=head1 DESCRIPTION
Parser module for Text::Tradition, given a GraphML file that describes
-a collation graph. For further information on the GraphML format for
-text collation, see http://gregor.middell.net/collatex/
+a collation graph. Returns the information about the graph that has
+been parsed out from the GraphML. This module is meant to be used
+with a module (e.g. CollateX or Self) that interprets the specific
+GraphML conventions of the source program.
=head1 METHODS
=item B<parse>
-parse( $graph, $graphml_string );
+parse( $init_opts );
-Takes an initialized Text::Tradition::Graph object and a string
-containing the GraphML; creates the appropriate nodes and edges on the
-graph.
+Takes a set of Tradition initialization options, among which should be either
+'file' or 'string'; parses that file or string and returns a list of nodes, edges,
+and their associated data.
=cut
-use vars qw/ $xpc %nodedata /;
+use vars qw/ $xpc $graphattr $nodedata $witnesses /;
+
+# Return graph -> nodeid -> { key1/val1, key2/val2, key3/val3 ... }
+# -> edgeid -> { source, target, wit1/val1, wit2/val2 ...}
sub parse {
- my( $tradition, $graphml_str ) = @_;
+ my( $opts ) = @_;
+
+ my $graph_hash = { 'nodes' => [],
+ 'edges' => [] };
- my $collation = $tradition->collation;
my $parser = XML::LibXML->new();
- my $doc = $parser->parse_string( $graphml_str );
+ my $doc;
+ if( exists $opts->{'string'} ) {
+ $doc = $parser->parse_string( $opts->{'string'} );
+ } elsif ( exists $opts->{'file'} ) {
+ $doc = $parser->parse_file( $opts->{'file'} );
+ } else {
+ warn "Could not find string or file option to parse";
+ return;
+ }
+
my $graphml = $doc->documentElement();
$xpc = XML::LibXML::XPathContext->new( $graphml );
$xpc->registerNs( 'g', 'http://graphml.graphdrawing.org/xmlns' );
# First get the ID keys, for witnesses and for collation data
- my %witnesses;
foreach my $k ( $xpc->findnodes( '//g:key' ) ) {
- # Each key has a 'for' attribute; the edge keys are witnesses, and
- # the node keys contain an ID and string for each node.
-
- if( $k->getAttribute( 'for' ) eq 'node' ) {
- # The node data keys we expect are:
- # 'number' -> unique node identifier
- # 'token' -> reading for the node
- # 'identical' -> the node of which this node is
- # a transposed version
- # 'position' -> a calculated position for the node
- $nodedata{ $k->getAttribute( 'attr.name' ) } = $k->getAttribute( 'id' );
- } else {
- $witnesses{ $k->getAttribute( 'id' ) } = $k->getAttribute( 'attr.name' );
- }
+ # Each key has a 'for' attribute; the edge keys are witnesses, and
+ # the node keys contain an ID and string for each node.
+ my $keyid = $k->getAttribute( 'id' );
+ my $keyname = $k->getAttribute( 'attr.name' );
+
+ # Keep track of the XML identifiers for the data carried
+ # in each node element.
+ my $dtype = $k->getAttribute( 'for' );
+ if( $dtype eq 'graph' ) {
+ $graphattr->{$keyid} = $keyname;
+ } elsif( $dtype eq 'node' ) {
+ $nodedata->{$keyid} = $keyname;
+ } else {
+ $witnesses->{$keyid} = $keyname;
+ }
}
- my $has_explicit_positions = defined $nodedata{'position'};
+ my $graph_el = $xpc->find( '/g:graphml/g:graph' )->[0];
- # Add the witnesses that we have found
- foreach my $wit ( values %witnesses ) {
- $tradition->add_witness( 'sigil' => $wit );
+ my $node_reg = {};
+
+ # Read in graph globals (if any).
+ print STDERR "Reading graphml global data\n";
+ foreach my $dkey ( keys %$graphattr ) {
+ my $keyname = $graphattr->{$dkey};
+ my $keyvalue = _lookup_node_data( $graph_el, $dkey );
+ $graph_hash->{'global'}->{$keyname} = $keyvalue;
}
- my $graph_el = $xpc->find( '/g:graphml/g:graph' )->[0];
-
- # Add the nodes to the graph. First delete the start node, because
- # GraphML graphs will have their own start nodes.
- $collation->del_reading( $collation->start() );
- # Map from XML IDs to node name/identity
- my %node_name;
- # Keep track of whatever extra info we're passed
- my $extra_data = {};
+ # Add the nodes to the graph hash.
+ print STDERR "Reading graphml nodes\n";
my @nodes = $xpc->findnodes( '//g:node' );
foreach my $n ( @nodes ) {
- my $id = _lookup_node_data( $n, 'number' );
- my $label = _lookup_node_data( $n, 'token' );
- my $gnode = $collation->add_reading( $id );
- $node_name{ $n->getAttribute('id') } = $id;
- $gnode->set_attribute( 'label', $label );
-
- # Now get the rest of the data, i.e. not the ID or label
- my $extra = {};
- foreach my $k ( keys %nodedata ) {
- next if $k =~ /^(number|token)$/;
- $extra->{ $k } = _lookup_node_data( $n, $k );
- }
- $extra_data->{ $id } = $extra;
+ # Could use a better way of registering these
+ my $node_hash = {};
+ foreach my $dkey ( keys %$nodedata ) {
+ my $keyname = $nodedata->{$dkey};
+ my $keyvalue = _lookup_node_data( $n, $dkey );
+ $node_hash->{$keyname} = $keyvalue if defined $keyvalue;
+ }
+ $node_reg->{$n->getAttribute( 'id' )} = $node_hash;
+ push( @{$graph_hash->{'nodes'}}, $node_hash );
}
-
- # Now add the edges.
+
+ # Now add the edges, and cross-ref with the node objects.
+ print STDERR "Reading graphml edges\n";
my @edges = $xpc->findnodes( '//g:edge' );
foreach my $e ( @edges ) {
- my $from = $node_name{ $e->getAttribute('source') };
- my $to = $node_name{ $e->getAttribute('target') };
- # Label according to the witnesses present.
- my @wit_ids = $xpc->findnodes( './g:data/attribute::key', $e );
- my @wit_names = map { $witnesses{ $_->getValue() } } @wit_ids;
- my $label = $collation->path_label( @wit_names );
- $collation->add_path( $from, $to, $label );
- }
-
- ## Reverse the node_name hash so that we have two-way lookup.
- my %node_id = reverse %node_name;
-
- ## Record the nodes that are marked as transposed.
- my $tr_xpath = '//g:node[g:data[@key="' . $nodedata{'identical'} . '"]]';
- my $transposition_nodes = $xpc->find( $tr_xpath );
- foreach my $tn ( @$transposition_nodes ) {
- my $id_xpath = sprintf( './g:data[@key="%s"]/text()',
- $nodedata{'identical'} );
- $collation->reading( $node_id{ $tn->getAttribute( 'id' ) } )->
- set_identical( $collation->reading(
- $node_name{ $xpc->findvalue( $id_xpath, $tn ) } ) );
- }
-
- # Find the beginning and end nodes of the graph. The beginning node
- # has no incoming edges; the end node has no outgoing edges.
- my( $begin_node, $end_node );
- foreach my $gnode ( $collation->readings() ) {
- # print STDERR "Checking node " . $gnode->name . "\n";
- my @outgoing = $gnode->outgoing();
- my @incoming = $gnode->incoming();
-
- unless( scalar @incoming ) {
- warn "Already have a beginning node" if $begin_node;
- $begin_node = $gnode;
- $collation->start( $gnode );
- }
- unless( scalar @outgoing ) {
- warn "Already have an ending node" if $end_node;
- $end_node = $gnode;
- }
- }
-
- my @common_nodes = $collation->walk_witness_paths( $end_node );
- # Now we have added the witnesses and their paths, so have also
- # implicitly marked the common nodes. Now we can calculate their
- # explicit permissions. This is separate because it won't always
- # be necessary with the GraphML parsing.
- if( $has_explicit_positions ) {
- # Record the positions that came with each graph node.
- # TODO we really need to translate these into our own style of
- # position identifier. That's why we defer this until now.
- foreach my $node_id ( keys %$extra_data ) {
- my $pos = $extra_data->{$node_id}->{'position'};
- $collation->reading( $node_name{$node_id} )->position( $pos );
- }
- } else {
- # Calculate a position for each graph node.
- $collation->calculate_positions( @common_nodes );
+ my $from = $e->getAttribute('source');
+ my $to = $e->getAttribute('target');
+
+ # We don't know whether the edge data is one per witness
+ # or one per witness type, or something else. So we just
+ # save it and let our calling parser decide.
+ my $edge_hash = {
+ 'source' => $node_reg->{$from},
+ 'target' => $node_reg->{$to},
+ };
+ foreach my $wkey( keys %$witnesses ) {
+ my $wname = $witnesses->{$wkey};
+ my $wlabel = _lookup_node_data( $e, $wkey );
+ $edge_hash->{$wname} = $wlabel if $wlabel;
+ }
+ push( @{$graph_hash->{'edges'}}, $edge_hash );
}
+ return $graph_hash;
}
sub _lookup_node_data {
my( $xmlnode, $key ) = @_;
my $lookup_xpath = './g:data[@key="%s"]/child::text()';
- my $data = $xpc->findvalue( sprintf( $lookup_xpath, $nodedata{$key} ),
- $xmlnode );
+ my $data = $xpc->find( sprintf( $lookup_xpath, $key ), $xmlnode );
+ # If we get back an empty nodelist, we return undef.
+ if( ref( $data ) ) {
+ return undef unless $data->size;
+ return $data->to_literal->value;
+ }
+ # Otherwise we got back a value. Return it.
return $data;
}
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