fpath-base

This repository defines 2 OCaml packages named fpath-sexplib0 and fpath-base, which extend the fpath package for projects using sexplib0 and/or base.

fpath-sexplib0

This package only depends on fpath and sexplib0. It defines a single module, Fpath_sexplib0, which is designed to be opened to shadow the Fpath module. This introduces three new modules to the scope: Fpart, Absolute_path and Relative_path.

Fpath is shadowed and retains all its original functionality, with the addition of a sexp serializer:

type t = Fpath.t

include module type of struct include Fpath end

val sexp_of_t : t -> Sexp.t

Additionally, it includes new helpers for casting between the types offered by the package, such as:

val classify
  :  Fpath.t
  -> [ `Absolute of Absolute_path.t | `Relative of Relative_path.t ]

Fpart is a helper module for representing and manipulating the elements that constitute the '/' separated segments of a path.

Absolute_path and Relative_path are helper modules that distinguish between classes of paths in the type system, enhancing type safety for applications manipulating paths. Both types are defined as private Fpath.t, making it easy to cast and convert paths.

fpath-base

This package further extends fpath-sexplib0 and adds a dependency on base. It is designed to be compatible with Base-style containers such as Map, Set, Hashtbl, Hash_set.

This package defines a single module, Fpath_base, which is designed to be opened to shadow and further extend the four modules from fpath-sexplib0: Fpath, Fpart, Absolute_path and Relative_path. It exports hashable and comparable interfaces.

module Fpath : sig
  type t = Fpath.t

  include module type of Fpath_sexp0.Fpath with type t := t
  include Comparable.S with type t := t

  val hash : t -> int
  val hash_fold_t : Hash.state -> t -> Hash.state
end

This allows for example:

open! Base
open! Fpath_base

let create_fpath_table () = Hashtbl.create (module Fpath)

and in the mli respectively:

open! Base

val create_fpath_hashtbl : unit -> _ Hashtbl.M(Fpath).t

Usage

• Fpath_sexplib0 only adds the sexplib0 dependency to fpath, making it suitable for various applications.
• Fpath_base is useful for applications that already depend on Base.

The intended usage for these packages is to open the single module they define and then continue using Fpath as usual.

You may do this either by opening the package in your ml/mli files or via dune flags, such as:

 (flags -open Fpath_sexplib0)

Motivations

We liked the Fpath module and wanted to make it seamlessly compatible with projects using sexp and base.

Code documentation

The code documentation of the latest release is built with odoc and published to GitHub pages here.

Acknowledgements

We would like to thank to Daniel Bünzli and the fpath programmers for the original fpath package, which this project extends. The implementation of Absolute_path and Relative_path is based on functionality from the Fpath module. We greatly appreciate Daniel's contribution to the open source community and the foundational work they provided, which has been instrumental in the development of this project. Fpath's copyright and permission notice are included at the root of this project, in the file LICENSE.fpath.

We would also like to acknowledge the Path module from Jane Street's Iron code review system, which we took some inspiration from during the development of the module Path in this project. Specifically, we were inspired by their idea of distinguishing between absolute and relative paths at the type level. While we did not reuse any of the implementation from the original Path module, the general concepts and some function names are similar due to the nature of the file path operations we are performing (such as extend and concat for extending and concatenating paths, etc.). We appreciate the work done by the Jane Street team and their contribution to the open source community. Their project is licensed under the Apache License version 2.0, which can be found here.