ocaml skeleton

ocaml_skeleton is a scaffolding framework to get up and running build OCaml applications quickly. It provides a filesystem structure, Makefile, and example unit tests.

OCaml is relatively difficult to navigate as a new user. While the language has ample online documentation, the development environment itself can be remarkably opaque. The problem is compounded by numerous sites providing half-working snippets of code that range from fresh to very, very old. The only way to discover 'the modern way of doing things' is through mailing lists or IRC. Since I hate interacting with humans and know others do as well, I thought it would be nice to provide a jumpstart environment for someone to get code up-and-running. An example application with unit tests seems to be a nice sandbox for language discovery.

Caveat Emptor: The system I've provided here works for me but I am still inexperienced with the language -- especially with respect to the module system and how ocamlbuild discovers dependencies. If you are more familiar with OCaml and have input on how larger, more established build systems operate than I would be grateful for any feedback.

instructions

os dependencies

For debian/ubuntu, running the following should work:

> sudo apt-get install aptitude` # if you don't have it already

> sudo aptitude install ocaml-base-nox ocaml-nox ocaml-batteries-included
ocaml-findlib ocaml-interp libounit-ocaml-dev

If you manage to get set up on other OSes (other Linuxen, OSX, BSD) please send me your strings!

usage

The Makefile contains 5 targets: main-native, main, tests-native, tests, and clean. -native are natively compiled (but not necessarily optimized) versions of the binaries while the others are byte-code versions. Binaries are copied into bin/ after being built with ocamlbuild.

In short:

  > make
  > bin/main.native

  > make tests

The source for the application is in src/main.ml and any subdirectories. If you add subdirectories, make sure you add an 'include' tag in the _tags file in the top directory (see the tag for src/calc). Tags are one per line and multiple lines are allowed for a target. More documentation on _tags can be found at the ocamlbuild user manual

The myocamlbuild.ml plugin contains code to look up and link OCaml packages registered with ocamlfind. Let's say you want to use the PCRE package installed with sudo aptitude install libpcre-ocaml-dev. You add open Pcre;; in src/calc/calc.ml, then add the following line to _tags:

"src/calc/calc.ml": pkg_pcre

To find what you need to put after pkg_, run ocamlfind list, i.e. pkg_unix or pkg_num.

Note: there is a bug related to this, look in the bugs section if you want to add a package to main.ml or tests.ml.

Tests are written in tests/tests.ml. Make sure the OUnit package is opened, open up your module, and write some tests using the OUnit framework. For a reference, here is a list of available testing methods. Note that you must add your tests to the suite for them to run. I tried adding in the code found at Skydeck but I couldn't make it work nicely with separate testing modules. However, having the tests hand-added gives you the full flexibility of OUnit.

todo

see the GitHub issues page, but:

• instructions for OSX/BSD/other distros
• make tests nicer (separate test files?)
• add optimized builds
• make ocamlbuild integration less hacky
• automatically make a library

bugs

see the GitHub issues page, but:

• _tags file, specifically the pkg_ integration, doesn't apply to 'top level targets,' these being main.ml and tests.ml. If you want to add packages to these, you can currently give them to ocamlbuild directly on the commandline via -tag, see the Makefile for how pkg_oUnit is passes to tests.byte.

resources

• OCaml style guide: http://www.cs.caltech.edu/~cs20/a/style.html
• Sample OCaml code (cross-referenced with other languages): http://pleac.sourceforge.net/pleac_ocaml/
• The default vim plugin for .ml files has an annoying textwidth setting. Try this to turn that off: echo "set tw=0" >> ~/.vim/after/indent/ocaml.vim

thanks

The OCaml community has a lot of high quality software written by high quality people. It's my hope that providing this starter kit will lure in many more.

If you'd like to contribute, branch off next and send a pull req.