Per Vognsen suggests a Haskell version of the damage function from my Schematic Tables talk:
data Attack = Magic | Melee hit surprise defense attack = damage where effectiveness = power * (if surprise then 3 else 2) (power, damage) = case attack of Magic -> (5, max 0 (effectiveness - defense)) Melee -> (4, 2 * effectiveness / defense)
This passes pairs of values (power, damage) through conditionals. That allows the conditionals to multiplex more than one value, rather than being repeated. I suspect I could stymie that approach with more complex data flows, but I am happy to acknowledge that Haskell does OK on this example. Thanks, Per.