NAME

       cant - CAnonicalize N-Triples

DESCRIPTION

       CAnonicalize N-Triples

OPTIONS

       --verbose
              -v      Print what you are doing as you go

       --help -h      Print this message and exit

       --from=uri
              -f uri  Specify an input file (or web resource)

       --diff=uri
              -d uri  Specify a difference file

       Can  have  any number of --from <file> parameters, in which case files are merged. If none
       are given, /dev/stdin is used.

       If any diff files are given then the diff files are read merged  separately  and  compared
       with  the  input  files.  the  result is a list of differences instead of the canonicalizd
       graph. This is NOT a minimal diff.  Exits with nonzero system  status  if  graphs  do  not
       match.

       This  is  an  independent  n-triples  cannonicalizer.  It  uses  heuristics,  and will not
       terminate on all graphs. It is designed for testing:  the output and the reference  output
       are both canonicalized and compared.

       It uses the very simple NTriples format. It is designed to be independent of the SWAP code
       so that it can be used to test the SWAP code. It doesn't boast any fancy algorithms - just
       tries to get the job done for the small files in the test datasets.

       The  algorithm  to generate a "signature" for each bnode. This is just found by looking in
       its immediate viscinity,  treating  any  local  bnode  as  a  blank.   Bnodes  which  have
       signatures  unique  within the graph can be allocated cannonical identifiers as a function
       of the ordering of the signatures. These are then treated as fixed nodes.  If another pass
       is done of the new graph, the signatures are more distinct.

       This  works  for  well-labelled  graphs,  and  graphs  which  don't  have  large  areas of
       interconnected bnodes or large duplicate areas. A particular failing is complete  lack  of
       treatment of symmetry between bnodes.

   References:
              .google           graph          isomorphism          See          also          eg
              http://www.w3.org/2000/10/rdf-tests/rdfcore/utils/ntc/compare.cc   NTriples:    see
              http://www.w3.org/TR/rdf-testcases/#ntriples

       Not to mention,
              published this month by coincidence:

       Kelly, Brian, [Whitehead Institute]
              "Graph cannonicalization", Dr Dobb's Journal, May 2003.

              $Id: cant.py,v 1.15 2007/06/26 02:36:15 syosi Exp $

       This   is   or   was   http://www.w3.org/2000/10/swap/cant.py   W3C  open  source  licence
       <http://www.w3.org/Consortium/Legal/copyright-software.html>.

       2004-02-31 Serious bug fixed.  This is a test program, shoul dbe itself tested.

              Quis custodiet ipsos custodes?