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70 lines
1.6 KiB
C
70 lines
1.6 KiB
C
/*
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** $Id: ltm.c,v 1.96 2002/06/24 20:17:59 roberto Exp roberto $
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** Tag methods
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** See Copyright Notice in lua.h
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*/
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#include <string.h>
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#include "lua.h"
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#include "lobject.h"
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#include "lstate.h"
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#include "lstring.h"
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#include "ltable.h"
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#include "ltm.h"
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const char *const luaT_typenames[] = {
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"nil", "number", "string", "boolean", "table",
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"userdata", "userdata", "function"
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};
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void luaT_init (lua_State *L) {
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static const char *const luaT_eventname[] = { /* ORDER TM */
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"__index", "__newindex",
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"__gc", "__eq", "__mode",
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"__gettable", "__settable",
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"__add", "__sub", "__mul", "__div",
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"__pow", "__unm", "__lt", "__le",
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"__concat", "__call"
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};
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int i;
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for (i=0; i<TM_N; i++) {
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G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]);
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luaS_fix(G(L)->tmname[i]); /* never collect these names */
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}
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}
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/*
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** function to be used with macro "fasttm": optimized for absence of
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** tag methods
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*/
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const TObject *luaT_gettm (Table *events, TMS event, TString *ename) {
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const TObject *tm = luaH_getstr(events, ename);
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lua_assert(event <= TM_MODE);
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if (ttype(tm) == LUA_TNIL) { /* no tag method? */
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events->flags |= (1u<<event); /* cache this fact */
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return NULL;
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}
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else return tm;
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}
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const TObject *luaT_gettmbyobj (lua_State *L, const TObject *o, TMS event) {
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TString *ename = G(L)->tmname[event];
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switch (ttype(o)) {
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case LUA_TTABLE:
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return luaH_getstr(hvalue(o)->metatable, ename);
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case LUA_TUSERDATA:
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return luaH_getstr(uvalue(o)->uv.metatable, ename);
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default:
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return &luaO_nilobject;
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}
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}
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