The idea is to use the gobject-introspection library in order to generate a configurable loader that will be able to construct automatically most of the Ctypes bindings of any C GObject libraries (not all but at least a big part).
Dune allows to easily use a custom code generator. Let's take the example of the gi-glib2 package : OCaml-GLib2 ctypes bindings.
Here is the directory tree of the repository:
λ › tree OCaml-c/OCaml-GLib2 dllist_string
.
├── config
│ ├── discover.ml
│ └── jbuild
├── COPYING
├── generator
│ ├── gen.ml
│ └── jbuild
├── gi-glib2.opam
├── gpl-3.0.txt
├── lib
│ ├── Core.ml
│ ├── Dllist.ml
│ ├── dyn_load_constants_stubs.c
│ └── jbuild
├── README.md
├── tests
│ ├── jbuild
│ ├── ...
├── tools
│ ├── jbuild
│ └── list_targets.ml
└── travis
├── ...
All the code of the bindings will be in the lib/ directory. The jbuild file of this directory define the rules to construct the lib. In it there is this part:
(rule
((targets (
Ascii_type.ml Ascii_type.mli
Bookmark_file_error.ml Bookmark_file_error.mli
; ...
; the names of the files that will be generated
; ...
Date_time.ml Date_time.mli
Time_val.ml Time_val.mli
Time_type.ml Time_type.mli
Time_zone.ml Time_zone.mli
))
(deps (../generator/gen.exe)) ; the name, path of the generator.
(action (run ${<} -o ${@})))) ; the command to run it.The code of the bindings generator is in the generator/ directory. And here is the code:
module BG = GI_bindings_generator
module Loader = BG.Loader
(** The namespace to be loaded: ie. the lib for which the bindings will be
* generated. *)
let namespace = "GLib"
(** A suffix for the filenames of the raw bindings of the Core part. For example,
* all the constants and functions defined directly in the namespace are defined
* in a "Core" module and generated in "Core.ml" and "Core.mli" files. But, in
* in order to be able to tweak those automatically generated bindings, a
* suffix is added. Here, all the constants and functions of the namespaces
* will be found in the module Core_raw. Then in the lib/Core.ml file, I just
* load/open the Core_raw. *)
let files_suffix = "Raw"
(** Instead of generate all the data structures (and theirs related methods or
* constants), the idea is to choose what is needed. *)
let data_structures =
["Error"; "Rand"; "Date"; "DateTime"; "TimeVal"; "TimeZone";]
(** One can choose to skip the bindings of some constants because they are not
* needed or because you want to create manually the bindings in the "Core.ml"
* file. *)
let const_to_skip = ["MAJOR_VERSION"; "MINOR_VERSION"; "MICRO_VERSION"]
(** Like for the data_structures, you have to choose with function should have
* its bindings generated. *)
let functions = ["random_double"; "random_double_range";
"random_int"; "random_int_range";
"get_current_time";
"filename_to_uri"; "get_charset";
"dir_make_tmp"]
let sources = Loader.generate_files ("Core" ^ files_suffix)
let () =
let _ = Loader.write_constant_bindings_for namespace sources const_to_skip in
let _ = Loader.write_function_bindings_for namespace sources functions in
let _ = Loader.write_enum_and_flag_bindings_for namespace in
let _ = Loader.write_bindings_for namespace data_structures in
BG.Binding_utils.Sources.close sourcesAfter that when you build your lib, all the files are generated and added in the _build/default/lib directory before the compilation and test part.
git clone git@github.com:cedlemo/OCaml-GObject-Introspection
opam pin add gobject-introspection OCaml-GObject-Introspection
git clone git@github.com:cedlemo/OCaml-GI-ctypes-bindings-generator
https://cedlemo.github.io/OCaml-GI-ctypes-bindings-generator/
https://github.com/cedlemo/OCaml-GI-ctypes-bindings-generator/wiki#introduction