[Freeciv-Dev] Re: Advice re making building respect effects in rulesets

[Ben Webb <ben@xxxxxxxxxxxxxxxxxxxxxx>]

On Wed, Dec 04, 2002 at 10:10:05PM -0500, Thomas M. Payerle wrote:
> Over the Thanksgiving holidays, I have been hacking the code to actually try
> to make it honor the effects field of the rulesets, instead of the hard-wired
> by building type that exists currently.  Have had some success, migrating code
> from one framework to the other piecemeal, and will share with the list when
> approaching something usable.

This has been done already. See the impr-gen patches at
http://freecivac.sf.net/. I suggest you work with them, rather than
duplicating what I've done already.

> 1) What is the intended meaning of EFR_BUILDING range?  I did not notice any
> examples of it in use.

See, for example, the Spy_Resistant effect.

> 2) Can someone explain the reason for having both EFT_CAPITAL_EXISTS and
> EFT_CAPITAL_CITY?

No idea. The distinction is removed in impr-gen.

> 3) It looks like wonders which should survive destruction of their city
> get attached to a city id of -1.   This would require that all corresponding
> effects either be EFT_NONE (?) or EFT_WORLD, as it is no longer able to be
> identified with either a player or a continent.  Is this a reasonable 
> limitation?

The current impr-gen code moves destroyed wonders into a player list,
and if that player is killed, into a global list, so such effects can
have either Player or World range.

> 4) Anyone think that a range EFR_ISLAND_ALL effecting _all_ cities on a given
> island, irregardless of owner might be useful?

See the archives for lots of discussion about this.

> How about EFR_DISTANCE and/or EFR_DISTANCE_PLAYER, with a distance
> parameter, affecting all cities (possibly owned by same player) within
> specified distance of the city with improvement

This would be rather hard to code efficiently.

> 5) I am currently hitting problems deciding about additivity and redundancy
> of effects.  I am currently leaning towards looking at a list of all effects
> of a given type affecting the city in question, and then looking if the 
> improvements causing the effect are listed as obsoleting/making redundant one
> of the improvements causing a similar effect

Eurgh. Look to see how the impr-gen code does it. It sounds rather more
simple and efficient than the scheme you describe. Most effects come in
an additive and a multiplicative form. The additive effects are
accumulated before the multiplicative ones.

        Ben
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