A library of bidirectional binary format combinators.

This is mainly based on “Composing Bidirectional Programs Monadically”, which demonstrates an approach for defining data-dependent (i.e. monadic) codecs.

Simple image format:

open Bidi_combinators

type t = {
  width : int;
  height : int;
  data : int32 array;
}

let width x = x.width
let height x = x.height
let data x = x.data

let format : t Format.value =
  let open Format.Syntax in

  let* width = width @= Format.int16_be
  and+ height = height @= Format.int16_be in
  let+ data = data @= Format.Array.repeat_len Format.int32_be (width * height) in

  { width; height; data }

More examples can be found in the examples directory.

• “Composing Bidirectional Programs Monadically” [doi:10.1007/978-3-030-17184-1_6]
• Towards monadic bidirectional serialization
• codec: Easy bidirectional serialization in Haskell [hackage:codec] [github:chpatrick/codec]
• tomland: Bidirectional TOML serialization [hackage:tomland] [github:kowainik/tomland]
• autodocodec: Self-documenting encoder and decoder [hackage:autodocodec] [github:NorfairKing/autodocodec]