                         Partially implemented features

   The compiler contains some code for the following features, which are
   not yet completed but work on which has stopped (often when the person
   doing that work has graduated) since finishing them off would be quite
   a bit more work, and our current priorities lie elsewhere. Still, these
   could make interesting and worthwhile projects if someone has the time
   for it.

     * We have incomplete support for a new, more expressive design for
       representing information about type classes and type class
       instances at runtime. When complete, the new design would allow
       runtime tests of type class membership, it would allow the tabling
       of predicates with type class constraints, and it would allow the
       debugger to print type_class_infos.
     * We have added support for dynamic link libraries (DLLs) on Windows.
       This is not yet enabled by default because it has not yet been
       tested properly.
     * There is an accurate garbage collector (the hlc.agc grade). See the
       comments in compiler/ml_elim_nested.m and the paper on our web page
       for more details.
     * There is a `--generate-bytecode' option, for a back-end that
       generates bytecode. The bytecode generator is basically complete,
       but we don't have a bytecode interpreter.
     * A new implementation of the mode system using constraints.
     * Support for automatic structure reuse (reusing old data structures
       that are no longer live, rather than allocating new memory on the
       heap) and compile time garbage collection.
     * A SOAP interface.
