Revision history for Perl extension AI::Prolog.

0.73  
      Added AI::Prolog::Cookbook as an introduction to common problems
        encountered when working with Prolog.
      TermList->to_string now causes listings to look very similar to
        SWI-Prolog.  Much easier to read.
      Term->to_string now identifies variables by letter, not /_\d+/.
      Completed decoupling of AI::Prolog::Parser from the engine.

0.72  Sun July 31, 2005
      Move builtins to their own class, AI::Prolog::Engine::Builtins
      Non-existent predicates now issue a warning even if trace is off.
      Added new predicates:
        halt/0 -- currently a no-op outside of the aiprolog shell
        help/0 -- list all builtin predicates for which help is available
        help/1 -- list help for builtin predicate
        write/1
        writeln/1
      Added ** operator (pow/1) to math preprocessor.  Leaving it out
        earlier was an oversight.

0.71  Sat June 25, 2005
      Removed _failgoal in Engine.pm.  We now backtrack if we need
        new results.
      Added several new regression tests.
      Fixed bug where code was not warning on unknown predicates.
        (Doug Wilson)
      Fixed bug where tracing fails when it tries to print a non-
        existent "next_clause".  (Doug Wilson)
      retract/1 now works correctly.  (Doug Wilson)
      Fixed unification bug that crept in in .62.
      Added data/sleepy.pro, a game that wasn't working because of
        the retract/1 bug.

0.7   Mon June 20, 2005 (Happy Birthday to me)
      Parsing errors now attempt to report the line number of the
        error.
      Added new predicates:
        consult/1
        listing/1
        ne/2
      Updated the license information display for aiprolog shell.
      Modified listing/0 to not show builtins.
      Added math preprocessor.  This transforms proper Prolog math
        into internal predicates the parser recognizes:

        X is N + 1. % is(X, plus(N, 1)).
        
      Pushed all parsing back to the Parser class.  No more parsing
        in TermList and Term :)
      Added anonymous variables:  foo(bar, _, baz).  I don't have
        any efficiency gains from this (yet) because they're just
        variables with hidden names, but they work.
      Added Test::Exception to the PREREQ_PM (thanks to rjray for
        pointing that out).
      Updated the docs and examples.

0.65  Wed May 11, 2005
      Added Term::ReadLine support to aiprolog shell.
      Added Term::ReadKey support to aiprolog shell.
      Minor doc corrections.

0.64  Mon May 09, 2005
      Change default behavior to AI::Prolog->raw_results(1).
      Added quote() method to allow Perl variables to be quoted
        and used at Prolog terms.
      Added list() method to allow a Perl list to be turned into
        a Prolog list.

0.63  Wed May 04, 2005
      Allow parser to properly handle positive and negative numbers
        and decimal points.
      Added pow(X,Y).
      Eliminated studlyCaps methods.
      Added trace. and notrace.
      Added a TODO test for a failing regression test.

0.62  Fri Feb 25, 2005
      Added code to avoid bug in some Perl's where "undef" looks
      like a number.
      Major performance improvement.  Now runs about 40% faster.
      Added 
        listing.
        println(X).
        is(X,Y).
        plus(X,Y).
        minus(X,Y).
        mult(X,Y).
        div(X,Y).
        mod(X,Y).
        ge(X,Y).
        gt(X,Y).
        le(X,Y).
        lt(X,Y).
      Added towers of hanoi and a scheduler to the examples/.

0.61  Mon Feb 21, 2005
      Added var(X).
      Disabled tracing in the aiprolog shell (whoops!)

0.6   Sun Feb 20, 2005
      Added tests for the cut, number, and clause classes.

      Added stub tests for step and primitive classes.

      Ensured that all classes at least had stub documentation and added
      POD tests.

      Updated the TODO list in AI::Prolog.

0.5   Sun Feb 13, 2005
      Put the database into its own class.

      Pulled engine backtracking out into its own method.

      Reduced the scope of many of the Engine::_run variables to ensure data
        wasn't leaking.

      Added simple "aiprolog" shell.

      Added cut operator, retract(X), and assert(X).

      Added more examples and simple adventure game to both demonstrate the shell
        and how Prolog works.

      Completely reworked the engine internals to allow new predicates to be
        easily added.

      * XXX Also screwed up the numbering scheme.  Grumble XXX *

0.04  Sun Jan 30, 2005
      Added support for quoting terms.  
      
      Added Engine->formatted method which allows results to be returned as
        either strings or as data structures.  The latter is more useful.

      When using AI::Prolog, the results() method now returns a "results"
        object.

      The AI::Prolog interface has been cleaned up and use of the supporting
        modules is now officially discouraged.

      Massive documentation update.

0.03  Sun Jan 23, 2005
      Added tests for built-in predicates.

      Added query() function to AI::Logic::Engine to allow successive queries
        without a new bootstrap.

0.02  Sun Jan 23, 2005
      First public release of AI::Prolog.

0.01  Thu Jan 20 20:47:49 PST 2005
	  original version; created by make_project 0.1
