[MLton] def-use-mode

[Vesa Karvonen]

I just committed (http://mlton.org/pipermail/mlton-commit/2007-January/001077.html)
a preliminary, semi-usable version of the def-use mode I started working on a long
time ago (http://mlton.org/pipermail/mlton/2006-April/028599.html).

To try it:
-1. svn up your MLton source tree.
 0. Compile the latest MLton from SVN.
 1. Generate a def-use file using MLton with the (new) -prefer-abs-paths true
    option.
 2. Load all of the def-use-*.el files and esml-def-use-mlton.el.
 3. M-x def-use-mode
 4. M-x esml-def-use-mlton-parse <path-to-def-use-file>
    (This may take from a few seconds to a minute or more.)
 5. Go to a SML source file covered by the def-use file and place the
    cursor over some variable (def or use).
The plan is to improve the usability (e.g. jump-to-next, automatic and asynchronous
reload of modified def-use file, automatic purging of def-use data when fiels are
modified) of this mode in the near future.

-Vesa Karvonen