Adds ocaml-top

OCaml-Top is a simple cross-platform OCaml code editor built for
top-level evaluation.

Homepage: http://www.typerex.org/ocaml-top.html

pkgs/development/tools/ocaml/ocaml-top/default.nix

@@ -0,0 +1,31 @@
+{ stdenv, fetchzip, ncurses, ocamlPackages, opam }:
+
+stdenv.mkDerivation {
+  name = "ocaml-top-1.1.2";
+  src = fetchzip {
+    url = https://github.com/OCamlPro/ocaml-top/archive/1.1.2.tar.gz;
+    sha256 = "10wfz8d6c1lbh31kayvlb5fj7qmgh5c6xhs3q595dnf9skrf091j";
+  };
+
+  buildInputs = [ ncurses opam ]
+    ++ (with ocamlPackages; [ ocaml ocpBuild findlib lablgtk ocp-index ]);
+
+  configurePhase = ''
+    export TERM=xterm
+    ocp-build -init
+  '';
+
+  buildPhase = "ocp-build ocaml-top";
+
+  installPhase = ''
+    opam-installer --script --prefix=$out ocaml-top.install | sh
+  '';
+
+  meta = {
+    homepage = http://www.typerex.org/ocaml-top.html;
+    license = stdenv.lib.licenses.gpl3;
+    description = "A simple cross-platform OCaml code editor built for top-level evaluation";
+    platforms = ocamlPackages.ocaml.meta.platforms;
+    maintainer = with stdenv.lib.maintainers; [ vbgl ];
+  };
+}

pkgs/top-level/all-packages.nix

@@ -4077,6 +4077,8 @@ let
 
   ocaml_make = callPackage ../development/ocaml-modules/ocamlmake { };
 
+  ocaml-top = callPackage ../development/tools/ocaml/ocaml-top { };
+
   opa = callPackage ../development/compilers/opa {
     ocamlPackages = ocamlPackages_4_00_1;
   };