[Freeciv-Dev] Re: Development Strategies [Was Documentation, Usability and Development]

[Daniel L Speyer <dspeyer@xxxxxxxxxxx>]

On Sun, 2 Dec 2001, Andrew Sutton wrote:

> On Saturday 01 December 2001 07:39 pm, Daniel L Speyer wrote:
> > Remember that java can be compiled to native object code (on GNU/Linux, at
> > least, using gjc).  I don't know how its performance is that way.
> >
> > If we look at that sort of massive changes, though, I think we should push
> > toward customizability.  It seems to me that units' special powers in
> > config files are a pretty ugly setup.  Basically, every special power
> > (paradrop, build fortresses...) is written in c, then specified to a unit
> > in config.  This makes it impossible for ruleset designers to add or edit
> > powers.
> >
> > I'd like to see a design with the most core/time-critical code in C/C++
> > but the bulk of it in freeciv-definition language -- sort of like how
> > emacs and mathematica work.
> 
> i gotta take a break from the language talk :)
> 
> i think you're right - to some degree. clearly there's got to be a separation 
> of declaration and instantiation. the declaration defines the capabilities 
> and the instantiation defines how they're used in a game. i've been mulling 
> this over for some time, and came to this solution:
> 
> declaration is performed in modules. for example, unit capabilities are 
> written as code and have a couple of associated parameters. each capability 
> is type static - that is to say that all units of a certain type have that 
> capability (e.g. setters build cities). parameters come in two flavors: type 
> static (like before) and instance value. type static parameters define a 
> parameter of a capability that is general to all units of a certain type. 
> instance value parameters are specific to the units themselves. a good 
> example of this is movement. all armor units can move 3 tiles. each unit 
> keeps track of how many moves it has left. another good example is ranged 
> flight and the dependancy on fuel.
> 
> this basically means that the data of capabilities is completely separated 
> from the capability itself, meaning that it is just an interface.
> 
> there's an option for extending this architecture to allow individual units 
> to acquire capabilties (instance capability?). this would provide an 
> interesting hook for extension. however, as far as i know, nothing in the civ 
> games does this, so i didn't spend time figuring it out.
> 
> instantiation comes in the form of a ruleset. a ruleset applies capabilities 
> and parameters to units. this is actually pretty similar to freeciv1, but 
> generalized.
> 
> for a ruleset to include new capabilities, there will have to be supporting 
> code. i know, it's not much fun, but that's currently the way it is.
> 
> an alternative would be to define a separate language that allowed the 
> specification of the extensions and would compile directly into code. 
> however, capabilties are pretty unique and it would probably be pretty hard 
> to generalize. if you think you can figure out how to do it though, i won't 
> complain ;)

This last feature is exactly what I was thinking of, though.  Modules move
toward it, but think how many cool things could happen (for
multiplayer) if it were really easy to write really interesting
units.  This would mean interpereted unit capability definitions.

I think the answer is to move all the unit handling code except for the
low-level map support into the rulesets.  Each unit would provide its own
goto, for example (there would have to be an easy way to assign a standard
one to ordinary units), and we wouldn't have such bug-prone ugliness to
handle triremes, planes, etc. (no offense intended toward whoever wrote
that code).  For something like this, we would probably want to include a
pre-existing language (we'll need real power, in any case).  I would
probably recomend python, even though I havn't used it, because it seems
to handle dynamicism almost as well as Lisp but has a syntax that's very
newbie-friendly.

Another thought is the simkin library (simkin.co.uk) that Gregor
mentioned.  It looks really cool, though I haven't had time to really
learn it yet.  Admittedly, it would require a switch to either C++ or
Java.

--Daniel Speyer
"May the /src be with you, always"


> 
> andy
>