Add ocp-indent as a formatter (#306)

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.

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Co-authored-by: Radon Rosborough <radon@intuitiveexplanations.com>

3 files changed, 75 insertions, 0 deletions

diff --git a/test/formatters/installers/ocp-indent.bash b/test/formatters/installers/ocp-indent.bash
new file mode 100644
index 0000000..0e449f2
--- /dev/null
+++ b/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/
diff --git a/test/formatters/samplecode/ocp-indent/in.ml b/test/formatters/samplecode/ocp-indent/in.ml
new file mode 100644
index 0000000..d647068
--- /dev/null
+++ b/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) ]
diff --git a/test/formatters/samplecode/ocp-indent/out.ml b/test/formatters/samplecode/ocp-indent/out.ml
new file mode 100644
index 0000000..dddb26b
--- /dev/null
+++ b/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) ]