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comparison lib/lua/lua-5.2.2/lparser.c @ 1866:41cc4dd3c122

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Lua 5.2.2 added.
author Nomad
date Wed, 16 Oct 2013 13:34:26 +0200
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1848:3b39b70e8e93 1866:41cc4dd3c122
1 /*
2 ** $Id: lparser.c,v 2.130 2013/02/06 13:37:39 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 = cast_int(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 ** 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.
519 */
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 */
524 }
525
526
527 static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
528 lua_State *L = ls->L;
529 Proto *f;
530 fs->prev = ls->fs; /* linked list of funcstates */
531 fs->ls = ls;
532 ls->fs = fs;
533 fs->pc = 0;
534 fs->lasttarget = 0;
535 fs->jpc = NO_JUMP;
536 fs->freereg = 0;
537 fs->nk = 0;
538 fs->np = 0;
539 fs->nups = 0;
540 fs->nlocvars = 0;
541 fs->nactvar = 0;
542 fs->firstlocal = ls->dyd->actvar.n;
543 fs->bl = NULL;
544 f = fs->f;
545 f->source = ls->source;
546 f->maxstacksize = 2; /* registers 0/1 are always valid */
547 fs->h = luaH_new(L);
548 /* anchor table of constants (to avoid being collected) */
549 sethvalue2s(L, L->top, fs->h);
550 incr_top(L);
551 enterblock(fs, bl, 0);
552 }
553
554
555 static void close_func (LexState *ls) {
556 lua_State *L = ls->L;
557 FuncState *fs = ls->fs;
558 Proto *f = fs->f;
559 luaK_ret(fs, 0, 0); /* final return */
560 leaveblock(fs);
561 luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
562 f->sizecode = fs->pc;
563 luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
564 f->sizelineinfo = fs->pc;
565 luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
566 f->sizek = fs->nk;
567 luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
568 f->sizep = fs->np;
569 luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
570 f->sizelocvars = fs->nlocvars;
571 luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc);
572 f->sizeupvalues = fs->nups;
573 lua_assert(fs->bl == NULL);
574 ls->fs = fs->prev;
575 /* last token read was anchored in defunct function; must re-anchor it */
576 anchor_token(ls);
577 L->top--; /* pop table of constants */
578 luaC_checkGC(L);
579 }
580
581
582
583 /*============================================================*/
584 /* GRAMMAR RULES */
585 /*============================================================*/
586
587
588 /*
589 ** check whether current token is in the follow set of a block.
590 ** 'until' closes syntactical blocks, but do not close scope,
591 ** so it handled in separate.
592 */
593 static int block_follow (LexState *ls, int withuntil) {
594 switch (ls->t.token) {
595 case TK_ELSE: case TK_ELSEIF:
596 case TK_END: case TK_EOS:
597 return 1;
598 case TK_UNTIL: return withuntil;
599 default: return 0;
600 }
601 }
602
603
604 static void statlist (LexState *ls) {
605 /* statlist -> { stat [`;'] } */
606 while (!block_follow(ls, 1)) {
607 if (ls->t.token == TK_RETURN) {
608 statement(ls);
609 return; /* 'return' must be last statement */
610 }
611 statement(ls);
612 }
613 }
614
615
616 static void fieldsel (LexState *ls, expdesc *v) {
617 /* fieldsel -> ['.' | ':'] NAME */
618 FuncState *fs = ls->fs;
619 expdesc key;
620 luaK_exp2anyregup(fs, v);
621 luaX_next(ls); /* skip the dot or colon */
622 checkname(ls, &key);
623 luaK_indexed(fs, v, &key);
624 }
625
626
627 static void yindex (LexState *ls, expdesc *v) {
628 /* index -> '[' expr ']' */
629 luaX_next(ls); /* skip the '[' */
630 expr(ls, v);
631 luaK_exp2val(ls->fs, v);
632 checknext(ls, ']');
633 }
634
635
636 /*
637 ** {======================================================================
638 ** Rules for Constructors
639 ** =======================================================================
640 */
641
642
643 struct ConsControl {
644 expdesc v; /* last list item read */
645 expdesc *t; /* table descriptor */
646 int nh; /* total number of `record' elements */
647 int na; /* total number of array elements */
648 int tostore; /* number of array elements pending to be stored */
649 };
650
651
652 static void recfield (LexState *ls, struct ConsControl *cc) {
653 /* recfield -> (NAME | `['exp1`]') = exp1 */
654 FuncState *fs = ls->fs;
655 int reg = ls->fs->freereg;
656 expdesc key, val;
657 int rkkey;
658 if (ls->t.token == TK_NAME) {
659 checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
660 checkname(ls, &key);
661 }
662 else /* ls->t.token == '[' */
663 yindex(ls, &key);
664 cc->nh++;
665 checknext(ls, '=');
666 rkkey = luaK_exp2RK(fs, &key);
667 expr(ls, &val);
668 luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val));
669 fs->freereg = reg; /* free registers */
670 }
671
672
673 static void closelistfield (FuncState *fs, struct ConsControl *cc) {
674 if (cc->v.k == VVOID) return; /* there is no list item */
675 luaK_exp2nextreg(fs, &cc->v);
676 cc->v.k = VVOID;
677 if (cc->tostore == LFIELDS_PER_FLUSH) {
678 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); /* flush */
679 cc->tostore = 0; /* no more items pending */
680 }
681 }
682
683
684 static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
685 if (cc->tostore == 0) return;
686 if (hasmultret(cc->v.k)) {
687 luaK_setmultret(fs, &cc->v);
688 luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET);
689 cc->na--; /* do not count last expression (unknown number of elements) */
690 }
691 else {
692 if (cc->v.k != VVOID)
693 luaK_exp2nextreg(fs, &cc->v);
694 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);
695 }
696 }
697
698
699 static void listfield (LexState *ls, struct ConsControl *cc) {
700 /* listfield -> exp */
701 expr(ls, &cc->v);
702 checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
703 cc->na++;
704 cc->tostore++;
705 }
706
707
708 static void field (LexState *ls, struct ConsControl *cc) {
709 /* field -> listfield | recfield */
710 switch(ls->t.token) {
711 case TK_NAME: { /* may be 'listfield' or 'recfield' */
712 if (luaX_lookahead(ls) != '=') /* expression? */
713 listfield(ls, cc);
714 else
715 recfield(ls, cc);
716 break;
717 }
718 case '[': {
719 recfield(ls, cc);
720 break;
721 }
722 default: {
723 listfield(ls, cc);
724 break;
725 }
726 }
727 }
728
729
730 static void constructor (LexState *ls, expdesc *t) {
731 /* constructor -> '{' [ field { sep field } [sep] ] '}'
732 sep -> ',' | ';' */
733 FuncState *fs = ls->fs;
734 int line = ls->linenumber;
735 int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
736 struct ConsControl cc;
737 cc.na = cc.nh = cc.tostore = 0;
738 cc.t = t;
739 init_exp(t, VRELOCABLE, pc);
740 init_exp(&cc.v, VVOID, 0); /* no value (yet) */
741 luaK_exp2nextreg(ls->fs, t); /* fix it at stack top */
742 checknext(ls, '{');
743 do {
744 lua_assert(cc.v.k == VVOID || cc.tostore > 0);
745 if (ls->t.token == '}') break;
746 closelistfield(fs, &cc);
747 field(ls, &cc);
748 } while (testnext(ls, ',') || testnext(ls, ';'));
749 check_match(ls, '}', '{', line);
750 lastlistfield(fs, &cc);
751 SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
752 SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */
753 }
754
755 /* }====================================================================== */
756
757
758
759 static void parlist (LexState *ls) {
760 /* parlist -> [ param { `,' param } ] */
761 FuncState *fs = ls->fs;
762 Proto *f = fs->f;
763 int nparams = 0;
764 f->is_vararg = 0;
765 if (ls->t.token != ')') { /* is `parlist' not empty? */
766 do {
767 switch (ls->t.token) {
768 case TK_NAME: { /* param -> NAME */
769 new_localvar(ls, str_checkname(ls));
770 nparams++;
771 break;
772 }
773 case TK_DOTS: { /* param -> `...' */
774 luaX_next(ls);
775 f->is_vararg = 1;
776 break;
777 }
778 default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected");
779 }
780 } while (!f->is_vararg && testnext(ls, ','));
781 }
782 adjustlocalvars(ls, nparams);
783 f->numparams = cast_byte(fs->nactvar);
784 luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */
785 }
786
787
788 static void body (LexState *ls, expdesc *e, int ismethod, int line) {
789 /* body -> `(' parlist `)' block END */
790 FuncState new_fs;
791 BlockCnt bl;
792 new_fs.f = addprototype(ls);
793 new_fs.f->linedefined = line;
794 open_func(ls, &new_fs, &bl);
795 checknext(ls, '(');
796 if (ismethod) {
797 new_localvarliteral(ls, "self"); /* create 'self' parameter */
798 adjustlocalvars(ls, 1);
799 }
800 parlist(ls);
801 checknext(ls, ')');
802 statlist(ls);
803 new_fs.f->lastlinedefined = ls->linenumber;
804 check_match(ls, TK_END, TK_FUNCTION, line);
805 codeclosure(ls, e);
806 close_func(ls);
807 }
808
809
810 static int explist (LexState *ls, expdesc *v) {
811 /* explist -> expr { `,' expr } */
812 int n = 1; /* at least one expression */
813 expr(ls, v);
814 while (testnext(ls, ',')) {
815 luaK_exp2nextreg(ls->fs, v);
816 expr(ls, v);
817 n++;
818 }
819 return n;
820 }
821
822
823 static void funcargs (LexState *ls, expdesc *f, int line) {
824 FuncState *fs = ls->fs;
825 expdesc args;
826 int base, nparams;
827 switch (ls->t.token) {
828 case '(': { /* funcargs -> `(' [ explist ] `)' */
829 luaX_next(ls);
830 if (ls->t.token == ')') /* arg list is empty? */
831 args.k = VVOID;
832 else {
833 explist(ls, &args);
834 luaK_setmultret(fs, &args);
835 }
836 check_match(ls, ')', '(', line);
837 break;
838 }
839 case '{': { /* funcargs -> constructor */
840 constructor(ls, &args);
841 break;
842 }
843 case TK_STRING: { /* funcargs -> STRING */
844 codestring(ls, &args, ls->t.seminfo.ts);
845 luaX_next(ls); /* must use `seminfo' before `next' */
846 break;
847 }
848 default: {
849 luaX_syntaxerror(ls, "function arguments expected");
850 }
851 }
852 lua_assert(f->k == VNONRELOC);
853 base = f->u.info; /* base register for call */
854 if (hasmultret(args.k))
855 nparams = LUA_MULTRET; /* open call */
856 else {
857 if (args.k != VVOID)
858 luaK_exp2nextreg(fs, &args); /* close last argument */
859 nparams = fs->freereg - (base+1);
860 }
861 init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
862 luaK_fixline(fs, line);
863 fs->freereg = base+1; /* call remove function and arguments and leaves
864 (unless changed) one result */
865 }
866
867
868
869
870 /*
871 ** {======================================================================
872 ** Expression parsing
873 ** =======================================================================
874 */
875
876
877 static void primaryexp (LexState *ls, expdesc *v) {
878 /* primaryexp -> NAME | '(' expr ')' */
879 switch (ls->t.token) {
880 case '(': {
881 int line = ls->linenumber;
882 luaX_next(ls);
883 expr(ls, v);
884 check_match(ls, ')', '(', line);
885 luaK_dischargevars(ls->fs, v);
886 return;
887 }
888 case TK_NAME: {
889 singlevar(ls, v);
890 return;
891 }
892 default: {
893 luaX_syntaxerror(ls, "unexpected symbol");
894 }
895 }
896 }
897
898
899 static void suffixedexp (LexState *ls, expdesc *v) {
900 /* suffixedexp ->
901 primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */
902 FuncState *fs = ls->fs;
903 int line = ls->linenumber;
904 primaryexp(ls, v);
905 for (;;) {
906 switch (ls->t.token) {
907 case '.': { /* fieldsel */
908 fieldsel(ls, v);
909 break;
910 }
911 case '[': { /* `[' exp1 `]' */
912 expdesc key;
913 luaK_exp2anyregup(fs, v);
914 yindex(ls, &key);
915 luaK_indexed(fs, v, &key);
916 break;
917 }
918 case ':': { /* `:' NAME funcargs */
919 expdesc key;
920 luaX_next(ls);
921 checkname(ls, &key);
922 luaK_self(fs, v, &key);
923 funcargs(ls, v, line);
924 break;
925 }
926 case '(': case TK_STRING: case '{': { /* funcargs */
927 luaK_exp2nextreg(fs, v);
928 funcargs(ls, v, line);
929 break;
930 }
931 default: return;
932 }
933 }
934 }
935
936
937 static void simpleexp (LexState *ls, expdesc *v) {
938 /* simpleexp -> NUMBER | STRING | NIL | TRUE | FALSE | ... |
939 constructor | FUNCTION body | suffixedexp */
940 switch (ls->t.token) {
941 case TK_NUMBER: {
942 init_exp(v, VKNUM, 0);
943 v->u.nval = ls->t.seminfo.r;
944 break;
945 }
946 case TK_STRING: {
947 codestring(ls, v, ls->t.seminfo.ts);
948 break;
949 }
950 case TK_NIL: {
951 init_exp(v, VNIL, 0);
952 break;
953 }
954 case TK_TRUE: {
955 init_exp(v, VTRUE, 0);
956 break;
957 }
958 case TK_FALSE: {
959 init_exp(v, VFALSE, 0);
960 break;
961 }
962 case TK_DOTS: { /* vararg */
963 FuncState *fs = ls->fs;
964 check_condition(ls, fs->f->is_vararg,
965 "cannot use " LUA_QL("...") " outside a vararg function");
966 init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
967 break;
968 }
969 case '{': { /* constructor */
970 constructor(ls, v);
971 return;
972 }
973 case TK_FUNCTION: {
974 luaX_next(ls);
975 body(ls, v, 0, ls->linenumber);
976 return;
977 }
978 default: {
979 suffixedexp(ls, v);
980 return;
981 }
982 }
983 luaX_next(ls);
984 }
985
986
987 static UnOpr getunopr (int op) {
988 switch (op) {
989 case TK_NOT: return OPR_NOT;
990 case '-': return OPR_MINUS;
991 case '#': return OPR_LEN;
992 default: return OPR_NOUNOPR;
993 }
994 }
995
996
997 static BinOpr getbinopr (int op) {
998 switch (op) {
999 case '+': return OPR_ADD;
1000 case '-': return OPR_SUB;
1001 case '*': return OPR_MUL;
1002 case '/': return OPR_DIV;
1003 case '%': return OPR_MOD;
1004 case '^': return OPR_POW;
1005 case TK_CONCAT: return OPR_CONCAT;
1006 case TK_NE: return OPR_NE;
1007 case TK_EQ: return OPR_EQ;
1008 case '<': return OPR_LT;
1009 case TK_LE: return OPR_LE;
1010 case '>': return OPR_GT;
1011 case TK_GE: return OPR_GE;
1012 case TK_AND: return OPR_AND;
1013 case TK_OR: return OPR_OR;
1014 default: return OPR_NOBINOPR;
1015 }
1016 }
1017
1018
1019 static const struct {
1020 lu_byte left; /* left priority for each binary operator */
1021 lu_byte right; /* right priority */
1022 } priority[] = { /* ORDER OPR */
1023 {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `*' `/' `%' */
1024 {10, 9}, {5, 4}, /* ^, .. (right associative) */
1025 {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */
1026 {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */
1027 {2, 2}, {1, 1} /* and, or */
1028 };
1029
1030 #define UNARY_PRIORITY 8 /* priority for unary operators */
1031
1032
1033 /*
1034 ** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
1035 ** where `binop' is any binary operator with a priority higher than `limit'
1036 */
1037 static BinOpr subexpr (LexState *ls, expdesc *v, int limit) {
1038 BinOpr op;
1039 UnOpr uop;
1040 enterlevel(ls);
1041 uop = getunopr(ls->t.token);
1042 if (uop != OPR_NOUNOPR) {
1043 int line = ls->linenumber;
1044 luaX_next(ls);
1045 subexpr(ls, v, UNARY_PRIORITY);
1046 luaK_prefix(ls->fs, uop, v, line);
1047 }
1048 else simpleexp(ls, v);
1049 /* expand while operators have priorities higher than `limit' */
1050 op = getbinopr(ls->t.token);
1051 while (op != OPR_NOBINOPR && priority[op].left > limit) {
1052 expdesc v2;
1053 BinOpr nextop;
1054 int line = ls->linenumber;
1055 luaX_next(ls);
1056 luaK_infix(ls->fs, op, v);
1057 /* read sub-expression with higher priority */
1058 nextop = subexpr(ls, &v2, priority[op].right);
1059 luaK_posfix(ls->fs, op, v, &v2, line);
1060 op = nextop;
1061 }
1062 leavelevel(ls);
1063 return op; /* return first untreated operator */
1064 }
1065
1066
1067 static void expr (LexState *ls, expdesc *v) {
1068 subexpr(ls, v, 0);
1069 }
1070
1071 /* }==================================================================== */
1072
1073
1074
1075 /*
1076 ** {======================================================================
1077 ** Rules for Statements
1078 ** =======================================================================
1079 */
1080
1081
1082 static void block (LexState *ls) {
1083 /* block -> statlist */
1084 FuncState *fs = ls->fs;
1085 BlockCnt bl;
1086 enterblock(fs, &bl, 0);
1087 statlist(ls);
1088 leaveblock(fs);
1089 }
1090
1091
1092 /*
1093 ** structure to chain all variables in the left-hand side of an
1094 ** assignment
1095 */
1096 struct LHS_assign {
1097 struct LHS_assign *prev;
1098 expdesc v; /* variable (global, local, upvalue, or indexed) */
1099 };
1100
1101
1102 /*
1103 ** check whether, in an assignment to an upvalue/local variable, the
1104 ** upvalue/local variable is begin used in a previous assignment to a
1105 ** table. If so, save original upvalue/local value in a safe place and
1106 ** use this safe copy in the previous assignment.
1107 */
1108 static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
1109 FuncState *fs = ls->fs;
1110 int extra = fs->freereg; /* eventual position to save local variable */
1111 int conflict = 0;
1112 for (; lh; lh = lh->prev) { /* check all previous assignments */
1113 if (lh->v.k == VINDEXED) { /* assigning to a table? */
1114 /* table is the upvalue/local being assigned now? */
1115 if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) {
1116 conflict = 1;
1117 lh->v.u.ind.vt = VLOCAL;
1118 lh->v.u.ind.t = extra; /* previous assignment will use safe copy */
1119 }
1120 /* index is the local being assigned? (index cannot be upvalue) */
1121 if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) {
1122 conflict = 1;
1123 lh->v.u.ind.idx = extra; /* previous assignment will use safe copy */
1124 }
1125 }
1126 }
1127 if (conflict) {
1128 /* copy upvalue/local value to a temporary (in position 'extra') */
1129 OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
1130 luaK_codeABC(fs, op, extra, v->u.info, 0);
1131 luaK_reserveregs(fs, 1);
1132 }
1133 }
1134
1135
1136 static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
1137 expdesc e;
1138 check_condition(ls, vkisvar(lh->v.k), "syntax error");
1139 if (testnext(ls, ',')) { /* assignment -> ',' suffixedexp assignment */
1140 struct LHS_assign nv;
1141 nv.prev = lh;
1142 suffixedexp(ls, &nv.v);
1143 if (nv.v.k != VINDEXED)
1144 check_conflict(ls, lh, &nv.v);
1145 checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS,
1146 "C levels");
1147 assignment(ls, &nv, nvars+1);
1148 }
1149 else { /* assignment -> `=' explist */
1150 int nexps;
1151 checknext(ls, '=');
1152 nexps = explist(ls, &e);
1153 if (nexps != nvars) {
1154 adjust_assign(ls, nvars, nexps, &e);
1155 if (nexps > nvars)
1156 ls->fs->freereg -= nexps - nvars; /* remove extra values */
1157 }
1158 else {
1159 luaK_setoneret(ls->fs, &e); /* close last expression */
1160 luaK_storevar(ls->fs, &lh->v, &e);
1161 return; /* avoid default */
1162 }
1163 }
1164 init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */
1165 luaK_storevar(ls->fs, &lh->v, &e);
1166 }
1167
1168
1169 static int cond (LexState *ls) {
1170 /* cond -> exp */
1171 expdesc v;
1172 expr(ls, &v); /* read condition */
1173 if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */
1174 luaK_goiftrue(ls->fs, &v);
1175 return v.f;
1176 }
1177
1178
1179 static void gotostat (LexState *ls, int pc) {
1180 int line = ls->linenumber;
1181 TString *label;
1182 int g;
1183 if (testnext(ls, TK_GOTO))
1184 label = str_checkname(ls);
1185 else {
1186 luaX_next(ls); /* skip break */
1187 label = luaS_new(ls->L, "break");
1188 }
1189 g = newlabelentry(ls, &ls->dyd->gt, label, line, pc);
1190 findlabel(ls, g); /* close it if label already defined */
1191 }
1192
1193
1194 /* check for repeated labels on the same block */
1195 static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) {
1196 int i;
1197 for (i = fs->bl->firstlabel; i < ll->n; i++) {
1198 if (luaS_eqstr(label, ll->arr[i].name)) {
1199 const char *msg = luaO_pushfstring(fs->ls->L,
1200 "label " LUA_QS " already defined on line %d",
1201 getstr(label), ll->arr[i].line);
1202 semerror(fs->ls, msg);
1203 }
1204 }
1205 }
1206
1207
1208 /* skip no-op statements */
1209 static void skipnoopstat (LexState *ls) {
1210 while (ls->t.token == ';' || ls->t.token == TK_DBCOLON)
1211 statement(ls);
1212 }
1213
1214
1215 static void labelstat (LexState *ls, TString *label, int line) {
1216 /* label -> '::' NAME '::' */
1217 FuncState *fs = ls->fs;
1218 Labellist *ll = &ls->dyd->label;
1219 int l; /* index of new label being created */
1220 checkrepeated(fs, ll, label); /* check for repeated labels */
1221 checknext(ls, TK_DBCOLON); /* skip double colon */
1222 /* create new entry for this label */
1223 l = newlabelentry(ls, ll, label, line, fs->pc);
1224 skipnoopstat(ls); /* skip other no-op statements */
1225 if (block_follow(ls, 0)) { /* label is last no-op statement in the block? */
1226 /* assume that locals are already out of scope */
1227 ll->arr[l].nactvar = fs->bl->nactvar;
1228 }
1229 findgotos(ls, &ll->arr[l]);
1230 }
1231
1232
1233 static void whilestat (LexState *ls, int line) {
1234 /* whilestat -> WHILE cond DO block END */
1235 FuncState *fs = ls->fs;
1236 int whileinit;
1237 int condexit;
1238 BlockCnt bl;
1239 luaX_next(ls); /* skip WHILE */
1240 whileinit = luaK_getlabel(fs);
1241 condexit = cond(ls);
1242 enterblock(fs, &bl, 1);
1243 checknext(ls, TK_DO);
1244 block(ls);
1245 luaK_jumpto(fs, whileinit);
1246 check_match(ls, TK_END, TK_WHILE, line);
1247 leaveblock(fs);
1248 luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
1249 }
1250
1251
1252 static void repeatstat (LexState *ls, int line) {
1253 /* repeatstat -> REPEAT block UNTIL cond */
1254 int condexit;
1255 FuncState *fs = ls->fs;
1256 int repeat_init = luaK_getlabel(fs);
1257 BlockCnt bl1, bl2;
1258 enterblock(fs, &bl1, 1); /* loop block */
1259 enterblock(fs, &bl2, 0); /* scope block */
1260 luaX_next(ls); /* skip REPEAT */
1261 statlist(ls);
1262 check_match(ls, TK_UNTIL, TK_REPEAT, line);
1263 condexit = cond(ls); /* read condition (inside scope block) */
1264 if (bl2.upval) /* upvalues? */
1265 luaK_patchclose(fs, condexit, bl2.nactvar);
1266 leaveblock(fs); /* finish scope */
1267 luaK_patchlist(fs, condexit, repeat_init); /* close the loop */
1268 leaveblock(fs); /* finish loop */
1269 }
1270
1271
1272 static int exp1 (LexState *ls) {
1273 expdesc e;
1274 int reg;
1275 expr(ls, &e);
1276 luaK_exp2nextreg(ls->fs, &e);
1277 lua_assert(e.k == VNONRELOC);
1278 reg = e.u.info;
1279 return reg;
1280 }
1281
1282
1283 static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
1284 /* forbody -> DO block */
1285 BlockCnt bl;
1286 FuncState *fs = ls->fs;
1287 int prep, endfor;
1288 adjustlocalvars(ls, 3); /* control variables */
1289 checknext(ls, TK_DO);
1290 prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
1291 enterblock(fs, &bl, 0); /* scope for declared variables */
1292 adjustlocalvars(ls, nvars);
1293 luaK_reserveregs(fs, nvars);
1294 block(ls);
1295 leaveblock(fs); /* end of scope for declared variables */
1296 luaK_patchtohere(fs, prep);
1297 if (isnum) /* numeric for? */
1298 endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP);
1299 else { /* generic for */
1300 luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
1301 luaK_fixline(fs, line);
1302 endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP);
1303 }
1304 luaK_patchlist(fs, endfor, prep + 1);
1305 luaK_fixline(fs, line);
1306 }
1307
1308
1309 static void fornum (LexState *ls, TString *varname, int line) {
1310 /* fornum -> NAME = exp1,exp1[,exp1] forbody */
1311 FuncState *fs = ls->fs;
1312 int base = fs->freereg;
1313 new_localvarliteral(ls, "(for index)");
1314 new_localvarliteral(ls, "(for limit)");
1315 new_localvarliteral(ls, "(for step)");
1316 new_localvar(ls, varname);
1317 checknext(ls, '=');
1318 exp1(ls); /* initial value */
1319 checknext(ls, ',');
1320 exp1(ls); /* limit */
1321 if (testnext(ls, ','))
1322 exp1(ls); /* optional step */
1323 else { /* default step = 1 */
1324 luaK_codek(fs, fs->freereg, luaK_numberK(fs, 1));
1325 luaK_reserveregs(fs, 1);
1326 }
1327 forbody(ls, base, line, 1, 1);
1328 }
1329
1330
1331 static void forlist (LexState *ls, TString *indexname) {
1332 /* forlist -> NAME {,NAME} IN explist forbody */
1333 FuncState *fs = ls->fs;
1334 expdesc e;
1335 int nvars = 4; /* gen, state, control, plus at least one declared var */
1336 int line;
1337 int base = fs->freereg;
1338 /* create control variables */
1339 new_localvarliteral(ls, "(for generator)");
1340 new_localvarliteral(ls, "(for state)");
1341 new_localvarliteral(ls, "(for control)");
1342 /* create declared variables */
1343 new_localvar(ls, indexname);
1344 while (testnext(ls, ',')) {
1345 new_localvar(ls, str_checkname(ls));
1346 nvars++;
1347 }
1348 checknext(ls, TK_IN);
1349 line = ls->linenumber;
1350 adjust_assign(ls, 3, explist(ls, &e), &e);
1351 luaK_checkstack(fs, 3); /* extra space to call generator */
1352 forbody(ls, base, line, nvars - 3, 0);
1353 }
1354
1355
1356 static void forstat (LexState *ls, int line) {
1357 /* forstat -> FOR (fornum | forlist) END */
1358 FuncState *fs = ls->fs;
1359 TString *varname;
1360 BlockCnt bl;
1361 enterblock(fs, &bl, 1); /* scope for loop and control variables */
1362 luaX_next(ls); /* skip `for' */
1363 varname = str_checkname(ls); /* first variable name */
1364 switch (ls->t.token) {
1365 case '=': fornum(ls, varname, line); break;
1366 case ',': case TK_IN: forlist(ls, varname); break;
1367 default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected");
1368 }
1369 check_match(ls, TK_END, TK_FOR, line);
1370 leaveblock(fs); /* loop scope (`break' jumps to this point) */
1371 }
1372
1373
1374 static void test_then_block (LexState *ls, int *escapelist) {
1375 /* test_then_block -> [IF | ELSEIF] cond THEN block */
1376 BlockCnt bl;
1377 FuncState *fs = ls->fs;
1378 expdesc v;
1379 int jf; /* instruction to skip 'then' code (if condition is false) */
1380 luaX_next(ls); /* skip IF or ELSEIF */
1381 expr(ls, &v); /* read condition */
1382 checknext(ls, TK_THEN);
1383 if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) {
1384 luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */
1385 enterblock(fs, &bl, 0); /* must enter block before 'goto' */
1386 gotostat(ls, v.t); /* handle goto/break */
1387 skipnoopstat(ls); /* skip other no-op statements */
1388 if (block_follow(ls, 0)) { /* 'goto' is the entire block? */
1389 leaveblock(fs);
1390 return; /* and that is it */
1391 }
1392 else /* must skip over 'then' part if condition is false */
1393 jf = luaK_jump(fs);
1394 }
1395 else { /* regular case (not goto/break) */
1396 luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */
1397 enterblock(fs, &bl, 0);
1398 jf = v.f;
1399 }
1400 statlist(ls); /* `then' part */
1401 leaveblock(fs);
1402 if (ls->t.token == TK_ELSE ||
1403 ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */
1404 luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */
1405 luaK_patchtohere(fs, jf);
1406 }
1407
1408
1409 static void ifstat (LexState *ls, int line) {
1410 /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
1411 FuncState *fs = ls->fs;
1412 int escapelist = NO_JUMP; /* exit list for finished parts */
1413 test_then_block(ls, &escapelist); /* IF cond THEN block */
1414 while (ls->t.token == TK_ELSEIF)
1415 test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */
1416 if (testnext(ls, TK_ELSE))
1417 block(ls); /* `else' part */
1418 check_match(ls, TK_END, TK_IF, line);
1419 luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */
1420 }
1421
1422
1423 static void localfunc (LexState *ls) {
1424 expdesc b;
1425 FuncState *fs = ls->fs;
1426 new_localvar(ls, str_checkname(ls)); /* new local variable */
1427 adjustlocalvars(ls, 1); /* enter its scope */
1428 body(ls, &b, 0, ls->linenumber); /* function created in next register */
1429 /* debug information will only see the variable after this point! */
1430 getlocvar(fs, b.u.info)->startpc = fs->pc;
1431 }
1432
1433
1434 static void localstat (LexState *ls) {
1435 /* stat -> LOCAL NAME {`,' NAME} [`=' explist] */
1436 int nvars = 0;
1437 int nexps;
1438 expdesc e;
1439 do {
1440 new_localvar(ls, str_checkname(ls));
1441 nvars++;
1442 } while (testnext(ls, ','));
1443 if (testnext(ls, '='))
1444 nexps = explist(ls, &e);
1445 else {
1446 e.k = VVOID;
1447 nexps = 0;
1448 }
1449 adjust_assign(ls, nvars, nexps, &e);
1450 adjustlocalvars(ls, nvars);
1451 }
1452
1453
1454 static int funcname (LexState *ls, expdesc *v) {
1455 /* funcname -> NAME {fieldsel} [`:' NAME] */
1456 int ismethod = 0;
1457 singlevar(ls, v);
1458 while (ls->t.token == '.')
1459 fieldsel(ls, v);
1460 if (ls->t.token == ':') {
1461 ismethod = 1;
1462 fieldsel(ls, v);
1463 }
1464 return ismethod;
1465 }
1466
1467
1468 static void funcstat (LexState *ls, int line) {
1469 /* funcstat -> FUNCTION funcname body */
1470 int ismethod;
1471 expdesc v, b;
1472 luaX_next(ls); /* skip FUNCTION */
1473 ismethod = funcname(ls, &v);
1474 body(ls, &b, ismethod, line);
1475 luaK_storevar(ls->fs, &v, &b);
1476 luaK_fixline(ls->fs, line); /* definition `happens' in the first line */
1477 }
1478
1479
1480 static void exprstat (LexState *ls) {
1481 /* stat -> func | assignment */
1482 FuncState *fs = ls->fs;
1483 struct LHS_assign v;
1484 suffixedexp(ls, &v.v);
1485 if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */
1486 v.prev = NULL;
1487 assignment(ls, &v, 1);
1488 }
1489 else { /* stat -> func */
1490 check_condition(ls, v.v.k == VCALL, "syntax error");
1491 SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */
1492 }
1493 }
1494
1495
1496 static void retstat (LexState *ls) {
1497 /* stat -> RETURN [explist] [';'] */
1498 FuncState *fs = ls->fs;
1499 expdesc e;
1500 int first, nret; /* registers with returned values */
1501 if (block_follow(ls, 1) || ls->t.token == ';')
1502 first = nret = 0; /* return no values */
1503 else {
1504 nret = explist(ls, &e); /* optional return values */
1505 if (hasmultret(e.k)) {
1506 luaK_setmultret(fs, &e);
1507 if (e.k == VCALL && nret == 1) { /* tail call? */
1508 SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
1509 lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
1510 }
1511 first = fs->nactvar;
1512 nret = LUA_MULTRET; /* return all values */
1513 }
1514 else {
1515 if (nret == 1) /* only one single value? */
1516 first = luaK_exp2anyreg(fs, &e);
1517 else {
1518 luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */
1519 first = fs->nactvar; /* return all `active' values */
1520 lua_assert(nret == fs->freereg - first);
1521 }
1522 }
1523 }
1524 luaK_ret(fs, first, nret);
1525 testnext(ls, ';'); /* skip optional semicolon */
1526 }
1527
1528
1529 static void statement (LexState *ls) {
1530 int line = ls->linenumber; /* may be needed for error messages */
1531 enterlevel(ls);
1532 switch (ls->t.token) {
1533 case ';': { /* stat -> ';' (empty statement) */
1534 luaX_next(ls); /* skip ';' */
1535 break;
1536 }
1537 case TK_IF: { /* stat -> ifstat */
1538 ifstat(ls, line);
1539 break;
1540 }
1541 case TK_WHILE: { /* stat -> whilestat */
1542 whilestat(ls, line);
1543 break;
1544 }
1545 case TK_DO: { /* stat -> DO block END */
1546 luaX_next(ls); /* skip DO */
1547 block(ls);
1548 check_match(ls, TK_END, TK_DO, line);
1549 break;
1550 }
1551 case TK_FOR: { /* stat -> forstat */
1552 forstat(ls, line);
1553 break;
1554 }
1555 case TK_REPEAT: { /* stat -> repeatstat */
1556 repeatstat(ls, line);
1557 break;
1558 }
1559 case TK_FUNCTION: { /* stat -> funcstat */
1560 funcstat(ls, line);
1561 break;
1562 }
1563 case TK_LOCAL: { /* stat -> localstat */
1564 luaX_next(ls); /* skip LOCAL */
1565 if (testnext(ls, TK_FUNCTION)) /* local function? */
1566 localfunc(ls);
1567 else
1568 localstat(ls);
1569 break;
1570 }
1571 case TK_DBCOLON: { /* stat -> label */
1572 luaX_next(ls); /* skip double colon */
1573 labelstat(ls, str_checkname(ls), line);
1574 break;
1575 }
1576 case TK_RETURN: { /* stat -> retstat */
1577 luaX_next(ls); /* skip RETURN */
1578 retstat(ls);
1579 break;
1580 }
1581 case TK_BREAK: /* stat -> breakstat */
1582 case TK_GOTO: { /* stat -> 'goto' NAME */
1583 gotostat(ls, luaK_jump(ls->fs));
1584 break;
1585 }
1586 default: { /* stat -> func | assignment */
1587 exprstat(ls);
1588 break;
1589 }
1590 }
1591 lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
1592 ls->fs->freereg >= ls->fs->nactvar);
1593 ls->fs->freereg = ls->fs->nactvar; /* free registers */
1594 leavelevel(ls);
1595 }
1596
1597 /* }====================================================================== */
1598
1599
1600 /*
1601 ** compiles the main function, which is a regular vararg function with an
1602 ** upvalue named LUA_ENV
1603 */
1604 static void mainfunc (LexState *ls, FuncState *fs) {
1605 BlockCnt bl;
1606 expdesc v;
1607 open_func(ls, fs, &bl);
1608 fs->f->is_vararg = 1; /* main function is always vararg */
1609 init_exp(&v, VLOCAL, 0); /* create and... */
1610 newupvalue(fs, ls->envn, &v); /* ...set environment upvalue */
1611 luaX_next(ls); /* read first token */
1612 statlist(ls); /* parse main body */
1613 check(ls, TK_EOS);
1614 close_func(ls);
1615 }
1616
1617
1618 Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
1619 Dyndata *dyd, const char *name, int firstchar) {
1620 LexState lexstate;
1621 FuncState funcstate;
1622 Closure *cl = luaF_newLclosure(L, 1); /* create main closure */
1623 /* anchor closure (to avoid being collected) */
1624 setclLvalue(L, L->top, cl);
1625 incr_top(L);
1626 funcstate.f = cl->l.p = luaF_newproto(L);
1627 funcstate.f->source = luaS_new(L, name); /* create and anchor TString */
1628 lexstate.buff = buff;
1629 lexstate.dyd = dyd;
1630 dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
1631 luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar);
1632 mainfunc(&lexstate, &funcstate);
1633 lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
1634 /* all scopes should be correctly finished */
1635 lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0);
1636 return cl; /* it's on the stack too */
1637 }
1638