Re: [Freeciv-Dev] City styles - proposal.

[David Pfitzner <dwp@xxxxxxxxxxxxxx>]

Ok, I've worked out a good (simple+flexible) way to do this,
(as least as far as the server side).  Think of tech trees, 
and unit obsolete_by.

The "standard" ruleset would be something like this:

>>>>>
; The first [citystyle_*] section is the default initial 
; style for nations which do not give an explicit style. 
; (Or could have a global entry to specify the default, 
; cf default_government.)

[citystyle_ancient]
name        = "Ancient"
graphic     = "cities.ancient"
graphic_alt = "-"
tech        = "None"
replaced_by = "Industrial"

[citystyle_industrial]
name        = "Industrial"
graphic     = "cities.industry"
graphic_alt = "-"
tech        = "Mathematics"   ;  FIXME
replaced_by = "Modern"

[citystyle_modern]
name        = "Modern"
graphic     = "cities.modern"
graphic_alt = "-"
tech        = "Monarchy"      ;  FIXME
replaced_by = "-"

[citystyle_oriental]
name        = "Oriental"
graphic     = "cities.oriental"
graphic_alt = "cities.ancient"
tech        = "None"
replaced_by = "Industrial"
<<<<<

Notes:

The techs for Industrial and Monarchy are from Jerzy's original
proposal, but I don't think these are really the appropriate techs.
Eg, they occur much too early, and all cities would look modern 
very soon after the start.

Adding extra styles like oriental above which have
replaced_by = "Industrial" (and put eg citystyle = "Oriental"
somewhere in nations ruleset) allows difference low-tech styles.

As long as the number of styles is not too limited (eg, allocate 
dynamically like governments etc), can be very flexible by using 
separate style sequence.  Eg, if ruleset designer wants, _could_ 
have different techs for different nations, and/or always different 
styles (eg, orcs vs humans) within above scheme.

I put the graphics tag explicitly (instead of eg deriving from
name) similar to what other rulesets do (eg terrain), and to
allow flexibility (eg, two separate style sequences which share 
some subset of graphics).  Allow graphics_alt, eg so if tileset 
doesn't provide "cities.oriental" then fall back to "cities.ancient".

-- David