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1/*
2** $Id: lparser.c,v 2.42 2006/06/05 15:57:59 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#define hasmultret(k)((k) == VCALL || (k) == VVARARG)
31
32#define getlocvar(fs, i)((fs)->f->locvars[(fs)->actvar[i]])
33
34#define luaY_checklimit(fs,v,l,m)if ((v)>(l)) errorlimit(fs,l,m)
35
36
37/*
38** nodes for block list (list of active blocks)
39*/
40typedef struct BlockCnt {
41 struct BlockCnt *previous; /* chain */
42 int breaklist; /* list of jumps out of this loop */
43 lu_byte nactvar; /* # active locals outside the breakable structure */
44 lu_byte upval; /* true if some variable in the block is an upvalue */
45 lu_byte isbreakable; /* true if `block' is a loop */
46} BlockCnt;
47
48
49
50/*
51** prototypes for recursive non-terminal functions
52*/
53static void chunk (LexState *ls);
54static void expr (LexState *ls, expdesc *v);
55
56
57static void anchor_token (LexState *ls) {
58 if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) {
59 TString *ts = ls->t.seminfo.ts;
60 luaX_newstring(ls, getstr(ts), ts->tsv.len);
61 }
62}
63
64
65static void error_expected (LexState *ls, int token) {
66 luaX_syntaxerror(ls,
67 luaO_pushfstring(ls->L, LUA_QS " expected", luaX_token2str(ls, token)));
68}
69
70
71static void errorlimit (FuncState *fs, int limit, const char *what) {
72 const char *msg = (fs->f->linedefined == 0) ?
73 luaO_pushfstring(fs->L, "main function has more than %d %s", limit, what) :
74 luaO_pushfstring(fs->L, "function at line %d has more than %d %s",
75 fs->f->linedefined, limit, what);
76 luaX_lexerror(fs->ls, msg, 0);
77}
78
79
80static int testnext (LexState *ls, int c) {
81 if (ls->t.token == c) {
82 luaX_next(ls);
83 return 1;
84 }
85 else return 0;
86}
87
88
89static void check (LexState *ls, int c) {
90 if (ls->t.token != c)
91 error_expected(ls, c);
92}
93
94static void checknext (LexState *ls, int c) {
95 check(ls, c);
96 luaX_next(ls);
97}
98
99
100#define check_condition(ls,c,msg){ if (!(c)) luaX_syntaxerror(ls, msg); }
101
102
103
104static void check_match (LexState *ls, int what, int who, int where) {
105 if (!testnext(ls, what)) {
106 if (where == ls->linenumber)
107 error_expected(ls, what);
108 else {
109 luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
110 LUA_QS " expected (to close " LUA_QS " at line %d)",
111 luaX_token2str(ls, what), luaX_token2str(ls, who), where));
112 }
113 }
114}
115
116
117static TString *str_checkname (LexState *ls) {
118 TString *ts;
119 check(ls, TK_NAME);
120 ts = ls->t.seminfo.ts;
121 luaX_next(ls);
122 return ts;
123}
124
125
126static void init_exp (expdesc *e, expkind k, int i) {
127 e->f = e->t = NO_JUMP;
128 e->k = k;
129 e->u.s.info = i;
130}
131
132
133static void codestring (LexState *ls, expdesc *e, TString *s) {
134 init_exp(e, VK, luaK_stringK(ls->fs, s));
135}
136
137
138static void checkname(LexState *ls, expdesc *e) {
139 codestring(ls, e, str_checkname(ls));
140}
141
142
143static int registerlocalvar (LexState *ls, TString *varname) {
144 FuncState *fs = ls->fs;
145 Proto *f = fs->f;
146 int oldsize = f->sizelocvars;
147 luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
148 LocVar, SHRT_MAX, "too many local variables");
149 while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL;
150 f->locvars[fs->nlocvars].varname = varname;
151 luaC_objbarrier(ls->L, f, varname);
152 return fs->nlocvars++;
153}
154
155
156#define new_localvarliteral(ls,v,n) \
157 new_localvar(ls, luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char))-1), n)
158
159
160static void new_localvar (LexState *ls, TString *name, int n) {
161 FuncState *fs = ls->fs;
162 luaY_checklimit(fs, fs->nactvar+n+1, LUAI_MAXVARS, "local variables");
163 fs->actvar[fs->nactvar+n] = cast(unsigned short, registerlocalvar(ls, name));
164}
165
166
167static void adjustlocalvars (LexState *ls, int nvars) {
168 FuncState *fs = ls->fs;
169 fs->nactvar = cast_byte(fs->nactvar + nvars);
170 for (; nvars; nvars--) {
171 getlocvar(fs, fs->nactvar - nvars).startpc = fs->pc;
172 }
173}
174
175
176static void removevars (LexState *ls, int tolevel) {
177 FuncState *fs = ls->fs;
178 while (fs->nactvar > tolevel)
179 getlocvar(fs, --fs->nactvar).endpc = fs->pc;
180}
181
182
183static int indexupvalue (FuncState *fs, TString *name, expdesc *v) {
184 int i;
185 Proto *f = fs->f;
186 int oldsize = f->sizeupvalues;
187 for (i=0; i<f->nups; i++) {
188 if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->u.s.info) {
189 lua_assert(f->upvalues[i] == name);
190 return i;
191 }
192 }
193 /* new one */
194 luaY_checklimit(fs, f->nups + 1, LUAI_MAXUPVALUES, "upvalues");
195 luaM_growvector(fs->L, f->upvalues, f->nups, f->sizeupvalues,
196 TString *, MAX_INT, "");
197 while (oldsize < f->sizeupvalues) f->upvalues[oldsize++] = NULL;
198 f->upvalues[f->nups] = name;
199 luaC_objbarrier(fs->L, f, name);
200 lua_assert(v->k == VLOCAL || v->k == VUPVAL);
201 fs->upvalues[f->nups].k = cast_byte(v->k);
202 fs->upvalues[f->nups].info = cast_byte(v->u.s.info);
203 return f->nups++;
204}
205
206
207static int searchvar (FuncState *fs, TString *n) {
208 int i;
209 for (i=fs->nactvar-1; i >= 0; i--) {
210 if (n == getlocvar(fs, i).varname)
211 return i;
212 }
213 return -1; /* not found */
214}
215
216
217static void markupval (FuncState *fs, int level) {
218 BlockCnt *bl = fs->bl;
219 while (bl && bl->nactvar > level) bl = bl->previous;
220 if (bl) bl->upval = 1;
221}
222
223
224static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
225 if (fs == NULL) { /* no more levels? */
226 init_exp(var, VGLOBAL, NO_REG); /* default is global variable */
227 return VGLOBAL;
228 }
229 else {
230 int v = searchvar(fs, n); /* look up at current level */
231 if (v >= 0) {
232 init_exp(var, VLOCAL, v);
233 if (!base)
234 markupval(fs, v); /* local will be used as an upval */
235 return VLOCAL;
236 }
237 else { /* not found at current level; try upper one */
238 if (singlevaraux(fs->prev, n, var, 0) == VGLOBAL)
239 return VGLOBAL;
240 var->u.s.info = indexupvalue(fs, n, var); /* else was LOCAL or UPVAL */
241 var->k = VUPVAL; /* upvalue in this level */
242 return VUPVAL;
243 }
244 }
245}
246
247
248static void singlevar (LexState *ls, expdesc *var) {
249 TString *varname = str_checkname(ls);
250 FuncState *fs = ls->fs;
251 if (singlevaraux(fs, varname, var, 1) == VGLOBAL)
252 var->u.s.info = luaK_stringK(fs, varname); /* info points to global name */
253}
254
255
256static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
257 FuncState *fs = ls->fs;
258 int extra = nvars - nexps;
259 if (hasmultret(e->k)) {
260 extra++; /* includes call itself */
261 if (extra < 0) extra = 0;
262 luaK_setreturns(fs, e, extra); /* last exp. provides the difference */
263 if (extra > 1) luaK_reserveregs(fs, extra-1);
264 }
265 else {
266 if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */
267 if (extra > 0) {
268 int reg = fs->freereg;
269 luaK_reserveregs(fs, extra);
270 luaK_nil(fs, reg, extra);
271 }
272 }
273}
274
275
276static void enterlevel (LexState *ls) {
277 if (++ls->L->nCcalls > LUAI_MAXCCALLS)
278luaX_lexerror(ls, "chunk has too many syntax levels", 0);
279}
280
281
282#define leavelevel(ls)((ls)->L->nCcalls--)
283
284
285static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isbreakable) {
286 bl->breaklist = NO_JUMP;
287 bl->isbreakable = isbreakable;
288 bl->nactvar = fs->nactvar;
289 bl->upval = 0;
290 bl->previous = fs->bl;
291 fs->bl = bl;
292 lua_assert(fs->freereg == fs->nactvar);
293}
294
295
296static void leaveblock (FuncState *fs) {
297 BlockCnt *bl = fs->bl;
298 fs->bl = bl->previous;
299 removevars(fs->ls, bl->nactvar);
300 if (bl->upval)
301 luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
302 /* a block either controls scope or breaks (never both) */
303 lua_assert(!bl->isbreakable || !bl->upval);
304 lua_assert(bl->nactvar == fs->nactvar);
305 fs->freereg = fs->nactvar; /* free registers */
306 luaK_patchtohere(fs, bl->breaklist);
307}
308
309
310static void pushclosure (LexState *ls, FuncState *func, expdesc *v) {
311 FuncState *fs = ls->fs;
312 Proto *f = fs->f;
313 int oldsize = f->sizep;
314 int i;
315 luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *,
316 MAXARG_Bx, "constant table overflow");
317 while (oldsize < f->sizep) f->p[oldsize++] = NULL;
318 f->p[fs->np++] = func->f;
319 luaC_objbarrier(ls->L, f, func->f);
320 init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np-1));
321 for (i=0; i<func->f->nups; i++) {
322 OpCode o = (func->upvalues[i].k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
323 luaK_codeABC(fs, o, 0, func->upvalues[i].info, 0);
324 }
325}
326
327
328static void open_func (LexState *ls, FuncState *fs) {
329 lua_State *L = ls->L;
330 Proto *f = luaF_newproto(L);
331 fs->f = f;
332 fs->prev = ls->fs; /* linked list of funcstates */
333 fs->ls = ls;
334 fs->L = L;
335 ls->fs = fs;
336 fs->pc = 0;
337 fs->lasttarget = -1;
338 fs->jpc = NO_JUMP;
339 fs->freereg = 0;
340 fs->nk = 0;
341 fs->np = 0;
342 fs->nlocvars = 0;
343 fs->nactvar = 0;
344 fs->bl = NULL;
345 f->source = ls->source;
346 f->maxstacksize = 2; /* registers 0/1 are always valid */
347 fs->h = luaH_new(L, 0, 0);
348 /* anchor table of constants and prototype (to avoid being collected) */
349 sethvalue2s(L, L->top, fs->h);
350 incr_top(L);
351 setptvalue2s(L, L->top, f);
352 incr_top(L);
353}
354
355
356static void close_func (LexState *ls) {
357 lua_State *L = ls->L;
358 FuncState *fs = ls->fs;
359 Proto *f = fs->f;
360 removevars(ls, 0);
361 luaK_ret(fs, 0, 0); /* final return */
362 luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
363 f->sizecode = fs->pc;
364 luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
365 f->sizelineinfo = fs->pc;
366 luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
367 f->sizek = fs->nk;
368 luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
369 f->sizep = fs->np;
370 luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
371 f->sizelocvars = fs->nlocvars;
372 luaM_reallocvector(L, f->upvalues, f->sizeupvalues, f->nups, TString *);
373 f->sizeupvalues = f->nups;
374 lua_assert(luaG_checkcode(f));
375 lua_assert(fs->bl == NULL);
376 ls->fs = fs->prev;
377 L->top -= 2; /* remove table and prototype from the stack */
378 /* last token read was anchored in defunct function; must reanchor it */
379 if (fs) anchor_token(ls);
380}
381
382
383Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
384 struct LexState lexstate;
385 struct FuncState funcstate;
386 lexstate.buff = buff;
387 luaX_setinput(L, &lexstate, z, luaS_new(L, name));
388 open_func(&lexstate, &funcstate);
389 funcstate.f->is_vararg = VARARG_ISVARARG; /* main func. is always vararg */
390 luaX_next(&lexstate); /* read first token */
391 chunk(&lexstate);
392 check(&lexstate, TK_EOS);
393 close_func(&lexstate);
394 lua_assert(funcstate.prev == NULL);
395 lua_assert(funcstate.f->nups == 0);
396 lua_assert(lexstate.fs == NULL);
397 return funcstate.f;
398}
399
400
401
402/*============================================================*/
403/* GRAMMAR RULES */
404/*============================================================*/
405
406
407static void field (LexState *ls, expdesc *v) {
408 /* field -> ['.' | ':'] NAME */
409 FuncState *fs = ls->fs;
410 expdesc key;
411 luaK_exp2anyreg(fs, v);
412 luaX_next(ls); /* skip the dot or colon */
413 checkname(ls, &key);
414 luaK_indexed(fs, v, &key);
415}
416
417
418static void yindex (LexState *ls, expdesc *v) {
419 /* index -> '[' expr ']' */
420 luaX_next(ls); /* skip the '[' */
421 expr(ls, v);
422 luaK_exp2val(ls->fs, v);
423 checknext(ls, ']');
424}
425
426
427/*
428** {======================================================================
429** Rules for Constructors
430** =======================================================================
431*/
432
433
434struct ConsControl {
435 expdesc v; /* last list item read */
436 expdesc *t; /* table descriptor */
437 int nh; /* total number of `record' elements */
438 int na; /* total number of array elements */
439 int tostore; /* number of array elements pending to be stored */
440};
441
442
443static void recfield (LexState *ls, struct ConsControl *cc) {
444 /* recfield -> (NAME | `['exp1`]') = exp1 */
445 FuncState *fs = ls->fs;
446 int reg = ls->fs->freereg;
447 expdesc key, val;
448 int rkkey;
449 if (ls->t.token == TK_NAME) {
450 luaY_checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
451 checkname(ls, &key);
452 }
453 else /* ls->t.token == '[' */
454 yindex(ls, &key);
455 cc->nh++;
456 checknext(ls, '=');
457 rkkey = luaK_exp2RK(fs, &key);
458 expr(ls, &val);
459 luaK_codeABC(fs, OP_SETTABLE, cc->t->u.s.info, rkkey, luaK_exp2RK(fs, &val));
460 fs->freereg = reg; /* free registers */
461}
462
463
464static void closelistfield (FuncState *fs, struct ConsControl *cc) {
465 if (cc->v.k == VVOID) return; /* there is no list item */
466 luaK_exp2nextreg(fs, &cc->v);
467 cc->v.k = VVOID;
468 if (cc->tostore == LFIELDS_PER_FLUSH) {
469 luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore); /* flush */
470 cc->tostore = 0; /* no more items pending */
471 }
472}
473
474
475static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
476 if (cc->tostore == 0) return;
477 if (hasmultret(cc->v.k)) {
478 luaK_setmultret(fs, &cc->v);
479 luaK_setlist(fs, cc->t->u.s.info, cc->na, LUA_MULTRET);
480 cc->na--; /* do not count last expression (unknown number of elements) */
481 }
482 else {
483 if (cc->v.k != VVOID)
484 luaK_exp2nextreg(fs, &cc->v);
485 luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore);
486 }
487}
488
489
490static void listfield (LexState *ls, struct ConsControl *cc) {
491 expr(ls, &cc->v);
492 luaY_checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
493 cc->na++;
494 cc->tostore++;
495}
496
497
498static void constructor (LexState *ls, expdesc *t) {
499 /* constructor -> ?? */
500 FuncState *fs = ls->fs;
501 int line = ls->linenumber;
502 int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
503 struct ConsControl cc;
504 cc.na = cc.nh = cc.tostore = 0;
505 cc.t = t;
506 init_exp(t, VRELOCABLE, pc);
507 init_exp(&cc.v, VVOID, 0); /* no value (yet) */
508 luaK_exp2nextreg(ls->fs, t); /* fix it at stack top (for gc) */
509 checknext(ls, '{');
510 do {
511 lua_assert(cc.v.k == VVOID || cc.tostore > 0);
512 if (ls->t.token == '}') break;
513 closelistfield(fs, &cc);
514 switch(ls->t.token) {
515 case TK_NAME: { /* may be listfields or recfields */
516 luaX_lookahead(ls);
517 if (ls->lookahead.token != '=') /* expression? */
518 listfield(ls, &cc);
519 else
520 recfield(ls, &cc);
521 break;
522 }
523 case '[': { /* constructor_item -> recfield */
524 recfield(ls, &cc);
525 break;
526 }
527 default: { /* constructor_part -> listfield */
528 listfield(ls, &cc);
529 break;
530 }
531 }
532 } while (testnext(ls, ',') || testnext(ls, ';'));
533 check_match(ls, '}', '{', line);
534 lastlistfield(fs, &cc);
535 SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
536 SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */
537}
538
539/* }====================================================================== */
540
541
542
543static void parlist (LexState *ls) {
544 /* parlist -> [ param { `,' param } ] */
545 FuncState *fs = ls->fs;
546 Proto *f = fs->f;
547 int nparams = 0;
548 f->is_vararg = 0;
549 if (ls->t.token != ')') { /* is `parlist' not empty? */
550 do {
551 switch (ls->t.token) {
552 case TK_NAME: { /* param -> NAME */
553 new_localvar(ls, str_checkname(ls), nparams++);
554 break;
555 }
556 case TK_DOTS: { /* param -> `...' */
557 luaX_next(ls);
558#if defined(LUA_COMPAT_VARARG)
559 /* use `arg' as default name */
560 new_localvarliteral(ls, "arg", nparams++);
561 f->is_vararg = VARARG_HASARG | VARARG_NEEDSARG;
562#endif
563 f->is_vararg |= VARARG_ISVARARG;
564 break;
565 }
566 default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected");
567 }
568 } while (!f->is_vararg && testnext(ls, ','));
569 }
570 adjustlocalvars(ls, nparams);
571 f->numparams = cast_byte(fs->nactvar - (f->is_vararg & VARARG_HASARG));
572 luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */
573}
574
575
576static void body (LexState *ls, expdesc *e, int needself, int line) {
577 /* body -> `(' parlist `)' chunk END */
578 FuncState new_fs;
579 open_func(ls, &new_fs);
580 new_fs.f->linedefined = line;
581 checknext(ls, '(');
582 if (needself) {
583 new_localvarliteral(ls, "self", 0);
584 adjustlocalvars(ls, 1);
585 }
586 parlist(ls);
587 checknext(ls, ')');
588 chunk(ls);
589 new_fs.f->lastlinedefined = ls->linenumber;
590 check_match(ls, TK_END, TK_FUNCTION, line);
591 close_func(ls);
592 pushclosure(ls, &new_fs, e);
593}
594
595
596static int explist1 (LexState *ls, expdesc *v) {
597 /* explist1 -> expr { `,' expr } */
598 int n = 1; /* at least one expression */
599 expr(ls, v);
600 while (testnext(ls, ',')) {
601 luaK_exp2nextreg(ls->fs, v);
602 expr(ls, v);
603 n++;
604 }
605 return n;
606}
607
608
609static void funcargs (LexState *ls, expdesc *f) {
610 FuncState *fs = ls->fs;
611 expdesc args;
612 int base, nparams;
613 int line = ls->linenumber;
614 switch (ls->t.token) {
615 case '(': { /* funcargs -> `(' [ explist1 ] `)' */
616 if (line != ls->lastline)
617 luaX_syntaxerror(ls,"ambiguous syntax (function call x new statement)");
618 luaX_next(ls);
619 if (ls->t.token == ')') /* arg list is empty? */
620 args.k = VVOID;
621 else {
622 explist1(ls, &args);
623 luaK_setmultret(fs, &args);
624 }
625 check_match(ls, ')', '(', line);
626 break;
627 }
628 case '{': { /* funcargs -> constructor */
629 constructor(ls, &args);
630 break;
631 }
632 case TK_STRING: { /* funcargs -> STRING */
633 codestring(ls, &args, ls->t.seminfo.ts);
634 luaX_next(ls); /* must use `seminfo' before `next' */
635 break;
636 }
637 default: {
638 luaX_syntaxerror(ls, "function arguments expected");
639 return;
640 }
641 }
642 lua_assert(f->k == VNONRELOC);
643 base = f->u.s.info; /* base register for call */
644 if (hasmultret(args.k))
645 nparams = LUA_MULTRET; /* open call */
646 else {
647 if (args.k != VVOID)
648 luaK_exp2nextreg(fs, &args); /* close last argument */
649 nparams = fs->freereg - (base+1);
650 }
651 init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
652 luaK_fixline(fs, line);
653 fs->freereg = base+1; /* call remove function and arguments and leaves
654 (unless changed) one result */
655}
656
657
658
659
660/*
661** {======================================================================
662** Expression parsing
663** =======================================================================
664*/
665
666
667static void prefixexp (LexState *ls, expdesc *v) {
668 /* prefixexp -> NAME | '(' expr ')' */
669 switch (ls->t.token) {
670 case '(': {
671 int line = ls->linenumber;
672 luaX_next(ls);
673 expr(ls, v);
674 check_match(ls, ')', '(', line);
675 luaK_dischargevars(ls->fs, v);
676 return;
677 }
678 case TK_NAME: {
679 singlevar(ls, v);
680 return;
681 }
682 default: {
683 luaX_syntaxerror(ls, "unexpected symbol");
684 return;
685 }
686 }
687}
688
689
690static void primaryexp (LexState *ls, expdesc *v) {
691 /* primaryexp ->
692 prefixexp { `.' NAME | `[' exp `]' | `:' NAME funcargs | funcargs } */
693 FuncState *fs = ls->fs;
694 prefixexp(ls, v);
695 for (;;) {
696 switch (ls->t.token) {
697 case '.': { /* field */
698 field(ls, v);
699 break;
700 }
701 case '[': { /* `[' exp1 `]' */
702 expdesc key;
703 luaK_exp2anyreg(fs, v);
704 yindex(ls, &key);
705 luaK_indexed(fs, v, &key);
706 break;
707 }
708 case ':': { /* `:' NAME funcargs */
709 expdesc key;
710 luaX_next(ls);
711 checkname(ls, &key);
712 luaK_self(fs, v, &key);
713 funcargs(ls, v);
714 break;
715 }
716 case '(': case TK_STRING: case '{': { /* funcargs */
717 luaK_exp2nextreg(fs, v);
718 funcargs(ls, v);
719 break;
720 }
721 default: return;
722 }
723 }
724}
725
726
727static void simpleexp (LexState *ls, expdesc *v) {
728 /* simpleexp -> NUMBER | STRING | NIL | true | false | ... |
729 constructor | FUNCTION body | primaryexp */
730 switch (ls->t.token) {
731 case TK_NUMBER: {
732 init_exp(v, VKNUM, 0);
733 v->u.nval = ls->t.seminfo.r;
734 break;
735 }
736 case TK_STRING: {
737 codestring(ls, v, ls->t.seminfo.ts);
738 break;
739 }
740 case TK_NIL: {
741 init_exp(v, VNIL, 0);
742 break;
743 }
744 case TK_TRUE: {
745 init_exp(v, VTRUE, 0);
746 break;
747 }
748 case TK_FALSE: {
749 init_exp(v, VFALSE, 0);
750 break;
751 }
752 case TK_DOTS: { /* vararg */
753 FuncState *fs = ls->fs;
754 check_condition(ls, fs->f->is_vararg,
755 "cannot use " LUA_QL("...") " outside a vararg function");
756 fs->f->is_vararg &= ~VARARG_NEEDSARG; /* don't need 'arg' */
757 init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
758 break;
759 }
760 case '{': { /* constructor */
761 constructor(ls, v);
762 return;
763 }
764 case TK_FUNCTION: {
765 luaX_next(ls);
766 body(ls, v, 0, ls->linenumber);
767 return;
768 }
769 default: {
770 primaryexp(ls, v);
771 return;
772 }
773 }
774 luaX_next(ls);
775}
776
777
778static UnOpr getunopr (int op) {
779 switch (op) {
780 case TK_NOT: return OPR_NOT;
781 case '-': return OPR_MINUS;
782 case '#': return OPR_LEN;
783 default: return OPR_NOUNOPR;
784 }
785}
786
787
788static BinOpr getbinopr (int op) {
789 switch (op) {
790 case '+': return OPR_ADD;
791 case '-': return OPR_SUB;
792 case '*': return OPR_MUL;
793 case '/': return OPR_DIV;
794 case '%': return OPR_MOD;
795 case '^': return OPR_POW;
796 case TK_CONCAT: return OPR_CONCAT;
797 case TK_NE: return OPR_NE;
798 case TK_EQ: return OPR_EQ;
799 case '<': return OPR_LT;
800 case TK_LE: return OPR_LE;
801 case '>': return OPR_GT;
802 case TK_GE: return OPR_GE;
803 case TK_AND: return OPR_AND;
804 case TK_OR: return OPR_OR;
805 default: return OPR_NOBINOPR;
806 }
807}
808
809
810static const struct {
811 lu_byte left; /* left priority for each binary operator */
812 lu_byte right; /* right priority */
813} priority[] = { /* ORDER OPR */
814 {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `/' `%' */
815 {10, 9}, {5, 4}, /* power and concat (right associative) */
816 {3, 3}, {3, 3}, /* equality and inequality */
817 {3, 3}, {3, 3}, {3, 3}, {3, 3}, /* order */
818 {2, 2}, {1, 1} /* logical (and/or) */
819};
820
821#define UNARY_PRIORITY8 /* priority for unary operators */
822
823
824/*
825** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
826** where `binop' is any binary operator with a priority higher than `limit'
827*/
828static BinOpr subexpr (LexState *ls, expdesc *v, unsigned int limit) {
829 BinOpr op;
830 UnOpr uop;
831 enterlevel(ls);
832 uop = getunopr(ls->t.token);
833 if (uop != OPR_NOUNOPR) {
834 luaX_next(ls);
835 subexpr(ls, v, UNARY_PRIORITY);
836 luaK_prefix(ls->fs, uop, v);
837 }
838 else simpleexp(ls, v);
839 /* expand while operators have priorities higher than `limit' */
840 op = getbinopr(ls->t.token);
841 while (op != OPR_NOBINOPR && priority[op].left > limit) {
842 expdesc v2;
843 BinOpr nextop;
844 luaX_next(ls);
845 luaK_infix(ls->fs, op, v);
846 /* read sub-expression with higher priority */
847 nextop = subexpr(ls, &v2, priority[op].right);
848 luaK_posfix(ls->fs, op, v, &v2);
849 op = nextop;
850 }
851 leavelevel(ls);
852 return op; /* return first untreated operator */
853}
854
855
856static void expr (LexState *ls, expdesc *v) {
857 subexpr(ls, v, 0);
858}
859
860/* }==================================================================== */
861
862
863
864/*
865** {======================================================================
866** Rules for Statements
867** =======================================================================
868*/
869
870
871static int block_follow (int token) {
872 switch (token) {
873 case TK_ELSE: case TK_ELSEIF: case TK_END:
874 case TK_UNTIL: case TK_EOS:
875 return 1;
876 default: return 0;
877 }
878}
879
880
881static void block (LexState *ls) {
882 /* block -> chunk */
883 FuncState *fs = ls->fs;
884 BlockCnt bl;
885 enterblock(fs, &bl, 0);
886 chunk(ls);
887 lua_assert(bl.breaklist == NO_JUMP);
888 leaveblock(fs);
889}
890
891
892/*
893** structure to chain all variables in the left-hand side of an
894** assignment
895*/
896struct LHS_assign {
897 struct LHS_assign *prev;
898 expdesc v; /* variable (global, local, upvalue, or indexed) */
899};
900
901
902/*
903** check whether, in an assignment to a local variable, the local variable
904** is needed in a previous assignment (to a table). If so, save original
905** local value in a safe place and use this safe copy in the previous
906** assignment.
907*/
908static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
909 FuncState *fs = ls->fs;
910 int extra = fs->freereg; /* eventual position to save local variable */
911 int conflict = 0;
912 for (; lh; lh = lh->prev) {
913 if (lh->v.k == VINDEXED) {
914 if (lh->v.u.s.info == v->u.s.info) { /* conflict? */
915 conflict = 1;
916 lh->v.u.s.info = extra; /* previous assignment will use safe copy */
917 }
918 if (lh->v.u.s.aux == v->u.s.info) { /* conflict? */
919 conflict = 1;
920 lh->v.u.s.aux = extra; /* previous assignment will use safe copy */
921 }
922 }
923 }
924 if (conflict) {
925 luaK_codeABC(fs, OP_MOVE, fs->freereg, v->u.s.info, 0); /* make copy */
926 luaK_reserveregs(fs, 1);
927 }
928}
929
930
931static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
932 expdesc e;
933 check_condition(ls, VLOCAL <= lh->v.k && lh->v.k <= VINDEXED,
934 "syntax error");
935 if (testnext(ls, ',')) { /* assignment -> `,' primaryexp assignment */
936 struct LHS_assign nv;
937 nv.prev = lh;
938 primaryexp(ls, &nv.v);
939 if (nv.v.k == VLOCAL)
940 check_conflict(ls, lh, &nv.v);
941 assignment(ls, &nv, nvars+1);
942 }
943 else { /* assignment -> `=' explist1 */
944 int nexps;
945 checknext(ls, '=');
946 nexps = explist1(ls, &e);
947 if (nexps != nvars) {
948 adjust_assign(ls, nvars, nexps, &e);
949 if (nexps > nvars)
950 ls->fs->freereg -= nexps - nvars; /* remove extra values */
951 }
952 else {
953 luaK_setoneret(ls->fs, &e); /* close last expression */
954 luaK_storevar(ls->fs, &lh->v, &e);
955 return; /* avoid default */
956 }
957 }
958 init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */
959 luaK_storevar(ls->fs, &lh->v, &e);
960}
961
962
963static int cond (LexState *ls) {
964 /* cond -> exp */
965 expdesc v;
966 expr(ls, &v); /* read condition */
967 if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */
968 luaK_goiftrue(ls->fs, &v);
969 return v.f;
970}
971
972
973static void breakstat (LexState *ls) {
974 FuncState *fs = ls->fs;
975 BlockCnt *bl = fs->bl;
976 int upval = 0;
977 while (bl && !bl->isbreakable) {
978 upval |= bl->upval;
979 bl = bl->previous;
980 }
981 if (!bl)
982 luaX_syntaxerror(ls, "no loop to break");
983 if (upval)
984 luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
985 luaK_concat(fs, &bl->breaklist, luaK_jump(fs));
986}
987
988
989static void whilestat (LexState *ls, int line) {
990 /* whilestat -> WHILE cond DO block END */
991 FuncState *fs = ls->fs;
992 int whileinit;
993 int condexit;
994 BlockCnt bl;
995 luaX_next(ls); /* skip WHILE */
996 whileinit = luaK_getlabel(fs);
997 condexit = cond(ls);
998 enterblock(fs, &bl, 1);
999 checknext(ls, TK_DO);
1000 block(ls);
1001 luaK_patchlist(fs, luaK_jump(fs), whileinit);
1002 check_match(ls, TK_END, TK_WHILE, line);
1003 leaveblock(fs);
1004 luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
1005}
1006
1007
1008static void repeatstat (LexState *ls, int line) {
1009 /* repeatstat -> REPEAT block UNTIL cond */
1010 int condexit;
1011 FuncState *fs = ls->fs;
1012 int repeat_init = luaK_getlabel(fs);
1013 BlockCnt bl1, bl2;
1014 enterblock(fs, &bl1, 1); /* loop block */
1015 enterblock(fs, &bl2, 0); /* scope block */
1016 luaX_next(ls); /* skip REPEAT */
1017 chunk(ls);
1018 check_match(ls, TK_UNTIL, TK_REPEAT, line);
1019 condexit = cond(ls); /* read condition (inside scope block) */
1020 if (!bl2.upval) { /* no upvalues? */
1021 leaveblock(fs); /* finish scope */
1022 luaK_patchlist(ls->fs, condexit, repeat_init); /* close the loop */
1023 }
1024 else { /* complete semantics when there are upvalues */
1025 breakstat(ls); /* if condition then break */
1026 luaK_patchtohere(ls->fs, condexit); /* else... */
1027 leaveblock(fs); /* finish scope... */
1028 luaK_patchlist(ls->fs, luaK_jump(fs), repeat_init); /* and repeat */
1029 }
1030 leaveblock(fs); /* finish loop */
1031}
1032
1033
1034static int exp1 (LexState *ls) {
1035 expdesc e;
1036 int k;
1037 expr(ls, &e);
1038 k = e.k;
1039 luaK_exp2nextreg(ls->fs, &e);
1040 return k;
1041}
1042
1043
1044static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
1045 /* forbody -> DO block */
1046 BlockCnt bl;
1047 FuncState *fs = ls->fs;
1048 int prep, endfor;
1049 adjustlocalvars(ls, 3); /* control variables */
1050 checknext(ls, TK_DO);
1051 prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
1052 enterblock(fs, &bl, 0); /* scope for declared variables */
1053 adjustlocalvars(ls, nvars);
1054 luaK_reserveregs(fs, nvars);
1055 block(ls);
1056 leaveblock(fs); /* end of scope for declared variables */
1057 luaK_patchtohere(fs, prep);
1058 endfor = (isnum) ? luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP) :
1059 luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars);
1060 luaK_fixline(fs, line); /* pretend that `OP_FOR' starts the loop */
1061 luaK_patchlist(fs, (isnum ? endfor : luaK_jump(fs)), prep + 1);
1062}
1063
1064
1065static void fornum (LexState *ls, TString *varname, int line) {
1066 /* fornum -> NAME = exp1,exp1[,exp1] forbody */
1067 FuncState *fs = ls->fs;
1068 int base = fs->freereg;
1069 new_localvarliteral(ls, "(for index)", 0);
1070 new_localvarliteral(ls, "(for limit)", 1);
1071 new_localvarliteral(ls, "(for step)", 2);
1072 new_localvar(ls, varname, 3);
1073 checknext(ls, '=');
1074 exp1(ls); /* initial value */
1075 checknext(ls, ',');
1076 exp1(ls); /* limit */
1077 if (testnext(ls, ','))
1078 exp1(ls); /* optional step */
1079 else { /* default step = 1 */
1080 luaK_codeABx(fs, OP_LOADK, fs->freereg, luaK_numberK(fs, 1));
1081 luaK_reserveregs(fs, 1);
1082 }
1083 forbody(ls, base, line, 1, 1);
1084}
1085
1086
1087static void forlist (LexState *ls, TString *indexname) {
1088 /* forlist -> NAME {,NAME} IN explist1 forbody */
1089 FuncState *fs = ls->fs;
1090 expdesc e;
1091 int nvars = 0;
1092 int line;
1093 int base = fs->freereg;
1094 /* create control variables */
1095 new_localvarliteral(ls, "(for generator)", nvars++);
1096 new_localvarliteral(ls, "(for state)", nvars++);
1097 new_localvarliteral(ls, "(for control)", nvars++);
1098 /* create declared variables */
1099 new_localvar(ls, indexname, nvars++);
1100 while (testnext(ls, ','))
1101 new_localvar(ls, str_checkname(ls), nvars++);
1102 checknext(ls, TK_IN);
1103 line = ls->linenumber;
1104 adjust_assign(ls, 3, explist1(ls, &e), &e);
1105 luaK_checkstack(fs, 3); /* extra space to call generator */
1106 forbody(ls, base, line, nvars - 3, 0);
1107}
1108
1109
1110static void forstat (LexState *ls, int line) {
1111 /* forstat -> FOR (fornum | forlist) END */
1112 FuncState *fs = ls->fs;
1113 TString *varname;
1114 BlockCnt bl;
1115 enterblock(fs, &bl, 1); /* scope for loop and control variables */
1116 luaX_next(ls); /* skip `for' */
1117 varname = str_checkname(ls); /* first variable name */
1118 switch (ls->t.token) {
1119 case '=': fornum(ls, varname, line); break;
1120 case ',': case TK_IN: forlist(ls, varname); break;
1121 default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected");
1122 }
1123 check_match(ls, TK_END, TK_FOR, line);
1124 leaveblock(fs); /* loop scope (`break' jumps to this point) */
1125}
1126
1127
1128static int test_then_block (LexState *ls) {
1129 /* test_then_block -> [IF | ELSEIF] cond THEN block */
1130 int condexit;
1131 luaX_next(ls); /* skip IF or ELSEIF */
1132 condexit = cond(ls);
1133 checknext(ls, TK_THEN);
1134 block(ls); /* `then' part */
1135 return condexit;
1136}
1137
1138
1139static void ifstat (LexState *ls, int line) {
1140 /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
1141 FuncState *fs = ls->fs;
1142 int flist;
1143 int escapelist = NO_JUMP;
1144 flist = test_then_block(ls); /* IF cond THEN block */
1145 while (ls->t.token == TK_ELSEIF) {
1146 luaK_concat(fs, &escapelist, luaK_jump(fs));
1147 luaK_patchtohere(fs, flist);
1148 flist = test_then_block(ls); /* ELSEIF cond THEN block */
1149 }
1150 if (ls->t.token == TK_ELSE) {
1151 luaK_concat(fs, &escapelist, luaK_jump(fs));
1152 luaK_patchtohere(fs, flist);
1153 luaX_next(ls); /* skip ELSE (after patch, for correct line info) */
1154 block(ls); /* `else' part */
1155 }
1156 else
1157 luaK_concat(fs, &escapelist, flist);
1158 luaK_patchtohere(fs, escapelist);
1159 check_match(ls, TK_END, TK_IF, line);
1160}
1161
1162
1163static void localfunc (LexState *ls) {
1164 expdesc v, b;
1165 FuncState *fs = ls->fs;
1166 new_localvar(ls, str_checkname(ls), 0);
1167 init_exp(&v, VLOCAL, fs->freereg);
1168 luaK_reserveregs(fs, 1);
1169 adjustlocalvars(ls, 1);
1170 body(ls, &b, 0, ls->linenumber);
1171 luaK_storevar(fs, &v, &b);
1172 /* debug information will only see the variable after this point! */
1173 getlocvar(fs, fs->nactvar - 1).startpc = fs->pc;
1174}
1175
1176
1177static void localstat (LexState *ls) {
1178 /* stat -> LOCAL NAME {`,' NAME} [`=' explist1] */
1179 int nvars = 0;
1180 int nexps;
1181 expdesc e;
1182 do {
1183 new_localvar(ls, str_checkname(ls), nvars++);
1184 } while (testnext(ls, ','));
1185 if (testnext(ls, '='))
1186 nexps = explist1(ls, &e);
1187 else {
1188 e.k = VVOID;
1189 nexps = 0;
1190 }
1191 adjust_assign(ls, nvars, nexps, &e);
1192 adjustlocalvars(ls, nvars);
1193}
1194
1195
1196static int funcname (LexState *ls, expdesc *v) {
1197 /* funcname -> NAME {field} [`:' NAME] */
1198 int needself = 0;
1199 singlevar(ls, v);
1200 while (ls->t.token == '.')
1201 field(ls, v);
1202 if (ls->t.token == ':') {
1203 needself = 1;
1204 field(ls, v);
1205 }
1206 return needself;
1207}
1208
1209
1210static void funcstat (LexState *ls, int line) {
1211 /* funcstat -> FUNCTION funcname body */
1212 int needself;
1213 expdesc v, b;
1214 luaX_next(ls); /* skip FUNCTION */
1215 needself = funcname(ls, &v);
1216 body(ls, &b, needself, line);
1217 luaK_storevar(ls->fs, &v, &b);
1218 luaK_fixline(ls->fs, line); /* definition `happens' in the first line */
1219}
1220
1221
1222static void exprstat (LexState *ls) {
1223 /* stat -> func | assignment */
1224 FuncState *fs = ls->fs;
1225 struct LHS_assign v;
1226 primaryexp(ls, &v.v);
1227 if (v.v.k == VCALL) /* stat -> func */
1228 SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */
1229 else { /* stat -> assignment */
1230 v.prev = NULL;
1231 assignment(ls, &v, 1);
1232 }
1233}
1234
1235
1236static void retstat (LexState *ls) {
1237 /* stat -> RETURN explist */
1238 FuncState *fs = ls->fs;
1239 expdesc e;
1240 int first, nret; /* registers with returned values */
1241 luaX_next(ls); /* skip RETURN */
1242 if (block_follow(ls->t.token) || ls->t.token == ';')
1243 first = nret = 0; /* return no values */
1244 else {
1245 nret = explist1(ls, &e); /* optional return values */
1246 if (hasmultret(e.k)) {
1247 luaK_setmultret(fs, &e);
1248 if (e.k == VCALL && nret == 1) { /* tail call? */
1249 SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
1250 lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
1251 }
1252 first = fs->nactvar;
1253 nret = LUA_MULTRET; /* return all values */
1254 }
1255 else {
1256 if (nret == 1) /* only one single value? */
1257 first = luaK_exp2anyreg(fs, &e);
1258 else {
1259 luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */
1260 first = fs->nactvar; /* return all `active' values */
1261 lua_assert(nret == fs->freereg - first);
1262 }
1263 }
1264 }
1265 luaK_ret(fs, first, nret);
1266}
1267
1268
1269static int statement (LexState *ls) {
1270 int line = ls->linenumber; /* may be needed for error messages */
1271 switch (ls->t.token) {
1272 case TK_IF: { /* stat -> ifstat */
1273 ifstat(ls, line);
1274 return 0;
1275 }
1276 case TK_WHILE: { /* stat -> whilestat */
1277 whilestat(ls, line);
1278 return 0;
1279 }
1280 case TK_DO: { /* stat -> DO block END */
1281 luaX_next(ls); /* skip DO */
1282 block(ls);
1283 check_match(ls, TK_END, TK_DO, line);
1284 return 0;
1285 }
1286 case TK_FOR: { /* stat -> forstat */
1287 forstat(ls, line);
1288 return 0;
1289 }
1290 case TK_REPEAT: { /* stat -> repeatstat */
1291 repeatstat(ls, line);
1292 return 0;
1293 }
1294 case TK_FUNCTION: {
1295 funcstat(ls, line); /* stat -> funcstat */
1296 return 0;
1297 }
1298 case TK_LOCAL: { /* stat -> localstat */
1299 luaX_next(ls); /* skip LOCAL */
1300 if (testnext(ls, TK_FUNCTION)) /* local function? */
1301 localfunc(ls);
1302 else
1303 localstat(ls);
1304 return 0;
1305 }
1306 case TK_RETURN: { /* stat -> retstat */
1307 retstat(ls);
1308 return 1; /* must be last statement */
1309 }
1310 case TK_BREAK: { /* stat -> breakstat */
1311 luaX_next(ls); /* skip BREAK */
1312 breakstat(ls);
1313 return 1; /* must be last statement */
1314 }
1315 default: {
1316 exprstat(ls);
1317 return 0; /* to avoid warnings */
1318 }
1319 }
1320}
1321
1322
1323static void chunk (LexState *ls) {
1324 /* chunk -> { stat [`;'] } */
1325 int islast = 0;
1326 enterlevel(ls);
1327 while (!islast && !block_follow(ls->t.token)) {
1328 islast = statement(ls);
1329 testnext(ls, ';');
1330 lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
1331 ls->fs->freereg >= ls->fs->nactvar);
1332 ls->fs->freereg = ls->fs->nactvar; /* free registers */
1333 }
1334 leavelevel(ls);
1335}
1336
1337/* }====================================================================== */

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