controlPointFromExpr :: TypedExpr -> [ControlPoint a] -> Maybe (ControlPoint a)
controlPointFromExpr (TEVar _ f) cps = find (\cp -> f == controlPointId cp) cps
controlPointFromExpr :: TypedExpr -> [ControlPoint a] -> Maybe (ControlPoint a)
controlPointFromExpr (TEVar _ f) cps = find (\cp -> f == controlPointId cp) cps
controlPointFromExpr (TEVar _ f) cps = find (\cp -> f == controlPointId cp) cps