Add ocp-indent as a formatter

ocp-indent allows indenting even partially compiling OCaml code, while
ocamlformat requires the code to compile correctly. Also, Doom Emacs
uses ocp-indent when ocamlformat's configuration file is not found, and
not having an ocp-indent formatter gives an error.

CHANGELOG.md

@@ -28,6 +28,10 @@ The format is based on [Keep a Changelog].
  called if provided. See [#204].
 
 ### Formatters
+* [`ocp-indent`](https://github.com/OCamlPro/ocp-indent) for
+ [Ocaml](https://ocaml.org/) ([#306]).
+* [`ocp-indent`](http://www.typerex.org/ocp-indent.html) for [Python](https://python.org) imports using ruff ([#279]).
+
 ### Bugs fixed
 * The point alignment algorithm, which has been slightly wrong since
  2019, has been fixed to more correctly use dynamic programming to

apheleia-formatters.el

@@ -95,6 +95,7 @@
  (nixfmt . ("nixfmt"))
  (ocamlformat . ("ocamlformat" "-" "--name" filepath
  "--enable-outside-detected-project"))
+ (ocp-indent . ("ocp-indent"))
  (ormolu . ("ormolu"))
  (perltidy . ("perltidy" "--quiet" "--standard-error-output"
  (apheleia-formatters-indent "-t" "-i")

test/formatters/installers/ocp-indent.bash

@@ -0,0 +1,5 @@
+apt-get install -y opam
+
+opam init -n --disable-sandboxing --root /opt/ocp-indent
+opam install ocp-indent -y --root /opt/ocp-indent
+ln -s /opt/ocp-indent/default/bin/ocp-indent /usr/local/bin/

test/formatters/samplecode/ocp-indent/in.ml

@@ -0,0 +1,35 @@
+(* https://github.com/OCamlPro/ocp-indent/blob/master/tests/failing/list_of_funs.ml *)
+
+let f x =
+ (fun x -> x [ (fun () -> 3) ;
+ (fun () -> 4) ])
+
+let f x = (fun x -> x [ (fun () -> 3) ;
+ (fun () -> 4) ])
+
+let f x =
+ x [ (fun () -> 3) ;
+ (fun () -> 4) ]
+
+let f x =
+ [ (fun () -> 3) ;
+ (fun () -> 4) ]
+
+let f x =
+ (fun x -> x [ (fun () ->
+ 3) ;
+ (fun () -> 4) ])
+
+let f x = (fun x -> x [ (fun () ->
+ 3) ;
+ (fun () -> 4) ])
+
+let f x =
+ x [ (fun () ->
+ 3) ;
+ (fun () -> 4) ]
+
+let f x =
+ [ (fun () ->
+ 3) ;
+ (fun () -> 4) ]

test/formatters/samplecode/ocp-indent/out.ml

@@ -0,0 +1,35 @@
+(* https://github.com/OCamlPro/ocp-indent/blob/master/tests/failing/list_of_funs.ml *)
+
+let f x =
+ (fun x -> x [ (fun () -> 3) ;
+ (fun () -> 4) ])
+
+let f x = (fun x -> x [ (fun () -> 3) ;
+ (fun () -> 4) ])
+
+let f x =
+ x [ (fun () -> 3) ;
+ (fun () -> 4) ]
+
+let f x =
+ [ (fun () -> 3) ;
+ (fun () -> 4) ]
+
+let f x =
+ (fun x -> x [ (fun () ->
+ 3) ;
+ (fun () -> 4) ])
+
+let f x = (fun x -> x [ (fun () ->
+ 3) ;
+ (fun () -> 4) ])
+
+let f x =
+ x [ (fun () ->
+ 3) ;
+ (fun () -> 4) ]
+
+let f x =
+ [ (fun () ->
+ 3) ;
+ (fun () -> 4) ]