Use more domain-specific type than Maybe

[coreyhaines]

https://github.com/seagreen/fpg-depths/blob/master/src/Building.elm#L10

Using Maybe can sometimes hide the domain meaning. Perhaps what you really have is something along the lines of

type BuildingCombatType
    = NotCombat
    | Combat { firepower : Int, sensors : Int }

(those names are bad, but perhaps better than using Maybe)

Or even move this up a ways, so you have a type alias for building stats, one for combat stats, then each building is something like

type Building
    = NonCombat BuildingData
    | Combat BuildingData CombatStats

Just a thought.