C# ILuaState.IsNil方法代码示例

 private static int IpairsAux( ILuaState lua )
 {
     int i = lua.ToInteger( 2 );
     i++; // next value
     lua.PushInteger( i );
     lua.RawGetI( 1, i );
     return lua.IsNil( -1 ) ? 1 : 2;
 }

		private static bool SortComp( ILuaState lua, int a, int b )
		{
			if( !lua.IsNil(2) ) // function?
			{
				lua.PushValue( 2 );
				lua.PushValue( a-1 ); // -1 to compensate function
				lua.PushValue( b-2 ); // -2 to compensate function add `a'
				lua.Call( 2, 1 );
				bool res = lua.ToBoolean( -1 );
				lua.Pop( 1 );
				return res;
			}
			else /// a < b?
				return lua.Compare( a, b, LuaEq.LUA_OPLT );
		}

		private static void FindLoader( ILuaState lua, string name )
		{
			// will be at index 3
			lua.GetField( lua.UpvalueIndex(1), "searchers" );
			if( ! lua.IsTable(3) )
				lua.L_Error("'package.searchers' must be a table");

			var sb = new StringBuilder();
			// iterator over available searchers to find a loader
			for( int i=1; ; ++i )
			{
				lua.RawGetI( 3, i ); // get a searcher
				if( lua.IsNil( -1 ) ) // no more searchers?
				{
					lua.Pop( 1 ); // remove nil
					lua.PushString( sb.ToString() );
					lua.L_Error( "module '{0}' not found:{1}",
						name, lua.ToString(-1));
					return;
				}

				lua.PushString( name );
				lua.Call( 1, 2 ); // call it
				if( lua.IsFunction(-2) ) // did it find a loader
					return; // module loader found
				else if( lua.IsString(-2) ) // searcher returned error message?
				{
					lua.Pop( 1 ); // return extra return
					sb.Append( lua.ToString(-1) );
				}
				else
					lua.Pop( 2 ); // remove both returns
			}
		}

		private static int LL_Require( ILuaState lua )
		{
			string name = lua.L_CheckString( 1 );
			lua.SetTop( 1 );
			// _LOADED table will be at index 2
			lua.GetField( LuaDef.LUA_REGISTRYINDEX, "_LOADED" );
			// _LOADED[name]
			lua.GetField( 2, name );
			// is it there?
			if( lua.ToBoolean( -1 ) )
				return 1; // package is already loaded
			// else must load package
			// remove `GetField' result
			lua.Pop( 1 );
			FindLoader( lua, name );
			lua.PushString( name ); // pass name as arg to module loader
			lua.Insert( -2 ); // name is 1st arg (before search data)
			lua.Call( 2, 1 ); // run loader to load module
			if( !lua.IsNil( -1 ) ) // non-nil return?
				lua.SetField( 2, name ); // _LOADED[name] = returned value
			lua.GetField( 2, name );
			if( lua.IsNil( -1 ) ) // module did not set a value?
			{
				lua.PushBoolean( true ); // use true as result
				lua.PushValue( -1 ); // extra copy to be returned
				lua.SetField( 2, name ); // _LOADED[name] = true
			}
			return 1;
		}

		private static int SearcherPreload( ILuaState lua )
		{
			string name = lua.L_CheckString( 1 );
			lua.GetField( LuaDef.LUA_REGISTRYINDEX, "_PRELOAD" );
			lua.GetField( -1, name );
			if( lua.IsNil(-1) ) // not found?
				lua.PushString( string.Format(
					"\n\tno field package.preload['{0}']", name ) );
			return 1;
		}