Using OCaml compilers for this course

The programming assignments in P505 will use the Caml dialect of ML. (Objective Caml, or OCaml for short, is the implementation of Caml.) You may use any remotely recent version of OCaml (nothing we do should depend on a particular version). Do not use F# (a Microsoft dialect of Caml), just because it is too difficult for the course staff to provide and grade code in two dialects/platforms. The differences between Caml and F# are minimal from P505's perspective, so we just picked one.

We recommend a research prototype called SEMINAL developed by Ben Lerner here at UW. SEMINAL differs from OCaml only in how it presents error messages from the type-checker. We believe it is better than the conventional approach, encourage you to use it, and would appreciate any feedback or suggestions.

Installation

Installing SEMINAL

SEMINAL is available on the department's instructional Linux server attu in /cse/courses/csep505/09wi/bin/. To use it by default, add /cse/courses/csep505/09wi/bin/ to the head of your $PATH, or alias ocamlc to /cse/courses/csep505/09wi/bin/ocamlc. If you have questions about using SEMINAL or want to install SEMINAL on your own machine, you can contact its developer Ben Lerner (blerner@cs). The course staff can also help with basic questions.

See below for usage instructions for SEMINAL; in particular if you do not use the -seminal command-line flag, you will not see any difference over the standard OCaml error messages.

SEMINAL does not have a special version of the read/eval/print loop (i.e., ocaml instead of ocamlc). There is a /cse/courses/csep505/09wi/bin/ocaml, but you cannot give it the -seminal option and you will not get SEMINAL-style error messages from it. However, there is no problem using both ocaml and the SEMINAL ocamlc.

Installing Standard OCaml at UW

If you do not wish to use SEMINAL, you are free to use the standard OCaml compiler.

• On the department Linux machines: OCaml is installed in /usr/bin/ocaml.
• On Linux: If you run Debian just run 'apt-get install ocaml'. Otherwise, the Caml website (http://caml.inria.fr/ocaml/release.en.html) has both source and binary downloads for Linux.
• On Windows with Cygwin: The easiest thing to do is to get the package named ocaml directly from cygwin.com. It is in categories Devel and Interpreters. See cygwin.com for how to use Cygwin's setup program.
• On Windows otherwise: Caml can be downloaded from the Caml website (http://caml.inria.fr/ocaml/release.en.html). The easiest way to install is to download the Windows binary and run the installer. It requires some Microsoft development tools or Cygwin (http://www.cygwin.com).
• On Macs: The Caml website (http://caml.inria.fr/ocaml/release.en.html) has both source and binary downloads for OSX.

Running OCaml:

• ocamlc: The Caml byte code compiler (see esp. the -i and -c options)
• ocamlopt: The Caml native code compiler
• ocaml: The read/eval/print loop for Caml

In general, you can use ocaml to experiment on the fly, and ocamlc to compile an entire file at once. To exit ocaml's read-eval-print loop, either use Ctrl+D (only works on Linux boxes), or "exit 0;;" (which works anywhere).

For further information, see part III of the system manual: http://caml.inria.fr/pub/docs/manual-ocaml/index.html

Running SEMINAL:

• ocamlc foo.ml will give you exactly the same output as the unmodified ocamlc compiler.
  
• ocamlc -seminal foo.ml will present a change that will make your program type-check or will present a change that will make one part of your program type-check while indicating that other errors remain. Performing this "triage" (finding the other errors that are ignored for the moment) can be slow, so there is an option...
  
• ocamlc -seminal -no-triage foo.ml will present a change that will make your entire program type-check. This will be quick, but the suggestion can be less precise (such as suggesting you remove a large portion of your program).