utop - a universal toplevel for OCaml

utop is an improved toplevel for OCaml. It can run in a terminal or in Emacs. It supports line edition, history, real-time and context sensitive completion, colors, and more.

It integrates with the tuareg and typerex modes in Emacs.

Dependencies

• OCaml (>= 3.12)
• findlib
• react
• lwt (>= 2.4.0) built with react support
• Camomile (>= 0.8)
• zed (>= 1.2)
• lambda-term (>= 1.2)

For building the development version, you also need to install oasis (>= 0.3.0).

utop also requires OCaml compiler libraries. Since OCaml 4.00 they are already installed, for previous versions:

• if you are using debian, they are available as the package ocaml-compiler-libs,
• if you are using godi, they are installed by default,
• if you installed ocaml by hand, you can run the script utils/install-compiler-libs.sh.

Installation

To build and install Lambda-Term:

$ ./configure
$ make
$ make install

Documentation and manual pages (optional)

To build the documentation:

$ make doc

It will then be installed by make install.

Tests (optionnal)

To build and execute tests:

$ ./configure --enable-tests
$ make test

Usage

To use utop, simply run:

$ utop

utop display a bar after the prompt which is used to show possible completions in real-time. You can navigate in it using Alt+Left and Alt+Right, and select one completion using Alt+Tab.

Customization

To add colors to utop, copy one of the files utoprc-dark or utoprc-light to ~/.utoprc. utoprc-dark is for terminals with dark colors (such as white on black) and utoprc-light is for terminals with light colors (such as black on white).

You can also customize the prompt of utop by setting the reference UTop.prompt.

Integration with emacs

To use utop in emacs, add the following line to your ~/.emacs file:

(autoload 'utop "utop" "Toplevel for OCaml" t)

Then you can run utop by executing the command utop in emacs.

Integration with the tuareg/typerex mode

You can replace the default toplevel used by the tuareg or typerex mode by utop, for that add the following lines to your ~/.emacs file:

(autoload 'utop-setup-ocaml-buffer "utop" "Toplevel for OCaml" t)
(add-hook 'tuareg-mode-hook 'utop-setup-ocaml-buffer)
(add-hook 'typerex-mode-hook 'utop-setup-ocaml-buffer)

You can also complete text in a tuareg or typerex buffer using the environment of the toplevel. For that bind the function utop-edit-complete to the key you want.