i didn't have an appreciation for the 'hot new special-syntax' until I compared my original hack against your last function with the infixing....

    (def area-situation (area sub-area)
        (let situation app*.area.sub-area
          (if (is (- situation.budget situation.forecast) 0.0)
            (= situation.budget 200)
          (prn "forecast " situation.forecast " budget " situation.budget))))