OCamlin' along with @rexim

example.ml

let on f g = fun x y -> f (g x) (g y)

# uncurry from https://thelema.github.io/batteries-included/hdoc/BatPervasives.html
# dunno if you can use that

# line 15 can't be rewritten like that.
# I'm still trying to come up with another solution, but it's really different from the other two
 
# line 16
List.map (fun (vx, vy) -> atan2 (float_of_int vy) (float_of_int vx))
# ...turns into...
List.map (uncurry (on atan2 float_of_int))
 
# line 19
List.sort (fun (_, a1) (_, a2) -> compare a1 a2)
# ...turns into...
List.sort (uncurry (on compare snd))