/* ** $Id: ltm.c,v 2.38.1.1 2017/04/19 17:39:34 roberto Exp $ ** Tag methods ** See Copyright Notice in lua.h */ #define ltm_c #define LUA_CORE #include "lprefix.h" #include #include "lua.h" #include "ldebug.h" #include "ldo.h" #include "lobject.h" #include "lstate.h" #include "lstring.h" #include "ltable.h" #include "ltm.h" #include "lvm.h" static const char udatatypename[] = "userdata"; LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTAGS] = { "no value", "nil", "boolean", udatatypename, "number", "string", "table", "function", udatatypename, "thread", "proto" /* this last case is used for tests only */ }; void luaT_init (lua_State *L) { static const char *const luaT_eventname[] = { /* ORDER TM */ "__index", "__newindex", "__gc", "__mode", "__len", "__eq", "__add", "__sub", "__mul", "__mod", "__pow", "__div", "__idiv", "__band", "__bor", "__bxor", "__shl", "__shr", "__unm", "__bnot", "__lt", "__le", "__concat", "__call" }; int i; for (i=0; itmname[i] = luaS_new(L, luaT_eventname[i]); luaC_fix(L, obj2gco(G(L)->tmname[i])); /* never collect these names */ } } /* ** function to be used with macro "fasttm": optimized for absence of ** tag methods */ const TValue *luaT_gettm (Table *events, TMS event, TString *ename) { const TValue *tm = luaH_getshortstr(events, ename); lua_assert(event <= TM_EQ); if (ttisnil(tm)) { /* no tag method? */ events->flags |= cast_byte(1u<metatable; break; case LUA_TUSERDATA: mt = uvalue(o)->metatable; break; default: mt = G(L)->mt[ttnov(o)]; } return (mt ? luaH_getshortstr(mt, G(L)->tmname[event]) : luaO_nilobject); } /* ** Return the name of the type of an object. For tables and userdata ** with metatable, use their '__name' metafield, if present. */ const char *luaT_objtypename (lua_State *L, const TValue *o) { Table *mt; if ((ttistable(o) && (mt = hvalue(o)->metatable) != NULL) || (ttisfulluserdata(o) && (mt = uvalue(o)->metatable) != NULL)) { const TValue *name = luaH_getshortstr(mt, luaS_new(L, "__name")); if (ttisstring(name)) /* is '__name' a string? */ return getstr(tsvalue(name)); /* use it as type name */ } return ttypename(ttnov(o)); /* else use standard type name */ } void luaT_callTM (lua_State *L, const TValue *f, const TValue *p1, const TValue *p2, TValue *p3, int hasres) { ptrdiff_t result = savestack(L, p3); StkId func = L->top; setobj2s(L, func, f); /* push function (assume EXTRA_STACK) */ setobj2s(L, func + 1, p1); /* 1st argument */ setobj2s(L, func + 2, p2); /* 2nd argument */ L->top += 3; if (!hasres) /* no result? 'p3' is third argument */ setobj2s(L, L->top++, p3); /* 3rd argument */ /* metamethod may yield only when called from Lua code */ if (isLua(L->ci)) luaD_call(L, func, hasres); else luaD_callnoyield(L, func, hasres); if (hasres) { /* if has result, move it to its place */ p3 = restorestack(L, result); setobjs2s(L, p3, --L->top); } } int luaT_callbinTM (lua_State *L, const TValue *p1, const TValue *p2, StkId res, TMS event) { const TValue *tm = luaT_gettmbyobj(L, p1, event); /* try first operand */ if (ttisnil(tm)) tm = luaT_gettmbyobj(L, p2, event); /* try second operand */ if (ttisnil(tm)) return 0; luaT_callTM(L, tm, p1, p2, res, 1); return 1; } void luaT_trybinTM (lua_State *L, const TValue *p1, const TValue *p2, StkId res, TMS event) { if (!luaT_callbinTM(L, p1, p2, res, event)) { switch (event) { case TM_CONCAT: luaG_concaterror(L, p1, p2); /* call never returns, but to avoid warnings: *//* FALLTHROUGH */ case TM_BAND: case TM_BOR: case TM_BXOR: case TM_SHL: case TM_SHR: case TM_BNOT: { lua_Number dummy; if (tonumber(p1, &dummy) && tonumber(p2, &dummy)) luaG_tointerror(L, p1, p2); else luaG_opinterror(L, p1, p2, "perform bitwise operation on"); } /* calls never return, but to avoid warnings: *//* FALLTHROUGH */ default: luaG_opinterror(L, p1, p2, "perform arithmetic on"); } } } int luaT_callorderTM (lua_State *L, const TValue *p1, const TValue *p2, TMS event) { if (!luaT_callbinTM(L, p1, p2, L->top, event)) return -1; /* no metamethod */ else return !l_isfalse(L->top); }