init - INI config file manipulation for OCaml#

Init provides bidirectional codecs for INI files following Python's configparser semantics. Define your configuration types once, and Init handles both parsing and serialization.

Features#

• Python-compatible: Follows configparser semantics for maximum compatibility
• Bidirectional codecs: Define once, use for both decoding and encoding
• Type-safe: Strongly-typed configuration with compile-time guarantees
• Multiline values: Support for continuation lines via indentation
• Interpolation: Basic %(name)s and extended ${section:name} variable substitution
• DEFAULT section: Automatic inheritance of default values
• Optional values: Graceful handling of missing configuration options

Installation#

opam install init

For parsing/encoding support, also install the bytesrw sub-library:

opam install init bytesrw

For Eio file system integration:

opam install init bytesrw eio bytesrw-eio

Quick Start#

(* Define your configuration type *)
type server_config = {
  host : string;
  port : int;
  debug : bool;
}

(* Define the codec *)
let server_codec = Init.Section.(
  obj (fun host port debug -> { host; port; debug })
  |> mem "host" Init.string ~enc:(fun c -> c.host)
  |> mem "port" Init.int ~enc:(fun c -> c.port)
  |> mem "debug" Init.bool ~dec_absent:false ~enc:(fun c -> c.debug)
  |> finish
)

let config_codec = Init.Document.(
  obj (fun server -> server)
  |> section "server" server_codec ~enc:Fun.id
  |> finish
)

(* Parse an INI file *)
let () =
  let ini = {|
[server]
host = localhost
port = 8080
debug = yes
|} in
  match Init_bytesrw.decode_string config_codec ini with
  | Ok config ->
      Printf.printf "Server: %s:%d (debug=%b)\n"
        config.host config.port config.debug
  | Error msg ->
      Printf.printf "Error: %s\n" msg

Sub-libraries#

• init: Core codec combinators (no dependencies)
• init.bytesrw: Parsing and encoding using bytesrw
• init.eio: Eio file system integration

Documentation#

See the API documentation for complete reference.

License#

ISC License. See LICENSE for details.