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TODO LIST:
----------

followvars.nl
-------------

- Make it work.

code_gen.nl
----------

- some semideterministic code generation (mostly done)

- nondeterministic code generation

- handle string equality, string constants, etc.

- types with constants only (enumerations) should be handled as ints.

typecheck.nl
------------

- improve error messages for unification of var & functor

- see also wish list comments at the start of typecheck.nl

modes.nl
--------

- detect incorrect usage of `bound(...)' insts.

- handle undefined insts/modes gracefully

- handle polymorphic modes

- see also comments at the start of modes.nl

stack_alloc.nl
--------------

- make it work: it needs to assign stack slots for variables
  which need to be saved over a call

general
-------

- tail recursion optimization (vanilla) and also pass-by-reference
  tail recursion.

- (modes.nl, make_hlds.nl, hlds.nl, codegen.nl): 
  split construct/deconstruct unifications into their atomic
  "micro-unification" pieces: functor construct/deconstruct and
  argument get/put.

- warn about predicates with no clauses.

- warn about predicates with no modes.

- handle abstract insts in the same way abstract types are handled (???)

- test & debug the determinism analysis 

- improve efficiency of implicit quantification

- renaming apart of different occurences
  of the same variable; warning about variables which occur in
  overlapping scopes.

- optimization of various sorts

- generate code for complicated_unify's (there are some comments about
  this in the paper.)

- array.nl: write a predicate to resize arrays.

- garbage collection

mercury_to_goedel.nl
--------------------

- see comments at the start of that file

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WISH LIST
---------

codegen.nl
----------

- The generated code should include some profiling hooks.
  In particular, we should add a version of the heap allocation
  macro which takes an extra string parameter identifying which
  routine allocated the memory.  Then we can do heap-allocation
  profiling to identify which routines use up all the bloody memory.

- Generate constant compound terms at compile time rather than at runtime.

- Add a peephole optimization pass

general
-------

- handle module qualifiers properly

- more work on module system, separate compilation, and the multiple
  specialization problem

- implement user-defined operators:
	Add a new construct `:- op(Pred, Type, Op).' as in Prolog;
	change prog_io.nl to parse this construct and call io__op
	accordingly.

- better error handling

- fix all the `XXX's, `xxx's, `YYY's and `%%%'s.

- implement a debugger and a profiler

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