SNePS NEWS -- history of user-visible changes.

Copyright (C) 1995
Research Foundation of State University of New York
See the end for copying conditions.

RCS: $Id: NEWS,v 1.8 1998/06/08 12:47:42 snwiz Exp $

Please send SNePS bug reports to snwiz@cs.buffalo.edu

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* Changes in SNePS 2.4.0
** Contexts now are numbered to speed up the system
** deducetrue, deducefalse, deducewh, deducewhnot introduced
** Tell-Ask interface introduced.
** Note: snepslog set-mode-3 is being rewritten, and therefore
is not included in this release.

* Changes in SNePS 2.3.3
** Fixed a bug in act.lisp that was causing an error under
Allegro acl 4.3
** Separated the installation of logical pathname translations
into another load file: load-logical-pathnames.lisp.  This
file is used both when loading interactively, and when the
ACL 4.3 dumped image starts up again.
** Added a garbage collector for nodes. Essentially, a node is a
garbage node if it is isolated and is not pointed to by any SNEPSUL
variable other than NODES and PATTERNS.  The garbage collector is
automatically invoked upon (clear-infer).
** As a consequence of having a garbage collector, a new SNEPSUL
variable has been created.  PRIMITIVE-ACTIONS contains all primitive
action nodes given actions by attach-primaction.  This variable is
updated automatically.
** In both versions of englex, lexin takes an additional keyword
parameter :merge.  When non-null, lexin will preserve any existing
lexicon.  This allows users to spread their lexical information over
multiple files.  Usage: (lexin <file> [:merge t])

* Changes in SNePS 2.3.2
** When using Englex, the user may now use 'presp or 'prptf as the
feature indicating the present participle form of an irregluar verb.

* Changes in SNePS 2.3.1

** SNePS now also works in Mac-Common-Lisp (MCL).

** Renamed `declare-primitve' into `attach-primaction'.

* Changes in SNePS 2.3.0

** SNeRE:  Deepak Kumar's implementation of the SNePS Rational Engine plus a
set of patches by Stu Shapiro are now fully merged with the main SNePS
release.  The result is called SNePS 2.3/SNeRE.

At the moment, SNeRE is documented separately in the file `sneremanual.ps',
but this manual should be merged soon into the main SNePS manual.  An online
HTML version of the manual can be found at the SNePS Web site under the URL
`http://www.cs.buffalo.edu/pub/sneps/WWW/Manuals/index.html'.

*** The old SNACTor demos now use SNeRE.  A new SNeRE demo demonstrates new
features such as `with-some' and `with-all' actions.

*** The user interface for defining primitive actions has been changed as
compared to SNACTor and earlier, experimental versions of SNeRE.  The main
vehicles to define new action functions is `define-primaction'.  To associate
a primitive action function with an actual action node one has to use
the function `declare-primitive'.  See the SNeRE manual for details.

*** The semantics of the built-in mental action `believe' has changed.
`believe(P)' now always retracts any direct opposites of P (e.g., ~P) and then
asserts P.  After the assertion of P forward inference is started on it via a
call to `dynamic-add'.

*** The mental action `forget' has been renamed into `disbelieve' to better
describe its semantics.  `disbelieve(P)' now always simply retracts P.
For backward compatibility `forget' is still available as an alias for
`disbelieve'.

*** `perform' is now a bona fide SNePSUL command.  This means it is a macro now
instead of the function it was before!  It now also takes a context specifier
similar to `!', `add', `deduce', etc.  Deductions and assertions triggered
during the performance of an act will be made in the specified context.  For
example `(perform (build action "pickup" object1 "C") :context Oscar)' would
carry out the action according to the propositions believed in the Oscar
context.

*** Bidirectional inference now works properly with `when-do's.

*** The set of initial relations available after a `(resetnet t)' has
been changed to the following: 

     (&ant ant arg forall cq dcq default emax emin etot exists
      max min pevb thresh threshmax
      when do if vars suchthat 
      condition then else
      act plan goal action precondition effect
      object1 object2))

*** The experimental variable `snip::*choose-randomly*' can be used to toggle
random choosing of actions and plans.  By default it is set to T which means
that choosing is done randomly (e.g., in a `do-one').  Deterministic choosing
can be desirable during debugging.


** Joongmin Choi's implementation of SNIP-22 is now fully merged with the main
SNePS release.  This means it cannot be turned off anymore as was possible
before.

*** With SNIP-22 the new SNePSUL command `clear-infer-all' does what was
previously done by `clear-infer'.  `clear-infer' was changed to not
purge some expertise information.  For example, known instances of rule nodes
are kept around.


** The parser now properly handles multiple parses.  If the variable
`*all-parses*' is t it generates all possible parse trees.  After
every final pop action the resulting parse tree is printed and the user is
asked whether s/he wants to continue with another parse.  If not the set of
currently accumulated parse trees gets returned.

** Handling of POP arcs got changed such that actions are only performed in
case the arc does not block.

** New demos that show features of the natural language components are now
available.  See the `(demo)' menu for details.


** A new set of functions to convert SNePS nodes into Lisp objects and vice
versa is now available.  For details see the manual.

** The set of helper functions used in the DBMS demo is now officially
available.  For details see the manual.


** `clear-infer' and `remove-from-context' are now available as SNePSLOG
commands.


** Some path-based inference problems have been fixed.  Now an arc can be
defined as synonymous to another arc, e.g., as in

      (define r1 r2)
      (define-path r1 r2)

`not' has been fixed to work the way it used to in SNePS 2.  Belief revision
does not work for nodes that were inferred via path-based inference that
involved `not' arcs.  A similar fix was made to `relative-complement'.

* SNePS 2.1 Rel-1.400 released
----------------------------------------------------------------------
Copyright information:

Copyright (C) 1995 
Research Foundation of State University of New York

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   Permission is granted to distribute modified versions
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