# $Id: gk0.n3,v 1.2 2003/08/25 14:54:59 timbl Exp $
#
# Experiments with Cwm rules.
#
# After my first attempt at home network configuration with RDF [1], I thought
# some more about Cwm rules for manipulating access permissions.  To get
# some purchase on the problem, I start by tackling some very much simpler
# rules based on the following properties:
#
#   ?A rule:append ( ?L ?T1 )
# is true when ?A is the same as the result of appending ?T1 to the list ?L.
#
#   ?A rule:reverse ?B
# is true when ?A is the same as the list obtained by reversing the members 
# of list ?B
#
# These goals are stated in structural terms, but I they can be motivated by
# semantic conditions about an ascending or descending list of numbers.
#
# Results:
#
# Not quite what I expected.  Using the Cwm --think option, the recursive 
# definition for rule:append gets applied just once.  Interestingly, though,
# if I apply Cwm to its own output, specifying the --think option again,
# I get an error:
#
#  File "F:\W3C\swap1111\llyn.py", line 482, in the
#    assert len(hits) == 1, "There should only be one match for %s %s %s." %(subj , pred, obj)
#  AssertionError: There should only be one match for _g1 first None.
#
#
# [1] http://www.ninebynine.org/SWAD-E/Intro.html#HomeNetAccessDemo
#
#--------+---------+---------+---------+---------+---------+---------+---------+
#
# Copyright (c) 2002, G. KLYNE
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. The name of the author may not be used to endorse or promote products
#    derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
#--------+---------+---------+---------+---------+---------+---------+---------+
# $Source: /w3ccvs/WWW/2000/10/swap/test/list/gk0.n3,v $
# $Author: timbl $
# $Date: 2003/08/25 14:54:59 $
# $Id: gk0.n3,v 1.2 2003/08/25 14:54:59 timbl Exp $
#--------+---------+---------+---------+---------+---------+---------+---------+
#        1         2         3         4         5         6         7         8

@prefix rdf:      <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs:     <http://www.w3.org/2000/01/rdf-schema#> .
@prefix log:      <http://www.w3.org/2000/10/swap/log#> .
@prefix string:   <http://www.w3.org/2000/10/swap/string#> .
@prefix daml:     <http://www.daml.org/2001/03/daml+oil#> .
@prefix foaf:     <http://xmlns.com/foaf/0.1/> .
@prefix rule:     <http://id.ninebynine.org/wip/2002/rule/> .
@prefix :         <#> .

#
# rule:append
# -----------
#
#   ?A rule:append ( ?L ?T1 )
#
# is true when ?A is the same as the result of appending ?T1 to the list ?L.
#
#   ?A rule:append ( [ ?H :: ?T ]  ?T1 )
# =>
#   ?A rdf:first ?H ;
#      rdf:rest  [ rule:append ( ?T ?T1 ) ] .
#
#   ?A rule:append ( rdf:nil ?T1 )
# =>
#   ?A rdf:first ?T1 ;
#      rdf:rest  rdf:nil .
#

{ 
  ?A rule:append ( [ rdf:first ?H ; rdf:rest ?T ] ?T1 ) .
}
log:implies
{ 
  ?A rdf:first ?H ;
     rdf:rest  [ rule:append ( ?T ?T1 ) ] .
} .

# The following rule, when enabled, causes a different error:
#
#  File "F:\W3C\swap1111\llyn.py", line 2402, in query2
#    existentials.remove(pair[0]) # Can't match anything anymore, need exact match
#  ValueError: list.remove(x): x not in list
#

{ 
  ?A rule:append ( rdf:nil ?T1 ) .
}
log:implies
{ 
  ?A rdf:first ?T1 ;
     rdf:rest  rdf:nil .
} .

# Test cases

:A0 rule:append ( ()  "L1" ).

#:A1 rule:append ( (  ) "L14" ) .

#:A2 rule:append (  :A1 "L2" ) .

#:A3 rule:append (  :A1 "L3" ) .

#
# I note that the notation
#   [ ?H :: ?T ]
# as a shorthand for:
#   [ rdf:first ?H ; rdf:rest ?T ]
# or
#   [ rdf:first ?H ; rdf:rest ?T ]
# might be convenient.
#


#
# End of network user details
#
#--------+---------+---------+---------+---------+---------+---------+---------+
# $Log: gk0.n3,v $
# Revision 1.2  2003/08/25 14:54:59  timbl
# Passes regression test. (make release)
#
# Revision 1.1  2003/08/14 00:00:23  timbl
# Re-engineered in places - See doc changes.html
#
# Revision 1.1  2003/01/16 05:06:45  timbl
# mm
#
# Revision 1.4  2002/12/19 17:45:08  graham
# Reduce to single test case
#
# Revision 1.3  2002/12/19 17:27:28  graham
# Tried adding append to nil (termination) rule
#
# Revision 1.2  2002/12/19 16:42:17  graham
# Append rule not working as expected
#
# Revision 1.1  2002/12/19 16:28:25  graham
# Add PlayRules files to CVS
#