Re: C++ creation of object, and Lua co-calling

["Robert Sadedin" <serenity@...>]

What's the advantage of using this method over exposing straight functions?
Or have I got something very wrong?
A static member function can't access the variables within a class, so with
my limited understanding this doesn't seem to help expose the methods of the
c++ object?
I do rather think I am wrong though :).

----- Original Message -----
From: "Gary Makin" <garym@ssg.com.au>
To: "Multiple recipients of list" <lua-l@tecgraf.puc-rio.br>
Sent: Monday, June 17, 2002 5:50 PM
Subject: Re: C++ creation of object, and Lua co-calling


> I think this answers the question you're asking:
>
> The C++ function you make available to Lua must be a static member
function.
> I really should have mentioned this. In Lua, I call the function using the
:
> operation, so it sticks a copy of the object on the stack. From that I
grab
> the ID, and that allows me to get at the C++ object.
>
> Gary
>
>
> On 17/6/02 17:08, "Robert Sadedin" <serenity@nosubstancesoftware.com>
wrote:
>
> > Hmmm.  Interesting, and cool.  How do you store a reference to the
methods
> > in a class?
> > I can store a pointer to an object no sweat, but I don't know how to
call a
> > method relating to that object without adding to lua to handle pointers
to a
> > specific class method.
> >
> > ----- Original Message -----
> > From: "Gary Makin" <garym@ssg.com.au>
> > To: "Multiple recipients of list" <lua-l@tecgraf.puc-rio.br>
> > Sent: Monday, June 17, 2002 1:33 PM
> > Subject: Re: C++ creation of object, and Lua co-calling
> >
> >
> >> I think the solution depends on just what you want to do. For my
project,
> >> I've decided to forego using tolua, and to do it all manually.
> >>
> >> I've got a bunch of different C++ classes, and objects of those
classes,
> > and
> >> I wanted to have parallel objects available in Lua. I ended up putting
a
> >> routine in each class to create the Lua object for each C++ object.
> >>
> >> The code creates a new Lua table, and gets a reference to it (telling
Lua
> >> not to garbage collect the table). The reference is stored in the C++
> >> object, and I use that whenever C++ needs to access Lua.
> >>
> >> In the Lua table I've added a read-only ID entry that I use to find the
> > C++
> >> object (I'm using STL, so pointers and iterators aren't always safe to
> >> store).
> >>
> >> For each method, or data item, that I want to have accessible from Lua,
> > I've
> >> added a table entry for the C++ routine. Of course, these C++ routines
> > need
> >> different parameters than a C++ only routine would need, so I've tended
to
> >> end up with two versions of a lot of the routines, with one calling the
> >> other.
> >>
> >> I've also added some inheritance, so I'm making a single table that's
the
> >> parent for all the tables of one class. For example, I've got one
master
> >> Ruin table that is the parent for all the Ruin tables that represent
real
> >> Ruins in the game. I've added all the common methods to the parent
Ruin,
> > so
> >> I don't need to have copies of all the functions in all the ruins, or
> > copies
> >> of pointers for C++ functions (as I'm using Lua functions to be called
fro
> > m
> >> Lua whenever possible).
> >>
> >> As a caveat, I've only got this working in the last week, so I don't
have
> > a
> >> fully working game using this, but it seems like the system will hold
up.
> >>
> >> Gary Makin
> >> Lead Programmer
> >> Strategic Studies Group
> >>
> >>
> >> On 17/6/02 6:55, "Robert Sadedin" <serenity@nosubstancesoftware.com>
> > wrote:
> >>
> >>> For my game scripting, I need to be able to expose methods from
objects
> >>> created in my c++ class to Lua.
> >>>
> >>> I know there are a number of solutions for providing c++ classes in
lua
> > so
> >>> long as they are created in Lua, but what about when the construction
is
> > in
> >>> the host application?
> >>>
> >>> Essentially, I need method sharing with the creation process being
> >>> consumated by the c++ app.
> >>>
> >>> What is the simplest, and least ambitious method for doing this that
you
> >>> experts can think of?
> >>>
> >>>
> >>> Thanks,
> >>>
> >>>
> >>>
> >>> Rob
> >>>
> >>
> >
>