AI游戏引擎程序设计.pdf(源码)

/* ** $Id: lparser.c,v 1.208 2003/04/03 13:35:34 roberto Exp $ ** Lua Parser ** See Copyright Notice in lua.h */ #include <string.h> #define lparser_c #include "lua.h" #include "lcode.h" #include "ldebug.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" #define getlocvar(fs, i) ((fs)->f->locvars[(fs)->actvar[i]]) #define enterlevel(ls) if (++(ls)->nestlevel > LUA_MAXPARSERLEVEL) \ luaX_syntaxerror(ls, "too many syntax levels"); #define leavelevel(ls) ((ls)->nestlevel--) /* ** nodes for block list (list of active blocks) */ typedef struct BlockCnt { struct BlockCnt *previous; /* chain */ int breaklist; /* list of jumps out of this loop */ int nactvar; /* # active local variables outside the breakable structure */ int upval; /* true if some variable in the block is an upvalue */ int isbreakable; /* true if `block' is a loop */ } BlockCnt; /* ** prototypes for recursive non-terminal functions */ static void chunk (LexState *ls); static void expr (LexState *ls, expdesc *v); static void next (LexState *ls) { ls->lastline = ls->linenumber; if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */ ls->t = ls->lookahead; /* use this one */ ls->lookahead.token = TK_EOS; /* and discharge it */ } else ls->t.token = luaX_lex(ls, &ls->t.seminfo); /* read next token */ } static void lookahead (LexState *ls) { lua_assert(ls->lookahead.token == TK_EOS); ls->lookahead.token = luaX_lex(ls, &ls->lookahead.seminfo); } static void error_expected (LexState *ls, int token) { luaX_syntaxerror(ls, luaO_pushfstring(ls->L, "`%s' expected", luaX_token2str(ls, token))); } static int testnext (LexState *ls, int c) { if (ls->t.token == c) { next(ls); return 1; } else return 0; } static void check (LexState *ls, int c) { if (!testnext(ls, c)) error_expected(ls, c); } #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_condition(ls, (ls->t.token == TK_NAME), "<name> expected"); ts = ls->t.seminfo.ts; next(ls); return ts; } static void init_exp (expdesc *e, expkind k, int i) { e->f = e->t = NO_JUMP; e->k = k; e->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 luaI_registerlocalvar (LexState *ls, TString *varname) { FuncState *fs = ls->fs; Proto *f = fs->f; luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars, LocVar, MAX_INT, ""); f->locvars[fs->nlocvars].varname = varname; return fs->nlocvars++; } static void new_localvar (LexState *ls, TString *name, int n) { FuncState *fs = ls->fs; luaX_checklimit(ls, fs->nactvar+n+1, MAXVARS, "local variables"); fs->actvar[fs->nactvar+n] = luaI_registerlocalvar(ls, name); } static void adjustlocalvars (LexState *ls, int nvars) { FuncState *fs = ls->fs; fs->nactvar += nvars; for (; nvars; nvars--) { getlocvar(fs, fs->nactvar - nvars).startpc = fs->pc; } } static void removevars (LexState *ls, int tolevel) { FuncState *fs = ls->fs; while (fs->nactvar > tolevel) getlocvar(fs, --fs->nactvar).endpc = fs->pc; } static void new_localvarstr (LexState *ls, const char *name, int n) { new_localvar(ls, luaS_new(ls->L, name), n); } static void create_local (LexState *ls, const char *name) { new_localvarstr(ls, name, 0); adjustlocalvars(ls, 1); } static int indexupvalue (FuncState *fs, TString *name, expdesc *v) { int i; Proto *f = fs->f; for (i=0; i<f->nups; i++) { if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->info) { lua_assert(fs->f->upvalues[i] == name); return i; } } /* new one */ luaX_checklimit(fs->ls, f->nups + 1, MAXUPVALUES, "upvalues"); luaM_growvector(fs->L, fs->f->upvalues, f->nups, fs->f->sizeupvalues, TString *, MAX_INT, ""); fs->f->upvalues[f->nups] = name; fs->upvalues[f->nups] = *v; return f->nups++; } static int searchvar (FuncState *fs, TString *n) { int i; for (i=fs->nactvar-1; i >= 0; i--) { if (n == getlocvar(fs, i).varname) return i; } return -1; /* not found */ } static void markupval (FuncState *fs, int level) { BlockCnt *bl = fs->bl; while (bl && bl->nactvar > level) bl = bl->previous; if (bl) bl->upval = 1; } static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { if (fs == NULL) /* no more levels? */ init_exp(var, VGLOBAL, NO_REG); /* default is global variable */ else { int v = searchvar(fs, n); /* look up at current level */ if (v >= 0) { init_exp(var, VLOCAL, v); if (!base) markupval(fs, v); /* local will be used as an upval */ } else { /* not found at current level; try upper one */ singlevaraux(fs->prev, n, var, 0); if (var->k == VGLOBAL) { if (base) var->info = luaK_stringK(fs, n); /* info points to global name */ } else { /* LOCAL or UPVAL */ var->info = indexupvalue(fs, n, var); var->k = VUPVAL; /* upvalue in this level */ } } } } static TString *singlevar (LexState *ls, expdesc *var, int base) { TString *varname = str_checkname(ls); singlevaraux(ls->fs, varname, var, base); return varname; } static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) { FuncState *fs = ls->fs; int extra = nvars - nexps; if (e->k == VCALL) { extra++; /* includes call itself */ if (extra <= 0) extra = 0; else luaK_reserveregs(fs, extra-1); luaK_setcallreturns(fs, e, extra); /* call provides the difference */ } else { if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */ if (extra > 0) { int reg = fs->freereg; luaK_reserveregs(fs, extra); luaK_nil(fs, reg, extra); } } } static void code_params (LexState *ls, int nparams, int dots) { FuncState *fs = ls->fs; adjustlocalvars(ls, nparams); luaX_checklimit(ls, fs->nactvar, MAXPARAMS, "parameters"); fs->f->numparams = cast(lu_byte, fs->nactvar); fs->f->is_vararg = cast(lu_byte, dots); if (dots) create_local(ls, "arg"); luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */ } static void enterblock (FuncState *fs, BlockCnt *bl, int isbreakable) { bl->breaklist = NO_JUMP; bl->isbreakable = isbreakable; bl->nactvar = fs->nactvar; bl->upval = 0; bl->previous = fs->bl; fs->bl = bl; lua_assert(fs->freereg == fs->nactvar); } static void leaveblock (FuncState *fs) { BlockCnt *bl = fs->bl; fs->bl = bl->previous; removevars(fs->ls, bl->nactvar); if (bl->upval) luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0); lua_assert(bl->nactvar == fs->nactvar); fs->freereg = fs->nactvar; /* free registers */ luaK_patchtohere(fs, bl->breaklist); } static void pushclosure (LexState *ls, FuncState *func, expdesc *v) { FuncState *fs = ls->fs; Proto *f = fs->f; int i; luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *,