fix code style

lib/solver/registry.ml

@@ -42,8 +42,7 @@ let all_years map =
   IntSet.to_list unique_years
 
 let all_days ~year map =
-  let filter_map key =
-    match key with
+  let filter_map = function
     | current_year, day, _ when current_year == year -> Some day
     | _ -> None
   in

lib/year_2015/day_01.ml

@@ -1,7 +1,5 @@
 let parse input =
-  let process char =
-    match char with '(' -> Some 1 | ')' -> Some (-1) | _ -> None
-  in
+  let process = function '(' -> Some 1 | ')' -> Some (-1) | _ -> None in
   input |> Parse.chars_of process
 
 let part_one input = input |> parse |> Seq.fold_left ( + ) 0 |> string_of_int

lib/year_2015/day_03.ml

@@ -1,8 +1,7 @@
 module Point_set = Set.Make (Geometry.Int_point_2d)
 
 let parse input =
-  let to_point char =
-    match char with
+  let to_point = function
     | '^' -> Some (0, 1)
     | 'v' -> Some (0, -1)
     | '>' -> Some (1, 0)