[Taqwus]

A 'ship class tree' might be an intriguing way to go (for a future installment; it's almost certainly too much to add at this point. I'd be happy to see it someday, 'tho.).

Essentially, one should be able to construct a directed acyclic graph (DAG) out of the various classes. The DAG may have branches where one class was upgraded into two different Versions (one earlier, one later but still not 50% more expensive -- or whatever limit is set in the .txt), both of which may be upgradable to the same. Alternately, if we have

in the case that A came first, some were refitted to B, then a design C was created that was barely cheap enough to be upgraded from A, but obsoletes both A and B -- and then D obsoletes C. However, ships of type A or B just returning from extended tours of duty (actually, that's rather limited by supply... as long as ships keep running in trouble faster than the _Enterprise_ =); but if there were ship morale, long tours between returns to port would surely affect it) have too high a price differential, so they'd have to be upgraded via A->B-D. The computer could easily calculate the upgrade cost (resources and time -- well, the latter needs to factor in repair time. Hm. Measure in damaged components.) per edge of the graph, and compute the 'best' upgrade path given either priority. Then, having a setting like 'Automatically upgrade idle ships using up to NN% of net income', or 'Automatically upgrade idle ships N or more generations behind' becomes possible, because it can figure out how to upgrade without fear of turning your missile boats into beamers, or so forth, unless you so choose -- because it can ignore disconnected ship class hierarchies (like E->F).

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-- The thing that goes bump in the night