1/*
2** $Id: lparser.c,v 2.155.1.2 2017/04/29 18:11:40 roberto Exp $
3** Lua Parser
4** See Copyright Notice in lua.h
5*/
6
7#define lparser_c
8#define LUA_CORE
9
10#include "lprefix.h"
11
12
13#include <string.h>
14
15#include "lua.h"
16
17#include "lcode.h"
18#include "ldebug.h"
19#include "ldo.h"
20#include "lfunc.h"
21#include "llex.h"
22#include "lmem.h"
23#include "lobject.h"
24#include "lopcodes.h"
25#include "lparser.h"
26#include "lstate.h"
27#include "lstring.h"
28#include "ltable.h"
29
30
31
32/* maximum number of local variables per function (must be smaller
33 than 250, due to the bytecode format) */
34#define MAXVARS 200
35
36
37#define hasmultret(k) ((k) == VCALL || (k) == VVARARG)
38
39
40/* because all strings are unified by the scanner, the parser
41 can use pointer equality for string equality */
42#define eqstr(a,b) ((a) == (b))
43
44
45/*
46** nodes for block list (list of active blocks)
47*/
48typedef struct BlockCnt {
49 struct BlockCnt *previous; /* chain */
50 int firstlabel; /* index of first label in this block */
51 int firstgoto; /* index of first pending goto in this block */
52 lu_byte nactvar; /* # active locals outside the block */
53 lu_byte upval; /* true if some variable in the block is an upvalue */
54 lu_byte isloop; /* true if 'block' is a loop */
55} BlockCnt;
56
57
58
59/*
60** prototypes for recursive non-terminal functions
61*/
62static void statement (LexState *ls);
63static void expr (LexState *ls, expdesc *v);
64
65
66/* semantic error */
67static l_noret semerror (LexState *ls, const char *msg) {
68 ls->t.token = 0; /* remove "near <token>" from final message */
69 luaX_syntaxerror(ls, msg);
70}
71
72
73static l_noret error_expected (LexState *ls, int token) {
74 luaX_syntaxerror(ls,
75 luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token)));
76}
77
78
79static l_noret errorlimit (FuncState *fs, int limit, const char *what) {
80 lua_State *L = fs->ls->L;
81 const char *msg;
82 int line = fs->f->linedefined;
83 const char *where = (line == 0)
84 ? "main function"
85 : luaO_pushfstring(L, "function at line %d", line);
86 msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s",
87 what, limit, where);
88 luaX_syntaxerror(fs->ls, msg);
89}
90
91
92static void checklimit (FuncState *fs, int v, int l, const char *what) {
93 if (v > l) errorlimit(fs, l, what);
94}
95
96
97static int testnext (LexState *ls, int c) {
98 if (ls->t.token == c) {
99 luaX_next(ls);
100 return 1;
101 }
102 else return 0;
103}
104
105
106static void check (LexState *ls, int c) {
107 if (ls->t.token != c)
108 error_expected(ls, c);
109}
110
111
112static void checknext (LexState *ls, int c) {
113 check(ls, c);
114 luaX_next(ls);
115}
116
117
118#define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); }
119
120
121
122static void check_match (LexState *ls, int what, int who, int where) {
123 if (!testnext(ls, what)) {
124 if (where == ls->linenumber)
125 error_expected(ls, what);
126 else {
127 luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
128 "%s expected (to close %s at line %d)",
129 luaX_token2str(ls, what), luaX_token2str(ls, who), where));
130 }
131 }
132}
133
134
135static TString *str_checkname (LexState *ls) {
136 TString *ts;
137 check(ls, TK_NAME);
138 ts = ls->t.seminfo.ts;
139 luaX_next(ls);
140 return ts;
141}
142
143
144static void init_exp (expdesc *e, expkind k, int i) {
145 e->f = e->t = NO_JUMP;
146 e->k = k;
147 e->u.info = i;
148}
149
150
151static void codestring (LexState *ls, expdesc *e, TString *s) {
152 init_exp(e, VK, luaK_stringK(ls->fs, s));
153}
154
155
156static void checkname (LexState *ls, expdesc *e) {
157 codestring(ls, e, str_checkname(ls));
158}
159
160
161static int registerlocalvar (LexState *ls, TString *varname) {
162 FuncState *fs = ls->fs;
163 Proto *f = fs->f;
164 int oldsize = f->sizelocvars;
165 luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
166 LocVar, SHRT_MAX, "local variables");
167 while (oldsize < f->sizelocvars)
168 f->locvars[oldsize++].varname = NULL;
169 f->locvars[fs->nlocvars].varname = varname;
170 luaC_objbarrier(ls->L, f, varname);
171 return fs->nlocvars++;
172}
173
174
175static void new_localvar (LexState *ls, TString *name) {
176 FuncState *fs = ls->fs;
177 Dyndata *dyd = ls->dyd;
178 int reg = registerlocalvar(ls, name);
179 checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal,
180 MAXVARS, "local variables");
181 luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1,
182 dyd->actvar.size, Vardesc, MAX_INT, "local variables");
183 dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg);
184}
185
186
187static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) {
188 new_localvar(ls, luaX_newstring(ls, name, sz));
189}
190
191#define new_localvarliteral(ls,v) \
192 new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1)
193
194
195static LocVar *getlocvar (FuncState *fs, int i) {
196 int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx;
197 lua_assert(idx < fs->nlocvars);
198 return &fs->f->locvars[idx];
199}
200
201
202static void adjustlocalvars (LexState *ls, int nvars) {
203 FuncState *fs = ls->fs;
204 fs->nactvar = cast_byte(fs->nactvar + nvars);
205 for (; nvars; nvars--) {
206 getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc;
207 }
208}
209
210
211static void removevars (FuncState *fs, int tolevel) {
212 fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel);
213 while (fs->nactvar > tolevel)
214 getlocvar(fs, --fs->nactvar)->endpc = fs->pc;
215}
216
217
218static int searchupvalue (FuncState *fs, TString *name) {
219 int i;
220 Upvaldesc *up = fs->f->upvalues;
221 for (i = 0; i < fs->nups; i++) {
222 if (eqstr(up[i].name, name)) return i;
223 }
224 return -1; /* not found */
225}
226
227
228static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
229 Proto *f = fs->f;
230 int oldsize = f->sizeupvalues;
231 checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues");
232 luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues,
233 Upvaldesc, MAXUPVAL, "upvalues");
234 while (oldsize < f->sizeupvalues)
235 f->upvalues[oldsize++].name = NULL;
236 f->upvalues[fs->nups].instack = (v->k == VLOCAL);
237 f->upvalues[fs->nups].idx = cast_byte(v->u.info);
238 f->upvalues[fs->nups].name = name;
239 luaC_objbarrier(fs->ls->L, f, name);
240 return fs->nups++;
241}
242
243
244static int searchvar (FuncState *fs, TString *n) {
245 int i;
246 for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) {
247 if (eqstr(n, getlocvar(fs, i)->varname))
248 return i;
249 }
250 return -1; /* not found */
251}
252
253
254/*
255 Mark block where variable at given level was defined
256 (to emit close instructions later).
257*/
258static void markupval (FuncState *fs, int level) {
259 BlockCnt *bl = fs->bl;
260 while (bl->nactvar > level)
261 bl = bl->previous;
262 bl->upval = 1;
263}
264
265
266/*
267 Find variable with given name 'n'. If it is an upvalue, add this
268 upvalue into all intermediate functions.
269*/
270static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
271 if (fs == NULL) /* no more levels? */
272 init_exp(var, VVOID, 0); /* default is global */
273 else {
274 int v = searchvar(fs, n); /* look up locals at current level */
275 if (v >= 0) { /* found? */
276 init_exp(var, VLOCAL, v); /* variable is local */
277 if (!base)
278 markupval(fs, v); /* local will be used as an upval */
279 }
280 else { /* not found as local at current level; try upvalues */
281 int idx = searchupvalue(fs, n); /* try existing upvalues */
282 if (idx < 0) { /* not found? */
283 singlevaraux(fs->prev, n, var, 0); /* try upper levels */
284 if (var->k == VVOID) /* not found? */
285 return; /* it is a global */
286 /* else was LOCAL or UPVAL */
287 idx = newupvalue(fs, n, var); /* will be a new upvalue */
288 }
289 init_exp(var, VUPVAL, idx); /* new or old upvalue */
290 }
291 }
292}
293
294
295static void singlevar (LexState *ls, expdesc *var) {
296 TString *varname = str_checkname(ls);
297 FuncState *fs = ls->fs;
298 singlevaraux(fs, varname, var, 1);
299 if (var->k == VVOID) { /* global name? */
300 expdesc key;
301 singlevaraux(fs, ls->envn, var, 1); /* get environment variable */
302 lua_assert(var->k != VVOID); /* this one must exist */
303 codestring(ls, &key, varname); /* key is variable name */
304 luaK_indexed(fs, var, &key); /* env[varname] */
305 }
306}
307
308
309static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
310 FuncState *fs = ls->fs;
311 int extra = nvars - nexps;
312 if (hasmultret(e->k)) {
313 extra++; /* includes call itself */
314 if (extra < 0) extra = 0;
315 luaK_setreturns(fs, e, extra); /* last exp. provides the difference */
316 if (extra > 1) luaK_reserveregs(fs, extra-1);
317 }
318 else {
319 if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */
320 if (extra > 0) {
321 int reg = fs->freereg;
322 luaK_reserveregs(fs, extra);
323 luaK_nil(fs, reg, extra);
324 }
325 }
326 if (nexps > nvars)
327 ls->fs->freereg -= nexps - nvars; /* remove extra values */
328}
329
330
331static void enterlevel (LexState *ls) {
332 lua_State *L = ls->L;
333 ++L->nCcalls;
334 checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "C levels");
335}
336
337
338#define leavelevel(ls) ((ls)->L->nCcalls--)
339
340
341static void closegoto (LexState *ls, int g, Labeldesc *label) {
342 int i;
343 FuncState *fs = ls->fs;
344 Labellist *gl = &ls->dyd->gt;
345 Labeldesc *gt = &gl->arr[g];
346 lua_assert(eqstr(gt->name, label->name));
347 if (gt->nactvar < label->nactvar) {
348 TString *vname = getlocvar(fs, gt->nactvar)->varname;
349 const char *msg = luaO_pushfstring(ls->L,
350 "<goto %s> at line %d jumps into the scope of local '%s'",
351 getstr(gt->name), gt->line, getstr(vname));
352 semerror(ls, msg);
353 }
354 luaK_patchlist(fs, gt->pc, label->pc);
355 /* remove goto from pending list */
356 for (i = g; i < gl->n - 1; i++)
357 gl->arr[i] = gl->arr[i + 1];
358 gl->n--;
359}
360
361
362/*
363** try to close a goto with existing labels; this solves backward jumps
364*/
365static int findlabel (LexState *ls, int g) {
366 int i;
367 BlockCnt *bl = ls->fs->bl;
368 Dyndata *dyd = ls->dyd;
369 Labeldesc *gt = &dyd->gt.arr[g];
370 /* check labels in current block for a match */
371 for (i = bl->firstlabel; i < dyd->label.n; i++) {
372 Labeldesc *lb = &dyd->label.arr[i];
373 if (eqstr(lb->name, gt->name)) { /* correct label? */
374 if (gt->nactvar > lb->nactvar &&
375 (bl->upval || dyd->label.n > bl->firstlabel))
376 luaK_patchclose(ls->fs, gt->pc, lb->nactvar);
377 closegoto(ls, g, lb); /* close it */
378 return 1;
379 }
380 }
381 return 0; /* label not found; cannot close goto */
382}
383
384
385static int newlabelentry (LexState *ls, Labellist *l, TString *name,
386 int line, int pc) {
387 int n = l->n;
388 luaM_growvector(ls->L, l->arr, n, l->size,
389 Labeldesc, SHRT_MAX, "labels/gotos");
390 l->arr[n].name = name;
391 l->arr[n].line = line;
392 l->arr[n].nactvar = ls->fs->nactvar;
393 l->arr[n].pc = pc;
394 l->n = n + 1;
395 return n;
396}
397
398
399/*
400** check whether new label 'lb' matches any pending gotos in current
401** block; solves forward jumps
402*/
403static void findgotos (LexState *ls, Labeldesc *lb) {
404 Labellist *gl = &ls->dyd->gt;
405 int i = ls->fs->bl->firstgoto;
406 while (i < gl->n) {
407 if (eqstr(gl->arr[i].name, lb->name))
408 closegoto(ls, i, lb);
409 else
410 i++;
411 }
412}
413
414
415/*
416** export pending gotos to outer level, to check them against
417** outer labels; if the block being exited has upvalues, and
418** the goto exits the scope of any variable (which can be the
419** upvalue), close those variables being exited.
420*/
421static void movegotosout (FuncState *fs, BlockCnt *bl) {
422 int i = bl->firstgoto;
423 Labellist *gl = &fs->ls->dyd->gt;
424 /* correct pending gotos to current block and try to close it
425 with visible labels */
426 while (i < gl->n) {
427 Labeldesc *gt = &gl->arr[i];
428 if (gt->nactvar > bl->nactvar) {
429 if (bl->upval)
430 luaK_patchclose(fs, gt->pc, bl->nactvar);
431 gt->nactvar = bl->nactvar;
432 }
433 if (!findlabel(fs->ls, i))
434 i++; /* move to next one */
435 }
436}
437
438
439static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) {
440 bl->isloop = isloop;
441 bl->nactvar = fs->nactvar;
442 bl->firstlabel = fs->ls->dyd->label.n;
443 bl->firstgoto = fs->ls->dyd->gt.n;
444 bl->upval = 0;
445 bl->previous = fs->bl;
446 fs->bl = bl;
447 lua_assert(fs->freereg == fs->nactvar);
448}
449
450
451/*
452** create a label named 'break' to resolve break statements
453*/
454static void breaklabel (LexState *ls) {
455 TString *n = luaS_new(ls->L, "break");
456 int l = newlabelentry(ls, &ls->dyd->label, n, 0, ls->fs->pc);
457 findgotos(ls, &ls->dyd->label.arr[l]);
458}
459
460/*
461** generates an error for an undefined 'goto'; choose appropriate
462** message when label name is a reserved word (which can only be 'break')
463*/
464static l_noret undefgoto (LexState *ls, Labeldesc *gt) {
465 const char *msg = isreserved(gt->name)
466 ? "<%s> at line %d not inside a loop"
467 : "no visible label '%s' for <goto> at line %d";
468 msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line);
469 semerror(ls, msg);
470}
471
472
473static void leaveblock (FuncState *fs) {
474 BlockCnt *bl = fs->bl;
475 LexState *ls = fs->ls;
476 if (bl->previous && bl->upval) {
477 /* create a 'jump to here' to close upvalues */
478 int j = luaK_jump(fs);
479 luaK_patchclose(fs, j, bl->nactvar);
480 luaK_patchtohere(fs, j);
481 }
482 if (bl->isloop)
483 breaklabel(ls); /* close pending breaks */
484 fs->bl = bl->previous;
485 removevars(fs, bl->nactvar);
486 lua_assert(bl->nactvar == fs->nactvar);
487 fs->freereg = fs->nactvar; /* free registers */
488 ls->dyd->label.n = bl->firstlabel; /* remove local labels */
489 if (bl->previous) /* inner block? */
490 movegotosout(fs, bl); /* update pending gotos to outer block */
491 else if (bl->firstgoto < ls->dyd->gt.n) /* pending gotos in outer block? */
492 undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]); /* error */
493}
494
495
496/*
497** adds a new prototype into list of prototypes
498*/
499static Proto *addprototype (LexState *ls) {
500 Proto *clp;
501 lua_State *L = ls->L;
502 FuncState *fs = ls->fs;
503 Proto *f = fs->f; /* prototype of current function */
504 if (fs->np >= f->sizep) {
505 int oldsize = f->sizep;
506 luaM_growvector(L, f->p, fs->np, f->sizep, Proto *, MAXARG_Bx, "functions");
507 while (oldsize < f->sizep)
508 f->p[oldsize++] = NULL;
509 }
510 f->p[fs->np++] = clp = luaF_newproto(L);
511 luaC_objbarrier(L, f, clp);
512 return clp;
513}
514
515
516/*
517** codes instruction to create new closure in parent function.
518** The OP_CLOSURE instruction must use the last available register,
519** so that, if it invokes the GC, the GC knows which registers
520** are in use at that time.
521*/
522static void codeclosure (LexState *ls, expdesc *v) {
523 FuncState *fs = ls->fs->prev;
524 init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1));
525 luaK_exp2nextreg(fs, v); /* fix it at the last register */
526}
527
528
529static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
530 Proto *f;
531 fs->prev = ls->fs; /* linked list of funcstates */
532 fs->ls = ls;
533 ls->fs = fs;
534 fs->pc = 0;
535 fs->lasttarget = 0;
536 fs->jpc = NO_JUMP;
537 fs->freereg = 0;
538 fs->nk = 0;
539 fs->np = 0;
540 fs->nups = 0;
541 fs->nlocvars = 0;
542 fs->nactvar = 0;
543 fs->firstlocal = ls->dyd->actvar.n;
544 fs->bl = NULL;
545 f = fs->f;
546 f->source = ls->source;
547 luaC_objbarrier(ls->L, f, f->source);
548 f->maxstacksize = 2; /* registers 0/1 are always valid */
549 enterblock(fs, bl, 0);
550}
551
552
553static void close_func (LexState *ls) {
554 lua_State *L = ls->L;
555 FuncState *fs = ls->fs;
556 Proto *f = fs->f;
557 luaK_ret(fs, 0, 0); /* final return */
558 leaveblock(fs);
559 luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
560 f->sizecode = fs->pc;
561 luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
562 f->sizelineinfo = fs->pc;
563 luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
564 f->sizek = fs->nk;
565 luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
566 f->sizep = fs->np;
567 luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
568 f->sizelocvars = fs->nlocvars;
569 luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc);
570 f->sizeupvalues = fs->nups;
571 lua_assert(fs->bl == NULL);
572 ls->fs = fs->prev;
573 luaC_checkGC(L);
574}
575
576
577
578/*============================================================*/
579/* GRAMMAR RULES */
580/*============================================================*/
581
582
583/*
584** check whether current token is in the follow set of a block.
585** 'until' closes syntactical blocks, but do not close scope,
586** so it is handled in separate.
587*/
588static int block_follow (LexState *ls, int withuntil) {
589 switch (ls->t.token) {
590 case TK_ELSE: case TK_ELSEIF:
591 case TK_END: case TK_EOS:
592 return 1;
593 case TK_UNTIL: return withuntil;
594 default: return 0;
595 }
596}
597
598
599static void statlist (LexState *ls) {
600 /* statlist -> { stat [';'] } */
601 while (!block_follow(ls, 1)) {
602 if (ls->t.token == TK_RETURN) {
603 statement(ls);
604 return; /* 'return' must be last statement */
605 }
606 statement(ls);
607 }
608}
609
610
611static void fieldsel (LexState *ls, expdesc *v) {
612 /* fieldsel -> ['.' | ':'] NAME */
613 FuncState *fs = ls->fs;
614 expdesc key;
615 luaK_exp2anyregup(fs, v);
616 luaX_next(ls); /* skip the dot or colon */
617 checkname(ls, &key);
618 luaK_indexed(fs, v, &key);
619}
620
621
622static void yindex (LexState *ls, expdesc *v) {
623 /* index -> '[' expr ']' */
624 luaX_next(ls); /* skip the '[' */
625 expr(ls, v);
626 luaK_exp2val(ls->fs, v);
627 checknext(ls, ']');
628}
629
630
631/*
632** {======================================================================
633** Rules for Constructors
634** =======================================================================
635*/
636
637
638struct ConsControl {
639 expdesc v; /* last list item read */
640 expdesc *t; /* table descriptor */
641 int nh; /* total number of 'record' elements */
642 int na; /* total number of array elements */
643 int tostore; /* number of array elements pending to be stored */
644};
645
646
647static void recfield (LexState *ls, struct ConsControl *cc) {
648 /* recfield -> (NAME | '['exp1']') = exp1 */
649 FuncState *fs = ls->fs;
650 int reg = ls->fs->freereg;
651 expdesc key, val;
652 int rkkey;
653 if (ls->t.token == TK_NAME) {
654 checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
655 checkname(ls, &key);
656 }
657 else /* ls->t.token == '[' */
658 yindex(ls, &key);
659 cc->nh++;
660 checknext(ls, '=');
661 rkkey = luaK_exp2RK(fs, &key);
662 expr(ls, &val);
663 luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val));
664 fs->freereg = reg; /* free registers */
665}
666
667
668static void closelistfield (FuncState *fs, struct ConsControl *cc) {
669 if (cc->v.k == VVOID) return; /* there is no list item */
670 luaK_exp2nextreg(fs, &cc->v);
671 cc->v.k = VVOID;
672 if (cc->tostore == LFIELDS_PER_FLUSH) {
673 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); /* flush */
674 cc->tostore = 0; /* no more items pending */
675 }
676}
677
678
679static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
680 if (cc->tostore == 0) return;
681 if (hasmultret(cc->v.k)) {
682 luaK_setmultret(fs, &cc->v);
683 luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET);
684 cc->na--; /* do not count last expression (unknown number of elements) */
685 }
686 else {
687 if (cc->v.k != VVOID)
688 luaK_exp2nextreg(fs, &cc->v);
689 luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore);
690 }
691}
692
693
694static void listfield (LexState *ls, struct ConsControl *cc) {
695 /* listfield -> exp */
696 expr(ls, &cc->v);
697 checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
698 cc->na++;
699 cc->tostore++;
700}
701
702
703static void field (LexState *ls, struct ConsControl *cc) {
704 /* field -> listfield | recfield */
705 switch(ls->t.token) {
706 case TK_NAME: { /* may be 'listfield' or 'recfield' */
707 if (luaX_lookahead(ls) != '=') /* expression? */
708 listfield(ls, cc);
709 else
710 recfield(ls, cc);
711 break;
712 }
713 case '[': {
714 recfield(ls, cc);
715 break;
716 }
717 default: {
718 listfield(ls, cc);
719 break;
720 }
721 }
722}
723
724
725static void constructor (LexState *ls, expdesc *t) {
726 /* constructor -> '{' [ field { sep field } [sep] ] '}'
727 sep -> ',' | ';' */
728 FuncState *fs = ls->fs;
729 int line = ls->linenumber;
730 int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
731 struct ConsControl cc;
732 cc.na = cc.nh = cc.tostore = 0;
733 cc.t = t;
734 init_exp(t, VRELOCABLE, pc);
735 init_exp(&cc.v, VVOID, 0); /* no value (yet) */
736 luaK_exp2nextreg(ls->fs, t); /* fix it at stack top */
737 checknext(ls, '{');
738 do {
739 lua_assert(cc.v.k == VVOID || cc.tostore > 0);
740 if (ls->t.token == '}') break;
741 closelistfield(fs, &cc);
742 field(ls, &cc);
743 } while (testnext(ls, ',') || testnext(ls, ';'));
744 check_match(ls, '}', '{', line);
745 lastlistfield(fs, &cc);
746 SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
747 SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */
748}
749
750/* }====================================================================== */
751
752
753
754static void parlist (LexState *ls) {
755 /* parlist -> [ param { ',' param } ] */
756 FuncState *fs = ls->fs;
757 Proto *f = fs->f;
758 int nparams = 0;
759 f->is_vararg = 0;
760 if (ls->t.token != ')') { /* is 'parlist' not empty? */
761 do {
762 switch (ls->t.token) {
763 case TK_NAME: { /* param -> NAME */
764 new_localvar(ls, str_checkname(ls));
765 nparams++;
766 break;
767 }
768 case TK_DOTS: { /* param -> '...' */
769 luaX_next(ls);
770 f->is_vararg = 1; /* declared vararg */
771 break;
772 }
773 default: luaX_syntaxerror(ls, "<name> or '...' expected");
774 }
775 } while (!f->is_vararg && testnext(ls, ','));
776 }
777 adjustlocalvars(ls, nparams);
778 f->numparams = cast_byte(fs->nactvar);
779 luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */
780}
781
782
783static void body (LexState *ls, expdesc *e, int ismethod, int line) {
784 /* body -> '(' parlist ')' block END */
785 FuncState new_fs;
786 BlockCnt bl;
787 new_fs.f = addprototype(ls);
788 new_fs.f->linedefined = line;
789 open_func(ls, &new_fs, &bl);
790 checknext(ls, '(');
791 if (ismethod) {
792 new_localvarliteral(ls, "self"); /* create 'self' parameter */
793 adjustlocalvars(ls, 1);
794 }
795 parlist(ls);
796 checknext(ls, ')');
797 statlist(ls);
798 new_fs.f->lastlinedefined = ls->linenumber;
799 check_match(ls, TK_END, TK_FUNCTION, line);
800 codeclosure(ls, e);
801 close_func(ls);
802}
803
804
805static int explist (LexState *ls, expdesc *v) {
806 /* explist -> expr { ',' expr } */
807 int n = 1; /* at least one expression */
808 expr(ls, v);
809 while (testnext(ls, ',')) {
810 luaK_exp2nextreg(ls->fs, v);
811 expr(ls, v);
812 n++;
813 }
814 return n;
815}
816
817
818static void funcargs (LexState *ls, expdesc *f, int line) {
819 FuncState *fs = ls->fs;
820 expdesc args;
821 int base, nparams;
822 switch (ls->t.token) {
823 case '(': { /* funcargs -> '(' [ explist ] ')' */
824 luaX_next(ls);
825 if (ls->t.token == ')') /* arg list is empty? */
826 args.k = VVOID;
827 else {
828 explist(ls, &args);
829 luaK_setmultret(fs, &args);
830 }
831 check_match(ls, ')', '(', line);
832 break;
833 }
834 case '{': { /* funcargs -> constructor */
835 constructor(ls, &args);
836 break;
837 }
838 case TK_STRING: { /* funcargs -> STRING */
839 codestring(ls, &args, ls->t.seminfo.ts);
840 luaX_next(ls); /* must use 'seminfo' before 'next' */
841 break;
842 }
843 default: {
844 luaX_syntaxerror(ls, "function arguments expected");
845 }
846 }
847 lua_assert(f->k == VNONRELOC);
848 base = f->u.info; /* base register for call */
849 if (hasmultret(args.k))
850 nparams = LUA_MULTRET; /* open call */
851 else {
852 if (args.k != VVOID)
853 luaK_exp2nextreg(fs, &args); /* close last argument */
854 nparams = fs->freereg - (base+1);
855 }
856 init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
857 luaK_fixline(fs, line);
858 fs->freereg = base+1; /* call remove function and arguments and leaves
859 (unless changed) one result */
860}
861
862
863
864
865/*
866** {======================================================================
867** Expression parsing
868** =======================================================================
869*/
870
871
872static void primaryexp (LexState *ls, expdesc *v) {
873 /* primaryexp -> NAME | '(' expr ')' */
874 switch (ls->t.token) {
875 case '(': {
876 int line = ls->linenumber;
877 luaX_next(ls);
878 expr(ls, v);
879 check_match(ls, ')', '(', line);
880 luaK_dischargevars(ls->fs, v);
881 return;
882 }
883 case TK_NAME: {
884 singlevar(ls, v);
885 return;
886 }
887 default: {
888 luaX_syntaxerror(ls, "unexpected symbol");
889 }
890 }
891}
892
893
894static void suffixedexp (LexState *ls, expdesc *v) {
895 /* suffixedexp ->
896 primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */
897 FuncState *fs = ls->fs;
898 int line = ls->linenumber;
899 primaryexp(ls, v);
900 for (;;) {
901 switch (ls->t.token) {
902 case '.': { /* fieldsel */
903 fieldsel(ls, v);
904 break;
905 }
906 case '[': { /* '[' exp1 ']' */
907 expdesc key;
908 luaK_exp2anyregup(fs, v);
909 yindex(ls, &key);
910 luaK_indexed(fs, v, &key);
911 break;
912 }
913 case ':': { /* ':' NAME funcargs */
914 expdesc key;
915 luaX_next(ls);
916 checkname(ls, &key);
917 luaK_self(fs, v, &key);
918 funcargs(ls, v, line);
919 break;
920 }
921 case '(': case TK_STRING: case '{': { /* funcargs */
922 luaK_exp2nextreg(fs, v);
923 funcargs(ls, v, line);
924 break;
925 }
926 default: return;
927 }
928 }
929}
930
931
932static void simpleexp (LexState *ls, expdesc *v) {
933 /* simpleexp -> FLT | INT | STRING | NIL | TRUE | FALSE | ... |
934 constructor | FUNCTION body | suffixedexp */
935 switch (ls->t.token) {
936 case TK_FLT: {
937 init_exp(v, VKFLT, 0);
938 v->u.nval = ls->t.seminfo.r;
939 break;
940 }
941 case TK_INT: {
942 init_exp(v, VKINT, 0);
943 v->u.ival = ls->t.seminfo.i;
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 '...' 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
987static UnOpr getunopr (int op) {
988 switch (op) {
989 case TK_NOT: return OPR_NOT;
990 case '-': return OPR_MINUS;
991 case '~': return OPR_BNOT;
992 case '#': return OPR_LEN;
993 default: return OPR_NOUNOPR;
994 }
995}
996
997
998static BinOpr getbinopr (int op) {
999 switch (op) {
1000 case '+': return OPR_ADD;
1001 case '-': return OPR_SUB;
1002 case '*': return OPR_MUL;
1003 case '%': return OPR_MOD;
1004 case '^': return OPR_POW;
1005 case '/': return OPR_DIV;
1006 case TK_IDIV: return OPR_IDIV;
1007 case '&': return OPR_BAND;
1008 case '|': return OPR_BOR;
1009 case '~': return OPR_BXOR;
1010 case TK_SHL: return OPR_SHL;
1011 case TK_SHR: return OPR_SHR;
1012 case TK_CONCAT: return OPR_CONCAT;
1013 case TK_NE: return OPR_NE;
1014 case TK_EQ: return OPR_EQ;
1015 case '<': return OPR_LT;
1016 case TK_LE: return OPR_LE;
1017 case '>': return OPR_GT;
1018 case TK_GE: return OPR_GE;
1019 case TK_AND: return OPR_AND;
1020 case TK_OR: return OPR_OR;
1021 default: return OPR_NOBINOPR;
1022 }
1023}
1024
1025
1026static const struct {
1027 lu_byte left; /* left priority for each binary operator */
1028 lu_byte right; /* right priority */
1029} priority[] = { /* ORDER OPR */
1030 {10, 10}, {10, 10}, /* '+' '-' */
1031 {11, 11}, {11, 11}, /* '*' '%' */
1032 {14, 13}, /* '^' (right associative) */
1033 {11, 11}, {11, 11}, /* '/' '//' */
1034 {6, 6}, {4, 4}, {5, 5}, /* '&' '|' '~' */
1035 {7, 7}, {7, 7}, /* '<<' '>>' */
1036 {9, 8}, /* '..' (right associative) */
1037 {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */
1038 {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */
1039 {2, 2}, {1, 1} /* and, or */
1040};
1041
1042#define UNARY_PRIORITY 12 /* priority for unary operators */
1043
1044
1045/*
1046** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
1047** where 'binop' is any binary operator with a priority higher than 'limit'
1048*/
1049static BinOpr subexpr (LexState *ls, expdesc *v, int limit) {
1050 BinOpr op;
1051 UnOpr uop;
1052 enterlevel(ls);
1053 uop = getunopr(ls->t.token);
1054 if (uop != OPR_NOUNOPR) {
1055 int line = ls->linenumber;
1056 luaX_next(ls);
1057 subexpr(ls, v, UNARY_PRIORITY);
1058 luaK_prefix(ls->fs, uop, v, line);
1059 }
1060 else simpleexp(ls, v);
1061 /* expand while operators have priorities higher than 'limit' */
1062 op = getbinopr(ls->t.token);
1063 while (op != OPR_NOBINOPR && priority[op].left > limit) {
1064 expdesc v2;
1065 BinOpr nextop;
1066 int line = ls->linenumber;
1067 luaX_next(ls);
1068 luaK_infix(ls->fs, op, v);
1069 /* read sub-expression with higher priority */
1070 nextop = subexpr(ls, &v2, priority[op].right);
1071 luaK_posfix(ls->fs, op, v, &v2, line);
1072 op = nextop;
1073 }
1074 leavelevel(ls);
1075 return op; /* return first untreated operator */
1076}
1077
1078
1079static void expr (LexState *ls, expdesc *v) {
1080 subexpr(ls, v, 0);
1081}
1082
1083/* }==================================================================== */
1084
1085
1086
1087/*
1088** {======================================================================
1089** Rules for Statements
1090** =======================================================================
1091*/
1092
1093
1094static void block (LexState *ls) {
1095 /* block -> statlist */
1096 FuncState *fs = ls->fs;
1097 BlockCnt bl;
1098 enterblock(fs, &bl, 0);
1099 statlist(ls);
1100 leaveblock(fs);
1101}
1102
1103
1104/*
1105** structure to chain all variables in the left-hand side of an
1106** assignment
1107*/
1108struct LHS_assign {
1109 struct LHS_assign *prev;
1110 expdesc v; /* variable (global, local, upvalue, or indexed) */
1111};
1112
1113
1114/*
1115** check whether, in an assignment to an upvalue/local variable, the
1116** upvalue/local variable is begin used in a previous assignment to a
1117** table. If so, save original upvalue/local value in a safe place and
1118** use this safe copy in the previous assignment.
1119*/
1120static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
1121 FuncState *fs = ls->fs;
1122 int extra = fs->freereg; /* eventual position to save local variable */
1123 int conflict = 0;
1124 for (; lh; lh = lh->prev) { /* check all previous assignments */
1125 if (lh->v.k == VINDEXED) { /* assigning to a table? */
1126 /* table is the upvalue/local being assigned now? */
1127 if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) {
1128 conflict = 1;
1129 lh->v.u.ind.vt = VLOCAL;
1130 lh->v.u.ind.t = extra; /* previous assignment will use safe copy */
1131 }
1132 /* index is the local being assigned? (index cannot be upvalue) */
1133 if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) {
1134 conflict = 1;
1135 lh->v.u.ind.idx = extra; /* previous assignment will use safe copy */
1136 }
1137 }
1138 }
1139 if (conflict) {
1140 /* copy upvalue/local value to a temporary (in position 'extra') */
1141 OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
1142 luaK_codeABC(fs, op, extra, v->u.info, 0);
1143 luaK_reserveregs(fs, 1);
1144 }
1145}
1146
1147
1148static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
1149 expdesc e;
1150 check_condition(ls, vkisvar(lh->v.k), "syntax error");
1151 if (testnext(ls, ',')) { /* assignment -> ',' suffixedexp assignment */
1152 struct LHS_assign nv;
1153 nv.prev = lh;
1154 suffixedexp(ls, &nv.v);
1155 if (nv.v.k != VINDEXED)
1156 check_conflict(ls, lh, &nv.v);
1157 checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS,
1158 "C levels");
1159 assignment(ls, &nv, nvars+1);
1160 }
1161 else { /* assignment -> '=' explist */
1162 int nexps;
1163 checknext(ls, '=');
1164 nexps = explist(ls, &e);
1165 if (nexps != nvars)
1166 adjust_assign(ls, nvars, nexps, &e);
1167 else {
1168 luaK_setoneret(ls->fs, &e); /* close last expression */
1169 luaK_storevar(ls->fs, &lh->v, &e);
1170 return; /* avoid default */
1171 }
1172 }
1173 init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */
1174 luaK_storevar(ls->fs, &lh->v, &e);
1175}
1176
1177
1178static int cond (LexState *ls) {
1179 /* cond -> exp */
1180 expdesc v;
1181 expr(ls, &v); /* read condition */
1182 if (v.k == VNIL) v.k = VFALSE; /* 'falses' are all equal here */
1183 luaK_goiftrue(ls->fs, &v);
1184 return v.f;
1185}
1186
1187
1188static void gotostat (LexState *ls, int pc) {
1189 int line = ls->linenumber;
1190 TString *label;
1191 int g;
1192 if (testnext(ls, TK_GOTO))
1193 label = str_checkname(ls);
1194 else {
1195 luaX_next(ls); /* skip break */
1196 label = luaS_new(ls->L, "break");
1197 }
1198 g = newlabelentry(ls, &ls->dyd->gt, label, line, pc);
1199 findlabel(ls, g); /* close it if label already defined */
1200}
1201
1202
1203/* check for repeated labels on the same block */
1204static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) {
1205 int i;
1206 for (i = fs->bl->firstlabel; i < ll->n; i++) {
1207 if (eqstr(label, ll->arr[i].name)) {
1208 const char *msg = luaO_pushfstring(fs->ls->L,
1209 "label '%s' already defined on line %d",
1210 getstr(label), ll->arr[i].line);
1211 semerror(fs->ls, msg);
1212 }
1213 }
1214}
1215
1216
1217/* skip no-op statements */
1218static void skipnoopstat (LexState *ls) {
1219 while (ls->t.token == ';' || ls->t.token == TK_DBCOLON)
1220 statement(ls);
1221}
1222
1223
1224static void labelstat (LexState *ls, TString *label, int line) {
1225 /* label -> '::' NAME '::' */
1226 FuncState *fs = ls->fs;
1227 Labellist *ll = &ls->dyd->label;
1228 int l; /* index of new label being created */
1229 checkrepeated(fs, ll, label); /* check for repeated labels */
1230 checknext(ls, TK_DBCOLON); /* skip double colon */
1231 /* create new entry for this label */
1232 l = newlabelentry(ls, ll, label, line, luaK_getlabel(fs));
1233 skipnoopstat(ls); /* skip other no-op statements */
1234 if (block_follow(ls, 0)) { /* label is last no-op statement in the block? */
1235 /* assume that locals are already out of scope */
1236 ll->arr[l].nactvar = fs->bl->nactvar;
1237 }
1238 findgotos(ls, &ll->arr[l]);
1239}
1240
1241
1242static void whilestat (LexState *ls, int line) {
1243 /* whilestat -> WHILE cond DO block END */
1244 FuncState *fs = ls->fs;
1245 int whileinit;
1246 int condexit;
1247 BlockCnt bl;
1248 luaX_next(ls); /* skip WHILE */
1249 whileinit = luaK_getlabel(fs);
1250 condexit = cond(ls);
1251 enterblock(fs, &bl, 1);
1252 checknext(ls, TK_DO);
1253 block(ls);
1254 luaK_jumpto(fs, whileinit);
1255 check_match(ls, TK_END, TK_WHILE, line);
1256 leaveblock(fs);
1257 luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
1258}
1259
1260
1261static void repeatstat (LexState *ls, int line) {
1262 /* repeatstat -> REPEAT block UNTIL cond */
1263 int condexit;
1264 FuncState *fs = ls->fs;
1265 int repeat_init = luaK_getlabel(fs);
1266 BlockCnt bl1, bl2;
1267 enterblock(fs, &bl1, 1); /* loop block */
1268 enterblock(fs, &bl2, 0); /* scope block */
1269 luaX_next(ls); /* skip REPEAT */
1270 statlist(ls);
1271 check_match(ls, TK_UNTIL, TK_REPEAT, line);
1272 condexit = cond(ls); /* read condition (inside scope block) */
1273 if (bl2.upval) /* upvalues? */
1274 luaK_patchclose(fs, condexit, bl2.nactvar);
1275 leaveblock(fs); /* finish scope */
1276 luaK_patchlist(fs, condexit, repeat_init); /* close the loop */
1277 leaveblock(fs); /* finish loop */
1278}
1279
1280
1281static int exp1 (LexState *ls) {
1282 expdesc e;
1283 int reg;
1284 expr(ls, &e);
1285 luaK_exp2nextreg(ls->fs, &e);
1286 lua_assert(e.k == VNONRELOC);
1287 reg = e.u.info;
1288 return reg;
1289}
1290
1291
1292static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
1293 /* forbody -> DO block */
1294 BlockCnt bl;
1295 FuncState *fs = ls->fs;
1296 int prep, endfor;
1297 adjustlocalvars(ls, 3); /* control variables */
1298 checknext(ls, TK_DO);
1299 prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
1300 enterblock(fs, &bl, 0); /* scope for declared variables */
1301 adjustlocalvars(ls, nvars);
1302 luaK_reserveregs(fs, nvars);
1303 block(ls);
1304 leaveblock(fs); /* end of scope for declared variables */
1305 luaK_patchtohere(fs, prep);
1306 if (isnum) /* numeric for? */
1307 endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP);
1308 else { /* generic for */
1309 luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
1310 luaK_fixline(fs, line);
1311 endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP);
1312 }
1313 luaK_patchlist(fs, endfor, prep + 1);
1314 luaK_fixline(fs, line);
1315}
1316
1317
1318static void fornum (LexState *ls, TString *varname, int line) {
1319 /* fornum -> NAME = exp1,exp1[,exp1] forbody */
1320 FuncState *fs = ls->fs;
1321 int base = fs->freereg;
1322 new_localvarliteral(ls, "(for index)");
1323 new_localvarliteral(ls, "(for limit)");
1324 new_localvarliteral(ls, "(for step)");
1325 new_localvar(ls, varname);
1326 checknext(ls, '=');
1327 exp1(ls); /* initial value */
1328 checknext(ls, ',');
1329 exp1(ls); /* limit */
1330 if (testnext(ls, ','))
1331 exp1(ls); /* optional step */
1332 else { /* default step = 1 */
1333 luaK_codek(fs, fs->freereg, luaK_intK(fs, 1));
1334 luaK_reserveregs(fs, 1);
1335 }
1336 forbody(ls, base, line, 1, 1);
1337}
1338
1339
1340static void forlist (LexState *ls, TString *indexname) {
1341 /* forlist -> NAME {,NAME} IN explist forbody */
1342 FuncState *fs = ls->fs;
1343 expdesc e;
1344 int nvars = 4; /* gen, state, control, plus at least one declared var */
1345 int line;
1346 int base = fs->freereg;
1347 /* create control variables */
1348 new_localvarliteral(ls, "(for generator)");
1349 new_localvarliteral(ls, "(for state)");
1350 new_localvarliteral(ls, "(for control)");
1351 /* create declared variables */
1352 new_localvar(ls, indexname);
1353 while (testnext(ls, ',')) {
1354 new_localvar(ls, str_checkname(ls));
1355 nvars++;
1356 }
1357 checknext(ls, TK_IN);
1358 line = ls->linenumber;
1359 adjust_assign(ls, 3, explist(ls, &e), &e);
1360 luaK_checkstack(fs, 3); /* extra space to call generator */
1361 forbody(ls, base, line, nvars - 3, 0);
1362}
1363
1364
1365static void forstat (LexState *ls, int line) {
1366 /* forstat -> FOR (fornum | forlist) END */
1367 FuncState *fs = ls->fs;
1368 TString *varname;
1369 BlockCnt bl;
1370 enterblock(fs, &bl, 1); /* scope for loop and control variables */
1371 luaX_next(ls); /* skip 'for' */
1372 varname = str_checkname(ls); /* first variable name */
1373 switch (ls->t.token) {
1374 case '=': fornum(ls, varname, line); break;
1375 case ',': case TK_IN: forlist(ls, varname); break;
1376 default: luaX_syntaxerror(ls, "'=' or 'in' expected");
1377 }
1378 check_match(ls, TK_END, TK_FOR, line);
1379 leaveblock(fs); /* loop scope ('break' jumps to this point) */
1380}
1381
1382
1383static void test_then_block (LexState *ls, int *escapelist) {
1384 /* test_then_block -> [IF | ELSEIF] cond THEN block */
1385 BlockCnt bl;
1386 FuncState *fs = ls->fs;
1387 expdesc v;
1388 int jf; /* instruction to skip 'then' code (if condition is false) */
1389 luaX_next(ls); /* skip IF or ELSEIF */
1390 expr(ls, &v); /* read condition */
1391 checknext(ls, TK_THEN);
1392 if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) {
1393 luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */
1394 enterblock(fs, &bl, 0); /* must enter block before 'goto' */
1395 gotostat(ls, v.t); /* handle goto/break */
1396 while (testnext(ls, ';')) {} /* skip colons */
1397 if (block_follow(ls, 0)) { /* 'goto' is the entire block? */
1398 leaveblock(fs);
1399 return; /* and that is it */
1400 }
1401 else /* must skip over 'then' part if condition is false */
1402 jf = luaK_jump(fs);
1403 }
1404 else { /* regular case (not goto/break) */
1405 luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */
1406 enterblock(fs, &bl, 0);
1407 jf = v.f;
1408 }
1409 statlist(ls); /* 'then' part */
1410 leaveblock(fs);
1411 if (ls->t.token == TK_ELSE ||
1412 ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */
1413 luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */
1414 luaK_patchtohere(fs, jf);
1415}
1416
1417
1418static void ifstat (LexState *ls, int line) {
1419 /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
1420 FuncState *fs = ls->fs;
1421 int escapelist = NO_JUMP; /* exit list for finished parts */
1422 test_then_block(ls, &escapelist); /* IF cond THEN block */
1423 while (ls->t.token == TK_ELSEIF)
1424 test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */
1425 if (testnext(ls, TK_ELSE))
1426 block(ls); /* 'else' part */
1427 check_match(ls, TK_END, TK_IF, line);
1428 luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */
1429}
1430
1431
1432static void localfunc (LexState *ls) {
1433 expdesc b;
1434 FuncState *fs = ls->fs;
1435 new_localvar(ls, str_checkname(ls)); /* new local variable */
1436 adjustlocalvars(ls, 1); /* enter its scope */
1437 body(ls, &b, 0, ls->linenumber); /* function created in next register */
1438 /* debug information will only see the variable after this point! */
1439 getlocvar(fs, b.u.info)->startpc = fs->pc;
1440}
1441
1442
1443static void localstat (LexState *ls) {
1444 /* stat -> LOCAL NAME {',' NAME} ['=' explist] */
1445 int nvars = 0;
1446 int nexps;
1447 expdesc e;
1448 do {
1449 new_localvar(ls, str_checkname(ls));
1450 nvars++;
1451 } while (testnext(ls, ','));
1452 if (testnext(ls, '='))
1453 nexps = explist(ls, &e);
1454 else {
1455 e.k = VVOID;
1456 nexps = 0;
1457 }
1458 adjust_assign(ls, nvars, nexps, &e);
1459 adjustlocalvars(ls, nvars);
1460}
1461
1462
1463static int funcname (LexState *ls, expdesc *v) {
1464 /* funcname -> NAME {fieldsel} [':' NAME] */
1465 int ismethod = 0;
1466 singlevar(ls, v);
1467 while (ls->t.token == '.')
1468 fieldsel(ls, v);
1469 if (ls->t.token == ':') {
1470 ismethod = 1;
1471 fieldsel(ls, v);
1472 }
1473 return ismethod;
1474}
1475
1476
1477static void funcstat (LexState *ls, int line) {
1478 /* funcstat -> FUNCTION funcname body */
1479 int ismethod;
1480 expdesc v, b;
1481 luaX_next(ls); /* skip FUNCTION */
1482 ismethod = funcname(ls, &v);
1483 body(ls, &b, ismethod, line);
1484 luaK_storevar(ls->fs, &v, &b);
1485 luaK_fixline(ls->fs, line); /* definition "happens" in the first line */
1486}
1487
1488
1489static void exprstat (LexState *ls) {
1490 /* stat -> func | assignment */
1491 FuncState *fs = ls->fs;
1492 struct LHS_assign v;
1493 suffixedexp(ls, &v.v);
1494 if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */
1495 v.prev = NULL;
1496 assignment(ls, &v, 1);
1497 }
1498 else { /* stat -> func */
1499 check_condition(ls, v.v.k == VCALL, "syntax error");
1500 SETARG_C(getinstruction(fs, &v.v), 1); /* call statement uses no results */
1501 }
1502}
1503
1504
1505static void retstat (LexState *ls) {
1506 /* stat -> RETURN [explist] [';'] */
1507 FuncState *fs = ls->fs;
1508 expdesc e;
1509 int first, nret; /* registers with returned values */
1510 if (block_follow(ls, 1) || ls->t.token == ';')
1511 first = nret = 0; /* return no values */
1512 else {
1513 nret = explist(ls, &e); /* optional return values */
1514 if (hasmultret(e.k)) {
1515 luaK_setmultret(fs, &e);
1516 if (e.k == VCALL && nret == 1) { /* tail call? */
1517 SET_OPCODE(getinstruction(fs,&e), OP_TAILCALL);
1518 lua_assert(GETARG_A(getinstruction(fs,&e)) == fs->nactvar);
1519 }
1520 first = fs->nactvar;
1521 nret = LUA_MULTRET; /* return all values */
1522 }
1523 else {
1524 if (nret == 1) /* only one single value? */
1525 first = luaK_exp2anyreg(fs, &e);
1526 else {
1527 luaK_exp2nextreg(fs, &e); /* values must go to the stack */
1528 first = fs->nactvar; /* return all active values */
1529 lua_assert(nret == fs->freereg - first);
1530 }
1531 }
1532 }
1533 luaK_ret(fs, first, nret);
1534 testnext(ls, ';'); /* skip optional semicolon */
1535}
1536
1537
1538static void statement (LexState *ls) {
1539 int line = ls->linenumber; /* may be needed for error messages */
1540 enterlevel(ls);
1541 switch (ls->t.token) {
1542 case ';': { /* stat -> ';' (empty statement) */
1543 luaX_next(ls); /* skip ';' */
1544 break;
1545 }
1546 case TK_IF: { /* stat -> ifstat */
1547 ifstat(ls, line);
1548 break;
1549 }
1550 case TK_WHILE: { /* stat -> whilestat */
1551 whilestat(ls, line);
1552 break;
1553 }
1554 case TK_DO: { /* stat -> DO block END */
1555 luaX_next(ls); /* skip DO */
1556 block(ls);
1557 check_match(ls, TK_END, TK_DO, line);
1558 break;
1559 }
1560 case TK_FOR: { /* stat -> forstat */
1561 forstat(ls, line);
1562 break;
1563 }
1564 case TK_REPEAT: { /* stat -> repeatstat */
1565 repeatstat(ls, line);
1566 break;
1567 }
1568 case TK_FUNCTION: { /* stat -> funcstat */
1569 funcstat(ls, line);
1570 break;
1571 }
1572 case TK_LOCAL: { /* stat -> localstat */
1573 luaX_next(ls); /* skip LOCAL */
1574 if (testnext(ls, TK_FUNCTION)) /* local function? */
1575 localfunc(ls);
1576 else
1577 localstat(ls);
1578 break;
1579 }
1580 case TK_DBCOLON: { /* stat -> label */
1581 luaX_next(ls); /* skip double colon */
1582 labelstat(ls, str_checkname(ls), line);
1583 break;
1584 }
1585 case TK_RETURN: { /* stat -> retstat */
1586 luaX_next(ls); /* skip RETURN */
1587 retstat(ls);
1588 break;
1589 }
1590 case TK_BREAK: /* stat -> breakstat */
1591 case TK_GOTO: { /* stat -> 'goto' NAME */
1592 gotostat(ls, luaK_jump(ls->fs));
1593 break;
1594 }
1595 default: { /* stat -> func | assignment */
1596 exprstat(ls);
1597 break;
1598 }
1599 }
1600 lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
1601 ls->fs->freereg >= ls->fs->nactvar);
1602 ls->fs->freereg = ls->fs->nactvar; /* free registers */
1603 leavelevel(ls);
1604}
1605
1606/* }====================================================================== */
1607
1608
1609/*
1610** compiles the main function, which is a regular vararg function with an
1611** upvalue named LUA_ENV
1612*/
1613static void mainfunc (LexState *ls, FuncState *fs) {
1614 BlockCnt bl;
1615 expdesc v;
1616 open_func(ls, fs, &bl);
1617 fs->f->is_vararg = 1; /* main function is always declared vararg */
1618 init_exp(&v, VLOCAL, 0); /* create and... */
1619 newupvalue(fs, ls->envn, &v); /* ...set environment upvalue */
1620 luaC_objbarrier(ls->L, fs->f, ls->envn);
1621 luaX_next(ls); /* read first token */
1622 statlist(ls); /* parse main body */
1623 check(ls, TK_EOS);
1624 close_func(ls);
1625}
1626
1627
1628LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
1629 Dyndata *dyd, const char *name, int firstchar) {
1630 LexState lexstate;
1631 FuncState funcstate;
1632 LClosure *cl = luaF_newLclosure(L, 1); /* create main closure */
1633 setclLvalue(L, L->top, cl); /* anchor it (to avoid being collected) */
1634 luaD_inctop(L);
1635 lexstate.h = luaH_new(L); /* create table for scanner */
1636 sethvalue(L, L->top, lexstate.h); /* anchor it */
1637 luaD_inctop(L);
1638 funcstate.f = cl->p = luaF_newproto(L);
1639 luaC_objbarrier(L, cl, cl->p);
1640 funcstate.f->source = luaS_new(L, name); /* create and anchor TString */
1641 lua_assert(iswhite(funcstate.f)); /* do not need barrier here */
1642 lexstate.buff = buff;
1643 lexstate.dyd = dyd;
1644 dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
1645 luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar);
1646 mainfunc(&lexstate, &funcstate);
1647 lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
1648 /* all scopes should be correctly finished */
1649 lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0);
1650 L->top--; /* remove scanner's table */
1651 return cl; /* closure is on the stack, too */
1652}
1653
1654