--- a/2023/aoc23.opam	Sat Dec 02 14:02:37 2023 +0100
+++ b/2023/aoc23.opam	Sat Dec 02 17:21:17 2023 +0100
@@ -12,6 +12,7 @@
 depends: [
   "ocaml"
   "dune" {>= "3.10"}
+  "angstrom"
   "base"
   "core"
   "stdio"

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/2023/day02.ml	Sat Dec 02 17:21:17 2023 +0100
@@ -0,0 +1,86 @@
+open Angstrom
+open Base
+open Core
+
+module Part1 = struct
+  module Parser = struct
+    type color = Red | Green | Blue [@@deriving sexp]
+    type reveal = { red : int; green : int; blue : int } [@@deriving sexp]
+    type game = { id : int; reveals : reveal list } [@@deriving sexp]
+
+    (* Parse a game like
+       "Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red"
+    *)
+    let intP =
+      take_while1 (function '0' .. '9' -> true | _ -> false) >>| Int.of_string
+
+    let game_idP = string "Game " *> intP <* string ": "
+
+    let colorP =
+      choice
+        [
+          string "red" *> return Red;
+          string "blue" *> return Blue;
+          string "green" *> return Green;
+        ]
+
+    let color_revealP =
+      let%bind.Angstrom count = intP in
+      let%bind.Angstrom () = skip_while Char.is_whitespace in
+      let%bind.Angstrom color = colorP in
+      return (count, color)
+
+    let revealP =
+      let f acc x =
+        match x with
+        | c, Red -> { acc with red = c }
+        | c, Blue -> { acc with blue = c }
+        | c, Green -> { acc with green = c }
+      in
+      let init = { red = 0; blue = 0; green = 0 } in
+      let%bind.Angstrom colors = sep_by1 (string ", ") color_revealP in
+      return @@ List.fold ~f ~init colors
+
+    let gameP =
+      let%bind.Angstrom id = game_idP in
+      let%bind.Angstrom reveals = sep_by1 (string "; ") revealP in
+      return { id; reveals }
+
+    let parse_game = parse_string ~consume:All gameP
+  end
+
+  exception Game_parse_failed of string
+
+  let process_line line =
+    match Parser.parse_game line with
+    | Ok o -> o
+    | Error e -> raise (Game_parse_failed e)
+
+  let check_reveal contents reveal =
+    let open Parser in
+    let { red = cr; green = cg; blue = cb } = contents in
+    let { red = rr; green = rg; blue = rb } = reveal in
+    rr <= cr && rg <= cg && rb <= cb
+
+  let check_game contents game =
+    let f acc x = acc && check_reveal contents x in
+    List.fold ~init:true ~f game
+
+  let check_line contents line =
+    let game = process_line line in
+    if check_game contents game.reveals then game.id else 0
+end
+
+let fold_lines contents =
+  let f acc line = acc + Part1.check_line contents line in
+  In_channel.fold_lines In_channel.stdin ~f ~init:0
+
+let _test1 () =
+  let line = Option.value_exn @@ In_channel.input_line In_channel.stdin in
+  let s = Part1.process_line line in
+  Out_channel.output_string Out_channel.stdout
+    (Sexp.to_string (Part1.Parser.sexp_of_game s))
+
+let () =
+  Out_channel.printf "%d\n"
+    (fold_lines Part1.Parser.{ red = 12; green = 13; blue = 14 })

--- a/2023/dune	Sat Dec 02 14:02:37 2023 +0100
+++ b/2023/dune	Sat Dec 02 17:21:17 2023 +0100
@@ -1,5 +1,13 @@
 (executable
  (name day01)
+ (modules day01)
  (libraries base core)
- (preprocess (pps ppx_let))
- )
+ (preprocess
+  (pps ppx_let)))
+
+(executable
+ (name day02)
+ (modules day02)
+ (libraries base core angstrom)
+ (preprocess
+  (pps ppx_let ppx_sexp_conv)))

--- a/2023/dune-project	Sat Dec 02 14:02:37 2023 +0100
+++ b/2023/dune-project	Sat Dec 02 17:21:17 2023 +0100
@@ -19,7 +19,7 @@
  (name aoc23)
  (synopsis "A short synopsis")
  (description "A longer description")
- (depends ocaml dune base core stdio)
+ (depends ocaml dune angstrom base core stdio)
  (tags
   (topics "to describe" your project)))
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/2023/input/02.txt	Sat Dec 02 17:21:17 2023 +0100
@@ -0,0 +1,100 @@
+Game 1: 4 red, 1 green, 15 blue; 6 green, 2 red, 10 blue; 7 blue, 6 green, 4 red; 12 blue, 10 green, 3 red
+Game 2: 3 green, 18 blue; 14 green, 4 red, 2 blue; 3 red, 14 green, 15 blue
+Game 3: 12 green, 2 blue; 9 green; 1 red, 11 blue, 4 green
+Game 4: 4 blue, 8 green, 5 red; 6 red, 7 blue, 9 green; 2 green, 2 red, 2 blue; 2 green, 6 blue, 9 red; 10 red, 9 green
+Game 5: 12 red, 1 green, 7 blue; 13 red, 16 blue; 16 blue, 10 red; 4 blue; 16 blue, 7 red; 1 blue, 7 red
+Game 6: 17 blue, 2 red; 5 blue, 6 green, 2 red; 5 green, 5 blue; 5 green, 12 blue, 4 red
+Game 7: 2 red, 1 blue, 10 green; 8 red, 14 green, 9 blue; 15 red, 1 blue, 6 green; 9 blue, 3 green, 10 red; 7 blue, 13 red, 4 green
+Game 8: 1 green, 2 blue; 7 red, 2 blue, 1 green; 1 red, 2 green; 4 red, 1 blue; 11 red, 2 green, 2 blue; 1 blue, 2 green, 11 red
+Game 9: 11 green, 11 blue, 6 red; 2 green, 3 blue, 2 red; 2 red, 11 blue, 14 green; 5 green, 7 red, 7 blue; 7 green, 1 red, 12 blue; 1 red, 8 green, 7 blue
+Game 10: 2 red, 8 green, 7 blue; 10 red, 5 green, 2 blue; 4 red, 8 green, 16 blue; 10 blue, 3 green, 15 red
+Game 11: 2 blue, 2 green, 5 red; 1 green, 3 red, 3 blue; 11 green, 1 red, 2 blue
+Game 12: 8 blue, 11 green, 14 red; 10 green, 13 red, 2 blue; 1 red, 6 green, 4 blue; 13 red, 11 green, 6 blue
+Game 13: 15 red, 17 green, 1 blue; 12 red, 1 blue, 1 green; 2 red, 1 blue, 14 green
+Game 14: 6 green, 11 red, 3 blue; 6 green, 2 blue; 2 green, 10 red, 8 blue; 2 red; 1 green, 9 red; 3 blue, 1 green, 3 red
+Game 15: 11 blue, 11 green, 4 red; 3 green, 10 blue; 2 red, 9 green, 9 blue
+Game 16: 2 blue, 11 green; 1 red, 1 blue, 11 green; 12 green, 1 blue, 1 red; 3 blue, 14 green, 1 red; 14 green, 4 blue; 2 blue, 12 green
+Game 17: 1 red, 2 blue, 4 green; 4 blue, 3 green; 1 green, 1 red, 6 blue; 1 red, 7 blue; 2 green
+Game 18: 3 red, 3 blue, 7 green; 2 blue, 2 red, 2 green; 4 red, 12 green; 5 green, 2 blue, 4 red; 3 red
+Game 19: 15 red, 7 blue, 10 green; 5 green, 8 red; 9 green, 8 red; 5 red, 10 green
+Game 20: 15 blue, 6 green, 11 red; 13 red, 9 blue, 1 green; 15 blue, 10 red, 11 green
+Game 21: 15 red, 4 green; 11 red, 2 blue, 4 green; 5 blue, 2 green, 4 red; 4 red, 5 blue; 6 red, 3 blue, 1 green
+Game 22: 4 green, 4 red, 13 blue; 3 red, 7 blue, 9 green; 12 blue, 13 green, 5 red
+Game 23: 20 green, 4 red; 6 blue, 9 red, 7 green; 6 green
+Game 24: 1 green, 3 blue, 6 red; 1 green, 1 blue, 2 red; 3 blue, 5 red, 1 green
+Game 25: 2 red, 9 blue, 2 green; 2 green, 1 red, 5 blue; 3 red, 1 green, 3 blue; 8 blue, 2 green, 3 red; 12 blue, 3 red; 1 blue, 2 green, 1 red
+Game 26: 2 blue, 5 green, 20 red; 2 blue, 6 red, 9 green; 3 red, 2 blue, 5 green
+Game 27: 17 blue, 2 red, 14 green; 15 green, 16 blue, 2 red; 13 blue, 13 green; 1 red, 7 green, 3 blue; 1 blue, 2 green
+Game 28: 5 blue, 6 red, 3 green; 7 red, 19 green; 11 blue, 13 green
+Game 29: 1 blue, 8 red, 7 green; 1 green, 1 red; 8 red, 7 green, 1 blue; 7 green, 2 red; 1 blue, 7 red; 1 blue, 2 red, 5 green
+Game 30: 3 red, 17 blue; 11 red, 3 blue, 8 green; 7 green, 12 blue, 10 red; 5 blue, 2 green
+Game 31: 14 blue, 7 green; 12 green, 14 blue, 2 red; 17 blue, 2 red, 8 green; 2 red, 3 blue, 11 green; 9 green, 4 blue; 1 red, 3 green, 1 blue
+Game 32: 15 red, 1 blue, 10 green; 15 green, 10 red, 1 blue; 2 red, 6 green, 1 blue
+Game 33: 10 green, 1 red, 16 blue; 11 blue, 14 green, 3 red; 14 green, 13 blue; 17 blue, 2 red, 3 green
+Game 34: 8 red, 7 blue, 8 green; 3 green, 1 red; 1 red, 1 green, 5 blue; 6 red, 8 green, 2 blue; 7 red, 8 blue, 3 green
+Game 35: 5 blue, 19 red; 2 blue, 11 red, 1 green; 16 red, 10 blue; 7 green, 3 blue, 6 red; 3 green, 18 red, 5 blue; 8 blue, 5 red
+Game 36: 9 red, 6 green, 10 blue; 9 red, 15 green, 6 blue; 6 red, 1 blue, 14 green
+Game 37: 7 green, 8 red, 2 blue; 3 blue, 5 red, 16 green; 1 green, 1 red, 3 blue
+Game 38: 5 green, 5 red, 3 blue; 10 blue, 19 red, 9 green; 2 red, 3 blue, 11 green
+Game 39: 15 red, 11 blue, 5 green; 11 green, 2 red, 6 blue; 2 blue, 3 green, 6 red; 15 red, 3 blue, 13 green
+Game 40: 7 green, 4 red, 1 blue; 6 blue, 6 green, 2 red; 2 blue, 3 red, 1 green; 1 blue, 3 red, 3 green; 2 red, 5 green, 3 blue
+Game 41: 10 blue, 8 green, 9 red; 7 blue, 9 red, 2 green; 10 blue, 4 red, 5 green
+Game 42: 8 blue, 13 green, 14 red; 8 blue, 1 green, 11 red; 4 red, 6 green, 3 blue; 14 green, 4 red, 2 blue
+Game 43: 2 red, 10 green, 19 blue; 5 blue, 4 green, 9 red; 9 green, 9 red, 2 blue
+Game 44: 6 red, 2 green, 3 blue; 2 blue, 12 red, 6 green; 1 red, 10 blue; 12 red, 6 green, 2 blue; 14 red, 13 green, 3 blue; 10 green, 9 blue, 11 red
+Game 45: 2 blue, 1 red, 1 green; 1 green, 1 blue; 2 green, 2 blue
+Game 46: 7 green, 1 red; 1 green, 4 blue, 1 red; 3 blue, 4 green, 1 red; 1 red, 4 green; 1 blue, 12 green, 1 red; 16 green, 1 blue
+Game 47: 4 blue, 8 green, 3 red; 6 red, 1 green, 3 blue; 16 green, 4 blue, 1 red; 4 blue, 8 red
+Game 48: 1 blue, 9 red, 8 green; 8 green, 2 blue, 6 red; 2 green; 4 blue, 5 red; 1 blue, 9 red, 9 green; 1 red, 1 blue, 3 green
+Game 49: 3 green, 2 blue; 7 blue, 4 red; 20 green, 5 red, 13 blue; 20 green, 1 red, 6 blue
+Game 50: 3 red, 3 green; 3 green, 3 red; 2 blue, 10 red; 3 blue, 5 green; 14 red, 2 green, 2 blue; 7 red, 2 green
+Game 51: 3 green, 3 blue, 2 red; 4 green, 16 red, 3 blue; 1 blue, 3 red; 9 red, 1 blue, 4 green
+Game 52: 6 red, 18 green, 7 blue; 2 blue, 1 red, 5 green; 8 blue, 6 red, 1 green; 1 red, 1 blue; 6 red, 3 green, 10 blue
+Game 53: 1 blue, 10 red, 3 green; 13 red, 2 green, 1 blue; 1 green, 2 red
+Game 54: 4 blue, 6 green, 2 red; 5 blue, 6 red, 2 green; 6 blue, 4 green, 8 red; 13 red, 10 blue, 1 green; 5 red, 5 green, 9 blue
+Game 55: 4 green, 18 red, 4 blue; 9 blue, 7 green, 16 red; 5 red, 6 blue, 14 green; 13 green, 11 red, 9 blue; 6 blue, 13 green, 1 red; 10 blue, 12 red, 14 green
+Game 56: 8 green, 5 blue, 10 red; 10 green, 7 red, 12 blue; 11 red, 12 blue, 1 green; 4 blue, 6 red, 10 green; 17 blue, 8 green, 2 red
+Game 57: 1 green, 2 red; 2 green, 5 red, 1 blue; 13 red, 3 green, 4 blue; 3 blue, 13 red, 9 green
+Game 58: 1 red, 7 blue, 4 green; 2 green, 1 blue, 1 red; 1 green, 11 blue; 12 blue; 1 blue, 5 green, 1 red; 3 green, 11 blue, 1 red
+Game 59: 5 green, 3 blue, 17 red; 2 red, 9 green; 1 blue, 4 green
+Game 60: 5 red, 5 green, 1 blue; 2 red, 2 blue, 6 green; 2 red, 3 blue, 3 green
+Game 61: 2 green, 3 blue, 4 red; 17 green, 1 blue; 1 green, 6 red, 4 blue; 3 blue, 9 green, 3 red; 18 green, 7 red, 2 blue
+Game 62: 5 red; 3 blue, 9 green; 3 red, 13 blue, 10 green; 14 green, 1 red, 2 blue; 7 blue, 13 green
+Game 63: 12 blue, 5 green; 5 green, 1 red, 1 blue; 4 red, 7 green, 9 blue; 8 blue, 2 green, 7 red
+Game 64: 3 blue, 11 green; 5 blue, 2 red, 5 green; 17 green, 5 blue, 1 red; 4 red, 3 blue, 4 green
+Game 65: 2 red, 1 blue, 2 green; 7 green, 2 red, 1 blue; 2 blue, 7 green, 1 red; 3 blue, 8 green, 3 red
+Game 66: 4 red, 12 blue, 1 green; 20 blue, 3 green, 2 red; 11 blue, 1 green
+Game 67: 12 blue, 10 red, 13 green; 19 green, 4 red, 7 blue; 12 red, 9 blue, 13 green
+Game 68: 2 blue, 17 green; 12 green, 2 red; 5 red, 2 green, 4 blue; 4 blue
+Game 69: 17 blue, 3 red, 1 green; 4 green, 8 blue, 8 red; 4 green, 7 red, 1 blue; 8 red, 1 green, 11 blue; 13 blue, 10 red, 9 green; 14 blue, 5 green, 6 red
+Game 70: 1 red, 2 blue, 4 green; 13 blue, 3 red, 2 green; 6 green, 8 blue
+Game 71: 5 red, 7 green, 1 blue; 11 green, 4 red, 1 blue; 1 red, 12 green, 10 blue; 1 red, 7 blue, 12 green
+Game 72: 9 blue, 4 green, 1 red; 6 green, 4 blue; 8 green, 5 blue, 1 red
+Game 73: 1 blue, 10 green, 14 red; 4 green; 2 blue, 9 red, 4 green; 2 blue, 13 green; 13 green, 13 red; 7 red, 5 green, 2 blue
+Game 74: 3 red, 1 blue, 3 green; 4 green, 1 blue, 1 red; 2 blue, 10 green, 1 red; 1 blue, 3 red, 1 green
+Game 75: 1 red, 1 blue, 1 green; 2 red, 1 green, 4 blue; 2 red, 4 blue; 1 blue, 1 red
+Game 76: 4 green, 2 blue, 6 red; 7 green, 1 red; 8 green, 4 red
+Game 77: 8 green, 7 blue, 5 red; 6 red, 14 green, 7 blue; 8 green, 7 blue; 1 red, 8 green, 8 blue
+Game 78: 6 red, 3 blue, 3 green; 7 blue, 10 red; 5 green, 10 blue, 1 red; 3 green, 11 blue, 4 red; 14 red, 9 blue, 2 green; 16 red, 2 green, 12 blue
+Game 79: 1 green; 5 green; 11 green, 3 blue, 2 red; 3 blue
+Game 80: 2 green, 2 red; 1 blue, 1 green, 1 red; 1 blue, 1 green, 2 red; 2 red; 5 green
+Game 81: 10 blue, 2 red, 9 green; 4 red, 12 blue, 5 green; 7 green, 4 blue, 6 red; 1 red, 13 green, 14 blue; 13 green, 11 blue
+Game 82: 4 blue, 2 green; 7 blue, 3 green, 5 red; 1 red, 4 blue, 3 green; 5 blue, 1 red, 6 green; 6 green, 4 red; 11 blue, 3 red, 5 green
+Game 83: 12 green; 5 red, 8 green; 11 red, 14 green, 1 blue; 9 green, 4 red
+Game 84: 5 blue, 1 red; 16 blue, 5 green; 1 red, 9 blue, 3 green; 11 blue; 1 green, 2 blue; 1 red, 7 blue, 4 green
+Game 85: 17 red, 5 blue; 18 blue, 2 red, 2 green; 18 blue, 2 green, 8 red
+Game 86: 4 red, 1 blue, 11 green; 6 blue, 7 green, 1 red; 3 green, 4 blue; 2 red, 7 blue, 2 green
+Game 87: 4 red, 5 blue; 1 green, 15 red, 1 blue; 11 blue, 12 red
+Game 88: 11 green, 3 red, 1 blue; 6 green, 1 blue, 1 red; 1 blue, 3 green; 2 blue, 4 green, 2 red
+Game 89: 2 green; 1 red, 2 green, 3 blue; 4 blue, 1 red, 10 green; 4 blue, 5 green; 6 blue, 1 red, 10 green
+Game 90: 15 red, 7 green, 17 blue; 7 blue, 1 red; 7 green, 6 red, 3 blue
+Game 91: 2 blue, 17 red, 6 green; 1 green, 1 blue, 6 red; 6 red, 4 blue; 10 green, 14 red, 1 blue; 7 blue, 10 green, 10 red; 16 red, 11 green, 9 blue
+Game 92: 1 green, 8 blue, 4 red; 4 green, 4 red, 4 blue; 1 green, 7 red, 4 blue
+Game 93: 11 blue, 12 red, 1 green; 9 blue, 2 green, 5 red; 7 red, 5 blue, 2 green
+Game 94: 7 blue, 10 green; 9 green, 9 blue, 2 red; 1 red, 5 green, 4 blue
+Game 95: 1 green, 1 blue, 2 red; 6 red; 1 blue; 1 green, 1 blue, 6 red
+Game 96: 1 blue, 1 red, 2 green; 4 red, 13 green, 1 blue; 1 blue, 13 green, 5 red; 7 green, 4 red
+Game 97: 10 blue, 5 red, 5 green; 4 red, 8 green, 2 blue; 5 red, 2 green, 15 blue; 2 red, 1 green, 4 blue; 2 red, 14 blue; 14 blue, 4 green
+Game 98: 11 red, 8 green, 9 blue; 3 blue, 1 green, 14 red; 10 blue, 2 red, 4 green; 7 blue, 11 red, 3 green; 5 red, 12 blue, 4 green; 7 green, 7 blue, 8 red
+Game 99: 3 green, 2 blue, 1 red; 15 red, 8 blue, 7 green; 18 red, 12 blue, 2 green
+Game 100: 11 red, 1 blue, 2 green; 3 red, 3 green; 1 blue, 8 red, 4 green; 5 green, 5 blue, 1 red; 2 green, 1 red, 6 blue; 2 green, 8 red, 1 blue