day 1

bracket.ml

@@ -0,0 +1,17 @@
+let bracket ~make ~act ~free =
+  let x = make () in
+  match act x with
+  | result      -> free x; result
+  | exception e -> free x; raise e
+
+let infile ~act name =
+  bracket ~make:(fun () -> open_in name) ~act ~free:close_in_noerr
+
+let infile_lines ~line:f ~of_seq name =
+  let get_line file =
+    match input_line file with
+    | exception End_of_file -> None
+    | line                  -> Some (f line, file)
+  in
+  let act file = of_seq (Seq.unfold get_line file) in
+  infile name ~act