using Delphi classes in lua :)

[paul_nicholls]

For you info, using jdarling's idea of an empty table + __index and __newindex I have updated my TLuaClass to check/protect methods + properties

example:

class declaration

    TLuaClassCounter = Class(TLuaClass)
    Private
        FCount: Integer;

        Function IncCount(L: lua_State): Integer;
        Function GetCount(L: lua_State): Integer;
    Protected
        Function  CallLuaMethod(L: lua_State; MethodIndex: Integer): Integer; Override;
        Procedure ReadPropertyValue(L: lua_State; PropertyIndex: Integer); Override;
        Procedure WritePropertyValue(L: lua_State; PropertyIndex: Integer); Override;
    Public
        Constructor Create; Override;
    End;

class body

Constructor TLuaClassCounter.Create;
Begin
    Inherited Create;

    RegisterLuaMethod  ('IncCount',0);
    RegisterLuaMethod  ('GetCount',1);
    RegisterLuaProperty('Count'   ,0,eIntegerProperty,False);
    RegisterLuaProperty('Count2x' ,1,eIntegerProperty,True);
    RegisterLuaProperty('Self'    ,2,eLuaClassProperty,True);

    FCount := 0;
End;
{.......................................................}

{.......................................................}
Function  TLuaClassCounter.IncCount(L: lua_State): Integer;
Begin
    Inc(FCount);

    Result := 0;
End;
{.......................................................}

{.......................................................}
Function  TLuaClassCounter.GetCount(L: lua_State): Integer; 
Begin
    lua_pushnumber(L,FCount);

    Result := 1;
End;
{.......................................................}

{.......................................................}
Function  TLuaClassCounter.CallLuaMethod(L: lua_State; MethodIndex: Integer): Integer;
Begin
    Result := 0;

    Case MethodIndex Of
        0 : Result := IncCount(L);
        1 : Result := GetCount(L);
    Else
    End;
End;
{.......................................................}

{.......................................................}
Procedure TLuaClassCounter.ReadPropertyValue(L: lua_State; PropertyIndex: Integer);
Begin
    Case PropertyIndex Of
        0 : lua_pushnumber(L,FCount);
        1 : lua_pushnumber(L,FCount * 2);
        2 : PushOntoLuaStack(L);
    Else
    End;

    Result := 1;
End;
{.......................................................}

{.......................................................}
Procedure TLuaClassCounter.WritePropertyValue(L: lua_State; PropertyIndex: Integer);
Var
    Value: Double;
Begin
    Case PropertyIndex Of
        0 : FCount := Trunc(lua_tonumber(L,3));
    Else
    End;
End;
{.......................................................}

{.......................................................}

Behind the scenes, no properties or methods can be overwritten in a Lua script, and read-only properties can't be written to in Lua script
Also, you can't assign the wrong type to writable properties and it will tell you

BTW, is there anywhere on this site that one can post largeish code/units to share with people?

cheers,
Paul