ba8b5c17 |
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 | |