Re: A Question of Style

[Rebel Neurofog <rebelneurofog@...>]

On Sat, Nov 26, 2011 at 5:03 PM, Marc Balmer <marc@msys.ch> wrote:
> Hi
>
> I have a stylistic question wrt/ calling Lua "callbacks" from a C
> program.  I see two obvious approaches:
>
> 1) Lua code registers callbacks explicitely using a RegisterCallback
> function that is provided by the C program; the C program later calls
> the callback function when one is registered.
>
> 2) Lua code does not register callbacks, but the callbacks must be
> functions with a certain name, e.g. "MouseMovedCallback"; C code will
> then see if a function with the correct name is available in the Lua
> state, and if so, call it.
>
> Are there advantages of one approach over the other?  Are there other
> approaches?  If you also use callback written in Lua, which you call
> from C, I'd like you to share your opinion (and/or experience).
>
> I experienced with both forms, I am unsure for which form to go...
>

I prefer the first case.
A function may contain also upvalues.
Here's the code:

local desktop = widget_system.create_desktop ()

-- Case 1
input.set_mouse_handler (desktop.mouse_move)

-- Case 2
function mouse_move_handler (dx, dy)
   desktop.mouse_move (dx, dy) -- note, there's no ":" here
end