lua5.3.0开发包

/* ** $Id: lparser.c,v 2.147 2014/12/27 20:31:43 roberto Exp $ ** Lua Parser ** See Copyright Notice in lua.h */ #define lparser_c #define LUA_CORE #include "lprefix.h" #include <string.h> #include "lua.h" #include "lcode.h" #include "ldebug.h" #include "ldo.h" #include "lfunc.h" #include "llex.h" #include "lmem.h" #include "lobject.h" #include "lopcodes.h" #include "lparser.h" #include "lstate.h" #include "lstring.h" #include "ltable.h" /* maximum number of local variables per function (must be smaller than 250, due to the bytecode format) */ #define MAXVARS 200 #define hasmultret(k) ((k) == VCALL || (k) == VVARARG) /* because all strings are unified by the scanner, the parser can use pointer equality for string equality */ #define eqstr(a,b) ((a) == (b)) /* ** nodes for block list (list of active blocks) */ typedef struct BlockCnt { struct BlockCnt *previous; /* chain */ int firstlabel; /* index of first label in this block */ int firstgoto; /* index of first pending goto in this block */ lu_byte nactvar; /* # active locals outside the block */ lu_byte upval; /* true if some variable in the block is an upvalue */ lu_byte isloop; /* true if 'block' is a loop */ } BlockCnt; /* ** prototypes for recursive non-terminal functions */ static void statement (LexState *ls); static void expr (LexState *ls, expdesc *v); /* semantic error */ static l_noret semerror (LexState *ls, const char *msg) { ls->t.token = 0; /* remove "near <token>" from final message */ luaX_syntaxerror(ls, msg); } static l_noret error_expected (LexState *ls, int token) { luaX_syntaxerror(ls, luaO_pushfstring(ls->L, "%s expected", luaX_token2str(ls, token))); } static l_noret errorlimit (FuncState *fs, int limit, const char *what) { lua_State *L = fs->ls->L; const char *msg; int line = fs->f->linedefined; const char *where = (line == 0) ? "main function" : luaO_pushfstring(L, "function at line %d", line); msg = luaO_pushfstring(L, "too many %s (limit is %d) in %s", what, limit, where); luaX_syntaxerror(fs->ls, msg); } static void checklimit (FuncState *fs, int v, int l, const char *what) { if (v > l) errorlimit(fs, l, what); } static int testnext (LexState *ls, int c) { if (ls->t.token == c) { luaX_next(ls); return 1; } else return 0; } static void check (LexState *ls, int c) { if (ls->t.token != c) error_expected(ls, c); } static void checknext (LexState *ls, int c) { check(ls, c); luaX_next(ls); } #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); } static void check_match (LexState *ls, int what, int who, int where) { if (!testnext(ls, what)) { if (where == ls->linenumber) error_expected(ls, what); else { luaX_syntaxerror(ls, luaO_pushfstring(ls->L, "%s expected (to close %s at line %d)", luaX_token2str(ls, what), luaX_token2str(ls, who), where)); } } } static TString *str_checkname (LexState *ls) { TString *ts; check(ls, TK_NAME); ts = ls->t.seminfo.ts; luaX_next(ls); return ts; } static void init_exp (expdesc *e, expkind k, int i) { e->f = e->t = NO_JUMP; e->k = k; e->u.info = i; } static void codestring (LexState *ls, expdesc *e, TString *s) { init_exp(e, VK, luaK_stringK(ls->fs, s)); } static void checkname (LexState *ls, expdesc *e) { codestring(ls, e, str_checkname(ls)); } static int registerlocalvar (LexState *ls, TString *varname) { FuncState *fs = ls->fs; Proto *f = fs->f; int oldsize = f->sizelocvars; luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars, LocVar, SHRT_MAX, "local variables"); while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL; f->locvars[fs->nlocvars].varname = varname; luaC_objbarrier(ls->L, f, varname); return fs->nlocvars++; } static void new_localvar (LexState *ls, TString *name) { FuncState *fs = ls->fs; Dyndata *dyd = ls->dyd; int reg = registerlocalvar(ls, name); checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal, MAXVARS, "local variables"); luaM_growvector(ls->L, dyd->actvar.arr, dyd->actvar.n + 1, dyd->actvar.size, Vardesc, MAX_INT, "local variables"); dyd->actvar.arr[dyd->actvar.n++].idx = cast(short, reg); } static void new_localvarliteral_ (LexState *ls, const char *name, size_t sz) { new_localvar(ls, luaX_newstring(ls, name, sz)); } #define new_localvarliteral(ls,v) \ new_localvarliteral_(ls, "" v, (sizeof(v)/sizeof(char))-1) static LocVar *getlocvar (FuncState *fs, int i) { int idx = fs->ls->dyd->actvar.arr[fs->firstlocal + i].idx; lua_assert(idx < fs->nlocvars); return &fs->f->locvars[idx]; } static void adjustlocalvars (LexState *ls, int nvars) { FuncState *fs = ls->fs; fs->nactvar = cast_byte(fs->nactvar + nvars); for (; nvars; nvars--) { getlocvar(fs, fs->nactvar - nvars)->startpc = fs->pc; } } static void removevars (FuncState *fs, int tolevel) { fs->ls->dyd->actvar.n -= (fs->nactvar - tolevel); while (fs->nactvar > tolevel) getlocvar(fs, --fs->nactvar)->endpc = fs->pc; } static int searchupvalue (FuncState *fs, TString *name) { int i; Upvaldesc *up = fs->f->upvalues; for (i = 0; i < fs->nups; i++) { if (eqstr(up[i].name, name)) return i; } return -1; /* not found */ } static int newupvalue (FuncState *fs, TString *name, expdesc *v) { Proto *f = fs->f; int oldsize = f->sizeupvalues; checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues"); luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues, Upvaldesc, MAXUPVAL, "upvalues"); while (oldsize < f->sizeupvalues) f->upvalues[oldsize++].name = NULL; f->upvalues[fs->nups].instack = (v->k == VLOCAL); f->upvalues[fs->nups].idx = cast_byte(v->u.info); f->upvalues[fs->nups].name = name; luaC_objbarrier(fs->ls->L, f, name); return fs->nups++; } static int searchvar (FuncState *fs, TString *n) { int i; for (i = cast_int(fs->nactvar) - 1; i >= 0; i--) { if (eqstr(n, getlocvar(fs, i)->varname)) return i; } return -1; /* not found */ } /* Mark block where variable at given level was defined (to emit close instructions later). */ static void markupval (FuncState *fs, int level) { BlockCnt *bl = fs->bl; while (bl->nactvar > level) bl = bl->previous; bl->upval = 1; } /* Find variable with given name 'n'. If it is an upvalue, add this upvalue into all intermediate functions. */ static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { if (fs == NULL) /* no more levels? */ return VVOID; /* default is global */ else { int v = searchvar(fs, n); /* look up locals at current level */ if (v >= 0) { /* found? */ init_exp(var, VLOCAL, v); /* variable is local */ if (!base) markupval(fs, v); /* local will be used as an upval */ return VLOCAL; } else { /* not found as local at current level; try upvalues */ int idx = searchupvalue(fs, n); /* try existing upvalues */ if (idx < 0) { /* not found? */ if (singlevaraux(fs->prev, n, var, 0) == VVOID) /* try upper levels */ return VVOID; /* not found; is a global */ /* else was LOCAL or UPVAL */ idx = newupvalue(fs, n, var); /* will be a new upvalue */ } init_exp(var, VUPVAL, idx); return VUPVAL; } } } static void singlevar (LexState *ls, expdesc *var) { TString *varname = str_checkname(ls); FuncState *fs = ls->fs; if (singlevaraux(fs, varname, var, 1) == VVOID) { /* global name? */ expdesc key; singlevaraux(fs, ls->envn, var, 1); /* get environment variable */ lua_assert(var->k == VLOCAL || var->k == VUPVAL); codestring(ls, &key, varname); /* key is variable name */ luaK_indexed(fs, var, &key); /* env[varname] */ } } static void adjust_assign (LexSt