| 1 | /* |
| 2 | ** $Id: lparser.c,v 2.130 2013/02/06 13:37:39 roberto Exp $ |
| 3 | ** Lua Parser |
| 4 | ** See Copyright Notice in lua.h |
| 5 | */ |
| 6 | |
| 7 | |
| 8 | #include <string.h> |
| 9 | |
| 10 | #define lparser_c |
| 11 | #define LUA_CORE |
| 12 | |
| 13 | #include "lua.h" |
| 14 | |
| 15 | #include "lcode.h" |
| 16 | #include "ldebug.h" |
| 17 | #include "ldo.h" |
| 18 | #include "lfunc.h" |
| 19 | #include "llex.h" |
| 20 | #include "lmem.h" |
| 21 | #include "lobject.h" |
| 22 | #include "lopcodes.h" |
| 23 | #include "lparser.h" |
| 24 | #include "lstate.h" |
| 25 | #include "lstring.h" |
| 26 | #include "ltable.h" |
| 27 | |
| 28 | |
| 29 | |
| 30 | /* maximum number of local variables per function (must be smaller |
| 31 | than 250, due to the bytecode format) */ |
| 32 | #define MAXVARS 200 |
| 33 | |
| 34 | |
| 35 | #define hasmultret(k) ((k) == VCALL || (k) == VVARARG) |
| 36 | |
| 37 | |
| 38 | |
| 39 | /* |
| 40 | ** nodes for block list (list of active blocks) |
| 41 | */ |
| 42 | typedef struct BlockCnt { |
| 43 | struct BlockCnt *previous; /* chain */ |
| 44 | short firstlabel; /* index of first label in this block */ |
| 45 | short firstgoto; /* index of first pending goto in this block */ |
| 46 | lu_byte nactvar; /* # active locals outside the block */ |
| 47 | lu_byte upval; /* true if some variable in the block is an upvalue */ |
| 48 | lu_byte isloop; /* true if `block' is a loop */ |
| 49 | } BlockCnt; |
| 50 | |
| 51 | |
| 52 | |
| 53 | /* |
| 54 | ** prototypes for recursive non-terminal functions |
| 55 | */ |
| 56 | static void statement (LexState *ls); |
| 57 | static void expr (LexState *ls, expdesc *v); |
| 58 | |
| 59 | |
| 60 | static void anchor_token (LexState *ls) { |
| 61 | /* last token from outer function must be EOS */ |
| 62 | lua_assert(ls->fs != NULL || ls->t.token == TK_EOS); |
| 63 | if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) { |
| 64 | TString *ts = ls->t.seminfo.ts; |
| 65 | luaX_newstring(ls, getstr(ts), ts->tsv.len); |
| 66 | } |
| 67 | } |
| 68 | |
| 69 | |
| 70 | /* semantic error */ |
| 71 | static l_noret semerror (LexState *ls, const char *msg) { |
| 72 | ls->t.token = 0; /* remove 'near to' from final message */ |
| 73 | luaX_syntaxerror(ls, msg); |
| 74 | } |
| 75 | |
| 76 | |
| 77 | static l_noret error_expected (LexState *ls, int token) { |
| 78 | luaX_syntaxerror(ls, |
| 79 | luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token))); |
| 80 | } |
| 81 | |
| 82 | |
| 83 | static l_noret errorlimit (FuncState *fs, int limit, const char *what) { |
| 84 | lua_State *L = fs->ls->L; |
| 85 | const char *msg; |
| 86 | int line = fs->f->linedefined; |
| 87 | const char *where = (line == 0) |
| 88 | ? "main function" |
| 89 | : luaO_pushfstring(L, "function at line %d", line); |
| 90 | msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s", |
| 91 | what, limit, where); |
| 92 | luaX_syntaxerror(fs->ls, msg); |
| 93 | } |
| 94 | |
| 95 | |
| 96 | static void checklimit (FuncState *fs, int v, int l, const char *what) { |
| 97 | if (v > l) errorlimit(fs, l, what); |
| 98 | } |
| 99 | |
| 100 | |
| 101 | static int testnext (LexState *ls, int c) { |
| 102 | if (ls->t.token == c) { |
| 103 | luaX_next(ls); |
| 104 | return 1; |
| 105 | } |
| 106 | else return 0; |
| 107 | } |
| 108 | |
| 109 | |
| 110 | static void check (LexState *ls, int c) { |
| 111 | if (ls->t.token != c) |
| 112 | error_expected(ls, c); |
| 113 | } |
| 114 | |
| 115 | |
| 116 | static void checknext (LexState *ls, int c) { |
| 117 | check(ls, c); |
| 118 | luaX_next(ls); |
| 119 | } |
| 120 | |
| 121 | |
| 122 | #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); } |
| 123 | |
| 124 | |
| 125 | |
| 126 | static void check_match (LexState *ls, int what, int who, int where) { |
| 127 | if (!testnext(ls, what)) { |
| 128 | if (where == ls->linenumber) |
| 129 | error_expected(ls, what); |
| 130 | else { |
| 131 | luaX_syntaxerror(ls, luaO_pushfstring(ls->L, |
| 132 | "%s expected (to close %s at line %d)", |
| 133 | luaX_token2str(ls, what), luaX_token2str(ls, who), where)); |
| 134 | } |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | |
| 139 | static TString *str_checkname (LexState *ls) { |
| 140 | TString *ts; |
| 141 | check(ls, TK_NAME); |
| 142 | ts = ls->t.seminfo.ts; |
| 143 | luaX_next(ls); |
| 144 | return ts; |
| 145 | } |
| 146 | |
| 147 | |
| 148 | static void init_exp (expdesc *e, expkind k, int i) { |
| 149 | e->f = e->t = NO_JUMP; |
| 150 | e->k = k; |
| 151 | e->u.info = i; |
| 152 | } |
| 153 | |
| 154 | |
| 155 | static void codestring (LexState *ls, expdesc *e, TString *s) { |
| 156 | init_exp(e, VK, luaK_stringK(ls->fs, s)); |
| 157 | } |
| 158 | |
| 159 | |
| 160 | static void checkname (LexState *ls, expdesc *e) { |
| 161 | codestring(ls, e, str_checkname(ls)); |
| 162 | } |
| 163 | |
| 164 | |
| 165 | static int registerlocalvar (LexState *ls, TString *varname) { |
| 166 | FuncState *fs = ls->fs; |
| 167 | Proto *f = fs->f; |
| 168 | int oldsize = f->sizelocvars; |
| 169 | luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars, |
| 170 | LocVar, SHRT_MAX, "local variables"); |
| 171 | while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL; |
| 172 | f->locvars[fs->nlocvars].varname = varname; |
| 173 | luaC_objbarrier(ls->L, f, varname); |
| 174 | return fs->nlocvars++; |
| 175 | } |
| 176 | |
| 177 | |
| 178 | static void new_localvar (LexState *ls, TString *name) { |
| 179 | FuncState *fs = ls->fs; |
| 180 | Dyndata *dyd = ls->dyd; |
| 181 | int reg = registerlocalvar(ls, name); |
| 182 | checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal, |
| 183 | MAXVARS, "local variables"); |
| 184 | luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1, |
| 185 | dyd->actvar.size, Vardesc, MAX_INT, "local variables"); |
| 186 | dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg); |
| 187 | } |
| 188 | |
| 189 | |
| 190 | static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) { |
| 191 | new_localvar(ls, luaX_newstring(ls, name, sz)); |
| 192 | } |
| 193 | |
| 194 | #define new_localvarliteral(ls,v) \ |
| 195 | new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1) |
| 196 | |
| 197 | |
| 198 | static LocVar *getlocvar (FuncState *fs, int i) { |
| 199 | int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx; |
| 200 | lua_assert(idx < fs->nlocvars); |
| 201 | return &fs->f->locvars[idx]; |
| 202 | } |
| 203 | |
| 204 | |
| 205 | static void adjustlocalvars (LexState *ls, int nvars) { |
| 206 | FuncState *fs = ls->fs; |
| 207 | fs->nactvar = cast_byte(fs->nactvar + nvars); |
| 208 | for (; nvars; nvars--) { |
| 209 | getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc; |
| 210 | } |
| 211 | } |
| 212 | |
| 213 | |
| 214 | static void removevars (FuncState *fs, int tolevel) { |
| 215 | fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel); |
| 216 | while (fs->nactvar > tolevel) |
| 217 | getlocvar(fs, --fs->nactvar)->endpc = fs->pc; |
| 218 | } |
| 219 | |
| 220 | |
| 221 | static int searchupvalue (FuncState *fs, TString *name) { |
| 222 | int i; |
| 223 | Upvaldesc *up = fs->f->upvalues; |
| 224 | for (i = 0; i < fs->nups; i++) { |
| 225 | if (luaS_eqstr(up[i].name, name)) return i; |
| 226 | } |
| 227 | return -1; /* not found */ |
| 228 | } |
| 229 | |
| 230 | |
| 231 | static int newupvalue (FuncState *fs, TString *name, expdesc *v) { |
| 232 | Proto *f = fs->f; |
| 233 | int oldsize = f->sizeupvalues; |
| 234 | checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues"); |
| 235 | luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues, |
| 236 | Upvaldesc, MAXUPVAL, "upvalues"); |
| 237 | while (oldsize < f->sizeupvalues) f->upvalues[oldsize++].name = NULL; |
| 238 | f->upvalues[fs->nups].instack = (v->k == VLOCAL); |
| 239 | f->upvalues[fs->nups].idx = cast_byte(v->u.info); |
| 240 | f->upvalues[fs->nups].name = name; |
| 241 | luaC_objbarrier(fs->ls->L, f, name); |
| 242 | return fs->nups++; |
| 243 | } |
| 244 | |
| 245 | |
| 246 | static int searchvar (FuncState *fs, TString *n) { |
| 247 | int i; |
| 248 | for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) { |
| 249 | if (luaS_eqstr(n, getlocvar(fs, i)->varname)) |
| 250 | return i; |
| 251 | } |
| 252 | return -1; /* not found */ |
| 253 | } |
| 254 | |
| 255 | |
| 256 | /* |
| 257 | Mark block where variable at given level was defined |
| 258 | (to emit close instructions later). |
| 259 | */ |
| 260 | static void markupval (FuncState *fs, int level) { |
| 261 | BlockCnt *bl = fs->bl; |
| 262 | while (bl->nactvar > level) bl = bl->previous; |
| 263 | bl->upval = 1; |
| 264 | } |
| 265 | |
| 266 | |
| 267 | /* |
| 268 | Find variable with given name 'n'. If it is an upvalue, add this |
| 269 | upvalue into all intermediate functions. |
| 270 | */ |
| 271 | static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { |
| 272 | if (fs == NULL) /* no more levels? */ |
| 273 | return VVOID; /* default is global */ |
| 274 | else { |
| 275 | int v = searchvar(fs, n); /* look up locals at current level */ |
| 276 | if (v >= 0) { /* found? */ |
| 277 | init_exp(var, VLOCAL, v); /* variable is local */ |
| 278 | if (!base) |
| 279 | markupval(fs, v); /* local will be used as an upval */ |
| 280 | return VLOCAL; |
| 281 | } |
| 282 | else { /* not found as local at current level; try upvalues */ |
| 283 | int idx = searchupvalue(fs, n); /* try existing upvalues */ |
| 284 | if (idx < 0) { /* not found? */ |
| 285 | if (singlevaraux(fs->prev, n, var, 0) == VVOID) /* try upper levels */ |
| 286 | return VVOID; /* not found; is a global */ |
| 287 | /* else was LOCAL or UPVAL */ |
| 288 | idx = newupvalue(fs, n, var); /* will be a new upvalue */ |
| 289 | } |
| 290 | init_exp(var, VUPVAL, idx); |
| 291 | return VUPVAL; |
| 292 | } |
| 293 | } |
| 294 | } |
| 295 | |
| 296 | |
| 297 | static void singlevar (LexState *ls, expdesc *var) { |
| 298 | TString *varname = str_checkname(ls); |
| 299 | FuncState *fs = ls->fs; |
| 300 | if (singlevaraux(fs, varname, var, 1) == VVOID) { /* global name? */ |
| 301 | expdesc key; |
| 302 | singlevaraux(fs, ls->envn, var, 1); /* get environment variable */ |
| 303 | lua_assert(var->k == VLOCAL || var->k == VUPVAL); |
| 304 | codestring(ls, &key, varname); /* key is variable name */ |
| 305 | luaK_indexed(fs, var, &key); /* env[varname] */ |
| 306 | } |
| 307 | } |
| 308 | |
| 309 | |
| 310 | static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) { |
| 311 | FuncState *fs = ls->fs; |
| 312 | int extra = nvars - nexps; |
| 313 | if (hasmultret(e->k)) { |
| 314 | extra++; /* includes call itself */ |
| 315 | if (extra < 0) extra = 0; |
| 316 | luaK_setreturns(fs, e, extra); /* last exp. provides the difference */ |
| 317 | if (extra > 1) luaK_reserveregs(fs, extra-1); |
| 318 | } |
| 319 | else { |
| 320 | if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */ |
| 321 | if (extra > 0) { |
| 322 | int reg = fs->freereg; |
| 323 | luaK_reserveregs(fs, extra); |
| 324 | luaK_nil(fs, reg, extra); |
| 325 | } |
| 326 | } |
| 327 | } |
| 328 | |
| 329 | |
| 330 | static void enterlevel (LexState *ls) { |
| 331 | lua_State *L = ls->L; |
| 332 | ++L->nCcalls; |
| 333 | checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "C levels"); |
| 334 | } |
| 335 | |
| 336 | |
| 337 | #define leavelevel(ls) ((ls)->L->nCcalls--) |
| 338 | |
| 339 | |
| 340 | static void closegoto (LexState *ls, int g, Labeldesc *label) { |
| 341 | int i; |
| 342 | FuncState *fs = ls->fs; |
| 343 | Labellist *gl = &ls->dyd->gt; |
| 344 | Labeldesc *gt = &gl->arr[g]; |
| 345 | lua_assert(luaS_eqstr(gt->name, label->name)); |
| 346 | if (gt->nactvar < label->nactvar) { |
| 347 | TString *vname = getlocvar(fs, gt->nactvar)->varname; |
| 348 | const char *msg = luaO_pushfstring(ls->L, |
| 349 | "<goto %s> at line %d jumps into the scope of local " LUA_QS, |
| 350 | getstr(gt->name), gt->line, getstr(vname)); |
| 351 | semerror(ls, msg); |
| 352 | } |
| 353 | luaK_patchlist(fs, gt->pc, label->pc); |
| 354 | /* remove goto from pending list */ |
| 355 | for (i = g; i < gl->n - 1; i++) |
| 356 | gl->arr[i] = gl->arr[i + 1]; |
| 357 | gl->n--; |
| 358 | } |
| 359 | |
| 360 | |
| 361 | /* |
| 362 | ** try to close a goto with existing labels; this solves backward jumps |
| 363 | */ |
| 364 | static int findlabel (LexState *ls, int g) { |
| 365 | int i; |
| 366 | BlockCnt *bl = ls->fs->bl; |
| 367 | Dyndata *dyd = ls->dyd; |
| 368 | Labeldesc *gt = &dyd->gt.arr[g]; |
| 369 | /* check labels in current block for a match */ |
| 370 | for (i = bl->firstlabel; i < dyd->label.n; i++) { |
| 371 | Labeldesc *lb = &dyd->label.arr[i]; |
| 372 | if (luaS_eqstr(lb->name, gt->name)) { /* correct label? */ |
| 373 | if (gt->nactvar > lb->nactvar && |
| 374 | (bl->upval || dyd->label.n > bl->firstlabel)) |
| 375 | luaK_patchclose(ls->fs, gt->pc, lb->nactvar); |
| 376 | closegoto(ls, g, lb); /* close it */ |
| 377 | return 1; |
| 378 | } |
| 379 | } |
| 380 | return 0; /* label not found; cannot close goto */ |
| 381 | } |
| 382 | |
| 383 | |
| 384 | static int newlabelentry (LexState *ls, Labellist *l, TString *name, |
| 385 | int line, int pc) { |
| 386 | int n = l->n; |
| 387 | luaM_growvector(ls->L, l->arr, n, l->size, |
| 388 | Labeldesc, SHRT_MAX, "labels/gotos"); |
| 389 | l->arr[n].name = name; |
| 390 | l->arr[n].line = line; |
| 391 | l->arr[n].nactvar = ls->fs->nactvar; |
| 392 | l->arr[n].pc = pc; |
| 393 | l->n++; |
| 394 | return n; |
| 395 | } |
| 396 | |
| 397 | |
| 398 | /* |
| 399 | ** check whether new label 'lb' matches any pending gotos in current |
| 400 | ** block; solves forward jumps |
| 401 | */ |
| 402 | static void findgotos (LexState *ls, Labeldesc *lb) { |
| 403 | Labellist *gl = &ls->dyd->gt; |
| 404 | int i = ls->fs->bl->firstgoto; |
| 405 | while (i < gl->n) { |
| 406 | if (luaS_eqstr(gl->arr[i].name, lb->name)) |
| 407 | closegoto(ls, i, lb); |
| 408 | else |
| 409 | i++; |
| 410 | } |
| 411 | } |
| 412 | |
| 413 | |
| 414 | /* |
| 415 | ** "export" pending gotos to outer level, to check them against |
| 416 | ** outer labels; if the block being exited has upvalues, and |
| 417 | ** the goto exits the scope of any variable (which can be the |
| 418 | ** upvalue), close those variables being exited. |
| 419 | */ |
| 420 | static void movegotosout (FuncState *fs, BlockCnt *bl) { |
| 421 | int i = bl->firstgoto; |
| 422 | Labellist *gl = &fs->ls->dyd->gt; |
| 423 | /* correct pending gotos to current block and try to close it |
| 424 | with visible labels */ |
| 425 | while (i < gl->n) { |
| 426 | Labeldesc *gt = &gl->arr[i]; |
| 427 | if (gt->nactvar > bl->nactvar) { |
| 428 | if (bl->upval) |
| 429 | luaK_patchclose(fs, gt->pc, bl->nactvar); |
| 430 | gt->nactvar = bl->nactvar; |
| 431 | } |
| 432 | if (!findlabel(fs->ls, i)) |
| 433 | i++; /* move to next one */ |
| 434 | } |
| 435 | } |
| 436 | |
| 437 | |
| 438 | static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isloop) { |
| 439 | bl->isloop = isloop; |
| 440 | bl->nactvar = fs->nactvar; |
| 441 | bl->firstlabel = fs->ls->dyd->label.n; |
| 442 | bl->firstgoto = fs->ls->dyd->gt.n; |
| 443 | bl->upval = 0; |
| 444 | bl->previous = fs->bl; |
| 445 | fs->bl = bl; |
| 446 | lua_assert(fs->freereg == fs->nactvar); |
| 447 | } |
| 448 | |
| 449 | |
| 450 | /* |
| 451 | ** create a label named "break" to resolve break statements |
| 452 | */ |
| 453 | static void breaklabel (LexState *ls) { |
| 454 | TString *n = luaS_new(ls->L, "break"); |
| 455 | int l = newlabelentry(ls, &ls->dyd->label, n, 0, ls->fs->pc); |
| 456 | findgotos(ls, &ls->dyd->label.arr[l]); |
| 457 | } |
| 458 | |
| 459 | /* |
| 460 | ** generates an error for an undefined 'goto'; choose appropriate |
| 461 | ** message when label name is a reserved word (which can only be 'break') |
| 462 | */ |
| 463 | static l_noret undefgoto (LexState *ls, Labeldesc *gt) { |
| 464 | const char *msg = isreserved(gt->name) |
| 465 | ? "<%s> at line %d not inside a loop" |
| 466 | : "no visible label " LUA_QS " for <goto> at line %d"; |
| 467 | msg = luaO_pushfstring(ls->L, msg, getstr(gt->name), gt->line); |
| 468 | semerror(ls, msg); |
| 469 | } |
| 470 | |
| 471 | |
| 472 | static void leaveblock (FuncState *fs) { |
| 473 | BlockCnt *bl = fs->bl; |
| 474 | LexState *ls = fs->ls; |
| 475 | if (bl->previous && bl->upval) { |
| 476 | /* create a 'jump to here' to close upvalues */ |
| 477 | int j = luaK_jump(fs); |
| 478 | luaK_patchclose(fs, j, bl->nactvar); |
| 479 | luaK_patchtohere(fs, j); |
| 480 | } |
| 481 | if (bl->isloop) |
| 482 | breaklabel(ls); /* close pending breaks */ |
| 483 | fs->bl = bl->previous; |
| 484 | removevars(fs, bl->nactvar); |
| 485 | lua_assert(bl->nactvar == fs->nactvar); |
| 486 | fs->freereg = fs->nactvar; /* free registers */ |
| 487 | ls->dyd->label.n = bl->firstlabel; /* remove local labels */ |
| 488 | if (bl->previous) /* inner block? */ |
| 489 | movegotosout(fs, bl); /* update pending gotos to outer block */ |
| 490 | else if (bl->firstgoto < ls->dyd->gt.n) /* pending gotos in outer block? */ |
| 491 | undefgoto(ls, &ls->dyd->gt.arr[bl->firstgoto]); /* error */ |
| 492 | } |
| 493 | |
| 494 | |
| 495 | /* |
| 496 | ** adds a new prototype into list of prototypes |
| 497 | */ |
| 498 | static Proto *addprototype (LexState *ls) { |
| 499 | Proto *clp; |
| 500 | lua_State *L = ls->L; |
| 501 | FuncState *fs = ls->fs; |
| 502 | Proto *f = fs->f; /* prototype of current function */ |
| 503 | if (fs->np >= f->sizep) { |
| 504 | int oldsize = f->sizep; |
| 505 | luaM_growvector(L, f->p, fs->np, f->sizep, Proto *, MAXARG_Bx, "functions"); |
| 506 | while (oldsize < f->sizep) f->p[oldsize++] = NULL; |
| 507 | } |
| 508 | f->p[fs->np++] = clp = luaF_newproto(L); |
| 509 | luaC_objbarrier(L, f, clp); |
| 510 | return clp; |
| 511 | } |
| 512 | |
| 513 | |
| 514 | /* |
| 515 | ** codes instruction to create new closure in parent function. |
| 516 | ** The OP_CLOSURE instruction must use the last available register, |
| 517 | ** so that, if it invokes the GC, the GC knows which registers |
| 518 | ** are in use at that time. |
| 519 | */ |
| 520 | static void codeclosure (LexState *ls, expdesc *v) { |
| 521 | FuncState *fs = ls->fs->prev; |
| 522 | init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np - 1)); |
| 523 | luaK_exp2nextreg(fs, v); /* fix it at the last register */ |
| 524 | } |
| 525 | |
| 526 | |
| 527 | static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) { |
| 528 | lua_State *L = ls->L; |
| 529 | Proto *f; |
| 530 | fs->prev = ls->fs; /* linked list of funcstates */ |
| 531 | fs->ls = ls; |
| 532 | ls->fs = fs; |
| 533 | fs->pc = 0; |
| 534 | fs->lasttarget = 0; |
| 535 | fs->jpc = NO_JUMP; |
| 536 | fs->freereg = 0; |
| 537 | fs->nk = 0; |
| 538 | fs->np = 0; |
| 539 | fs->nups = 0; |
| 540 | fs->nlocvars = 0; |
| 541 | fs->nactvar = 0; |
| 542 | fs->firstlocal = ls->dyd->actvar.n; |
| 543 | fs->bl = NULL; |
| 544 | f = fs->f; |
| 545 | f->source = ls->source; |
| 546 | f->maxstacksize = 2; /* registers 0/1 are always valid */ |
| 547 | fs->h = luaH_new(L); |
| 548 | /* anchor table of constants (to avoid being collected) */ |
| 549 | sethvalue2s(L, L->top, fs->h); |
| 550 | incr_top(L); |
| 551 | enterblock(fs, bl, 0); |
| 552 | } |
| 553 | |
| 554 | |
| 555 | static void close_func (LexState *ls) { |
| 556 | lua_State *L = ls->L; |
| 557 | FuncState *fs = ls->fs; |
| 558 | Proto *f = fs->f; |
| 559 | luaK_ret(fs, 0, 0); /* final return */ |
| 560 | leaveblock(fs); |
| 561 | luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction); |
| 562 | f->sizecode = fs->pc; |
| 563 | luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int); |
| 564 | f->sizelineinfo = fs->pc; |
| 565 | luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue); |
| 566 | f->sizek = fs->nk; |
| 567 | luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *); |
| 568 | f->sizep = fs->np; |
| 569 | luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar); |
| 570 | f->sizelocvars = fs->nlocvars; |
| 571 | luaM_reallocvector(L, f->upvalues, f->sizeupvalues, fs->nups, Upvaldesc); |
| 572 | f->sizeupvalues = fs->nups; |
| 573 | lua_assert(fs->bl == NULL); |
| 574 | ls->fs = fs->prev; |
| 575 | /* last token read was anchored in defunct function; must re-anchor it */ |
| 576 | anchor_token(ls); |
| 577 | L->top--; /* pop table of constants */ |
| 578 | luaC_checkGC(L); |
| 579 | } |
| 580 | |
| 581 | |
| 582 | |
| 583 | /*============================================================*/ |
| 584 | /* GRAMMAR RULES */ |
| 585 | /*============================================================*/ |
| 586 | |
| 587 | |
| 588 | /* |
| 589 | ** check whether current token is in the follow set of a block. |
| 590 | ** 'until' closes syntactical blocks, but do not close scope, |
| 591 | ** so it handled in separate. |
| 592 | */ |
| 593 | static int block_follow (LexState *ls, int withuntil) { |
| 594 | switch (ls->t.token) { |
| 595 | case TK_ELSE: case TK_ELSEIF: |
| 596 | case TK_END: case TK_EOS: |
| 597 | return 1; |
| 598 | case TK_UNTIL: return withuntil; |
| 599 | default: return 0; |
| 600 | } |
| 601 | } |
| 602 | |
| 603 | |
| 604 | static void statlist (LexState *ls) { |
| 605 | /* statlist -> { stat [`;'] } */ |
| 606 | while (!block_follow(ls, 1)) { |
| 607 | if (ls->t.token == TK_RETURN) { |
| 608 | statement(ls); |
| 609 | return; /* 'return' must be last statement */ |
| 610 | } |
| 611 | statement(ls); |
| 612 | } |
| 613 | } |
| 614 | |
| 615 | |
| 616 | static void fieldsel (LexState *ls, expdesc *v) { |
| 617 | /* fieldsel -> ['.' | ':'] NAME */ |
| 618 | FuncState *fs = ls->fs; |
| 619 | expdesc key; |
| 620 | luaK_exp2anyregup(fs, v); |
| 621 | luaX_next(ls); /* skip the dot or colon */ |
| 622 | checkname(ls, &key); |
| 623 | luaK_indexed(fs, v, &key); |
| 624 | } |
| 625 | |
| 626 | |
| 627 | static void yindex (LexState *ls, expdesc *v) { |
| 628 | /* index -> '[' expr ']' */ |
| 629 | luaX_next(ls); /* skip the '[' */ |
| 630 | expr(ls, v); |
| 631 | luaK_exp2val(ls->fs, v); |
| 632 | checknext(ls, ']'); |
| 633 | } |
| 634 | |
| 635 | |
| 636 | /* |
| 637 | ** {====================================================================== |
| 638 | ** Rules for Constructors |
| 639 | ** ======================================================================= |
| 640 | */ |
| 641 | |
| 642 | |
| 643 | struct ConsControl { |
| 644 | expdesc v; /* last list item read */ |
| 645 | expdesc *t; /* table descriptor */ |
| 646 | int nh; /* total number of `record' elements */ |
| 647 | int na; /* total number of array elements */ |
| 648 | int tostore; /* number of array elements pending to be stored */ |
| 649 | }; |
| 650 | |
| 651 | |
| 652 | static void recfield (LexState *ls, struct ConsControl *cc) { |
| 653 | /* recfield -> (NAME | `['exp1`]') = exp1 */ |
| 654 | FuncState *fs = ls->fs; |
| 655 | int reg = ls->fs->freereg; |
| 656 | expdesc key, val; |
| 657 | int rkkey; |
| 658 | if (ls->t.token == TK_NAME) { |
| 659 | checklimit(fs, cc->nh, MAX_INT, "items in a constructor"); |
| 660 | checkname(ls, &key); |
| 661 | } |
| 662 | else /* ls->t.token == '[' */ |
| 663 | yindex(ls, &key); |
| 664 | cc->nh++; |
| 665 | checknext(ls, '='); |
| 666 | rkkey = luaK_exp2RK(fs, &key); |
| 667 | expr(ls, &val); |
| 668 | luaK_codeABC(fs, OP_SETTABLE, cc->t->u.info, rkkey, luaK_exp2RK(fs, &val)); |
| 669 | fs->freereg = reg; /* free registers */ |
| 670 | } |
| 671 | |
| 672 | |
| 673 | static void closelistfield (FuncState *fs, struct ConsControl *cc) { |
| 674 | if (cc->v.k == VVOID) return; /* there is no list item */ |
| 675 | luaK_exp2nextreg(fs, &cc->v); |
| 676 | cc->v.k = VVOID; |
| 677 | if (cc->tostore == LFIELDS_PER_FLUSH) { |
| 678 | luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); /* flush */ |
| 679 | cc->tostore = 0; /* no more items pending */ |
| 680 | } |
| 681 | } |
| 682 | |
| 683 | |
| 684 | static void lastlistfield (FuncState *fs, struct ConsControl *cc) { |
| 685 | if (cc->tostore == 0) return; |
| 686 | if (hasmultret(cc->v.k)) { |
| 687 | luaK_setmultret(fs, &cc->v); |
| 688 | luaK_setlist(fs, cc->t->u.info, cc->na, LUA_MULTRET); |
| 689 | cc->na--; /* do not count last expression (unknown number of elements) */ |
| 690 | } |
| 691 | else { |
| 692 | if (cc->v.k != VVOID) |
| 693 | luaK_exp2nextreg(fs, &cc->v); |
| 694 | luaK_setlist(fs, cc->t->u.info, cc->na, cc->tostore); |
| 695 | } |
| 696 | } |
| 697 | |
| 698 | |
| 699 | static void listfield (LexState *ls, struct ConsControl *cc) { |
| 700 | /* listfield -> exp */ |
| 701 | expr(ls, &cc->v); |
| 702 | checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor"); |
| 703 | cc->na++; |
| 704 | cc->tostore++; |
| 705 | } |
| 706 | |
| 707 | |
| 708 | static void field (LexState *ls, struct ConsControl *cc) { |
| 709 | /* field -> listfield | recfield */ |
| 710 | switch(ls->t.token) { |
| 711 | case TK_NAME: { /* may be 'listfield' or 'recfield' */ |
| 712 | if (luaX_lookahead(ls) != '=') /* expression? */ |
| 713 | listfield(ls, cc); |
| 714 | else |
| 715 | recfield(ls, cc); |
| 716 | break; |
| 717 | } |
| 718 | case '[': { |
| 719 | recfield(ls, cc); |
| 720 | break; |
| 721 | } |
| 722 | default: { |
| 723 | listfield(ls, cc); |
| 724 | break; |
| 725 | } |
| 726 | } |
| 727 | } |
| 728 | |
| 729 | |
| 730 | static void constructor (LexState *ls, expdesc *t) { |
| 731 | /* constructor -> '{' [ field { sep field } [sep] ] '}' |
| 732 | sep -> ',' | ';' */ |
| 733 | FuncState *fs = ls->fs; |
| 734 | int line = ls->linenumber; |
| 735 | int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0); |
| 736 | struct ConsControl cc; |
| 737 | cc.na = cc.nh = cc.tostore = 0; |
| 738 | cc.t = t; |
| 739 | init_exp(t, VRELOCABLE, pc); |
| 740 | init_exp(&cc.v, VVOID, 0); /* no value (yet) */ |
| 741 | luaK_exp2nextreg(ls->fs, t); /* fix it at stack top */ |
| 742 | checknext(ls, '{'); |
| 743 | do { |
| 744 | lua_assert(cc.v.k == VVOID || cc.tostore > 0); |
| 745 | if (ls->t.token == '}') break; |
| 746 | closelistfield(fs, &cc); |
| 747 | field(ls, &cc); |
| 748 | } while (testnext(ls, ',') || testnext(ls, ';')); |
| 749 | check_match(ls, '}', '{', line); |
| 750 | lastlistfield(fs, &cc); |
| 751 | SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */ |
| 752 | SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */ |
| 753 | } |
| 754 | |
| 755 | /* }====================================================================== */ |
| 756 | |
| 757 | |
| 758 | |
| 759 | static void parlist (LexState *ls) { |
| 760 | /* parlist -> [ param { `,' param } ] */ |
| 761 | FuncState *fs = ls->fs; |
| 762 | Proto *f = fs->f; |
| 763 | int nparams = 0; |
| 764 | f->is_vararg = 0; |
| 765 | if (ls->t.token != ')') { /* is `parlist' not empty? */ |
| 766 | do { |
| 767 | switch (ls->t.token) { |
| 768 | case TK_NAME: { /* param -> NAME */ |
| 769 | new_localvar(ls, str_checkname(ls)); |
| 770 | nparams++; |
| 771 | break; |
| 772 | } |
| 773 | case TK_DOTS: { /* param -> `...' */ |
| 774 | luaX_next(ls); |
| 775 | f->is_vararg = 1; |
| 776 | break; |
| 777 | } |
| 778 | default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected"); |
| 779 | } |
| 780 | } while (!f->is_vararg && testnext(ls, ',')); |
| 781 | } |
| 782 | adjustlocalvars(ls, nparams); |
| 783 | f->numparams = cast_byte(fs->nactvar); |
| 784 | luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */ |
| 785 | } |
| 786 | |
| 787 | |
| 788 | static void body (LexState *ls, expdesc *e, int ismethod, int line) { |
| 789 | /* body -> `(' parlist `)' block END */ |
| 790 | FuncState new_fs; |
| 791 | BlockCnt bl; |
| 792 | new_fs.f = addprototype(ls); |
| 793 | new_fs.f->linedefined = line; |
| 794 | open_func(ls, &new_fs, &bl); |
| 795 | checknext(ls, '('); |
| 796 | if (ismethod) { |
| 797 | new_localvarliteral(ls, "self"); /* create 'self' parameter */ |
| 798 | adjustlocalvars(ls, 1); |
| 799 | } |
| 800 | parlist(ls); |
| 801 | checknext(ls, ')'); |
| 802 | statlist(ls); |
| 803 | new_fs.f->lastlinedefined = ls->linenumber; |
| 804 | check_match(ls, TK_END, TK_FUNCTION, line); |
| 805 | codeclosure(ls, e); |
| 806 | close_func(ls); |
| 807 | } |
| 808 | |
| 809 | |
| 810 | static int explist (LexState *ls, expdesc *v) { |
| 811 | /* explist -> expr { `,' expr } */ |
| 812 | int n = 1; /* at least one expression */ |
| 813 | expr(ls, v); |
| 814 | while (testnext(ls, ',')) { |
| 815 | luaK_exp2nextreg(ls->fs, v); |
| 816 | expr(ls, v); |
| 817 | n++; |
| 818 | } |
| 819 | return n; |
| 820 | } |
| 821 | |
| 822 | |
| 823 | static void funcargs (LexState *ls, expdesc *f, int line) { |
| 824 | FuncState *fs = ls->fs; |
| 825 | expdesc args; |
| 826 | int base, nparams; |
| 827 | switch (ls->t.token) { |
| 828 | case '(': { /* funcargs -> `(' [ explist ] `)' */ |
| 829 | luaX_next(ls); |
| 830 | if (ls->t.token == ')') /* arg list is empty? */ |
| 831 | args.k = VVOID; |
| 832 | else { |
| 833 | explist(ls, &args); |
| 834 | luaK_setmultret(fs, &args); |
| 835 | } |
| 836 | check_match(ls, ')', '(', line); |
| 837 | break; |
| 838 | } |
| 839 | case '{': { /* funcargs -> constructor */ |
| 840 | constructor(ls, &args); |
| 841 | break; |
| 842 | } |
| 843 | case TK_STRING: { /* funcargs -> STRING */ |
| 844 | codestring(ls, &args, ls->t.seminfo.ts); |
| 845 | luaX_next(ls); /* must use `seminfo' before `next' */ |
| 846 | break; |
| 847 | } |
| 848 | default: { |
| 849 | luaX_syntaxerror(ls, "function arguments expected"); |
| 850 | } |
| 851 | } |
| 852 | lua_assert(f->k == VNONRELOC); |
| 853 | base = f->u.info; /* base register for call */ |
| 854 | if (hasmultret(args.k)) |
| 855 | nparams = LUA_MULTRET; /* open call */ |
| 856 | else { |
| 857 | if (args.k != VVOID) |
| 858 | luaK_exp2nextreg(fs, &args); /* close last argument */ |
| 859 | nparams = fs->freereg - (base+1); |
| 860 | } |
| 861 | init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2)); |
| 862 | luaK_fixline(fs, line); |
| 863 | fs->freereg = base+1; /* call remove function and arguments and leaves |
| 864 | (unless changed) one result */ |
| 865 | } |
| 866 | |
| 867 | |
| 868 | |
| 869 | |
| 870 | /* |
| 871 | ** {====================================================================== |
| 872 | ** Expression parsing |
| 873 | ** ======================================================================= |
| 874 | */ |
| 875 | |
| 876 | |
| 877 | static void primaryexp (LexState *ls, expdesc *v) { |
| 878 | /* primaryexp -> NAME | '(' expr ')' */ |
| 879 | switch (ls->t.token) { |
| 880 | case '(': { |
| 881 | int line = ls->linenumber; |
| 882 | luaX_next(ls); |
| 883 | expr(ls, v); |
| 884 | check_match(ls, ')', '(', line); |
| 885 | luaK_dischargevars(ls->fs, v); |
| 886 | return; |
| 887 | } |
| 888 | case TK_NAME: { |
| 889 | singlevar(ls, v); |
| 890 | return; |
| 891 | } |
| 892 | default: { |
| 893 | luaX_syntaxerror(ls, "unexpected symbol"); |
| 894 | } |
| 895 | } |
| 896 | } |
| 897 | |
| 898 | |
| 899 | static void suffixedexp (LexState *ls, expdesc *v) { |
| 900 | /* suffixedexp -> |
| 901 | primaryexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } */ |
| 902 | FuncState *fs = ls->fs; |
| 903 | int line = ls->linenumber; |
| 904 | primaryexp(ls, v); |
| 905 | for (;;) { |
| 906 | switch (ls->t.token) { |
| 907 | case '.': { /* fieldsel */ |
| 908 | fieldsel(ls, v); |
| 909 | break; |
| 910 | } |
| 911 | case '[': { /* `[' exp1 `]' */ |
| 912 | expdesc key; |
| 913 | luaK_exp2anyregup(fs, v); |
| 914 | yindex(ls, &key); |
| 915 | luaK_indexed(fs, v, &key); |
| 916 | break; |
| 917 | } |
| 918 | case ':': { /* `:' NAME funcargs */ |
| 919 | expdesc key; |
| 920 | luaX_next(ls); |
| 921 | checkname(ls, &key); |
| 922 | luaK_self(fs, v, &key); |
| 923 | funcargs(ls, v, line); |
| 924 | break; |
| 925 | } |
| 926 | case '(': case TK_STRING: case '{': { /* funcargs */ |
| 927 | luaK_exp2nextreg(fs, v); |
| 928 | funcargs(ls, v, line); |
| 929 | break; |
| 930 | } |
| 931 | default: return; |
| 932 | } |
| 933 | } |
| 934 | } |
| 935 | |
| 936 | |
| 937 | static void simpleexp (LexState *ls, expdesc *v) { |
| 938 | /* simpleexp -> NUMBER | STRING | NIL | TRUE | FALSE | ... | |
| 939 | constructor | FUNCTION body | suffixedexp */ |
| 940 | switch (ls->t.token) { |
| 941 | case TK_NUMBER: { |
| 942 | init_exp(v, VKNUM, 0); |
| 943 | v->u.nval = ls->t.seminfo.r; |
| 944 | break; |
| 945 | } |
| 946 | case TK_STRING: { |
| 947 | codestring(ls, v, ls->t.seminfo.ts); |
| 948 | break; |
| 949 | } |
| 950 | case TK_NIL: { |
| 951 | init_exp(v, VNIL, 0); |
| 952 | break; |
| 953 | } |
| 954 | case TK_TRUE: { |
| 955 | init_exp(v, VTRUE, 0); |
| 956 | break; |
| 957 | } |
| 958 | case TK_FALSE: { |
| 959 | init_exp(v, VFALSE, 0); |
| 960 | break; |
| 961 | } |
| 962 | case TK_DOTS: { /* vararg */ |
| 963 | FuncState *fs = ls->fs; |
| 964 | check_condition(ls, fs->f->is_vararg, |
| 965 | "cannot use " LUA_QL("...") " outside a vararg function"); |
| 966 | init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0)); |
| 967 | break; |
| 968 | } |
| 969 | case '{': { /* constructor */ |
| 970 | constructor(ls, v); |
| 971 | return; |
| 972 | } |
| 973 | case TK_FUNCTION: { |
| 974 | luaX_next(ls); |
| 975 | body(ls, v, 0, ls->linenumber); |
| 976 | return; |
| 977 | } |
| 978 | default: { |
| 979 | suffixedexp(ls, v); |
| 980 | return; |
| 981 | } |
| 982 | } |
| 983 | luaX_next(ls); |
| 984 | } |
| 985 | |
| 986 | |
| 987 | static UnOpr getunopr (int op) { |
| 988 | switch (op) { |
| 989 | case TK_NOT: return OPR_NOT; |
| 990 | case '-': return OPR_MINUS; |
| 991 | case '#': return OPR_LEN; |
| 992 | default: return OPR_NOUNOPR; |
| 993 | } |
| 994 | } |
| 995 | |
| 996 | |
| 997 | static BinOpr getbinopr (int op) { |
| 998 | switch (op) { |
| 999 | case '+': return OPR_ADD; |
| 1000 | case '-': return OPR_SUB; |
| 1001 | case '*': return OPR_MUL; |
| 1002 | case '/': return OPR_DIV; |
| 1003 | case '%': return OPR_MOD; |
| 1004 | case '^': return OPR_POW; |
| 1005 | case TK_CONCAT: return OPR_CONCAT; |
| 1006 | case TK_NE: return OPR_NE; |
| 1007 | case TK_EQ: return OPR_EQ; |
| 1008 | case '<': return OPR_LT; |
| 1009 | case TK_LE: return OPR_LE; |
| 1010 | case '>': return OPR_GT; |
| 1011 | case TK_GE: return OPR_GE; |
| 1012 | case TK_AND: return OPR_AND; |
| 1013 | case TK_OR: return OPR_OR; |
| 1014 | default: return OPR_NOBINOPR; |
| 1015 | } |
| 1016 | } |
| 1017 | |
| 1018 | |
| 1019 | static const struct { |
| 1020 | lu_byte left; /* left priority for each binary operator */ |
| 1021 | lu_byte right; /* right priority */ |
| 1022 | } priority[] = { /* ORDER OPR */ |
| 1023 | {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, /* `+' `-' `*' `/' `%' */ |
| 1024 | {10, 9}, {5, 4}, /* ^, .. (right associative) */ |
| 1025 | {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */ |
| 1026 | {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */ |
| 1027 | {2, 2}, {1, 1} /* and, or */ |
| 1028 | }; |
| 1029 | |
| 1030 | #define UNARY_PRIORITY 8 /* priority for unary operators */ |
| 1031 | |
| 1032 | |
| 1033 | /* |
| 1034 | ** subexpr -> (simpleexp | unop subexpr) { binop subexpr } |
| 1035 | ** where `binop' is any binary operator with a priority higher than `limit' |
| 1036 | */ |
| 1037 | static BinOpr subexpr (LexState *ls, expdesc *v, int limit) { |
| 1038 | BinOpr op; |
| 1039 | UnOpr uop; |
| 1040 | enterlevel(ls); |
| 1041 | uop = getunopr(ls->t.token); |
| 1042 | if (uop != OPR_NOUNOPR) { |
| 1043 | int line = ls->linenumber; |
| 1044 | luaX_next(ls); |
| 1045 | subexpr(ls, v, UNARY_PRIORITY); |
| 1046 | luaK_prefix(ls->fs, uop, v, line); |
| 1047 | } |
| 1048 | else simpleexp(ls, v); |
| 1049 | /* expand while operators have priorities higher than `limit' */ |
| 1050 | op = getbinopr(ls->t.token); |
| 1051 | while (op != OPR_NOBINOPR && priority[op].left > limit) { |
| 1052 | expdesc v2; |
| 1053 | BinOpr nextop; |
| 1054 | int line = ls->linenumber; |
| 1055 | luaX_next(ls); |
| 1056 | luaK_infix(ls->fs, op, v); |
| 1057 | /* read sub-expression with higher priority */ |
| 1058 | nextop = subexpr(ls, &v2, priority[op].right); |
| 1059 | luaK_posfix(ls->fs, op, v, &v2, line); |
| 1060 | op = nextop; |
| 1061 | } |
| 1062 | leavelevel(ls); |
| 1063 | return op; /* return first untreated operator */ |
| 1064 | } |
| 1065 | |
| 1066 | |
| 1067 | static void expr (LexState *ls, expdesc *v) { |
| 1068 | subexpr(ls, v, 0); |
| 1069 | } |
| 1070 | |
| 1071 | /* }==================================================================== */ |
| 1072 | |
| 1073 | |
| 1074 | |
| 1075 | /* |
| 1076 | ** {====================================================================== |
| 1077 | ** Rules for Statements |
| 1078 | ** ======================================================================= |
| 1079 | */ |
| 1080 | |
| 1081 | |
| 1082 | static void block (LexState *ls) { |
| 1083 | /* block -> statlist */ |
| 1084 | FuncState *fs = ls->fs; |
| 1085 | BlockCnt bl; |
| 1086 | enterblock(fs, &bl, 0); |
| 1087 | statlist(ls); |
| 1088 | leaveblock(fs); |
| 1089 | } |
| 1090 | |
| 1091 | |
| 1092 | /* |
| 1093 | ** structure to chain all variables in the left-hand side of an |
| 1094 | ** assignment |
| 1095 | */ |
| 1096 | struct LHS_assign { |
| 1097 | struct LHS_assign *prev; |
| 1098 | expdesc v; /* variable (global, local, upvalue, or indexed) */ |
| 1099 | }; |
| 1100 | |
| 1101 | |
| 1102 | /* |
| 1103 | ** check whether, in an assignment to an upvalue/local variable, the |
| 1104 | ** upvalue/local variable is begin used in a previous assignment to a |
| 1105 | ** table. If so, save original upvalue/local value in a safe place and |
| 1106 | ** use this safe copy in the previous assignment. |
| 1107 | */ |
| 1108 | static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) { |
| 1109 | FuncState *fs = ls->fs; |
| 1110 | int extra = fs->freereg; /* eventual position to save local variable */ |
| 1111 | int conflict = 0; |
| 1112 | for (; lh; lh = lh->prev) { /* check all previous assignments */ |
| 1113 | if (lh->v.k == VINDEXED) { /* assigning to a table? */ |
| 1114 | /* table is the upvalue/local being assigned now? */ |
| 1115 | if (lh->v.u.ind.vt == v->k && lh->v.u.ind.t == v->u.info) { |
| 1116 | conflict = 1; |
| 1117 | lh->v.u.ind.vt = VLOCAL; |
| 1118 | lh->v.u.ind.t = extra; /* previous assignment will use safe copy */ |
| 1119 | } |
| 1120 | /* index is the local being assigned? (index cannot be upvalue) */ |
| 1121 | if (v->k == VLOCAL && lh->v.u.ind.idx == v->u.info) { |
| 1122 | conflict = 1; |
| 1123 | lh->v.u.ind.idx = extra; /* previous assignment will use safe copy */ |
| 1124 | } |
| 1125 | } |
| 1126 | } |
| 1127 | if (conflict) { |
| 1128 | /* copy upvalue/local value to a temporary (in position 'extra') */ |
| 1129 | OpCode op = (v->k == VLOCAL) ? OP_MOVE : OP_GETUPVAL; |
| 1130 | luaK_codeABC(fs, op, extra, v->u.info, 0); |
| 1131 | luaK_reserveregs(fs, 1); |
| 1132 | } |
| 1133 | } |
| 1134 | |
| 1135 | |
| 1136 | static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) { |
| 1137 | expdesc e; |
| 1138 | check_condition(ls, vkisvar(lh->v.k), "syntax error"); |
| 1139 | if (testnext(ls, ',')) { /* assignment -> ',' suffixedexp assignment */ |
| 1140 | struct LHS_assign nv; |
| 1141 | nv.prev = lh; |
| 1142 | suffixedexp(ls, &nv.v); |
| 1143 | if (nv.v.k != VINDEXED) |
| 1144 | check_conflict(ls, lh, &nv.v); |
| 1145 | checklimit(ls->fs, nvars + ls->L->nCcalls, LUAI_MAXCCALLS, |
| 1146 | "C levels"); |
| 1147 | assignment(ls, &nv, nvars+1); |
| 1148 | } |
| 1149 | else { /* assignment -> `=' explist */ |
| 1150 | int nexps; |
| 1151 | checknext(ls, '='); |
| 1152 | nexps = explist(ls, &e); |
| 1153 | if (nexps != nvars) { |
| 1154 | adjust_assign(ls, nvars, nexps, &e); |
| 1155 | if (nexps > nvars) |
| 1156 | ls->fs->freereg -= nexps - nvars; /* remove extra values */ |
| 1157 | } |
| 1158 | else { |
| 1159 | luaK_setoneret(ls->fs, &e); /* close last expression */ |
| 1160 | luaK_storevar(ls->fs, &lh->v, &e); |
| 1161 | return; /* avoid default */ |
| 1162 | } |
| 1163 | } |
| 1164 | init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */ |
| 1165 | luaK_storevar(ls->fs, &lh->v, &e); |
| 1166 | } |
| 1167 | |
| 1168 | |
| 1169 | static int cond (LexState *ls) { |
| 1170 | /* cond -> exp */ |
| 1171 | expdesc v; |
| 1172 | expr(ls, &v); /* read condition */ |
| 1173 | if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */ |
| 1174 | luaK_goiftrue(ls->fs, &v); |
| 1175 | return v.f; |
| 1176 | } |
| 1177 | |
| 1178 | |
| 1179 | static void gotostat (LexState *ls, int pc) { |
| 1180 | int line = ls->linenumber; |
| 1181 | TString *label; |
| 1182 | int g; |
| 1183 | if (testnext(ls, TK_GOTO)) |
| 1184 | label = str_checkname(ls); |
| 1185 | else { |
| 1186 | luaX_next(ls); /* skip break */ |
| 1187 | label = luaS_new(ls->L, "break"); |
| 1188 | } |
| 1189 | g = newlabelentry(ls, &ls->dyd->gt, label, line, pc); |
| 1190 | findlabel(ls, g); /* close it if label already defined */ |
| 1191 | } |
| 1192 | |
| 1193 | |
| 1194 | /* check for repeated labels on the same block */ |
| 1195 | static void checkrepeated (FuncState *fs, Labellist *ll, TString *label) { |
| 1196 | int i; |
| 1197 | for (i = fs->bl->firstlabel; i < ll->n; i++) { |
| 1198 | if (luaS_eqstr(label, ll->arr[i].name)) { |
| 1199 | const char *msg = luaO_pushfstring(fs->ls->L, |
| 1200 | "label " LUA_QS " already defined on line %d", |
| 1201 | getstr(label), ll->arr[i].line); |
| 1202 | semerror(fs->ls, msg); |
| 1203 | } |
| 1204 | } |
| 1205 | } |
| 1206 | |
| 1207 | |
| 1208 | /* skip no-op statements */ |
| 1209 | static void skipnoopstat (LexState *ls) { |
| 1210 | while (ls->t.token == ';' || ls->t.token == TK_DBCOLON) |
| 1211 | statement(ls); |
| 1212 | } |
| 1213 | |
| 1214 | |
| 1215 | static void labelstat (LexState *ls, TString *label, int line) { |
| 1216 | /* label -> '::' NAME '::' */ |
| 1217 | FuncState *fs = ls->fs; |
| 1218 | Labellist *ll = &ls->dyd->label; |
| 1219 | int l; /* index of new label being created */ |
| 1220 | checkrepeated(fs, ll, label); /* check for repeated labels */ |
| 1221 | checknext(ls, TK_DBCOLON); /* skip double colon */ |
| 1222 | /* create new entry for this label */ |
| 1223 | l = newlabelentry(ls, ll, label, line, fs->pc); |
| 1224 | skipnoopstat(ls); /* skip other no-op statements */ |
| 1225 | if (block_follow(ls, 0)) { /* label is last no-op statement in the block? */ |
| 1226 | /* assume that locals are already out of scope */ |
| 1227 | ll->arr[l].nactvar = fs->bl->nactvar; |
| 1228 | } |
| 1229 | findgotos(ls, &ll->arr[l]); |
| 1230 | } |
| 1231 | |
| 1232 | |
| 1233 | static void whilestat (LexState *ls, int line) { |
| 1234 | /* whilestat -> WHILE cond DO block END */ |
| 1235 | FuncState *fs = ls->fs; |
| 1236 | int whileinit; |
| 1237 | int condexit; |
| 1238 | BlockCnt bl; |
| 1239 | luaX_next(ls); /* skip WHILE */ |
| 1240 | whileinit = luaK_getlabel(fs); |
| 1241 | condexit = cond(ls); |
| 1242 | enterblock(fs, &bl, 1); |
| 1243 | checknext(ls, TK_DO); |
| 1244 | block(ls); |
| 1245 | luaK_jumpto(fs, whileinit); |
| 1246 | check_match(ls, TK_END, TK_WHILE, line); |
| 1247 | leaveblock(fs); |
| 1248 | luaK_patchtohere(fs, condexit); /* false conditions finish the loop */ |
| 1249 | } |
| 1250 | |
| 1251 | |
| 1252 | static void repeatstat (LexState *ls, int line) { |
| 1253 | /* repeatstat -> REPEAT block UNTIL cond */ |
| 1254 | int condexit; |
| 1255 | FuncState *fs = ls->fs; |
| 1256 | int repeat_init = luaK_getlabel(fs); |
| 1257 | BlockCnt bl1, bl2; |
| 1258 | enterblock(fs, &bl1, 1); /* loop block */ |
| 1259 | enterblock(fs, &bl2, 0); /* scope block */ |
| 1260 | luaX_next(ls); /* skip REPEAT */ |
| 1261 | statlist(ls); |
| 1262 | check_match(ls, TK_UNTIL, TK_REPEAT, line); |
| 1263 | condexit = cond(ls); /* read condition (inside scope block) */ |
| 1264 | if (bl2.upval) /* upvalues? */ |
| 1265 | luaK_patchclose(fs, condexit, bl2.nactvar); |
| 1266 | leaveblock(fs); /* finish scope */ |
| 1267 | luaK_patchlist(fs, condexit, repeat_init); /* close the loop */ |
| 1268 | leaveblock(fs); /* finish loop */ |
| 1269 | } |
| 1270 | |
| 1271 | |
| 1272 | static int exp1 (LexState *ls) { |
| 1273 | expdesc e; |
| 1274 | int reg; |
| 1275 | expr(ls, &e); |
| 1276 | luaK_exp2nextreg(ls->fs, &e); |
| 1277 | lua_assert(e.k == VNONRELOC); |
| 1278 | reg = e.u.info; |
| 1279 | return reg; |
| 1280 | } |
| 1281 | |
| 1282 | |
| 1283 | static void forbody (LexState *ls, int base, int line, int nvars, int isnum) { |
| 1284 | /* forbody -> DO block */ |
| 1285 | BlockCnt bl; |
| 1286 | FuncState *fs = ls->fs; |
| 1287 | int prep, endfor; |
| 1288 | adjustlocalvars(ls, 3); /* control variables */ |
| 1289 | checknext(ls, TK_DO); |
| 1290 | prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs); |
| 1291 | enterblock(fs, &bl, 0); /* scope for declared variables */ |
| 1292 | adjustlocalvars(ls, nvars); |
| 1293 | luaK_reserveregs(fs, nvars); |
| 1294 | block(ls); |
| 1295 | leaveblock(fs); /* end of scope for declared variables */ |
| 1296 | luaK_patchtohere(fs, prep); |
| 1297 | if (isnum) /* numeric for? */ |
| 1298 | endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP); |
| 1299 | else { /* generic for */ |
| 1300 | luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars); |
| 1301 | luaK_fixline(fs, line); |
| 1302 | endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP); |
| 1303 | } |
| 1304 | luaK_patchlist(fs, endfor, prep + 1); |
| 1305 | luaK_fixline(fs, line); |
| 1306 | } |
| 1307 | |
| 1308 | |
| 1309 | static void fornum (LexState *ls, TString *varname, int line) { |
| 1310 | /* fornum -> NAME = exp1,exp1[,exp1] forbody */ |
| 1311 | FuncState *fs = ls->fs; |
| 1312 | int base = fs->freereg; |
| 1313 | new_localvarliteral(ls, "(for index)"); |
| 1314 | new_localvarliteral(ls, "(for limit)"); |
| 1315 | new_localvarliteral(ls, "(for step)"); |
| 1316 | new_localvar(ls, varname); |
| 1317 | checknext(ls, '='); |
| 1318 | exp1(ls); /* initial value */ |
| 1319 | checknext(ls, ','); |
| 1320 | exp1(ls); /* limit */ |
| 1321 | if (testnext(ls, ',')) |
| 1322 | exp1(ls); /* optional step */ |
| 1323 | else { /* default step = 1 */ |
| 1324 | luaK_codek(fs, fs->freereg, luaK_numberK(fs, 1)); |
| 1325 | luaK_reserveregs(fs, 1); |
| 1326 | } |
| 1327 | forbody(ls, base, line, 1, 1); |
| 1328 | } |
| 1329 | |
| 1330 | |
| 1331 | static void forlist (LexState *ls, TString *indexname) { |
| 1332 | /* forlist -> NAME {,NAME} IN explist forbody */ |
| 1333 | FuncState *fs = ls->fs; |
| 1334 | expdesc e; |
| 1335 | int nvars = 4; /* gen, state, control, plus at least one declared var */ |
| 1336 | int line; |
| 1337 | int base = fs->freereg; |
| 1338 | /* create control variables */ |
| 1339 | new_localvarliteral(ls, "(for generator)"); |
| 1340 | new_localvarliteral(ls, "(for state)"); |
| 1341 | new_localvarliteral(ls, "(for control)"); |
| 1342 | /* create declared variables */ |
| 1343 | new_localvar(ls, indexname); |
| 1344 | while (testnext(ls, ',')) { |
| 1345 | new_localvar(ls, str_checkname(ls)); |
| 1346 | nvars++; |
| 1347 | } |
| 1348 | checknext(ls, TK_IN); |
| 1349 | line = ls->linenumber; |
| 1350 | adjust_assign(ls, 3, explist(ls, &e), &e); |
| 1351 | luaK_checkstack(fs, 3); /* extra space to call generator */ |
| 1352 | forbody(ls, base, line, nvars - 3, 0); |
| 1353 | } |
| 1354 | |
| 1355 | |
| 1356 | static void forstat (LexState *ls, int line) { |
| 1357 | /* forstat -> FOR (fornum | forlist) END */ |
| 1358 | FuncState *fs = ls->fs; |
| 1359 | TString *varname; |
| 1360 | BlockCnt bl; |
| 1361 | enterblock(fs, &bl, 1); /* scope for loop and control variables */ |
| 1362 | luaX_next(ls); /* skip `for' */ |
| 1363 | varname = str_checkname(ls); /* first variable name */ |
| 1364 | switch (ls->t.token) { |
| 1365 | case '=': fornum(ls, varname, line); break; |
| 1366 | case ',': case TK_IN: forlist(ls, varname); break; |
| 1367 | default: luaX_syntaxerror(ls, LUA_QL("=") " or " LUA_QL("in") " expected"); |
| 1368 | } |
| 1369 | check_match(ls, TK_END, TK_FOR, line); |
| 1370 | leaveblock(fs); /* loop scope (`break' jumps to this point) */ |
| 1371 | } |
| 1372 | |
| 1373 | |
| 1374 | static void test_then_block (LexState *ls, int *escapelist) { |
| 1375 | /* test_then_block -> [IF | ELSEIF] cond THEN block */ |
| 1376 | BlockCnt bl; |
| 1377 | FuncState *fs = ls->fs; |
| 1378 | expdesc v; |
| 1379 | int jf; /* instruction to skip 'then' code (if condition is false) */ |
| 1380 | luaX_next(ls); /* skip IF or ELSEIF */ |
| 1381 | expr(ls, &v); /* read condition */ |
| 1382 | checknext(ls, TK_THEN); |
| 1383 | if (ls->t.token == TK_GOTO || ls->t.token == TK_BREAK) { |
| 1384 | luaK_goiffalse(ls->fs, &v); /* will jump to label if condition is true */ |
| 1385 | enterblock(fs, &bl, 0); /* must enter block before 'goto' */ |
| 1386 | gotostat(ls, v.t); /* handle goto/break */ |
| 1387 | skipnoopstat(ls); /* skip other no-op statements */ |
| 1388 | if (block_follow(ls, 0)) { /* 'goto' is the entire block? */ |
| 1389 | leaveblock(fs); |
| 1390 | return; /* and that is it */ |
| 1391 | } |
| 1392 | else /* must skip over 'then' part if condition is false */ |
| 1393 | jf = luaK_jump(fs); |
| 1394 | } |
| 1395 | else { /* regular case (not goto/break) */ |
| 1396 | luaK_goiftrue(ls->fs, &v); /* skip over block if condition is false */ |
| 1397 | enterblock(fs, &bl, 0); |
| 1398 | jf = v.f; |
| 1399 | } |
| 1400 | statlist(ls); /* `then' part */ |
| 1401 | leaveblock(fs); |
| 1402 | if (ls->t.token == TK_ELSE || |
| 1403 | ls->t.token == TK_ELSEIF) /* followed by 'else'/'elseif'? */ |
| 1404 | luaK_concat(fs, escapelist, luaK_jump(fs)); /* must jump over it */ |
| 1405 | luaK_patchtohere(fs, jf); |
| 1406 | } |
| 1407 | |
| 1408 | |
| 1409 | static void ifstat (LexState *ls, int line) { |
| 1410 | /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */ |
| 1411 | FuncState *fs = ls->fs; |
| 1412 | int escapelist = NO_JUMP; /* exit list for finished parts */ |
| 1413 | test_then_block(ls, &escapelist); /* IF cond THEN block */ |
| 1414 | while (ls->t.token == TK_ELSEIF) |
| 1415 | test_then_block(ls, &escapelist); /* ELSEIF cond THEN block */ |
| 1416 | if (testnext(ls, TK_ELSE)) |
| 1417 | block(ls); /* `else' part */ |
| 1418 | check_match(ls, TK_END, TK_IF, line); |
| 1419 | luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */ |
| 1420 | } |
| 1421 | |
| 1422 | |
| 1423 | static void localfunc (LexState *ls) { |
| 1424 | expdesc b; |
| 1425 | FuncState *fs = ls->fs; |
| 1426 | new_localvar(ls, str_checkname(ls)); /* new local variable */ |
| 1427 | adjustlocalvars(ls, 1); /* enter its scope */ |
| 1428 | body(ls, &b, 0, ls->linenumber); /* function created in next register */ |
| 1429 | /* debug information will only see the variable after this point! */ |
| 1430 | getlocvar(fs, b.u.info)->startpc = fs->pc; |
| 1431 | } |
| 1432 | |
| 1433 | |
| 1434 | static void localstat (LexState *ls) { |
| 1435 | /* stat -> LOCAL NAME {`,' NAME} [`=' explist] */ |
| 1436 | int nvars = 0; |
| 1437 | int nexps; |
| 1438 | expdesc e; |
| 1439 | do { |
| 1440 | new_localvar(ls, str_checkname(ls)); |
| 1441 | nvars++; |
| 1442 | } while (testnext(ls, ',')); |
| 1443 | if (testnext(ls, '=')) |
| 1444 | nexps = explist(ls, &e); |
| 1445 | else { |
| 1446 | e.k = VVOID; |
| 1447 | nexps = 0; |
| 1448 | } |
| 1449 | adjust_assign(ls, nvars, nexps, &e); |
| 1450 | adjustlocalvars(ls, nvars); |
| 1451 | } |
| 1452 | |
| 1453 | |
| 1454 | static int funcname (LexState *ls, expdesc *v) { |
| 1455 | /* funcname -> NAME {fieldsel} [`:' NAME] */ |
| 1456 | int ismethod = 0; |
| 1457 | singlevar(ls, v); |
| 1458 | while (ls->t.token == '.') |
| 1459 | fieldsel(ls, v); |
| 1460 | if (ls->t.token == ':') { |
| 1461 | ismethod = 1; |
| 1462 | fieldsel(ls, v); |
| 1463 | } |
| 1464 | return ismethod; |
| 1465 | } |
| 1466 | |
| 1467 | |
| 1468 | static void funcstat (LexState *ls, int line) { |
| 1469 | /* funcstat -> FUNCTION funcname body */ |
| 1470 | int ismethod; |
| 1471 | expdesc v, b; |
| 1472 | luaX_next(ls); /* skip FUNCTION */ |
| 1473 | ismethod = funcname(ls, &v); |
| 1474 | body(ls, &b, ismethod, line); |
| 1475 | luaK_storevar(ls->fs, &v, &b); |
| 1476 | luaK_fixline(ls->fs, line); /* definition `happens' in the first line */ |
| 1477 | } |
| 1478 | |
| 1479 | |
| 1480 | static void exprstat (LexState *ls) { |
| 1481 | /* stat -> func | assignment */ |
| 1482 | FuncState *fs = ls->fs; |
| 1483 | struct LHS_assign v; |
| 1484 | suffixedexp(ls, &v.v); |
| 1485 | if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */ |
| 1486 | v.prev = NULL; |
| 1487 | assignment(ls, &v, 1); |
| 1488 | } |
| 1489 | else { /* stat -> func */ |
| 1490 | check_condition(ls, v.v.k == VCALL, "syntax error"); |
| 1491 | SETARG_C(getcode(fs, &v.v), 1); /* call statement uses no results */ |
| 1492 | } |
| 1493 | } |
| 1494 | |
| 1495 | |
| 1496 | static void retstat (LexState *ls) { |
| 1497 | /* stat -> RETURN [explist] [';'] */ |
| 1498 | FuncState *fs = ls->fs; |
| 1499 | expdesc e; |
| 1500 | int first, nret; /* registers with returned values */ |
| 1501 | if (block_follow(ls, 1) || ls->t.token == ';') |
| 1502 | first = nret = 0; /* return no values */ |
| 1503 | else { |
| 1504 | nret = explist(ls, &e); /* optional return values */ |
| 1505 | if (hasmultret(e.k)) { |
| 1506 | luaK_setmultret(fs, &e); |
| 1507 | if (e.k == VCALL && nret == 1) { /* tail call? */ |
| 1508 | SET_OPCODE(getcode(fs,&e), OP_TAILCALL); |
| 1509 | lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar); |
| 1510 | } |
| 1511 | first = fs->nactvar; |
| 1512 | nret = LUA_MULTRET; /* return all values */ |
| 1513 | } |
| 1514 | else { |
| 1515 | if (nret == 1) /* only one single value? */ |
| 1516 | first = luaK_exp2anyreg(fs, &e); |
| 1517 | else { |
| 1518 | luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */ |
| 1519 | first = fs->nactvar; /* return all `active' values */ |
| 1520 | lua_assert(nret == fs->freereg - first); |
| 1521 | } |
| 1522 | } |
| 1523 | } |
| 1524 | luaK_ret(fs, first, nret); |
| 1525 | testnext(ls, ';'); /* skip optional semicolon */ |
| 1526 | } |
| 1527 | |
| 1528 | |
| 1529 | static void statement (LexState *ls) { |
| 1530 | int line = ls->linenumber; /* may be needed for error messages */ |
| 1531 | enterlevel(ls); |
| 1532 | switch (ls->t.token) { |
| 1533 | case ';': { /* stat -> ';' (empty statement) */ |
| 1534 | luaX_next(ls); /* skip ';' */ |
| 1535 | break; |
| 1536 | } |
| 1537 | case TK_IF: { /* stat -> ifstat */ |
| 1538 | ifstat(ls, line); |
| 1539 | break; |
| 1540 | } |
| 1541 | case TK_WHILE: { /* stat -> whilestat */ |
| 1542 | whilestat(ls, line); |
| 1543 | break; |
| 1544 | } |
| 1545 | case TK_DO: { /* stat -> DO block END */ |
| 1546 | luaX_next(ls); /* skip DO */ |
| 1547 | block(ls); |
| 1548 | check_match(ls, TK_END, TK_DO, line); |
| 1549 | break; |
| 1550 | } |
| 1551 | case TK_FOR: { /* stat -> forstat */ |
| 1552 | forstat(ls, line); |
| 1553 | break; |
| 1554 | } |
| 1555 | case TK_REPEAT: { /* stat -> repeatstat */ |
| 1556 | repeatstat(ls, line); |
| 1557 | break; |
| 1558 | } |
| 1559 | case TK_FUNCTION: { /* stat -> funcstat */ |
| 1560 | funcstat(ls, line); |
| 1561 | break; |
| 1562 | } |
| 1563 | case TK_LOCAL: { /* stat -> localstat */ |
| 1564 | luaX_next(ls); /* skip LOCAL */ |
| 1565 | if (testnext(ls, TK_FUNCTION)) /* local function? */ |
| 1566 | localfunc(ls); |
| 1567 | else |
| 1568 | localstat(ls); |
| 1569 | break; |
| 1570 | } |
| 1571 | case TK_DBCOLON: { /* stat -> label */ |
| 1572 | luaX_next(ls); /* skip double colon */ |
| 1573 | labelstat(ls, str_checkname(ls), line); |
| 1574 | break; |
| 1575 | } |
| 1576 | case TK_RETURN: { /* stat -> retstat */ |
| 1577 | luaX_next(ls); /* skip RETURN */ |
| 1578 | retstat(ls); |
| 1579 | break; |
| 1580 | } |
| 1581 | case TK_BREAK: /* stat -> breakstat */ |
| 1582 | case TK_GOTO: { /* stat -> 'goto' NAME */ |
| 1583 | gotostat(ls, luaK_jump(ls->fs)); |
| 1584 | break; |
| 1585 | } |
| 1586 | default: { /* stat -> func | assignment */ |
| 1587 | exprstat(ls); |
| 1588 | break; |
| 1589 | } |
| 1590 | } |
| 1591 | lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg && |
| 1592 | ls->fs->freereg >= ls->fs->nactvar); |
| 1593 | ls->fs->freereg = ls->fs->nactvar; /* free registers */ |
| 1594 | leavelevel(ls); |
| 1595 | } |
| 1596 | |
| 1597 | /* }====================================================================== */ |
| 1598 | |
| 1599 | |
| 1600 | /* |
| 1601 | ** compiles the main function, which is a regular vararg function with an |
| 1602 | ** upvalue named LUA_ENV |
| 1603 | */ |
| 1604 | static void mainfunc (LexState *ls, FuncState *fs) { |
| 1605 | BlockCnt bl; |
| 1606 | expdesc v; |
| 1607 | open_func(ls, fs, &bl); |
| 1608 | fs->f->is_vararg = 1; /* main function is always vararg */ |
| 1609 | init_exp(&v, VLOCAL, 0); /* create and... */ |
| 1610 | newupvalue(fs, ls->envn, &v); /* ...set environment upvalue */ |
| 1611 | luaX_next(ls); /* read first token */ |
| 1612 | statlist(ls); /* parse main body */ |
| 1613 | check(ls, TK_EOS); |
| 1614 | close_func(ls); |
| 1615 | } |
| 1616 | |
| 1617 | |
| 1618 | Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, |
| 1619 | Dyndata *dyd, const char *name, int firstchar) { |
| 1620 | LexState lexstate; |
| 1621 | FuncState funcstate; |
| 1622 | Closure *cl = luaF_newLclosure(L, 1); /* create main closure */ |
| 1623 | /* anchor closure (to avoid being collected) */ |
| 1624 | setclLvalue(L, L->top, cl); |
| 1625 | incr_top(L); |
| 1626 | funcstate.f = cl->l.p = luaF_newproto(L); |
| 1627 | funcstate.f->source = luaS_new(L, name); /* create and anchor TString */ |
| 1628 | lexstate.buff = buff; |
| 1629 | lexstate.dyd = dyd; |
| 1630 | dyd->actvar.n = dyd->gt.n = dyd->label.n = 0; |
| 1631 | luaX_setinput(L, &lexstate, z, funcstate.f->source, firstchar); |
| 1632 | mainfunc(&lexstate, &funcstate); |
| 1633 | lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs); |
| 1634 | /* all scopes should be correctly finished */ |
| 1635 | lua_assert(dyd->actvar.n == 0 && dyd->gt.n == 0 && dyd->label.n == 0); |
| 1636 | return cl; /* it's on the stack too */ |
| 1637 | } |
| 1638 | |