs->nups; i++) {
225 if (luaS_eqstr(up[i].name, name)) return i;
226 }
227 return -1; /* not found */
228 }
229
230
231 static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
232 Proto *f = fs->f;
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);
242 return fs->nups++;
243 }
244
245
246 static int searchvar (FuncState *fs, TString *n) {
247 int i;
248 for (i=fs->nactvar-1; i >= 0; i--) {
249 if (luaS_eqstr(n, getlocvar(fs, i)->varname))
250 return i;
251 }
252 return -1; /* not found */
253 }
254
255
256 /*
257 Mark block where variable at given level was defined
258 (to emit close instructions later).
259 */
260 static void markupval (FuncState *fs, int level) {
261 BlockCnt *bl = fs->bl;
262 while (bl->nactvar > level) bl = bl->previous;
263 bl->upval = 1;
264 }
265
266
267 /*
268 Find variable with given name 'n'. If it is an upvalue, add this
269 upvalue into all intermediate functions.
270 */
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 */
274 else {
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 */
278 if (!base)
279 markupval(fs, v); /* local will be used as an upval */
280 return VLOCAL;
281 }
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 */
289 }
290 init_exp(var, VUPVAL, idx);
291 return VUPVAL;
292 }
293 }
294 }
295
296
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? */
301 expdesc key;
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] */
306 }
307 }
308
309
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);
318 }
319 else {
320 if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */
321 if (extra > 0) {
322 int reg = fs->freereg;
323 luaK_reserveregs(fs, extra);
324 luaK_nil(fs, reg, extra);
325 }
326 }
327 }
328
329
330 static void enterlevel (LexState *ls) {
331 lua_State *L = ls->L;
332 ++L->nCcalls;
333 checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "C levels");
334 }
335
336
337 #define leavelevel(ls) ((ls)->L->nCcalls--)
338
339
340 static void closegoto (LexState *ls, int g, Labeldesc *label) {
341 int i;
342 FuncState *fs = ls->fs;
343 Labellist *gl = &ls->dyd->gt;
344 Labeldesc *gt = &gl->arr[g];
345 lua_assert(luaS_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 " LUA_QS,
350 getstr(gt->name), gt->line, getstr(vname));
351 semerror(ls, msg);
352 }
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];
357 gl->n--;
358 }
359
360
361 /*
362 ** try to close a goto with existing labels; this solves backward jumps
363 */
364 static int findlabel (LexState *ls, int g) {
365 int i;
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 (luaS_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 */
377 return 1;
378 }
379 }
380 return 0; /* label not found; cannot close goto */
381 }
382
383
384 static int newlabelentry (LexState *ls, Labellist *l, TString *name,
385 int line, int pc) {
386 int n = l->n;
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;
392 l->arr[n].pc = pc;
393 l->n++;
394 return n;
395 }
396
397
398 /*
399 ** check whether new label 'lb' matches any pending gotos in current
400 ** block; solves forward jumps
401 */
402 static void findgotos (LexState *ls, Labeldesc *lb) {
403 Labellist *gl = &ls->dyd->gt;
404 int i = ls->fs->bl->firstgoto;
405 while (i < gl->n) {
406 if (luaS_eqstr(gl->arr[i].name, lb->name))
407 closegoto(ls, i, lb);
408 else
409 i++;
410 }
411 }
412
413
414 /*
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.
419 */
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 */
425 while (i < gl->n) {
426 Labeldesc *gt = &gl->arr[i];
427 if (gt->nactvar > bl->nactvar) {
428 if (bl->upval)
429 luaK_patchclose(fs, gt->pc, bl->nactvar);
430 gt->nactvar = bl->nactvar;
431 }
432 if (!findlabel(fs->ls, i))
433 i++; /* move to next one */
434 }
435 }
436
437
438 static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) {
439 bl->isloop = isloop;
440 bl->nactvar = fs->nactvar;
441 bl->firstlabel = fs->ls->dyd->label.n;
442 bl->firstgoto = fs->ls->dyd->gt.n;
443 bl->upval = 0;
444 bl->previous = fs->bl;
445 fs->bl = bl;
446 lua_assert(fs->freereg == fs->nactvar);
447 }
448
449
450 /*
451 ** create a label named "break" to resolve break statements
452 */
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]);
457 }
458
459 /*
460 ** generates an error for an undefined 'goto'; choose appropriate
461 ** message when label name is a reserved word (which can only be 'break')
462 */
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 " LUA_QS " for <goto> at line %d";
467 msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line);
468 semerror(ls, msg);
469 }
470
471
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);
480 }
481 if (bl->isloop)
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 */
492 }
493
494
495 /*
496 ** adds a new prototype into list of prototypes
497 */
498 static Proto *addprototype (LexState *ls) {
499 Proto *clp;
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;
507 }
508 f->p[fs->np++] = clp = luaF_newproto(L);
509 luaC_objbarrier(L, f, clp);
510 return clp;
511 }
512
513
514 /*
515 ** codes instruction to create new closure in parent function
516 */
517 static void codeclosure (LexState *ls, expdesc *v) {
518 FuncState *fs = ls->fs->prev;
519 init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1));
520 luaK_exp2nextreg(fs, v); /* fix it at stack top (for GC) */
521 }
522
523
524 static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
525 lua_State *L = ls->L;
526 Proto *f;
527 fs->prev = ls->fs; /* linked list of funcstates */
528 fs->ls = ls;
529 ls->fs = fs;
530 fs->pc = 0;
531 fs->lasttarget = 0;
532 fs->jpc = NO_JUMP;
533 fs->freereg = 0;
534 fs->nk = 0;
535 fs->np = 0;
536 fs->nups = 0;
537 fs->nlocvars = 0;
538 fs->nactvar = 0;
539 fs->firstlocal = ls->dyd->actvar.n;
540 fs->bl = NULL;
541 f = fs->f;
542 f->source = ls->source;
543 f->maxstacksize = 2; /* registers 0/1 are always valid */
544 fs->h = luaH_new(L);
545 /* anchor table of constants (to avoid being collected) */
546 sethvalue2s(L, L->top, fs->h);
547 incr_top(L);
548 enterblock(fs, bl, 0);
549 }
550
551
552 static void close_func (LexState *ls) {
553 lua_State *L = ls->L;
554 FuncState *fs = ls->fs;
555 Proto *f = fs->f;
556 luaK_ret(fs, 0, 0); /* final return */
557 leaveblock(fs);
558 luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
559 f->sizecode = fs->pc;
560 luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
561 f->sizelineinfo = fs->pc;
562 luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
563 f->sizek = fs->nk;
564 luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
565 f->sizep = fs->np;
566 luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
567 f->sizelocvars = fs->nlocvars;
568 luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc);
569 f->sizeupvalues = fs->nups;
570 lua_assert(fs->bl == NULL);
571 ls->fs = fs->prev;
572 /* last token read was anchored in defunct function; must re-anchor it */
573 anchor_token(ls);
574 L->top--; /* pop table of constants */
575 luaC_checkGC(L);
576 }
577
578
579
580 /*============================================================*/
581 /* GRAMMAR RULES */
582 /*============================================================*/
583
584
585 /*
586 ** check whether current token is in the follow set of a block.
587 ** 'until' closes syntactical blocks, but do not close scope,
588 ** so it handled in separate.
589 */
590 static int block_follow (LexState *ls, int withuntil) {
591 switch (ls->t.token) {
592 case TK_ELSE: case TK_ELSEIF:
593 case TK_END: case TK_EOS:
594 return 1;
595 case TK_UNTIL: return withuntil;
596 default: return 0;
597 }
598 }
599
600
601 static void statlist (LexState *ls) {
602 /* statlist -> { stat [`;'] } */
603 while (!block_follow(ls, 1)) {
604 if (ls->t.token == TK_RETURN) {
605 statement(ls);
606 return; /* 'return' must be last statement */
607 }
608 statement(ls);
609 }
610 }
611
612
613 static void fieldsel (LexState *ls, expdesc *v) {
614 /* fieldsel -> ['.' | ':'] NAME */
615 FuncState *fs = ls->fs;
616 expdesc key;
617 luaK_exp2anyregup(fs, v);
618 luaX_next(ls); /* skip the dot or colon */
619 checkname(ls, &key);
620 luaK_indexed(fs, v, &key);
621 }
622
623
624 static void yindex (LexState *ls, expdesc *v) {
625 /* index -> '[' expr ']' */
626 luaX_next(ls); /* skip the '[' */
627 expr(ls, v);
628 luaK_exp2val(ls->fs, v);
629 checknext(ls, ']');
630 }
631
632
633 /*
634 ** {======================================================================
635 ** Rules for Constructors
636 ** =======================================================================
637 */
638
639
640 struct ConsControl {
641 expdesc v; /* last list item read */
642 expdesc *t; /* table descriptor */
643 int nh; /* total number of `record' elements */
644 int na; /* total number of array elements */
645 int tostore; /* number of array elements pending to be stored */
646 };
647
648
649 static void recfield (LexState *ls, struct ConsControl *cc) {
650 /* recfield -> (NAME | `['exp1`]') = exp1 */
651 FuncState *fs = ls->fs;
652 int reg = ls->fs->freereg;
653 expdesc key, val;
654 int rkkey;
655 if (ls->t.token == TK_NAME) {
656 checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
657 checkname(ls, &key);
658 }
659 else /* ls->t.token == '[' */
660 yindex(ls, &key);
661 cc->nh++;
662 checknext(ls, '=');
663 rkkey = luaK_exp2RK(fs, &key);
664 expr(ls, &val);
665 luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val));
666 fs->freereg = reg; /* free registers */
667 }
668
669
670 static void closelistfield (FuncState *fs, struct ConsControl *cc) {
671 if (cc->v.k == VVOID) return; /* there is no list item */
672 luaK_exp2nextreg(fs, &cc->v);
673 cc->v.k = VVOID;
674 if (cc->tostore == LFIELDS_PER_FLUSH) {
675 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); /* flush */
676 cc->tostore = 0; /* no more items pending */
677 }
678 }
679
680
681 static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
682 if (cc->tostore == 0) return;
683 if (hasmultret(cc->v.k)) {
684 luaK_setmultret(fs, &cc->v);
685 luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET);
686 cc->na--; /* do not count last expression (unknown number of elements) */
687 }
688 else {
689 if (cc->v.k != VVOID)
690 luaK_exp2nextreg(fs, &cc->v);
691 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);
692 }
693 }
694
695
696 static void listfield (LexState *ls, struct ConsControl *cc) {
697 /* listfield -> exp */
698 expr(ls, &cc->v);
699 checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
700 cc->na++;
701 cc->tostore++;
702 }
703
704
705 static void field (LexState *ls, struct ConsControl *cc) {
706 /* field -> listfield | recfield */
707 switch(ls->t.token) {
708 case TK_NAME: { /* may be 'listfield' or 'recfield' */
709 if (luaX_lookahead(ls) != '=') /* expression? */
710 listfield(ls, cc);
711 else
712 recfield(ls, cc);
713 break;
714 }
715 case '[': {
716 recfield(ls, cc);
717 break;
718 }
719 default: {
720 listfield(ls, cc);
721 break;
722 }
723 }
724 }
725
726
727 static void constructor (LexState *ls, expdesc *t) {
728 /* constructor -> '{' [ field { sep field } [sep] ] '}'
729 sep -> ',' | ';' */
730 FuncState *fs = ls->fs;
731 int line = ls->linenumber;
732 int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
733 struct ConsControl cc;
734 cc.na = cc.nh = cc.tostore = 0;
735 cc.t = t;
736 init_exp(t, VRELOCABLE, pc);
737 init_exp(&cc.v, VVOID, 0); /* no value (yet) */
738 luaK_exp2nextreg(ls->fs, t); /* fix it at stack top */
739 checknext(ls, '{');
740 do {
741 lua_assert(cc.v.k == VVOID || cc.tostore > 0);
742 if (ls->t.token == '}') break;
743 closelistfield(fs, &cc);
744 field(ls, &cc);
745 } while (testnext(ls, ',') || testnext(ls, ';'));
746 check_match(ls, '}', '{', line);
747 lastlistfield(fs, &cc);
748 SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
749 SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */
750 }
751
752 /* }====================================================================== */
753
754
755
756 static void parlist (LexState *ls) {
757 /* parlist -> [ param { `,' param } ] */
758 FuncState *fs = ls->fs;
759 Proto *f = fs->f;
760 int nparams = 0;
761 f->is_vararg = 0;
762 if (ls->t.token != ')') { /* is `parlist' not empty? */
763 do {
764 switch (ls->t.token) {
765 case TK_NAME: { /* param -> NAME */
766 new_localvar(ls, str_checkname(ls));
767 nparams++;
768 break;
769 }
770 case TK_DOTS: { /* param -> `...' */
771 luaX_next(ls);
772 f->is_vararg = 1;
773 break;
774 }
775 default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected");
776 }
777 } while (!f->is_vararg && testnext(ls, ','));
778 }
779 adjustlocalvars(ls, nparams);
780 f->numparams = cast_byte(fs->nactvar);
781 luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */
782 }
783
784
785 static void body (LexState *ls, expdesc *e, int ismethod, int line) {
786 /* body -> `(' parlist `)' block END */
787 FuncState new_fs;
788 BlockCnt bl;
789 new_fs.f = addprototype(ls);
790 new_fs.f->linedefined = line;
791 open_func(ls, &new_fs, &bl);
792 checknext(ls, '(');
793 if (ismethod) {
794 new_localvarliteral(ls, "self"); /* create 'self' parameter */
795 adjustlocalvars(ls, 1);
796 }
797 parlist(ls);
798 checknext(ls, ')');
799 statlist(ls);
800 new_fs.f->lastlinedefined = ls->linenumber;
801 check_match(ls, TK_END, TK_FUNCTION, line);
802 codeclosure(ls, e);
803 close_func(ls);
804 }
805
806
807 static int explist (LexState *ls, expdesc *v) {
808 /* explist -> expr { `,' expr } */
809 int n = 1; /* at least one expression */
810 expr(ls, v);
811 while (testnext(ls, ',')) {
812 luaK_exp2nextreg(ls->fs, v);
813 expr(ls, v);
814 n++;
815 }
816 return n;
817 }
818
819
820 static void funcargs (LexState *ls, expdesc *f, int line) {
821 FuncState *fs = ls->fs;
822 expdesc args;
823 int base, nparams;
824 switch (ls->t.token) {
825 case '(': { /* funcargs -> `(' [ explist ] `)' */
826 luaX_next(ls);
827 if (ls->t.token == ')') /* arg list is empty? */
828 args.k = VVOID;
829 else {
830 explist(ls, &args);
831 luaK_setmultret(fs, &args);
832 }
833 check_match(ls, ')', '(', line);
834 break;
835 }
836 case '{': { /* funcargs -> constructor */
837 constructor(ls, &args);
838 break;
839 }
840 case TK_STRING: { /* funcargs -> STRING */
841 codestring(ls, &args, ls->t.seminfo.ts);
842 luaX_next(ls); /* must use `seminfo' before `next' */
843 break;
844 }
845 default: {
846 luaX_syntaxerror(ls, "function arguments expected");
847 }
848 }
849 lua_assert(f->k == VNONRELOC);
850 base = f->u.info; /* base register for call */
851 if (hasmultret(args.k))
852 nparams = LUA_MULTRET; /* open call */
853 else {
854 if (args.k != VVOID)
855 luaK_exp2nextreg(fs, &args); /* close last argument */
856 nparams = fs->freereg - (base+1);
857 }
858 init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
859 luaK_fixline(fs, line);
860 fs->freereg = base+1; /* call remove function and arguments and leaves
861 (unless changed) one result */
862 }
863
864
865
866
867 /*
868 ** {======================================================================
869 ** Expression parsing
870 ** =======================================================================
871 */
872
873
874 static void primaryexp (LexState *ls, expdesc *v) {
875 /* primaryexp -> NAME | '(' expr ')' */
876 switch (ls->t.token) {
877 case '(': {
878 int line = ls->linenumber;
879 luaX_next(ls);
880 expr(ls, v);
881 check_match(ls, ')', '(', line);
882 luaK_dischargevars(ls->fs, v);
883 return;
884 }
885 case TK_NAME: {
886 singlevar(ls, v);
887 return;
888 }
889 default: {
890 luaX_syntaxerror(ls, "unexpected symbol");
891 }
892 }
893 }
894
895
896 static void suffixedexp (LexState *ls, expdesc *v) {
897 /* suffixedexp ->
898 primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */
899 FuncState *fs = ls->fs;
900 int line = ls->linenumber;
901 primaryexp(ls, v);
902 for (;;) {
903 switch (ls->t.token) {
904 case '.': { /* fieldsel */
905 fieldsel(ls, v);
906 break;
907 }
908 case '[': { /* `[' exp1 `]' */
909 expdesc key;
910 luaK_exp2anyregup(fs, v);
911 yindex(ls, &key);
912 luaK_indexed(fs, v, &key);
913 break;
914 }
915 case ':': { /* `:' NAME funcargs */
916 expdesc key;
917 luaX_next(ls);
918 checkname(ls, &key);
919 luaK_self(fs, v, &key);
920 funcargs(ls, v, line);
921 break;
922 }
923 case '(': case TK_STRING: case '{': { /* funcargs */
924 luaK_exp2nextreg(fs, v);
925 funcargs(ls, v, line);
926 break;
927 }
928 default: return;
929 }
930 }
931 }
932
933
934 static void simpleexp (LexState *ls, expdesc *v) {
935 /* simpleexp -> NUMBER | STRING | NIL | TRUE | FALSE | ... |
936 constructor | FUNCTION body | suffixedexp */
937 switch (ls->t.token) {
938 case TK_NUMBER: {
939 init_exp(v, VKNUM, 0);
940 v->u.nval = ls->t.seminfo.r;
941 break;
942 }
943 case TK_STRING: {
944 codestring(ls, v, ls->t.seminfo.ts);
945 break;
946 }
947 case TK_NIL: {
948 init_exp(v, VNIL, 0);
949 break;
950 }
951 case TK_TRUE: {
952 init_exp(v, VTRUE, 0);
953 break;
954 }
955 case TK_FALSE: {
956 init_exp(v, VFALSE, 0);
957 break;
958 }
959 case TK_DOTS: { /* vararg */
960 FuncState *fs = ls->fs;
961 check_condition(ls, fs->f->is_vararg,
962 "cannot use " LUA_QL("...") " outside a vararg function");
963 init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
964 break;
965 }
966 case '{': { /* constructor */
967 constructor(ls, v);
968 return;
969 }
970 case TK_FUNCTION: {
971 luaX_next(ls);
972 body(ls, v, 0, ls->linenumber);
973 return;
974 }
975 default: {
976 suffixedexp(ls, v);
977 return;
978 }
979 }
980 luaX_next(ls);
981 }
982
983
984 static UnOpr getunopr (int op) {
985 switch (op) {
986 case TK_NOT: return OPR_NOT;
987 case '-': return OPR_MINUS;
988 case '#': return OPR_LEN;
989 default: return OPR_NOUNOPR;
990 }
991 }
992
993
994 static BinOpr getbinopr (int op) {
995 switch (op) {
996 case '+': return OPR_ADD;
997 case '-': return OPR_SUB;
998 case '*': return OPR_MUL;
999 case '/': return OPR_DIV;
1000 case '%': return OPR_MOD;
1001 case '^': return OPR_POW;
1002 case TK_CONCAT: return OPR_CONCAT;
1003 case TK_NE: return OPR_NE;
1004 case TK_EQ: return OPR_EQ;
1005 case '<': return OPR_LT;
1006 case TK_LE: return OPR_LE;
1007 case '>': return OPR_GT;
1008 case TK_GE: return OPR_GE;
1009 case TK_AND: return OPR_AND;
1010 case TK_OR: return OPR_OR;
1011 default: return OPR_NOBINOPR;
1012 }
1013 }
1014
1015
1016 static const struct {
1017 lu_byte left; /* left priority for each binary operator */
1018 lu_byte right; /* right priority */
1019 } priority[] = { /* ORDER OPR */
1020 {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `*' `/' `%' */
1021 {10, 9}, {5, 4}, /* ^, .. (right associative) */
1022 {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */
1023 {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */
1024 {2, 2}, {1, 1} /* and, or */
1025 };
1026
1027 #define UNARY_PRIORITY 8 /* priority for unary operators */
1028
1029
1030 /*
1031 ** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
1032 ** where `binop' is any binary operator with a priority higher than `limit'
1033 */
1034 static BinOpr subexpr (LexState *ls, expdesc *v, int limit) {
1035 BinOpr op;
1036 UnOpr uop;
1037 enterlevel(ls);
1038 uop = getunopr(ls->t.token);
1039 if (uop != OPR_NOUNOPR) {
1040 int line = ls->linenumber;
1041 luaX_next(ls);
1042 subexpr(ls, v, UNARY_PRIORITY);
1043 luaK_prefix(ls->fs, uop, v, line);
1044 }
1045 else simpleexp(ls, v);
1046 /* expand while operators have priorities higher than `limit' */
1047 op = getbinopr(ls->t.token);
1048 while (op != OPR_NOBINOPR && priority[op].left > limit) {
1049 expdesc v2;
1050 BinOpr nextop;
1051 int line = ls->linenumber;
1052 luaX_next(ls);
1053 luaK_infix(ls->fs, op, v);
1054 /* read sub-expression with higher priority */
1055 nextop = subexpr(ls, &v2, priority[op].right);
1056 luaK_posfix(ls->fs, op, v, &v2, line);
1057 op = nextop;
1058 }
1059 leavelevel(ls);
1060 return op; /* return first untreated operator */
1061 }
1062
1063
1064 static void expr (LexState *ls, expdesc *v) {
1065 subexpr(ls, v, 0);
1066 }
1067
1068 /* }==================================================================== */
1069
1070
1071
1072 /*
1073 ** {======================================================================
1074 ** Rules for Statements
1075 ** =======================================================================
1076 */
1077
1078
1079 static void block (LexState *ls) {
1080 /* block -> statlist */
1081 FuncState *fs = ls->fs;
1082 BlockCnt bl;
1083 enterblock(fs, &bl, 0);
1084 statlist(ls);
1085 leaveblock(fs);
1086 }
1087
1088
1089 /*
1090 ** structure to chain all variables in the left-hand side of an
1091 ** assignment
1092 */
1093 struct LHS_assign {
1094 struct LHS_assign *prev;
1095 expdesc v; /* variable (global, local, upvalue, or indexed) */
1096 };
1097
1098
1099 /*
1100 ** check whether, in an assignment to an upvalue/local variable, the
1101 ** upvalue/local variable is begin used in a previous assignment to a
1102 ** table. If so, save original upvalue/local value in a safe place and
1103 ** use this safe copy in the previous assignment.
1104 */
1105 static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
1106 FuncState *fs = ls->fs;
1107 int extra = fs->freereg; /* eventual position to save local variable */
1108 int conflict = 0;
1109 for (; lh; lh = lh->prev) { /* check all previous assignments */
1110 if (lh->v.k == VINDEXED) { /* assigning to a table? */
1111 /* table is the upvalue/local being assigned now? */
1112 if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) {
1113 conflict = 1;
1114 lh->v.u.ind.vt = VLOCAL;
1115 lh->v.u.ind.t = extra; /* previous assignment will use safe copy */
1116 }
1117 /* index is the local being assigned? (index cannot be upvalue) */
1118 if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) {
1119 conflict = 1;
1120 lh->v.u.ind.idx = extra; /* previous assignment will use safe copy */
1121 }
1122 }
1123 }
1124 if (conflict) {
1125 /* copy upvalue/local value to a temporary (in position 'extra') */
1126 OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
1127 luaK_codeABC(fs, op, extra, v->u.info, 0);
1128 luaK_reserveregs(fs, 1);
1129 }
1130 }
1131
1132
1133 static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
1134 expdesc e;
1135 check_condition(ls, vkisvar(lh->v.k), "syntax error");
1136 if (testnext(ls, ',')) { /* assignment -> ',' suffixedexp assignment */
1137 struct LHS_assign nv;
1138 nv.prev = lh;
1139 suffixedexp(ls, &nv.v);
1140 if (nv.v.k != VINDEXED)
1141 check_conflict(ls, lh, &nv.v);
1142 checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS,
1143 "C levels");
1144 assignment(ls, &nv, nvars+1);
1145 }
1146 else { /* assignment -> `=' explist */
1147 int nexps;
1148 checknext(ls, '=');
1149 nexps = explist(ls, &e);
1150 if (nexps != nvars) {
1151 adjust_assign(ls, nvars, nexps, &e);
1152 if (nexps > nvars)
1153 ls->fs->freereg -= nexps - nvars; /* remove extra values */
1154 }
1155 else {
1156 luaK_setoneret(ls->fs, &e); /* close last expression */
1157 luaK_storevar(ls->fs, &lh->v, &e);
1158 return; /* avoid default */
1159 }
1160 }
1161 init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */
1162 luaK_storevar(ls->fs, &lh->v, &e);
1163 }
1164
1165
1166 static int cond (LexState *ls) {
1167 /* cond -> exp */
1168 expdesc v;
1169 expr(ls, &v); /* read condition */
1170 if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */
1171 luaK_goiftrue(ls->fs, &v);
1172 return v.f;
1173 }
1174
1175
1176 static void gotostat (LexState *ls, int pc) {
1177 int line = ls->linenumber;
1178 TString *label;
1179 int g;
1180 if (testnext(ls, TK_GOTO))
1181 label = str_checkname(ls);
1182 else {
1183 luaX_next(ls); /* skip break */
1184 label = luaS_new(ls->L, "break");
1185 }
1186 g = newlabelentry(ls, &ls->dyd->gt, label, line, pc);
1187 findlabel(ls, g); /* close it if label already defined */
1188 }
1189
1190
1191 /* check for repeated labels on the same block */
1192 static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) {
1193 int i;
1194 for (i = fs->bl->firstlabel; i < ll->n; i++) {
1195 if (luaS_eqstr(label, ll->arr[i].name)) {
1196 const char *msg = luaO_pushfstring(fs->ls->L,
1197 "label " LUA_QS " already defined on line %d",
1198 getstr(label), ll->arr[i].line);
1199 semerror(fs->ls, msg);
1200 }
1201 }
1202 }
1203
1204
1205 /* skip no-op statements */
1206 static void skipnoopstat (LexState *ls) {
1207 while (ls->t.token == ';' || ls->t.token == TK_DBCOLON)
1208 statement(ls);
1209 }
1210
1211
1212 static void labelstat (LexState *ls, TString *label, int line) {
1213 /* label -> '::' NAME '::' */
1214 FuncState *fs = ls->fs;
1215 Labellist *ll = &ls->dyd->label;
1216 int l; /* index of new label being created */
1217 checkrepeated(fs, ll, label); /* check for repeated labels */
1218 checknext(ls, TK_DBCOLON); /* skip double colon */
1219 /* create new entry for this label */
1220 l = newlabelentry(ls, ll, label, line, fs->pc);
1221 skipnoopstat(ls); /* skip other no-op statements */
1222 if (block_follow(ls, 0)) { /* label is last no-op statement in the block? */
1223 /* assume that locals are already out of scope */
1224 ll->arr[l].nactvar = fs->bl->nactvar;
1225 }
1226 findgotos(ls, &ll->arr[l]);
1227 }
1228
1229
1230 static void whilestat (LexState *ls, int line) {
1231 /* whilestat -> WHILE cond DO block END */
1232 FuncState *fs = ls->fs;
1233 int whileinit;
1234 int condexit;
1235 BlockCnt bl;
1236 luaX_next(ls); /* skip WHILE */
1237 whileinit = luaK_getlabel(fs);
1238 condexit = cond(ls);
1239 enterblock(fs, &bl, 1);
1240 checknext(ls, TK_DO);
1241 block(ls);
1242 luaK_jumpto(fs, whileinit);
1243 check_match(ls, TK_END, TK_WHILE, line);
1244 leaveblock(fs);
1245 luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
1246 }
1247
1248
1249 static void repeatstat (LexState *ls, int line) {
1250 /* repeatstat -> REPEAT block UNTIL cond */
1251 int condexit;
1252 FuncState *fs = ls->fs;
1253 int repeat_init = luaK_getlabel(fs);
1254 BlockCnt bl1, bl2;
1255 enterblock(fs, &bl1, 1); /* loop block */
1256 enterblock(fs, &bl2, 0); /* scope block */
1257 luaX_next(ls); /* skip REPEAT */
1258 statlist(ls);
1259 check_match(ls, TK_UNTIL, TK_REPEAT, line);
1260 condexit = cond(ls); /* read condition (inside scope block) */
1261 if (bl2.upval) /* upvalues? */
1262 luaK_patchclose(fs, condexit, bl2.nactvar);
1263 leaveblock(fs); /* finish scope */
1264 luaK_patchlist(fs, condexit, repeat_init); /* close the loop */
1265 leaveblock(fs); /* finish loop */
1266 }
1267
1268
1269 static int exp1 (LexState *ls) {
1270 expdesc e;
1271 int reg;
1272 expr(ls, &e);
1273 luaK_exp2nextreg(ls->fs, &e);
1274 lua_assert(e.k == VNONRELOC);
1275 reg = e.u.info;
1276 return reg;
1277 }
1278
1279
1280 static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
1281 /* forbody -> DO block */
1282 BlockCnt bl;
1283 FuncState *fs = ls->fs;
1284 int prep, endfor;
1285 adjustlocalvars(ls, 3); /* control variables */
1286 checknext(ls, TK_DO);
1287 prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
1288 enterblock(fs, &bl, 0); /* scope for declared variables */
1289 adjustlocalvars(ls, nvars);
1290 luaK_reserveregs(fs, nvars);
1291 block(ls);
1292 leaveblock(fs); /* end of scope for declared variables */
1293 luaK_patchtohere(fs, prep);
1294 if (isnum) /* numeric for? */
1295 endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP);
1296 else { /* generic for */
1297 luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
1298 luaK_fixline(fs, line);
1299 endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP);
1300 }
1301 luaK_patchlist(fs, endfor, prep + 1);
1302 luaK_fixline(fs, line);
1303 }
1304
1305
1306 static void fornum (LexState *ls, TString *varname, int line) {
1307 /* fornum -> NAME = exp1,exp1[,exp1] forbody */
1308 FuncState *fs = ls->fs;
1309 int base = fs->freereg;
1310 new_localvarliteral(ls, "(for index)");
1311 new_localvarliteral(ls, "(for limit)");
1312 new_localvarliteral(ls, "(for step)");
1313 new_localvar(ls, varname);
1314 checknext(ls, '=');
1315 exp1(ls); /* initial value */
1316 checknext(ls, ',');
1317 exp1(ls); /* limit */
1318 if (testnext(ls, ','))
1319 exp1(ls); /* optional step */
1320 else { /* default step = 1 */
1321 luaK_codek(fs, fs->freereg, luaK_numberK(fs, 1));
1322 luaK_reserveregs(fs, 1);
1323 }
1324 forbody(ls, base, line, 1, 1);
1325 }
1326
1327
1328 static void forlist (LexState *ls, TString *indexname) {
1329 /* forlist -> NAME {,NAME} IN explist forbody */
1330 FuncState *fs = ls->fs;
1331 expdesc e;
1332 int nvars = 4; /* gen, state, control, plus at least one declared var */
1333 int line;
1334 int base = fs->freereg;
1335 /* create control variables */
1336 new_localvarliteral(ls, "(for generator)");
1337 new_localvarliteral(ls, "(for state)");
1338 new_localvarliteral(ls, "(for control)");
1339 /* create declared variables */
1340 new_localvar(ls, indexname);
1341 while (testnext(ls, ',')) {
1342 new_localvar(ls, str_checkname(ls));
1343 nvars++;
1344 }
1345 checknext(ls, TK_IN);
1346 line = ls->linenumber;
1347 adjust_assign(ls, 3, explist(ls, &e), &e);
1348 luaK_checkstack(fs, 3); /* extra space to call generator */
1349 forbody(ls, base, line, nvars - 3, 0);
1350 }
1351
1352
1353 static void forstat (LexState *ls, int line) {
1354 /* forstat -> FOR (fornum | forlist) END */
1355 FuncState *fs = ls->fs;
1356 TString *varname;
1357 BlockCnt bl;
1358 enterblock(fs, &bl, 1); /* scope for loop and control variables */
1359 luaX_next(ls); /* skip `for' */
1360 varname = str_checkname(ls); /* first variable name */
1361 switch (ls->t.token) {
1362 case '=': fornum(ls, varname, line); break;
1363 case ',': case TK_IN: forlist(ls, varname); break;
1364 default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected");
1365 }
1366 check_match(ls, TK_END, TK_FOR, line);
1367 leaveblock(fs); /* loop scope (`break' jumps to this point) */
1368 }
1369
1370
1371 static void test_then_block (LexState *ls, int *escapelist) {
1372 /* test_then_block -> [IF | ELSEIF] cond THEN block */
1373 BlockCnt bl;
1374 FuncState *fs = ls->fs;
1375 expdesc v;
1376 int jf; /* instruction to skip 'then' code (if condition is false) */
1377 luaX_next(ls); /* skip IF or ELSEIF */
1378 expr(ls, &v); /* read condition */
1379 checknext(ls, TK_THEN);
1380 if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) {
1381 luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */
1382 enterblock(fs, &bl, 0); /* must enter block before 'goto' */
1383 gotostat(ls, v.t); /* handle goto/break */
1384 skipnoopstat(ls); /* skip other no-op statements */
1385 if (block_follow(ls, 0)) { /* 'goto' is the entire block? */
1386 leaveblock(fs);
1387 return; /* and that is it */
1388 }
1389 else /* must skip over 'then' part if condition is false */
1390 jf = luaK_jump(fs);
1391 }
1392 else { /* regular case (not goto/break) */
1393 luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */
1394 enterblock(fs, &bl, 0);
1395 jf = v.f;
1396 }
1397 statlist(ls); /* `then' part */
1398 leaveblock(fs);
1399 if (ls->t.token == TK_ELSE ||
1400 ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */
1401 luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */
1402 luaK_patchtohere(fs, jf);
1403 }
1404
1405
1406 static void ifstat (LexState *ls, int line) {
1407 /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
1408 FuncState *fs = ls->fs;
1409 int escapelist = NO_JUMP; /* exit list for finished parts */
1410 test_then_block(ls, &escapelist); /* IF cond THEN block */
1411 while (ls->t.token == TK_ELSEIF)
1412 test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */
1413 if (testnext(ls, TK_ELSE))
1414 block(ls); /* `else' part */
1415 check_match(ls, TK_END, TK_IF, line);
1416 luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */
1417 }
1418
1419
1420 static void localfunc (LexState *ls) {
1421 expdesc b;
1422 FuncState *fs = ls->fs;
1423 new_localvar(ls, str_checkname(ls)); /* new local variable */
1424 adjustlocalvars(ls, 1); /* enter its scope */
1425 body(ls, &b, 0, ls->linenumber); /* function created in next register */
1426 /* debug information will only see the variable after this point! */
1427 getlocvar(fs, b.u.info)->startpc = fs->pc;
1428 }
1429
1430
1431 static void localstat (LexState *ls) {
1432 /* stat -> LOCAL NAME {`,' NAME} [`=' explist] */
1433 int nvars = 0;
1434 int nexps;
1435 expdesc e;
1436 do {
1437 new_localvar(ls, str_checkname(ls));
1438 nvars++;
1439 } while (testnext(ls, ','));
1440 if (testnext(ls, '='))
1441 nexps = explist(ls, &e);
1442 else {
1443 e.k = VVOID;
1444 nexps = 0;
1445 }
1446 adjust_assign(ls, nvars, nexps, &e);
1447 adjustlocalvars(ls, nvars);
1448 }
1449
1450
1451 static int funcname (LexState *ls, expdesc *v) {
1452 /* funcname -> NAME {fieldsel} [`:' NAME] */
1453 int ismethod = 0;
1454 singlevar(ls, v);
1455 while (ls->t.token == '.')
1456 fieldsel(ls, v);
1457 if (ls->t.token == ':') {
1458 ismethod = 1;
1459 fieldsel(ls, v);
1460 }
1461 return ismethod;
1462 }
1463
1464
1465 static void funcstat (LexState *ls, int line) {
1466 /* funcstat -> FUNCTION funcname body */
1467 int ismethod;
1468 expdesc v, b;
1469 luaX_next(ls); /* skip FUNCTION */
1470 ismethod = funcname(ls, &v);
1471 body(ls, &b, ismethod, line);
1472 luaK_storevar(ls->fs, &v, &b);
1473 luaK_fixline(ls->fs, line); /* definition `happens' in the first line */
1474 }
1475
1476
1477 static void exprstat (LexState *ls) {
1478 /* stat -> func | assignment */
1479 FuncState *fs = ls->fs;
1480 struct LHS_assign v;
1481 suffixedexp(ls, &v.v);
1482 if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */
1483 v.prev = NULL;
1484 assignment(ls, &v, 1);
1485 }
1486 else { /* stat -> func */
1487 check_condition(ls, v.v.k == VCALL, "syntax error");
1488 SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */
1489 }
1490 }
1491
1492
1493 static void retstat (LexState *ls) {
1494 /* stat -> RETURN [explist] [';'] */
1495 FuncState *fs = ls->fs;
1496 expdesc e;
1497 int first, nret; /* registers with returned values */
1498 if (block_follow(ls, 1) || ls->t.token == ';')
1499 first = nret = 0; /* return no values */
1500 else {
1501 nret = explist(ls, &e); /* optional return values */
1502 if (hasmultret(e.k)) {
1503 luaK_setmultret(fs, &e);
1504 if (e.k == VCALL && nret == 1) { /* tail call? */
1505 SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
1506 lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
1507 }
1508 first = fs->nactvar;
1509 nret = LUA_MULTRET; /* return all values */
1510 }
1511 else {
1512 if (nret == 1) /* only one single value? */
1513 first = luaK_exp2anyreg(fs, &e);
1514 else {
1515 luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */
1516 first = fs->nactvar; /* return all `active' values */
1517 lua_assert(nret == fs->freereg - first);
1518 }
1519 }
1520 }
1521 luaK_ret(fs, first, nret);
1522 testnext(ls, ';'); /* skip optional semicolon */
1523 }
1524
1525
1526 static void statement (LexState *ls) {
1527 int line = ls->linenumber; /* may be needed for error messages */
1528 enterlevel(ls);
1529 switch (ls->t.token) {
1530 case ';': { /* stat -> ';' (empty statement) */
1531 luaX_next(ls); /* skip ';' */
1532 break;
1533 }
1534 case TK_IF: { /* stat -> ifstat */
1535 ifstat(ls, line);
1536 break;
1537 }
1538 case TK_WHILE: { /* stat -> whilestat */
1539 whilestat(ls, line);
1540 break;
1541 }
1542 case TK_DO: { /* stat -> DO block END */
1543 luaX_next(ls); /* skip DO */
1544 block(ls);
1545 check_match(ls, TK_END, TK_DO, line);
1546 break;
1547 }
1548 case TK_FOR: { /* stat -> forstat */
1549 forstat(ls, line);
1550 break;
1551 }
1552 case TK_REPEAT: { /* stat -> repeatstat */
1553 repeatstat(ls, line);
1554 break;
1555 }
1556 case TK_FUNCTION: { /* stat -> funcstat */
1557 funcstat(ls, line);
1558 break;
1559 }
1560 case TK_LOCAL: { /* stat -> localstat */
1561 luaX_next(ls); /* skip LOCAL */
1562 if (testnext(ls, TK_FUNCTION)) /* local function? */
1563 localfunc(ls);
1564 else
1565 localstat(ls);
1566 break;
1567 }
1568 case TK_DBCOLON: { /* stat -> label */
1569 luaX_next(ls); /* skip double colon */
1570 labelstat(ls, str_checkname(ls), line);
1571 break;
1572 }
1573 case TK_RETURN: { /* stat -> retstat */
1574 luaX_next(ls); /* skip RETURN */
1575 retstat(ls);
1576 break;
1577 }
1578 case TK_BREAK: /* stat -> breakstat */
1579 case TK_GOTO: { /* stat -> 'goto' NAME */
1580 gotostat(ls, luaK_jump(ls->fs));
1581 break;
1582 }
1583 default: { /* stat -> func | assignment */
1584 exprstat(ls);
1585 break;
1586 }
1587 }
1588 lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
1589 ls->fs->freereg >= ls->fs->nactvar);
1590 ls->fs->freereg = ls->fs->nactvar; /* free registers */
1591 leavelevel(ls);
1592 }
1593
1594 /* }====================================================================== */
1595
1596
1597 /*
1598 ** compiles the main function, which is a regular vararg function with an
1599 ** upvalue named LUA_ENV
1600 */
1601 static void mainfunc (LexState *ls, FuncState *fs) {
1602 BlockCnt bl;
1603 expdesc v;
1604 open_func(ls, fs, &bl);
1605 fs->f->is_vararg = 1; /* main function is always vararg */
1606 init_exp(&v, VLOCAL, 0); /* create and... */
1607 newupvalue(fs, ls->envn, &v); /* ...set environment upvalue */
1608 luaX_next(ls); /* read first token */
1609 statlist(ls); /* parse main body */
1610 check(ls, TK_EOS);
1611 close_func(ls);
1612 }
1613
1614
1615 Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
1616 Dyndata *dyd, const char *name, int firstchar) {
1617 LexState lexstate;
1618 FuncState funcstate;
1619 Closure *cl = luaF_newLclosure(L, 1); /* create main closure */
1620 /* anchor closure (to avoid being collected) */
1621 setclLvalue(L, L->top, cl);
1622 incr_top(L);
1623 funcstate.f = cl->l.p = luaF_newproto(L);
1624 funcstate.f->source = luaS_new(L, name); /* create and anchor TString */
1625 lexstate.buff = buff;
1626 lexstate.dyd = dyd;
1627 dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
1628 luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar);
1629 mainfunc(&lexstate, &funcstate);
1630 lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
1631 /* all scopes should be correctly finished */
1632 lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0);
1633 return cl; /* it's on the stack too */
1634 }
1635