refactor!: change repo directory structure for ocaml

51 files changed, 229 insertions, 299 deletions

diff --git a/ocaml/lib/application/d05p01.ml b/ocaml/lib/application/d05p01.ml
deleted file mode 100644
index 4bf79ab..0000000
--- a/ocaml/lib/application/d05p01.ml
+++ /dev/null
@@ -1,3 +0,0 @@
-let err_empty_input = "input is empty"
-
-let solve input () = if input = "" then Error err_empty_input else Ok 0
diff --git a/ocaml/lib/application/d05p01.mli b/ocaml/lib/application/d05p01.mli
deleted file mode 100644
index 85c3dd5..0000000
--- a/ocaml/lib/application/d05p01.mli
+++ /dev/null
@@ -1,4 +0,0 @@
-val solve : string -> unit -> (int, string) result
-(** [solve input ()] is the solution for the first part of the five day of advent of code 2025 for [input].
-    The solution for an empty input is [Error msg].
-    Requires: [input] to be a string. *)
diff --git a/ocaml/lib/infrastructure/dune b/ocaml/lib/infrastructure/dune
deleted file mode 100644
index b9d250f..0000000
--- a/ocaml/lib/infrastructure/dune
+++ /dev/null
@@ -1,15 +0,0 @@
-(library
-  (name infrastructure)
-  (libraries
-    application
-    domain
-    fmt
-    logs)
-  (inline_tests)
-  (preprocess
-    (pps
-      ppx_deriving.show
-      ppx_deriving.eq
-      ppx_deriving.ord
-      ppx_inline_test
-      ppx_expect)))
diff --git a/ocaml/lib/infrastructure/file.mli b/ocaml/lib/infrastructure/file.mli
deleted file mode 100644
index 17d4495..0000000
--- a/ocaml/lib/infrastructure/file.mli
+++ /dev/null
@@ -1,3 +0,0 @@
-val read : string -> string
-(** [read filename] is the contents of [filename] as a string.
-    The empty string is returned if [filename] does not exist. *)
diff --git a/ocaml/lib/presentation/cli.ml b/ocaml/lib/presentation/cli.ml
deleted file mode 100644
index 7864e7f..0000000
--- a/ocaml/lib/presentation/cli.ml
+++ /dev/null
@@ -1,62 +0,0 @@
-(* Business logic behind CLI *)
-
-let run_solver name solver filepath =
-  let content = Infrastructure.File.read filepath in
-  match solver content () with
-  | Error msg ->
-      Logs.app (fun m -> m "[%s] Err=%s" name msg)
-  | Ok answer ->
-      Logs.app (fun m -> m "[%s] ANSWER=%d" name answer)
-
-let run_day _ = function
-  | 1 ->
-      let filepath = "../_input/day_01.txt" in
-      run_solver "D01P01" Application.D01p01.solve filepath ;
-      run_solver "D01P02" Application.D01p02.solve filepath ;
-      0
-  | 2 ->
-      let filepath = "../_input/day_02.txt" in
-      run_solver "D02P01" Application.D02p01.solve filepath ;
-      run_solver "D02P02" Application.D02p02.solve filepath ;
-      0
-  | 3 ->
-      let filepath = "../_input/day_03.txt" in
-      run_solver "D03P01" Application.D03p01.solve filepath ;
-      run_solver "D03P02" Application.D03p02.solve filepath ;
-      0
-  | 4 ->
-      let filepath = "../_input/day_04.txt" in
-      run_solver "D04P01" Application.D04p01.solve filepath ;
-      run_solver "D04P02" Application.D04p02.solve filepath ;
-      0
-  | 5 ->
-      let filepath = "../_input/day_05.txt" in
-      run_solver "D05P01" Application.D05p01.solve filepath ;
-      0
-  | 6 ->
-      let filepath = "../_input/day_06.txt" in
-      run_solver "D06P01" Application.D06p01.solve filepath ;
-      run_solver "D06P02" Application.D06p02.solve filepath ;
-      0
-  | _ ->
-      failwith "day not implemented"
-
-(* Command line interface *)
-
-open Cmdliner
-
-let setup_log style_renderer = Fmt_tty.setup_std_outputs ?style_renderer ()
-
-let setup_log_t = Term.(const setup_log $ Fmt_cli.style_renderer ())
-
-let day_arg =
-  let doc = "Day to run. MUST be in range of 1-12." in
-  Arg.(value & pos 0 int 1 & info [] ~docv:"DAY" ~doc)
-
-let day_t = Term.(const run_day $ setup_log_t $ day_arg)
-
-let cmd =
-  let info = Cmd.info "aoc" ~version:"0.1.0" in
-  Cmd.v info day_t
-
-let run () = Cmd.eval' cmd
diff --git a/ocaml/lib/presentation/dune b/ocaml/lib/presentation/dune
deleted file mode 100644
index ae1fcb1..0000000
--- a/ocaml/lib/presentation/dune
+++ /dev/null
@@ -1,16 +0,0 @@
-(library
-  (name presentation)
-  (libraries
-    application
-    domain
-    infrastructure
-    cmdliner
-    fmt.cli
-    fmt.tty)
-  (inline_tests)
-  (preprocess
-    (pps
-      ppx_deriving.show
-      ppx_deriving.eq
-      ppx_deriving.ord
-      ppx_expect)))
diff --git a/ocaml/lib/domain/dune b/ocaml/lib/shared/dune
index 5b13d31..f71a5fe 100644
--- a/ocaml/lib/domain/dune
+++ b/ocaml/lib/shared/dune
@@ -1,13 +1,10 @@
 (library
-  (name domain)
+  (name shared)
   (inline_tests)
-  (libraries
-    fmt
-    logs)
   (preprocess
     (pps
       ppx_deriving.show
       ppx_deriving.eq
       ppx_deriving.ord
-      ppx_inline_test
-      ppx_expect)))
+      ppx_expect
+      ppx_inline_test)))
diff --git a/ocaml/lib/infrastructure/file.ml b/ocaml/lib/shared/file.ml
index 3b49c01..74b5abc 100644
--- a/ocaml/lib/infrastructure/file.ml
+++ b/ocaml/lib/shared/file.ml
@@ -1,3 +1,5 @@
+(** [read filename] is the contents of [filename] as a string.
+    The empty string is returned if [filename] does not exist. *)
 let read filename =
   let chan = In_channel.open_text filename in
   let content = In_channel.input_all chan in
diff --git a/ocaml/lib/domain/matrix.ml b/ocaml/lib/shared/matrix.ml
index fdf476f..fdf476f 100644
--- a/ocaml/lib/domain/matrix.ml
+++ b/ocaml/lib/shared/matrix.ml
diff --git a/ocaml/lib/application/parser.ml b/ocaml/lib/shared/parser.ml
index 099900b..099900b 100644
--- a/ocaml/lib/application/parser.ml
+++ b/ocaml/lib/shared/parser.ml
diff --git a/ocaml/lib/domain/range.ml b/ocaml/lib/shared/range.ml
index a1bdc00..a1bdc00 100644
--- a/ocaml/lib/domain/range.ml
+++ b/ocaml/lib/shared/range.ml
diff --git a/ocaml/lib/domain/d01p01.ml b/ocaml/lib/year2025/day01/part01/dial.ml
index 6b531f4..6b531f4 100644
--- a/ocaml/lib/domain/d01p01.ml
+++ b/ocaml/lib/year2025/day01/part01/dial.ml
diff --git a/ocaml/lib/application/d01p01.ml b/ocaml/lib/year2025/day01/part01/solver.ml
index 206e757..f4f0dde 100644
--- a/ocaml/lib/application/d01p01.ml
+++ b/ocaml/lib/year2025/day01/part01/solver.ml
@@ -1,4 +1,4 @@
-open Domain.D01p01
+open Dial
 
 let err_empty_input = "input is empty"
 
diff --git a/ocaml/lib/application/d01p01.mli b/ocaml/lib/year2025/day01/part01/solver.mli
index 2eecf19..2eecf19 100644
--- a/ocaml/lib/application/d01p01.mli
+++ b/ocaml/lib/year2025/day01/part01/solver.mli
diff --git a/ocaml/lib/domain/d01p02.ml b/ocaml/lib/year2025/day01/part02/dial.ml
index f71e965..e061d6d 100644
--- a/ocaml/lib/domain/d01p02.ml
+++ b/ocaml/lib/year2025/day01/part02/dial.ml
@@ -66,30 +66,3 @@ end = struct
     | Right n ->
         "Right " ^ string_of_int n
 end
-
-module Turner : sig
-  val turn : Dial.t -> int -> Dial.direction -> Dial.t * int
-  (** [turn dial direction] is the new state of the dial after turning [direction] on [dial] *)
-end = struct
-  (** [turn dial direction] is the new state of the dial after turning [direction] on [dial].
-      Raises: [dial_out_of_range] if the dial is moved to an invalid state. *)
-  let rec turn dial zero_count direction =
-    let open Dial in
-    match direction with
-    | Left 0 ->
-        (dial, zero_count)
-    | Left n ->
-        let dial' = prev dial in
-        let zero_count' =
-          if Dial.is_zero dial' then zero_count + 1 else zero_count
-        in
-        turn dial' zero_count' (Left (n - 1))
-    | Right 0 ->
-        (dial, zero_count)
-    | Right n ->
-        let dial' = next dial in
-        let zero_count' =
-          if Dial.is_zero dial' then zero_count + 1 else zero_count
-        in
-        turn dial' zero_count' (Right (n - 1))
-end
diff --git a/ocaml/lib/application/d01p02.ml b/ocaml/lib/year2025/day01/part02/solver.ml
index 7910486..452209f 100644
--- a/ocaml/lib/application/d01p02.ml
+++ b/ocaml/lib/year2025/day01/part02/solver.ml
@@ -1,4 +1,5 @@
-open Domain.D01p02
+open Dial
+open Turner
 
 let err_empty_input = "input is empty"
 
diff --git a/ocaml/lib/application/d01p02.mli b/ocaml/lib/year2025/day01/part02/solver.mli
index 9e9a2f2..9e9a2f2 100644
--- a/ocaml/lib/application/d01p02.mli
+++ b/ocaml/lib/year2025/day01/part02/solver.mli
diff --git a/ocaml/lib/year2025/day01/part02/turner.ml b/ocaml/lib/year2025/day01/part02/turner.ml
new file mode 100644
index 0000000..7477093
--- /dev/null
+++ b/ocaml/lib/year2025/day01/part02/turner.ml
@@ -0,0 +1,28 @@
+open Dial
+
+module Turner : sig
+  val turn : Dial.t -> int -> Dial.direction -> Dial.t * int
+  (** [turn dial direction] is the new state of the dial after turning [direction] on [dial] *)
+end = struct
+  (** [turn dial direction] is the new state of the dial after turning [direction] on [dial].
+      Raises: [dial_out_of_range] if the dial is moved to an invalid state. *)
+  let rec turn dial zero_count direction =
+    let open Dial in
+    match direction with
+    | Left 0 ->
+        (dial, zero_count)
+    | Left n ->
+        let dial' = prev dial in
+        let zero_count' =
+          if Dial.is_zero dial' then zero_count + 1 else zero_count
+        in
+        turn dial' zero_count' (Left (n - 1))
+    | Right 0 ->
+        (dial, zero_count)
+    | Right n ->
+        let dial' = next dial in
+        let zero_count' =
+          if Dial.is_zero dial' then zero_count + 1 else zero_count
+        in
+        turn dial' zero_count' (Right (n - 1))
+end
diff --git a/ocaml/lib/year2025/day02/part01/id.ml b/ocaml/lib/year2025/day02/part01/id.ml
new file mode 100644
index 0000000..b7a3bd2
--- /dev/null
+++ b/ocaml/lib/year2025/day02/part01/id.ml
@@ -0,0 +1,16 @@
+module ID = struct
+  (** *)
+  type t = int
+
+  let create num = num
+
+  let validate rules id = List.fold_left (fun acc r -> acc && r id) true rules
+
+  let incr = ( + ) 1
+
+  let to_int id = id
+
+  let to_string = string_of_int
+
+  let pp id = "ID=" ^ string_of_int id
+end
diff --git a/ocaml/lib/domain/d02p01.mli b/ocaml/lib/year2025/day02/part01/id.mli
index 55665fe..63d5942 100644
--- a/ocaml/lib/domain/d02p01.mli
+++ b/ocaml/lib/year2025/day02/part01/id.mli
@@ -20,17 +20,3 @@ module ID : sig
   val pp : t -> string
   (** [pp id] is a pretty string representing [id] *)
 end
-
-module Range : sig
-  (** [t] is a range of values *)
-  type t
-
-  val create : int * int -> t
-  (** [create (s, e)] is a range starting at [s] and ending at [e]. *)
-
-  val collect : t -> ID.t list
-  (** [collect r] is a list containing all elements within the range (inclusive). *)
-
-  val pp : t -> string
-  (** [pp r] is a pretty string representing [r] *)
-end
diff --git a/ocaml/lib/domain/d02p02.ml b/ocaml/lib/year2025/day02/part01/range.ml
index b2b55f1..ba27568 100644
--- a/ocaml/lib/domain/d02p02.ml
+++ b/ocaml/lib/year2025/day02/part01/range.ml
@@ -1,15 +1,4 @@
-module ID = struct
-  (** *)
-  type t = int
-
-  let create num = num
-
-  let incr = ( + ) 1
-
-  let to_string = string_of_int
-
-  let pp id = "ID=" ^ string_of_int id
-end
+open Id
 
 module Range = struct
   type t = ID.t * ID.t
diff --git a/ocaml/lib/year2025/day02/part01/range.mli b/ocaml/lib/year2025/day02/part01/range.mli
new file mode 100644
index 0000000..e525e43
--- /dev/null
+++ b/ocaml/lib/year2025/day02/part01/range.mli
@@ -0,0 +1,15 @@
+open Id
+
+module Range : sig
+  (** [t] is a range of values *)
+  type t
+
+  val create : int * int -> t
+  (** [create (s, e)] is a range starting at [s] and ending at [e]. *)
+
+  val collect : t -> ID.t list
+  (** [collect r] is a list containing all elements within the range (inclusive). *)
+
+  val pp : t -> string
+  (** [pp r] is a pretty string representing [r] *)
+end
diff --git a/ocaml/lib/application/d02p01.ml b/ocaml/lib/year2025/day02/part01/solver.ml
index f313149..417aa0d 100644
--- a/ocaml/lib/application/d02p01.ml
+++ b/ocaml/lib/year2025/day02/part01/solver.ml
@@ -1,4 +1,5 @@
-open Domain.D02p01
+open Id
+open Range
 
 let err_empty_input = "input is empty"
 
diff --git a/ocaml/lib/application/d02p01.mli b/ocaml/lib/year2025/day02/part01/solver.mli
index 8a8eb32..8a8eb32 100644
--- a/ocaml/lib/application/d02p01.mli
+++ b/ocaml/lib/year2025/day02/part01/solver.mli
diff --git a/ocaml/lib/year2025/day02/part02/id.ml b/ocaml/lib/year2025/day02/part02/id.ml
new file mode 100644
index 0000000..f26c395
--- /dev/null
+++ b/ocaml/lib/year2025/day02/part02/id.ml
@@ -0,0 +1,12 @@
+module ID = struct
+  (** *)
+  type t = int
+
+  let create num = num
+
+  let incr = ( + ) 1
+
+  let to_string = string_of_int
+
+  let pp id = "ID=" ^ string_of_int id
+end
diff --git a/ocaml/lib/domain/d02p02.mli b/ocaml/lib/year2025/day02/part02/id.mli
index f918ae1..a512593 100644
--- a/ocaml/lib/domain/d02p02.mli
+++ b/ocaml/lib/year2025/day02/part02/id.mli
@@ -14,17 +14,3 @@ module ID : sig
   val pp : t -> string
   (** [pp id] is a pretty string representing [id] *)
 end
-
-module Range : sig
-  (** [t] is a range of values *)
-  type t
-
-  val create : int * int -> t
-  (** [create (s, e)] is a range starting at [s] and ending at [e]. *)
-
-  val collect : t -> ID.t list
-  (** [collect r] is a list containing all elements within the range (inclusive). *)
-
-  val pp : t -> string
-  (** [pp r] is a pretty string representing [r] *)
-end
diff --git a/ocaml/lib/domain/d02p01.ml b/ocaml/lib/year2025/day02/part02/range.ml
index 725d4b1..ba27568 100644
--- a/ocaml/lib/domain/d02p01.ml
+++ b/ocaml/lib/year2025/day02/part02/range.ml
@@ -1,19 +1,4 @@
-module ID = struct
-  (** *)
-  type t = int
-
-  let create num = num
-
-  let validate rules id = List.fold_left (fun acc r -> acc && r id) true rules
-
-  let incr = ( + ) 1
-
-  let to_int id = id
-
-  let to_string = string_of_int
-
-  let pp id = "ID=" ^ string_of_int id
-end
+open Id
 
 module Range = struct
   type t = ID.t * ID.t
diff --git a/ocaml/lib/year2025/day02/part02/range.mli b/ocaml/lib/year2025/day02/part02/range.mli
new file mode 100644
index 0000000..e525e43
--- /dev/null
+++ b/ocaml/lib/year2025/day02/part02/range.mli
@@ -0,0 +1,15 @@
+open Id
+
+module Range : sig
+  (** [t] is a range of values *)
+  type t
+
+  val create : int * int -> t
+  (** [create (s, e)] is a range starting at [s] and ending at [e]. *)
+
+  val collect : t -> ID.t list
+  (** [collect r] is a list containing all elements within the range (inclusive). *)
+
+  val pp : t -> string
+  (** [pp r] is a pretty string representing [r] *)
+end
diff --git a/ocaml/lib/application/d02p02.ml b/ocaml/lib/year2025/day02/part02/solver.ml
index d062f7b..f5fdf0c 100644
--- a/ocaml/lib/application/d02p02.ml
+++ b/ocaml/lib/year2025/day02/part02/solver.ml
@@ -1,4 +1,5 @@
-open Domain.D02p02
+open Id
+open Range
 
 (* Errors *)
 
diff --git a/ocaml/lib/application/d02p02.mli b/ocaml/lib/year2025/day02/part02/solver.mli
index 8a8eb32..8a8eb32 100644
--- a/ocaml/lib/application/d02p02.mli
+++ b/ocaml/lib/year2025/day02/part02/solver.mli
diff --git a/ocaml/lib/year2025/day03/part01/battery.ml b/ocaml/lib/year2025/day03/part01/battery.ml
new file mode 100644
index 0000000..cb2d9e5
--- /dev/null
+++ b/ocaml/lib/year2025/day03/part01/battery.ml
@@ -0,0 +1,13 @@
+module Battery = struct
+  type t = int
+
+  let of_int i = i
+
+  let to_int b = b
+
+  let to_string = string_of_int
+
+  let compare = Int.compare
+
+  let pp = string_of_int
+end
diff --git a/ocaml/lib/year2025/day03/part01/battery.mli b/ocaml/lib/year2025/day03/part01/battery.mli
new file mode 100644
index 0000000..e00940b
--- /dev/null
+++ b/ocaml/lib/year2025/day03/part01/battery.mli
@@ -0,0 +1,13 @@
+module Battery : sig
+  type t
+
+  val of_int : int -> t
+
+  val to_int : t -> int
+
+  val to_string : t -> string
+
+  val compare : t -> t -> int
+
+  val pp : t -> string
+end
diff --git a/ocaml/lib/domain/d03p01.ml b/ocaml/lib/year2025/day03/part01/battery_bank.ml
index 1367712..7ebce75 100644
--- a/ocaml/lib/domain/d03p01.ml
+++ b/ocaml/lib/year2025/day03/part01/battery_bank.ml
@@ -1,45 +1,6 @@
-module Battery : sig
-  type t
+open Battery
 
-  val of_int : int -> t
-
-  val to_int : t -> int
-
-  val to_string : t -> string
-
-  val compare : t -> t -> int
-
-  val pp : t -> string
-end = struct
-  type t = int
-
-  let of_int i = i
-
-  let to_int b = b
-
-  let to_string = string_of_int
-
-  let compare = Int.compare
-
-  let pp = string_of_int
-end
-
-module BatteryBank : sig
-  type t
-
-  val highest_joltage : t -> int
-  (** [highest_joltage bb] is an integer created from the two highest
-      digits in [bb].
-      Raises: [Assert_failure] if [bb] is empty. *)
-
-  val of_string : string -> t
-
-  val of_list : Battery.t list -> t
-
-  val to_list : t -> Battery.t list
-
-  val pp : t -> string
-end = struct
+module BatteryBank = struct
   type t = Battery.t list
 
   let rec highest_joltage bb =
diff --git a/ocaml/lib/year2025/day03/part01/battery_bank.mli b/ocaml/lib/year2025/day03/part01/battery_bank.mli
new file mode 100644
index 0000000..bffc4cb
--- /dev/null
+++ b/ocaml/lib/year2025/day03/part01/battery_bank.mli
@@ -0,0 +1,18 @@
+open Battery
+
+module BatteryBank : sig
+  type t
+
+  val highest_joltage : t -> int
+  (** [highest_joltage bb] is an integer created from the two highest
+      digits in [bb].
+      Raises: [Assert_failure] if [bb] is empty. *)
+
+  val of_string : string -> t
+
+  val of_list : Battery.t list -> t
+
+  val to_list : t -> Battery.t list
+
+  val pp : t -> string
+end
diff --git a/ocaml/lib/application/d03p01.ml b/ocaml/lib/year2025/day03/part01/solver.ml
index 522f5d0..4a06e83 100644
--- a/ocaml/lib/application/d03p01.ml
+++ b/ocaml/lib/year2025/day03/part01/solver.ml
@@ -1,4 +1,4 @@
-open Domain.D03p01
+open Battery_bank
 
 let err_empty_input = "input is empty"
 
diff --git a/ocaml/lib/application/d03p01.mli b/ocaml/lib/year2025/day03/part01/solver.mli
index 31dd0cd..31dd0cd 100644
--- a/ocaml/lib/application/d03p01.mli
+++ b/ocaml/lib/year2025/day03/part01/solver.mli
diff --git a/ocaml/lib/year2025/day03/part02/battery.ml b/ocaml/lib/year2025/day03/part02/battery.ml
new file mode 100644
index 0000000..e8f0443
--- /dev/null
+++ b/ocaml/lib/year2025/day03/part02/battery.ml
@@ -0,0 +1,25 @@
+module Battery : sig
+  type t
+
+  val of_int : int -> t
+
+  val to_int : t -> int
+
+  val to_string : t -> string
+
+  val compare : t -> t -> int
+
+  val pp : t -> string
+end = struct
+  type t = int
+
+  let of_int i = i
+
+  let to_int b = b
+
+  let to_string = string_of_int
+
+  let compare = Int.compare
+
+  let pp = string_of_int
+end
diff --git a/ocaml/lib/year2025/day03/part02/battery.mli b/ocaml/lib/year2025/day03/part02/battery.mli
new file mode 100644
index 0000000..e00940b
--- /dev/null
+++ b/ocaml/lib/year2025/day03/part02/battery.mli
@@ -0,0 +1,13 @@
+module Battery : sig
+  type t
+
+  val of_int : int -> t
+
+  val to_int : t -> int
+
+  val to_string : t -> string
+
+  val compare : t -> t -> int
+
+  val pp : t -> string
+end
diff --git a/ocaml/lib/domain/d03p02.ml b/ocaml/lib/year2025/day03/part02/battery_bank.ml
index 88257d0..d7dc213 100644
--- a/ocaml/lib/domain/d03p02.ml
+++ b/ocaml/lib/year2025/day03/part02/battery_bank.ml
@@ -1,45 +1,6 @@
-module Battery : sig
-  type t
+open Battery
 
-  val of_int : int -> t
-
-  val to_int : t -> int
-
-  val to_string : t -> string
-
-  val compare : t -> t -> int
-
-  val pp : t -> string
-end = struct
-  type t = int
-
-  let of_int i = i
-
-  let to_int b = b
-
-  let to_string = string_of_int
-
-  let compare = Int.compare
-
-  let pp = string_of_int
-end
-
-module BatteryBank : sig
-  type t
-
-  val highest_joltage : t -> int
-  (** [highest_joltage bb] is an integer created from the two highest
-      digits in [bb].
-      Raises: [Assert_failure] if [bb] is empty. *)
-
-  val of_string : string -> t
-
-  val of_list : Battery.t list -> t
-
-  val to_list : t -> Battery.t list
-
-  val pp : t -> string
-end = struct
+module BatteryBank = struct
   type t = Battery.t list
 
   type highest = {one: Battery.t option; two: Battery.t option}
diff --git a/ocaml/lib/year2025/day03/part02/battery_bank.mli b/ocaml/lib/year2025/day03/part02/battery_bank.mli
new file mode 100644
index 0000000..bffc4cb
--- /dev/null
+++ b/ocaml/lib/year2025/day03/part02/battery_bank.mli
@@ -0,0 +1,18 @@
+open Battery
+
+module BatteryBank : sig
+  type t
+
+  val highest_joltage : t -> int
+  (** [highest_joltage bb] is an integer created from the two highest
+      digits in [bb].
+      Raises: [Assert_failure] if [bb] is empty. *)
+
+  val of_string : string -> t
+
+  val of_list : Battery.t list -> t
+
+  val to_list : t -> Battery.t list
+
+  val pp : t -> string
+end
diff --git a/ocaml/lib/application/d03p02.ml b/ocaml/lib/year2025/day03/part02/solver.ml
index 743c658..4a06e83 100644
--- a/ocaml/lib/application/d03p02.ml
+++ b/ocaml/lib/year2025/day03/part02/solver.ml
@@ -1,4 +1,4 @@
-open Domain.D03p02
+open Battery_bank
 
 let err_empty_input = "input is empty"
 
diff --git a/ocaml/lib/application/d03p02.mli b/ocaml/lib/year2025/day03/part02/solver.mli
index 93d3b98..93d3b98 100644
--- a/ocaml/lib/application/d03p02.mli
+++ b/ocaml/lib/year2025/day03/part02/solver.mli
diff --git a/ocaml/lib/application/d04p01.ml b/ocaml/lib/year2025/day04/part01/solver.ml
index 7c69de4..7cc54f6 100644
--- a/ocaml/lib/application/d04p01.ml
+++ b/ocaml/lib/year2025/day04/part01/solver.ml
@@ -1,21 +1,21 @@
-open Domain
-
 let err_empty_input = "input is empty"
 
 let rec solve input () =
   if input = "" then Error err_empty_input
   else
-    let matrix = Matrix.M.of_string input in
+    let matrix = Shared.Matrix.M.of_string input in
     let count_paper lst = List.length @@ List.filter (fun c -> c <> ".") lst in
     let accessible_rolls_of_paper = ref 0 in
     for y = 0 to Array.length matrix - 1 do
       for x = 0 to Array.length matrix.(y) - 1 do
         if matrix.(y).(x) = "." then ()
         else
-          let neighbour_coords = Matrix.M.get_valid_neighbours matrix x y in
+          let neighbour_coords =
+            Shared.Matrix.M.get_valid_neighbours matrix x y
+          in
           let neighbours =
             List.map
-              (fun (x', y') -> Matrix.M.get matrix x' y')
+              (fun (x', y') -> Shared.Matrix.M.get matrix x' y')
               neighbour_coords
           in
           let paper_count = count_paper neighbours in
diff --git a/ocaml/lib/application/d04p01.mli b/ocaml/lib/year2025/day04/part01/solver.mli
index 873acff..873acff 100644
--- a/ocaml/lib/application/d04p01.mli
+++ b/ocaml/lib/year2025/day04/part01/solver.mli
diff --git a/ocaml/lib/application/d04p02.ml b/ocaml/lib/year2025/day04/part02/solver.ml
index 75b1236..e92c982 100644
--- a/ocaml/lib/application/d04p02.ml
+++ b/ocaml/lib/year2025/day04/part02/solver.ml
@@ -1,5 +1,3 @@
-open Domain
-
 let err_empty_input = "input is empty"
 
 let rec count_accessible_rolls matrix =
@@ -21,9 +19,13 @@ and count_accessible_rolls_aux matrix count_paper accessible_rolls_of_paper =
     for x = 0 to Array.length matrix.(y) - 1 do
       if matrix.(y).(x) = "." then ()
       else
-        let neighbour_coords = Matrix.M.get_valid_neighbours matrix x y in
+        let neighbour_coords =
+          Shared.Matrix.M.get_valid_neighbours matrix x y
+        in
         let neighbours =
-          List.map (fun (nx, ny) -> Matrix.M.get matrix nx ny) neighbour_coords
+          List.map
+            (fun (nx, ny) -> Shared.Matrix.M.get matrix nx ny)
+            neighbour_coords
         in
         let paper_count = count_paper neighbours in
         let is_accessible = paper_count < 4 in
@@ -34,7 +36,7 @@ and count_accessible_rolls_aux matrix count_paper accessible_rolls_of_paper =
     done
   done ;
   List.iter
-    (fun (x', y') -> Matrix.M.set matrix x' y' ".")
+    (fun (x', y') -> Shared.Matrix.M.set matrix x' y' ".")
     !accessible_rolls_of_paper
 
 and print_iteration_debug_msg x y neighbour_coords neighbours paper_count
@@ -59,6 +61,6 @@ and print_iteration_debug_msg x y neighbour_coords neighbours paper_count
 let solve input () =
   if input = "" then Error err_empty_input
   else
-    let matrix = Matrix.M.of_string input in
+    let matrix = Shared.Matrix.M.of_string input in
     let accessible_rolls_of_paper = count_accessible_rolls matrix in
     Ok accessible_rolls_of_paper
diff --git a/ocaml/lib/application/d04p02.mli b/ocaml/lib/year2025/day04/part02/solver.mli
index 388ec56..388ec56 100644
--- a/ocaml/lib/application/d04p02.mli
+++ b/ocaml/lib/year2025/day04/part02/solver.mli
diff --git a/ocaml/lib/application/d06p01.ml b/ocaml/lib/year2025/day06/part01/solver.ml
index 9425810..d992ac2 100644
--- a/ocaml/lib/application/d06p01.ml
+++ b/ocaml/lib/year2025/day06/part01/solver.ml
@@ -1,7 +1,7 @@
 let err_empty_input = "input is empty"
 
 let log_matrix matrix =
-  let open Domain.Matrix in
+  let open Shared.Matrix in
   Logs.debug (fun m -> m "%s" (M.of_list matrix |> M.pp (fun elt -> elt)))
 
 let log_list lst =
@@ -13,7 +13,7 @@ type operation = Mult | Add
 let solve input () =
   if input = "" then Error err_empty_input
   else
-    let input' = Parser.columns_of_string input in
+    let input' = Shared.Parser.columns_of_string input in
     assert (input' <> []) ;
     log_matrix input' ;
     let nums =
diff --git a/ocaml/lib/application/d06p01.mli b/ocaml/lib/year2025/day06/part01/solver.mli
index b3abc1e..b3abc1e 100644
--- a/ocaml/lib/application/d06p01.mli
+++ b/ocaml/lib/year2025/day06/part01/solver.mli
diff --git a/ocaml/lib/application/d06p02.ml b/ocaml/lib/year2025/day06/part02/solver.ml
index 9425810..d992ac2 100644
--- a/ocaml/lib/application/d06p02.ml
+++ b/ocaml/lib/year2025/day06/part02/solver.ml
@@ -1,7 +1,7 @@
 let err_empty_input = "input is empty"
 
 let log_matrix matrix =
-  let open Domain.Matrix in
+  let open Shared.Matrix in
   Logs.debug (fun m -> m "%s" (M.of_list matrix |> M.pp (fun elt -> elt)))
 
 let log_list lst =
@@ -13,7 +13,7 @@ type operation = Mult | Add
 let solve input () =
   if input = "" then Error err_empty_input
   else
-    let input' = Parser.columns_of_string input in
+    let input' = Shared.Parser.columns_of_string input in
     assert (input' <> []) ;
     log_matrix input' ;
     let nums =
diff --git a/ocaml/lib/application/d06p02.mli b/ocaml/lib/year2025/day06/part02/solver.mli
index 49444de..49444de 100644
--- a/ocaml/lib/application/d06p02.mli
+++ b/ocaml/lib/year2025/day06/part02/solver.mli
diff --git a/ocaml/lib/application/dune b/ocaml/lib/year2025/dune
index b78613a..99d5c0a 100644
--- a/ocaml/lib/application/dune
+++ b/ocaml/lib/year2025/dune
@@ -1,7 +1,9 @@
+(include_subdirs qualified)
+
 (library
-  (name application)
+  (name year2025)
   (libraries
-    domain
+    shared
     fmt
     logs)
   (inline_tests)
@@ -10,5 +12,5 @@
       ppx_deriving.show
       ppx_deriving.eq
       ppx_deriving.ord
-      ppx_inline_test
-      ppx_expect)))
+      ppx_expect
+      ppx_inline_test)))