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lparser.c 36 KB

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  1. /*
  2. ** $Id: lparser.c,v 2.34 2005/08/24 17:41:10 roberto Exp $
  3. ** Lua Parser
  4. ** See Copyright Notice in lua.h
  5. */
  6. #include <string.h>
  7. #define lparser_c
  8. #define LUA_CORE
  9. #include "lua.h"
  10. #include "lcode.h"
  11. #include "ldebug.h"
  12. #include "ldo.h"
  13. #include "lfunc.h"
  14. #include "llex.h"
  15. #include "lmem.h"
  16. #include "lobject.h"
  17. #include "lopcodes.h"
  18. #include "lparser.h"
  19. #include "lstate.h"
  20. #include "lstring.h"
  21. #define hasmultret(k) ((k) == VCALL || (k) == VVARARG)
  22. #define getlocvar(fs, i) ((fs)->f->locvars[(fs)->actvar[i]])
  23. #define luaY_checklimit(fs,v,l,m) if ((v)>(l)) errorlimit(fs,l,m)
  24. /*
  25. ** nodes for block list (list of active blocks)
  26. */
  27. typedef struct BlockCnt {
  28. struct BlockCnt *previous; /* chain */
  29. int breaklist; /* list of jumps out of this loop */
  30. lu_byte nactvar; /* # active locals outside the breakable structure */
  31. lu_byte upval; /* true if some variable in the block is an upvalue */
  32. lu_byte isbreakable; /* true if `block' is a loop */
  33. } BlockCnt;
  34. /*
  35. ** prototypes for recursive non-terminal functions
  36. */
  37. static void chunk (LexState *ls);
  38. static void expr (LexState *ls, expdesc *v);
  39. static void next (LexState *ls) {
  40. ls->lastline = ls->linenumber;
  41. if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */
  42. ls->t = ls->lookahead; /* use this one */
  43. ls->lookahead.token = TK_EOS; /* and discharge it */
  44. }
  45. else
  46. ls->t.token = luaX_lex(ls, &ls->t.seminfo); /* read next token */
  47. }
  48. static void lookahead (LexState *ls) {
  49. lua_assert(ls->lookahead.token == TK_EOS);
  50. ls->lookahead.token = luaX_lex(ls, &ls->lookahead.seminfo);
  51. }
  52. static void anchor_token (LexState *ls) {
  53. if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) {
  54. TString *ts = ls->t.seminfo.ts;
  55. luaX_newstring(ls, getstr(ts), ts->tsv.len);
  56. }
  57. }
  58. static void error_expected (LexState *ls, int token) {
  59. luaX_syntaxerror(ls,
  60. luaO_pushfstring(ls->L, LUA_QS " expected", luaX_token2str(ls, token)));
  61. }
  62. static void errorlimit (FuncState *fs, int limit, const char *what) {
  63. const char *msg = (fs->f->linedefined == 0) ?
  64. luaO_pushfstring(fs->L, "main function has more than %d %s", limit, what) :
  65. luaO_pushfstring(fs->L, "function at line %d has more than %d %s",
  66. fs->f->linedefined, limit, what);
  67. luaX_lexerror(fs->ls, msg, 0);
  68. }
  69. static int testnext (LexState *ls, int c) {
  70. if (ls->t.token == c) {
  71. next(ls);
  72. return 1;
  73. }
  74. else return 0;
  75. }
  76. static void check (LexState *ls, int c) {
  77. if (ls->t.token != c)
  78. error_expected(ls, c);
  79. }
  80. static void checknext (LexState *ls, int c) {
  81. check(ls, c);
  82. next(ls);
  83. }
  84. #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); }
  85. static void check_match (LexState *ls, int what, int who, int where) {
  86. if (!testnext(ls, what)) {
  87. if (where == ls->linenumber)
  88. error_expected(ls, what);
  89. else {
  90. luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
  91. LUA_QS " expected (to close " LUA_QS " at line %d)",
  92. luaX_token2str(ls, what), luaX_token2str(ls, who), where));
  93. }
  94. }
  95. }
  96. static TString *str_checkname (LexState *ls) {
  97. TString *ts;
  98. check(ls, TK_NAME);
  99. ts = ls->t.seminfo.ts;
  100. next(ls);
  101. return ts;
  102. }
  103. static void init_exp (expdesc *e, expkind k, int i) {
  104. e->f = e->t = NO_JUMP;
  105. e->k = k;
  106. e->info = i;
  107. }
  108. static void codestring (LexState *ls, expdesc *e, TString *s) {
  109. init_exp(e, VK, luaK_stringK(ls->fs, s));
  110. }
  111. static void checkname(LexState *ls, expdesc *e) {
  112. codestring(ls, e, str_checkname(ls));
  113. }
  114. static int registerlocalvar (LexState *ls, TString *varname) {
  115. FuncState *fs = ls->fs;
  116. Proto *f = fs->f;
  117. int oldsize = f->sizelocvars;
  118. luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
  119. LocVar, SHRT_MAX, "too many local variables");
  120. while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL;
  121. f->locvars[fs->nlocvars].varname = varname;
  122. luaC_objbarrier(ls->L, f, varname);
  123. return fs->nlocvars++;
  124. }
  125. #define new_localvarliteral(ls,v,n) \
  126. new_localvar(ls, luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char))-1), n)
  127. static void new_localvar (LexState *ls, TString *name, int n) {
  128. FuncState *fs = ls->fs;
  129. luaY_checklimit(fs, fs->nactvar+n+1, LUAI_MAXVARS, "local variables");
  130. fs->actvar[fs->nactvar+n] = cast(unsigned short, registerlocalvar(ls, name));
  131. }
  132. static void adjustlocalvars (LexState *ls, int nvars) {
  133. FuncState *fs = ls->fs;
  134. fs->nactvar += nvars;
  135. for (; nvars; nvars--) {
  136. getlocvar(fs, fs->nactvar - nvars).startpc = fs->pc;
  137. }
  138. }
  139. static void removevars (LexState *ls, int tolevel) {
  140. FuncState *fs = ls->fs;
  141. while (fs->nactvar > tolevel)
  142. getlocvar(fs, --fs->nactvar).endpc = fs->pc;
  143. }
  144. static int indexupvalue (FuncState *fs, TString *name, expdesc *v) {
  145. int i;
  146. Proto *f = fs->f;
  147. int oldsize = f->sizeupvalues;
  148. for (i=0; i<f->nups; i++) {
  149. if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->info) {
  150. lua_assert(f->upvalues[i] == name);
  151. return i;
  152. }
  153. }
  154. /* new one */
  155. luaY_checklimit(fs, f->nups + 1, LUAI_MAXUPVALUES, "upvalues");
  156. luaM_growvector(fs->L, f->upvalues, f->nups, f->sizeupvalues,
  157. TString *, MAX_INT, "");
  158. while (oldsize < f->sizeupvalues) f->upvalues[oldsize++] = NULL;
  159. f->upvalues[f->nups] = name;
  160. luaC_objbarrier(fs->L, f, name);
  161. lua_assert(v->k == VLOCAL || v->k == VUPVAL);
  162. fs->upvalues[f->nups].k = cast(lu_byte, v->k);
  163. fs->upvalues[f->nups].info = cast(lu_byte, v->info);
  164. return f->nups++;
  165. }
  166. static int searchvar (FuncState *fs, TString *n) {
  167. int i;
  168. for (i=fs->nactvar-1; i >= 0; i--) {
  169. if (n == getlocvar(fs, i).varname)
  170. return i;
  171. }
  172. return -1; /* not found */
  173. }
  174. static void markupval (FuncState *fs, int level) {
  175. BlockCnt *bl = fs->bl;
  176. while (bl && bl->nactvar > level) bl = bl->previous;
  177. if (bl) bl->upval = 1;
  178. }
  179. static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
  180. if (fs == NULL) { /* no more levels? */
  181. init_exp(var, VGLOBAL, NO_REG); /* default is global variable */
  182. return VGLOBAL;
  183. }
  184. else {
  185. int v = searchvar(fs, n); /* look up at current level */
  186. if (v >= 0) {
  187. init_exp(var, VLOCAL, v);
  188. if (!base)
  189. markupval(fs, v); /* local will be used as an upval */
  190. return VLOCAL;
  191. }
  192. else { /* not found at current level; try upper one */
  193. if (singlevaraux(fs->prev, n, var, 0) == VGLOBAL)
  194. return VGLOBAL;
  195. var->info = indexupvalue(fs, n, var); /* else was LOCAL or UPVAL */
  196. var->k = VUPVAL; /* upvalue in this level */
  197. return VUPVAL;
  198. }
  199. }
  200. }
  201. static void singlevar (LexState *ls, expdesc *var) {
  202. TString *varname = str_checkname(ls);
  203. FuncState *fs = ls->fs;
  204. if (singlevaraux(fs, varname, var, 1) == VGLOBAL)
  205. var->info = luaK_stringK(fs, varname); /* info points to global name */
  206. }
  207. static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
  208. FuncState *fs = ls->fs;
  209. int extra = nvars - nexps;
  210. if (hasmultret(e->k)) {
  211. extra++; /* includes call itself */
  212. if (extra < 0) extra = 0;
  213. luaK_setreturns(fs, e, extra); /* last exp. provides the difference */
  214. if (extra > 1) luaK_reserveregs(fs, extra-1);
  215. }
  216. else {
  217. if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */
  218. if (extra > 0) {
  219. int reg = fs->freereg;
  220. luaK_reserveregs(fs, extra);
  221. luaK_nil(fs, reg, extra);
  222. }
  223. }
  224. }
  225. static void enterlevel (LexState *ls) {
  226. if (++ls->L->nCcalls > LUAI_MAXCCALLS)
  227. luaX_lexerror(ls, "chunk has too many syntax levels", 0);
  228. }
  229. #define leavelevel(ls) ((ls)->L->nCcalls--)
  230. static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isbreakable) {
  231. bl->breaklist = NO_JUMP;
  232. bl->isbreakable = isbreakable;
  233. bl->nactvar = fs->nactvar;
  234. bl->upval = 0;
  235. bl->previous = fs->bl;
  236. fs->bl = bl;
  237. lua_assert(fs->freereg == fs->nactvar);
  238. }
  239. static void leaveblock (FuncState *fs) {
  240. BlockCnt *bl = fs->bl;
  241. fs->bl = bl->previous;
  242. removevars(fs->ls, bl->nactvar);
  243. if (bl->upval)
  244. luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
  245. lua_assert(!bl->isbreakable || !bl->upval); /* loops have no body */
  246. lua_assert(bl->nactvar == fs->nactvar);
  247. fs->freereg = fs->nactvar; /* free registers */
  248. luaK_patchtohere(fs, bl->breaklist);
  249. }
  250. static void pushclosure (LexState *ls, FuncState *func, expdesc *v) {
  251. FuncState *fs = ls->fs;
  252. Proto *f = fs->f;
  253. int oldsize = f->sizep;
  254. int i;
  255. luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *,
  256. MAXARG_Bx, "constant table overflow");
  257. while (oldsize < f->sizep) f->p[oldsize++] = NULL;
  258. f->p[fs->np++] = func->f;
  259. luaC_objbarrier(ls->L, f, func->f);
  260. init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np-1));
  261. for (i=0; i<func->f->nups; i++) {
  262. OpCode o = (func->upvalues[i].k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
  263. luaK_codeABC(fs, o, 0, func->upvalues[i].info, 0);
  264. }
  265. }
  266. static void open_func (LexState *ls, FuncState *fs) {
  267. lua_State *L = ls->L;
  268. Proto *f = luaF_newproto(L);
  269. fs->f = f;
  270. fs->prev = ls->fs; /* linked list of funcstates */
  271. fs->ls = ls;
  272. fs->L = L;
  273. ls->fs = fs;
  274. fs->pc = 0;
  275. fs->lasttarget = 0;
  276. fs->jpc = NO_JUMP;
  277. fs->freereg = 0;
  278. fs->nk = 0;
  279. fs->np = 0;
  280. fs->nlocvars = 0;
  281. fs->nactvar = 0;
  282. fs->bl = NULL;
  283. f->source = ls->source;
  284. f->maxstacksize = 2; /* registers 0/1 are always valid */
  285. fs->h = luaH_new(L, 0, 0);
  286. /* anchor table of constants and prototype (to avoid being collected) */
  287. sethvalue2s(L, L->top, fs->h);
  288. incr_top(L);
  289. setptvalue2s(L, L->top, f);
  290. incr_top(L);
  291. }
  292. static void close_func (LexState *ls) {
  293. lua_State *L = ls->L;
  294. FuncState *fs = ls->fs;
  295. Proto *f = fs->f;
  296. removevars(ls, 0);
  297. luaK_ret(fs, 0, 0); /* final return */
  298. luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
  299. f->sizecode = fs->pc;
  300. luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
  301. f->sizelineinfo = fs->pc;
  302. luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
  303. f->sizek = fs->nk;
  304. luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
  305. f->sizep = fs->np;
  306. luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
  307. f->sizelocvars = fs->nlocvars;
  308. luaM_reallocvector(L, f->upvalues, f->sizeupvalues, f->nups, TString *);
  309. f->sizeupvalues = f->nups;
  310. lua_assert(luaG_checkcode(f));
  311. lua_assert(fs->bl == NULL);
  312. ls->fs = fs->prev;
  313. L->top -= 2; /* remove table and prototype from the stack */
  314. /* last token read was anchored in defunct function; must reanchor it */
  315. if (fs) anchor_token(ls);
  316. }
  317. Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
  318. struct LexState lexstate;
  319. struct FuncState funcstate;
  320. lexstate.buff = buff;
  321. luaX_setinput(L, &lexstate, z, luaS_new(L, name));
  322. open_func(&lexstate, &funcstate);
  323. funcstate.f->is_vararg = VARARG_ISVARARG; /* main func. is always vararg */
  324. next(&lexstate); /* read first token */
  325. chunk(&lexstate);
  326. check(&lexstate, TK_EOS);
  327. close_func(&lexstate);
  328. lua_assert(funcstate.prev == NULL);
  329. lua_assert(funcstate.f->nups == 0);
  330. lua_assert(lexstate.fs == NULL);
  331. return funcstate.f;
  332. }
  333. /*============================================================*/
  334. /* GRAMMAR RULES */
  335. /*============================================================*/
  336. static void field (LexState *ls, expdesc *v) {
  337. /* field -> ['.' | ':'] NAME */
  338. FuncState *fs = ls->fs;
  339. expdesc key;
  340. luaK_exp2anyreg(fs, v);
  341. next(ls); /* skip the dot or colon */
  342. checkname(ls, &key);
  343. luaK_indexed(fs, v, &key);
  344. }
  345. static void yindex (LexState *ls, expdesc *v) {
  346. /* index -> '[' expr ']' */
  347. next(ls); /* skip the '[' */
  348. expr(ls, v);
  349. luaK_exp2val(ls->fs, v);
  350. checknext(ls, ']');
  351. }
  352. /*
  353. ** {======================================================================
  354. ** Rules for Constructors
  355. ** =======================================================================
  356. */
  357. struct ConsControl {
  358. expdesc v; /* last list item read */
  359. expdesc *t; /* table descriptor */
  360. int nh; /* total number of `record' elements */
  361. int na; /* total number of array elements */
  362. int tostore; /* number of array elements pending to be stored */
  363. };
  364. static void recfield (LexState *ls, struct ConsControl *cc) {
  365. /* recfield -> (NAME | `['exp1`]') = exp1 */
  366. FuncState *fs = ls->fs;
  367. int reg = ls->fs->freereg;
  368. expdesc key, val;
  369. if (ls->t.token == TK_NAME) {
  370. luaY_checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
  371. checkname(ls, &key);
  372. }
  373. else /* ls->t.token == '[' */
  374. yindex(ls, &key);
  375. cc->nh++;
  376. checknext(ls, '=');
  377. luaK_exp2RK(fs, &key);
  378. expr(ls, &val);
  379. luaK_codeABC(fs, OP_SETTABLE, cc->t->info, luaK_exp2RK(fs, &key),
  380. luaK_exp2RK(fs, &val));
  381. fs->freereg = reg; /* free registers */
  382. }
  383. static void closelistfield (FuncState *fs, struct ConsControl *cc) {
  384. if (cc->v.k == VVOID) return; /* there is no list item */
  385. luaK_exp2nextreg(fs, &cc->v);
  386. cc->v.k = VVOID;
  387. if (cc->tostore == LFIELDS_PER_FLUSH) {
  388. luaK_setlist(fs, cc->t->info, cc->na, cc->tostore); /* flush */
  389. cc->tostore = 0; /* no more items pending */
  390. }
  391. }
  392. static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
  393. if (cc->tostore == 0) return;
  394. if (hasmultret(cc->v.k)) {
  395. luaK_setmultret(fs, &cc->v);
  396. luaK_setlist(fs, cc->t->info, cc->na, LUA_MULTRET);
  397. cc->na--; /* do not count last expression (unknown number of elements) */
  398. }
  399. else {
  400. if (cc->v.k != VVOID)
  401. luaK_exp2nextreg(fs, &cc->v);
  402. luaK_setlist(fs, cc->t->info, cc->na, cc->tostore);
  403. }
  404. }
  405. static void listfield (LexState *ls, struct ConsControl *cc) {
  406. expr(ls, &cc->v);
  407. luaY_checklimit(ls->fs, cc->na, MAXARG_Bx, "items in a constructor");
  408. cc->na++;
  409. cc->tostore++;
  410. }
  411. static void constructor (LexState *ls, expdesc *t) {
  412. /* constructor -> ?? */
  413. FuncState *fs = ls->fs;
  414. int line = ls->linenumber;
  415. int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
  416. struct ConsControl cc;
  417. cc.na = cc.nh = cc.tostore = 0;
  418. cc.t = t;
  419. init_exp(t, VRELOCABLE, pc);
  420. init_exp(&cc.v, VVOID, 0); /* no value (yet) */
  421. luaK_exp2nextreg(ls->fs, t); /* fix it at stack top (for gc) */
  422. checknext(ls, '{');
  423. do {
  424. lua_assert(cc.v.k == VVOID || cc.tostore > 0);
  425. if (ls->t.token == '}') break;
  426. closelistfield(fs, &cc);
  427. switch(ls->t.token) {
  428. case TK_NAME: { /* may be listfields or recfields */
  429. lookahead(ls);
  430. if (ls->lookahead.token != '=') /* expression? */
  431. listfield(ls, &cc);
  432. else
  433. recfield(ls, &cc);
  434. break;
  435. }
  436. case '[': { /* constructor_item -> recfield */
  437. recfield(ls, &cc);
  438. break;
  439. }
  440. default: { /* constructor_part -> listfield */
  441. listfield(ls, &cc);
  442. break;
  443. }
  444. }
  445. } while (testnext(ls, ',') || testnext(ls, ';'));
  446. check_match(ls, '}', '{', line);
  447. lastlistfield(fs, &cc);
  448. SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
  449. SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */
  450. }
  451. /* }====================================================================== */
  452. static void parlist (LexState *ls) {
  453. /* parlist -> [ param { `,' param } ] */
  454. FuncState *fs = ls->fs;
  455. Proto *f = fs->f;
  456. int nparams = 0;
  457. f->is_vararg = 0;
  458. if (ls->t.token != ')') { /* is `parlist' not empty? */
  459. do {
  460. switch (ls->t.token) {
  461. case TK_NAME: { /* param -> NAME */
  462. new_localvar(ls, str_checkname(ls), nparams++);
  463. break;
  464. }
  465. case TK_DOTS: { /* param -> `...' */
  466. next(ls);
  467. #if defined(LUA_COMPAT_VARARG)
  468. /* use `arg' as default name */
  469. new_localvarliteral(ls, "arg", nparams++);
  470. f->is_vararg = VARARG_HASARG | VARARG_NEEDSARG;
  471. #endif
  472. f->is_vararg |= VARARG_ISVARARG;
  473. break;
  474. }
  475. default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected");
  476. }
  477. } while (!f->is_vararg && testnext(ls, ','));
  478. }
  479. adjustlocalvars(ls, nparams);
  480. f->numparams = fs->nactvar - (f->is_vararg & VARARG_HASARG);
  481. luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */
  482. }
  483. static void body (LexState *ls, expdesc *e, int needself, int line) {
  484. /* body -> `(' parlist `)' chunk END */
  485. FuncState new_fs;
  486. open_func(ls, &new_fs);
  487. new_fs.f->linedefined = line;
  488. checknext(ls, '(');
  489. if (needself) {
  490. new_localvarliteral(ls, "self", 0);
  491. adjustlocalvars(ls, 1);
  492. }
  493. parlist(ls);
  494. checknext(ls, ')');
  495. chunk(ls);
  496. new_fs.f->lastlinedefined = ls->linenumber;
  497. check_match(ls, TK_END, TK_FUNCTION, line);
  498. close_func(ls);
  499. pushclosure(ls, &new_fs, e);
  500. }
  501. static int explist1 (LexState *ls, expdesc *v) {
  502. /* explist1 -> expr { `,' expr } */
  503. int n = 1; /* at least one expression */
  504. expr(ls, v);
  505. while (testnext(ls, ',')) {
  506. luaK_exp2nextreg(ls->fs, v);
  507. expr(ls, v);
  508. n++;
  509. }
  510. return n;
  511. }
  512. static void funcargs (LexState *ls, expdesc *f) {
  513. FuncState *fs = ls->fs;
  514. expdesc args;
  515. int base, nparams;
  516. int line = ls->linenumber;
  517. switch (ls->t.token) {
  518. case '(': { /* funcargs -> `(' [ explist1 ] `)' */
  519. if (line != ls->lastline)
  520. luaX_syntaxerror(ls,"ambiguous syntax (function call x new statement)");
  521. next(ls);
  522. if (ls->t.token == ')') /* arg list is empty? */
  523. args.k = VVOID;
  524. else {
  525. explist1(ls, &args);
  526. luaK_setmultret(fs, &args);
  527. }
  528. check_match(ls, ')', '(', line);
  529. break;
  530. }
  531. case '{': { /* funcargs -> constructor */
  532. constructor(ls, &args);
  533. break;
  534. }
  535. case TK_STRING: { /* funcargs -> STRING */
  536. codestring(ls, &args, ls->t.seminfo.ts);
  537. next(ls); /* must use `seminfo' before `next' */
  538. break;
  539. }
  540. default: {
  541. luaX_syntaxerror(ls, "function arguments expected");
  542. return;
  543. }
  544. }
  545. lua_assert(f->k == VNONRELOC);
  546. base = f->info; /* base register for call */
  547. if (hasmultret(args.k))
  548. nparams = LUA_MULTRET; /* open call */
  549. else {
  550. if (args.k != VVOID)
  551. luaK_exp2nextreg(fs, &args); /* close last argument */
  552. nparams = fs->freereg - (base+1);
  553. }
  554. init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
  555. luaK_fixline(fs, line);
  556. fs->freereg = base+1; /* call remove function and arguments and leaves
  557. (unless changed) one result */
  558. }
  559. /*
  560. ** {======================================================================
  561. ** Expression parsing
  562. ** =======================================================================
  563. */
  564. static void prefixexp (LexState *ls, expdesc *v) {
  565. /* prefixexp -> NAME | '(' expr ')' */
  566. switch (ls->t.token) {
  567. case '(': {
  568. int line = ls->linenumber;
  569. next(ls);
  570. expr(ls, v);
  571. check_match(ls, ')', '(', line);
  572. luaK_dischargevars(ls->fs, v);
  573. return;
  574. }
  575. case TK_NAME: {
  576. singlevar(ls, v);
  577. return;
  578. }
  579. default: {
  580. luaX_syntaxerror(ls, "unexpected symbol");
  581. return;
  582. }
  583. }
  584. }
  585. static void primaryexp (LexState *ls, expdesc *v) {
  586. /* primaryexp ->
  587. prefixexp { `.' NAME | `[' exp `]' | `:' NAME funcargs | funcargs } */
  588. FuncState *fs = ls->fs;
  589. prefixexp(ls, v);
  590. for (;;) {
  591. switch (ls->t.token) {
  592. case '.': { /* field */
  593. field(ls, v);
  594. break;
  595. }
  596. case '[': { /* `[' exp1 `]' */
  597. expdesc key;
  598. luaK_exp2anyreg(fs, v);
  599. yindex(ls, &key);
  600. luaK_indexed(fs, v, &key);
  601. break;
  602. }
  603. case ':': { /* `:' NAME funcargs */
  604. expdesc key;
  605. next(ls);
  606. checkname(ls, &key);
  607. luaK_self(fs, v, &key);
  608. funcargs(ls, v);
  609. break;
  610. }
  611. case '(': case TK_STRING: case '{': { /* funcargs */
  612. luaK_exp2nextreg(fs, v);
  613. funcargs(ls, v);
  614. break;
  615. }
  616. default: return;
  617. }
  618. }
  619. }
  620. static void simpleexp (LexState *ls, expdesc *v) {
  621. /* simpleexp -> NUMBER | STRING | NIL | true | false | ... |
  622. constructor | FUNCTION body | primaryexp */
  623. switch (ls->t.token) {
  624. case TK_NUMBER: {
  625. init_exp(v, VK, luaK_numberK(ls->fs, ls->t.seminfo.r));
  626. break;
  627. }
  628. case TK_STRING: {
  629. codestring(ls, v, ls->t.seminfo.ts);
  630. break;
  631. }
  632. case TK_NIL: {
  633. init_exp(v, VNIL, 0);
  634. break;
  635. }
  636. case TK_TRUE: {
  637. init_exp(v, VTRUE, 0);
  638. break;
  639. }
  640. case TK_FALSE: {
  641. init_exp(v, VFALSE, 0);
  642. break;
  643. }
  644. case TK_DOTS: { /* vararg */
  645. FuncState *fs = ls->fs;
  646. check_condition(ls, fs->f->is_vararg,
  647. "cannot use " LUA_QL("...") " outside a vararg function");
  648. fs->f->is_vararg &= ~VARARG_NEEDSARG; /* don't need 'arg' */
  649. init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
  650. break;
  651. }
  652. case '{': { /* constructor */
  653. constructor(ls, v);
  654. return;
  655. }
  656. case TK_FUNCTION: {
  657. next(ls);
  658. body(ls, v, 0, ls->linenumber);
  659. return;
  660. }
  661. default: {
  662. primaryexp(ls, v);
  663. return;
  664. }
  665. }
  666. next(ls);
  667. }
  668. static UnOpr getunopr (int op) {
  669. switch (op) {
  670. case TK_NOT: return OPR_NOT;
  671. case '-': return OPR_MINUS;
  672. case '#': return OPR_LEN;
  673. default: return OPR_NOUNOPR;
  674. }
  675. }
  676. static BinOpr getbinopr (int op) {
  677. switch (op) {
  678. case '+': return OPR_ADD;
  679. case '-': return OPR_SUB;
  680. case '*': return OPR_MULT;
  681. case '/': return OPR_DIV;
  682. case '%': return OPR_MOD;
  683. case '^': return OPR_POW;
  684. case TK_CONCAT: return OPR_CONCAT;
  685. case TK_NE: return OPR_NE;
  686. case TK_EQ: return OPR_EQ;
  687. case '<': return OPR_LT;
  688. case TK_LE: return OPR_LE;
  689. case '>': return OPR_GT;
  690. case TK_GE: return OPR_GE;
  691. case TK_AND: return OPR_AND;
  692. case TK_OR: return OPR_OR;
  693. default: return OPR_NOBINOPR;
  694. }
  695. }
  696. static const struct {
  697. lu_byte left; /* left priority for each binary operator */
  698. lu_byte right; /* right priority */
  699. } priority[] = { /* ORDER OPR */
  700. {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `/' `%' */
  701. {10, 9}, {5, 4}, /* power and concat (right associative) */
  702. {3, 3}, {3, 3}, /* equality and inequality */
  703. {3, 3}, {3, 3}, {3, 3}, {3, 3}, /* order */
  704. {2, 2}, {1, 1} /* logical (and/or) */
  705. };
  706. #define UNARY_PRIORITY 8 /* priority for unary operators */
  707. /*
  708. ** subexpr -> (simpleexp | unop subexpr) { binop subexpr }
  709. ** where `binop' is any binary operator with a priority higher than `limit'
  710. */
  711. static BinOpr subexpr (LexState *ls, expdesc *v, unsigned int limit) {
  712. BinOpr op;
  713. UnOpr uop;
  714. enterlevel(ls);
  715. uop = getunopr(ls->t.token);
  716. if (uop != OPR_NOUNOPR) {
  717. next(ls);
  718. subexpr(ls, v, UNARY_PRIORITY);
  719. luaK_prefix(ls->fs, uop, v);
  720. }
  721. else simpleexp(ls, v);
  722. /* expand while operators have priorities higher than `limit' */
  723. op = getbinopr(ls->t.token);
  724. while (op != OPR_NOBINOPR && priority[op].left > limit) {
  725. expdesc v2;
  726. BinOpr nextop;
  727. next(ls);
  728. luaK_infix(ls->fs, op, v);
  729. /* read sub-expression with higher priority */
  730. nextop = subexpr(ls, &v2, priority[op].right);
  731. luaK_posfix(ls->fs, op, v, &v2);
  732. op = nextop;
  733. }
  734. leavelevel(ls);
  735. return op; /* return first untreated operator */
  736. }
  737. static void expr (LexState *ls, expdesc *v) {
  738. subexpr(ls, v, 0);
  739. }
  740. /* }==================================================================== */
  741. /*
  742. ** {======================================================================
  743. ** Rules for Statements
  744. ** =======================================================================
  745. */
  746. static int block_follow (int token) {
  747. switch (token) {
  748. case TK_ELSE: case TK_ELSEIF: case TK_END:
  749. case TK_UNTIL: case TK_EOS:
  750. return 1;
  751. default: return 0;
  752. }
  753. }
  754. static void block (LexState *ls) {
  755. /* block -> chunk */
  756. FuncState *fs = ls->fs;
  757. BlockCnt bl;
  758. enterblock(fs, &bl, 0);
  759. chunk(ls);
  760. lua_assert(bl.breaklist == NO_JUMP);
  761. leaveblock(fs);
  762. }
  763. /*
  764. ** structure to chain all variables in the left-hand side of an
  765. ** assignment
  766. */
  767. struct LHS_assign {
  768. struct LHS_assign *prev;
  769. expdesc v; /* variable (global, local, upvalue, or indexed) */
  770. };
  771. /*
  772. ** check whether, in an assignment to a local variable, the local variable
  773. ** is needed in a previous assignment (to a table). If so, save original
  774. ** local value in a safe place and use this safe copy in the previous
  775. ** assignment.
  776. */
  777. static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
  778. FuncState *fs = ls->fs;
  779. int extra = fs->freereg; /* eventual position to save local variable */
  780. int conflict = 0;
  781. for (; lh; lh = lh->prev) {
  782. if (lh->v.k == VINDEXED) {
  783. if (lh->v.info == v->info) { /* conflict? */
  784. conflict = 1;
  785. lh->v.info = extra; /* previous assignment will use safe copy */
  786. }
  787. if (lh->v.aux == v->info) { /* conflict? */
  788. conflict = 1;
  789. lh->v.aux = extra; /* previous assignment will use safe copy */
  790. }
  791. }
  792. }
  793. if (conflict) {
  794. luaK_codeABC(fs, OP_MOVE, fs->freereg, v->info, 0); /* make copy */
  795. luaK_reserveregs(fs, 1);
  796. }
  797. }
  798. static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
  799. expdesc e;
  800. check_condition(ls, VLOCAL <= lh->v.k && lh->v.k <= VINDEXED,
  801. "syntax error");
  802. if (testnext(ls, ',')) { /* assignment -> `,' primaryexp assignment */
  803. struct LHS_assign nv;
  804. nv.prev = lh;
  805. primaryexp(ls, &nv.v);
  806. if (nv.v.k == VLOCAL)
  807. check_conflict(ls, lh, &nv.v);
  808. assignment(ls, &nv, nvars+1);
  809. }
  810. else { /* assignment -> `=' explist1 */
  811. int nexps;
  812. checknext(ls, '=');
  813. nexps = explist1(ls, &e);
  814. if (nexps != nvars) {
  815. adjust_assign(ls, nvars, nexps, &e);
  816. if (nexps > nvars)
  817. ls->fs->freereg -= nexps - nvars; /* remove extra values */
  818. }
  819. else {
  820. luaK_setoneret(ls->fs, &e); /* close last expression */
  821. luaK_storevar(ls->fs, &lh->v, &e);
  822. return; /* avoid default */
  823. }
  824. }
  825. init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */
  826. luaK_storevar(ls->fs, &lh->v, &e);
  827. }
  828. static int cond (LexState *ls) {
  829. /* cond -> exp */
  830. expdesc v;
  831. expr(ls, &v); /* read condition */
  832. if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */
  833. luaK_goiftrue(ls->fs, &v);
  834. return v.f;
  835. }
  836. static void breakstat (LexState *ls) {
  837. FuncState *fs = ls->fs;
  838. BlockCnt *bl = fs->bl;
  839. int upval = 0;
  840. while (bl && !bl->isbreakable) {
  841. upval |= bl->upval;
  842. bl = bl->previous;
  843. }
  844. if (!bl)
  845. luaX_syntaxerror(ls, "no loop to break");
  846. if (upval)
  847. luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
  848. luaK_concat(fs, &bl->breaklist, luaK_jump(fs));
  849. }
  850. static void whilestat (LexState *ls, int line) {
  851. /* whilestat -> WHILE cond DO block END */
  852. FuncState *fs = ls->fs;
  853. int whileinit;
  854. int condexit;
  855. BlockCnt bl;
  856. next(ls); /* skip WHILE */
  857. whileinit = luaK_getlabel(fs);
  858. condexit = cond(ls);
  859. enterblock(fs, &bl, 1);
  860. checknext(ls, TK_DO);
  861. block(ls);
  862. luaK_patchlist(fs, luaK_jump(fs), whileinit);
  863. check_match(ls, TK_END, TK_WHILE, line);
  864. leaveblock(fs);
  865. luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
  866. }
  867. static void repeatstat (LexState *ls, int line) {
  868. /* repeatstat -> REPEAT block UNTIL cond */
  869. int condexit;
  870. FuncState *fs = ls->fs;
  871. int repeat_init = luaK_getlabel(fs);
  872. BlockCnt bl1, bl2;
  873. enterblock(fs, &bl1, 1); /* loop block */
  874. enterblock(fs, &bl2, 0); /* scope block */
  875. next(ls); /* skip REPEAT */
  876. chunk(ls);
  877. check_match(ls, TK_UNTIL, TK_REPEAT, line);
  878. condexit = cond(ls); /* read condition (inside scope block) */
  879. if (!bl2.upval) { /* no upvalues? */
  880. leaveblock(fs); /* finish scope */
  881. luaK_patchlist(ls->fs, condexit, repeat_init); /* close the loop */
  882. }
  883. else { /* complete semantics when there are upvalues */
  884. breakstat(ls); /* if condition then break */
  885. luaK_patchtohere(ls->fs, condexit); /* else... */
  886. leaveblock(fs); /* finish scope... */
  887. luaK_patchlist(ls->fs, luaK_jump(fs), repeat_init); /* and repeat */
  888. }
  889. leaveblock(fs); /* finish loop */
  890. }
  891. static int exp1 (LexState *ls) {
  892. expdesc e;
  893. int k;
  894. expr(ls, &e);
  895. k = e.k;
  896. luaK_exp2nextreg(ls->fs, &e);
  897. return k;
  898. }
  899. static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
  900. /* forbody -> DO block */
  901. BlockCnt bl;
  902. FuncState *fs = ls->fs;
  903. int prep, endfor;
  904. adjustlocalvars(ls, 3); /* control variables */
  905. checknext(ls, TK_DO);
  906. prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
  907. enterblock(fs, &bl, 0); /* scope for declared variables */
  908. adjustlocalvars(ls, nvars);
  909. luaK_reserveregs(fs, nvars);
  910. block(ls);
  911. leaveblock(fs); /* end of scope for declared variables */
  912. luaK_patchtohere(fs, prep);
  913. endfor = (isnum) ? luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP) :
  914. luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars);
  915. luaK_fixline(fs, line); /* pretend that `OP_FOR' starts the loop */
  916. luaK_patchlist(fs, (isnum ? endfor : luaK_jump(fs)), prep + 1);
  917. }
  918. static void fornum (LexState *ls, TString *varname, int line) {
  919. /* fornum -> NAME = exp1,exp1[,exp1] forbody */
  920. FuncState *fs = ls->fs;
  921. int base = fs->freereg;
  922. new_localvarliteral(ls, "(for index)", 0);
  923. new_localvarliteral(ls, "(for limit)", 1);
  924. new_localvarliteral(ls, "(for step)", 2);
  925. new_localvar(ls, varname, 3);
  926. checknext(ls, '=');
  927. exp1(ls); /* initial value */
  928. checknext(ls, ',');
  929. exp1(ls); /* limit */
  930. if (testnext(ls, ','))
  931. exp1(ls); /* optional step */
  932. else { /* default step = 1 */
  933. luaK_codeABx(fs, OP_LOADK, fs->freereg, luaK_numberK(fs, 1));
  934. luaK_reserveregs(fs, 1);
  935. }
  936. forbody(ls, base, line, 1, 1);
  937. }
  938. static void forlist (LexState *ls, TString *indexname) {
  939. /* forlist -> NAME {,NAME} IN explist1 forbody */
  940. FuncState *fs = ls->fs;
  941. expdesc e;
  942. int nvars = 0;
  943. int line;
  944. int base = fs->freereg;
  945. /* create control variables */
  946. new_localvarliteral(ls, "(for generator)", nvars++);
  947. new_localvarliteral(ls, "(for state)", nvars++);
  948. new_localvarliteral(ls, "(for control)", nvars++);
  949. /* create declared variables */
  950. new_localvar(ls, indexname, nvars++);
  951. while (testnext(ls, ','))
  952. new_localvar(ls, str_checkname(ls), nvars++);
  953. checknext(ls, TK_IN);
  954. line = ls->linenumber;
  955. adjust_assign(ls, 3, explist1(ls, &e), &e);
  956. luaK_checkstack(fs, 3); /* extra space to call generator */
  957. forbody(ls, base, line, nvars - 3, 0);
  958. }
  959. static void forstat (LexState *ls, int line) {
  960. /* forstat -> FOR (fornum | forlist) END */
  961. FuncState *fs = ls->fs;
  962. TString *varname;
  963. BlockCnt bl;
  964. enterblock(fs, &bl, 1); /* scope for loop and control variables */
  965. next(ls); /* skip `for' */
  966. varname = str_checkname(ls); /* first variable name */
  967. switch (ls->t.token) {
  968. case '=': fornum(ls, varname, line); break;
  969. case ',': case TK_IN: forlist(ls, varname); break;
  970. default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected");
  971. }
  972. check_match(ls, TK_END, TK_FOR, line);
  973. leaveblock(fs); /* loop scope (`break' jumps to this point) */
  974. }
  975. static int test_then_block (LexState *ls) {
  976. /* test_then_block -> [IF | ELSEIF] cond THEN block */
  977. int condexit;
  978. next(ls); /* skip IF or ELSEIF */
  979. condexit = cond(ls);
  980. checknext(ls, TK_THEN);
  981. block(ls); /* `then' part */
  982. return condexit;
  983. }
  984. static void ifstat (LexState *ls, int line) {
  985. /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
  986. FuncState *fs = ls->fs;
  987. int flist;
  988. int escapelist = NO_JUMP;
  989. flist = test_then_block(ls); /* IF cond THEN block */
  990. while (ls->t.token == TK_ELSEIF) {
  991. luaK_concat(fs, &escapelist, luaK_jump(fs));
  992. luaK_patchtohere(fs, flist);
  993. flist = test_then_block(ls); /* ELSEIF cond THEN block */
  994. }
  995. if (ls->t.token == TK_ELSE) {
  996. luaK_concat(fs, &escapelist, luaK_jump(fs));
  997. luaK_patchtohere(fs, flist);
  998. next(ls); /* skip ELSE (after patch, for correct line info) */
  999. block(ls); /* `else' part */
  1000. }
  1001. else
  1002. luaK_concat(fs, &escapelist, flist);
  1003. luaK_patchtohere(fs, escapelist);
  1004. check_match(ls, TK_END, TK_IF, line);
  1005. }
  1006. static void localfunc (LexState *ls) {
  1007. expdesc v, b;
  1008. FuncState *fs = ls->fs;
  1009. new_localvar(ls, str_checkname(ls), 0);
  1010. init_exp(&v, VLOCAL, fs->freereg);
  1011. luaK_reserveregs(fs, 1);
  1012. adjustlocalvars(ls, 1);
  1013. body(ls, &b, 0, ls->linenumber);
  1014. luaK_storevar(fs, &v, &b);
  1015. /* debug information will only see the variable after this point! */
  1016. getlocvar(fs, fs->nactvar - 1).startpc = fs->pc;
  1017. }
  1018. static void localstat (LexState *ls) {
  1019. /* stat -> LOCAL NAME {`,' NAME} [`=' explist1] */
  1020. int nvars = 0;
  1021. int nexps;
  1022. expdesc e;
  1023. do {
  1024. new_localvar(ls, str_checkname(ls), nvars++);
  1025. } while (testnext(ls, ','));
  1026. if (testnext(ls, '='))
  1027. nexps = explist1(ls, &e);
  1028. else {
  1029. e.k = VVOID;
  1030. nexps = 0;
  1031. }
  1032. adjust_assign(ls, nvars, nexps, &e);
  1033. adjustlocalvars(ls, nvars);
  1034. }
  1035. static int funcname (LexState *ls, expdesc *v) {
  1036. /* funcname -> NAME {field} [`:' NAME] */
  1037. int needself = 0;
  1038. singlevar(ls, v);
  1039. while (ls->t.token == '.')
  1040. field(ls, v);
  1041. if (ls->t.token == ':') {
  1042. needself = 1;
  1043. field(ls, v);
  1044. }
  1045. return needself;
  1046. }
  1047. static void funcstat (LexState *ls, int line) {
  1048. /* funcstat -> FUNCTION funcname body */
  1049. int needself;
  1050. expdesc v, b;
  1051. next(ls); /* skip FUNCTION */
  1052. needself = funcname(ls, &v);
  1053. body(ls, &b, needself, line);
  1054. luaK_storevar(ls->fs, &v, &b);
  1055. luaK_fixline(ls->fs, line); /* definition `happens' in the first line */
  1056. }
  1057. static void exprstat (LexState *ls) {
  1058. /* stat -> func | assignment */
  1059. FuncState *fs = ls->fs;
  1060. struct LHS_assign v;
  1061. primaryexp(ls, &v.v);
  1062. if (v.v.k == VCALL) /* stat -> func */
  1063. SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */
  1064. else { /* stat -> assignment */
  1065. v.prev = NULL;
  1066. assignment(ls, &v, 1);
  1067. }
  1068. }
  1069. static void retstat (LexState *ls) {
  1070. /* stat -> RETURN explist */
  1071. FuncState *fs = ls->fs;
  1072. expdesc e;
  1073. int first, nret; /* registers with returned values */
  1074. next(ls); /* skip RETURN */
  1075. if (block_follow(ls->t.token) || ls->t.token == ';')
  1076. first = nret = 0; /* return no values */
  1077. else {
  1078. nret = explist1(ls, &e); /* optional return values */
  1079. if (hasmultret(e.k)) {
  1080. luaK_setmultret(fs, &e);
  1081. if (e.k == VCALL && nret == 1) { /* tail call? */
  1082. SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
  1083. lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
  1084. }
  1085. first = fs->nactvar;
  1086. nret = LUA_MULTRET; /* return all values */
  1087. }
  1088. else {
  1089. if (nret == 1) /* only one single value? */
  1090. first = luaK_exp2anyreg(fs, &e);
  1091. else {
  1092. luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */
  1093. first = fs->nactvar; /* return all `active' values */
  1094. lua_assert(nret == fs->freereg - first);
  1095. }
  1096. }
  1097. }
  1098. luaK_ret(fs, first, nret);
  1099. }
  1100. static int statement (LexState *ls) {
  1101. int line = ls->linenumber; /* may be needed for error messages */
  1102. switch (ls->t.token) {
  1103. case TK_IF: { /* stat -> ifstat */
  1104. ifstat(ls, line);
  1105. return 0;
  1106. }
  1107. case TK_WHILE: { /* stat -> whilestat */
  1108. whilestat(ls, line);
  1109. return 0;
  1110. }
  1111. case TK_DO: { /* stat -> DO block END */
  1112. next(ls); /* skip DO */
  1113. block(ls);
  1114. check_match(ls, TK_END, TK_DO, line);
  1115. return 0;
  1116. }
  1117. case TK_FOR: { /* stat -> forstat */
  1118. forstat(ls, line);
  1119. return 0;
  1120. }
  1121. case TK_REPEAT: { /* stat -> repeatstat */
  1122. repeatstat(ls, line);
  1123. return 0;
  1124. }
  1125. case TK_FUNCTION: {
  1126. funcstat(ls, line); /* stat -> funcstat */
  1127. return 0;
  1128. }
  1129. case TK_LOCAL: { /* stat -> localstat */
  1130. next(ls); /* skip LOCAL */
  1131. if (testnext(ls, TK_FUNCTION)) /* local function? */
  1132. localfunc(ls);
  1133. else
  1134. localstat(ls);
  1135. return 0;
  1136. }
  1137. case TK_RETURN: { /* stat -> retstat */
  1138. retstat(ls);
  1139. return 1; /* must be last statement */
  1140. }
  1141. case TK_BREAK: { /* stat -> breakstat */
  1142. next(ls); /* skip BREAK */
  1143. breakstat(ls);
  1144. return 1; /* must be last statement */
  1145. }
  1146. default: {
  1147. exprstat(ls);
  1148. return 0; /* to avoid warnings */
  1149. }
  1150. }
  1151. }
  1152. static void chunk (LexState *ls) {
  1153. /* chunk -> { stat [`;'] } */
  1154. int islast = 0;
  1155. enterlevel(ls);
  1156. while (!islast && !block_follow(ls->t.token)) {
  1157. islast = statement(ls);
  1158. testnext(ls, ';');
  1159. lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
  1160. ls->fs->freereg >= ls->fs->nactvar);
  1161. ls->fs->freereg = ls->fs->nactvar; /* free registers */
  1162. }
  1163. leavelevel(ls);
  1164. }
  1165. /* }====================================================================== */