Python: add prompt_toolkit 0.26: powerful command lines

pkgs/top-level/python-packages.nix

@@ -7276,6 +7276,32 @@ let
   };
 
 
+  prompt_toolkit = buildPythonPackage rec {
+    name = "prompt_toolkit-${version}";
+    version = "0.26";
+
+    src = pkgs.fetchurl {
+      url = "https://pypi.python.org/packages/source/p/prompt_toolkit/${name}.tar.gz";
+      sha256 = "1rd9gy3bcwp08agw5hiqckhaxbsz1i1kgkhjqw6vwhjdfgdjiq9l";
+    };
+
+    buildInputs = with self; [ jedi ipython pygments ];
+    propagatedBuildInputs = with self; [ docopt six wcwidth ];
+
+    meta = with stdenv.lib; {
+      description = "Python library for building powerful interactive command lines";
+      longDescription = ''
+        prompt_toolkit could be a replacement for readline, but it can be
+        much more than that. It is cross-platform, everything that you build
+        with it should run fine on both Unix and Windows systems. Also ships
+        with a nice interactive Python shell (called ptpython) built on top.
+      '';
+      homepage = https://github.com/jonathanslenders/python-prompt-toolkit;
+      license = with licenses; [ bsd3 ];
+      maintainers = with maintainers; [ nckx ];
+    };
+  };
+
   protobuf = buildPythonPackage rec {
     inherit (pkgs.protobuf) name src;