[Freeciv-Dev] Re: Working on client APIs

[Raimar Falke <hawk@xxxxxxxxxxxxxxxxxxxxxxxxx>]

On Mon, Jul 17, 2000 at 04:56:35PM -0400, Jed Davis wrote:
> This would also be very useful for client-side 
> scripting/automation/whatever.  However I'm not quite clear what a callback 
> would involve here: 

The term "control program" is misleading. My current idea consists only 
of one process, which would be the interpreter of the scipting language. 
The general layer is a dynamic library which will be loaded into the 
process. There is a module/class in the scipting language which does the 
loading of the library and mapping between the C interface of the general 
layer and the module/class. So the execution starts in the control program 
and after some initiation it gives control to the network handler of the 
general layer.

> I first thought that it would involve calling a C 
> function (which could dispatch the call to an embedded interpreter), but 
> the "written in any language" implies that these callbacks involve some 
> kind of IPC with the controller running as a separate process, which is 
> probably a better idea in the long run.  Since I'm sort of working on 
> (read: planning and trying in vain to find time for) GUILE scripting, I'd 
> appreciate any information on this.

Using seperate processes and some communication channel 
(IPC/pipes/socket/...) between them:
 pro:
  - cleaner distinction
 con:
  - the general layer stub would be very small
  - another protocol

Using more processes will IMHO the multithreading question obsolete.

IMHO can the protocol issue reduced by using some higher level mechanism. 
CORBA for example.

        Raimar

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