X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FText%2FTradition%2FCollation.pm;h=f66e902856eabb828e025cb9cc7073105246cb23;hb=32014ec936b48809e9f2dae8f20a01c887253427;hp=aa905d2223d09022af844e2368d8768e69bc3004;hpb=e290206835dd4bc540d751ea2d1849255dd192f2;p=scpubgit%2Fstemmatology.git

diff --git a/lib/Text/Tradition/Collation.pm b/lib/Text/Tradition/Collation.pm
index aa905d2..f66e902 100644
--- a/lib/Text/Tradition/Collation.pm
+++ b/lib/Text/Tradition/Collation.pm
@@ -3,6 +3,8 @@ package Text::Tradition::Collation;
 use Graph::Easy;
 use IPC::Run qw( run binary );
 use Text::Tradition::Collation::Reading;
+use Text::Tradition::Collation::Path;
+use XML::LibXML;
 use Moose;
 
 has 'graph' => (
@@ -17,6 +19,7 @@ has 'graph' => (
 	path => 'edge',
 	readings => 'nodes',
 	paths => 'edges',
+	relationships => 'edges',
     },
     default => sub { Graph::Easy->new( undirected => 0 ) },
     );
@@ -34,16 +37,9 @@ has 'svg' => (
     predicate => 'has_svg',
     );
 
-has 'graphviz' => (
-    is => 'ro',
-    isa => 'Str',
-    writer => '_save_graphviz',
-    predicate => 'has_graphviz',
-    );
-
 has 'graphml' => (
     is => 'ro',
-    isa => 'XML::LibXML::Document',
+    isa => 'Str',
     writer => '_save_graphml',
     predicate => 'has_graphml',
     );
@@ -57,10 +53,34 @@ has 'lemmata' => (
     );
 
 has 'wit_list_separator' => (
-			     is => 'rw',
-			     isa => 'Str',
-			     default => ', ',
-			     );
+    is => 'rw',
+    isa => 'Str',
+    default => ', ',
+    );
+
+has 'baselabel' => (
+    is => 'rw',
+    isa => 'Str',
+    default => 'base text',
+    );
+
+has 'collapsed' => (
+    is => 'rw',
+    isa => 'Bool',
+    );
+
+has 'linear' => (
+    is => 'rw',
+    isa => 'Bool',
+    default => 1,
+    );
+
+has 'ac_label' => (
+    is => 'rw',
+    isa => 'Str',
+    default => ' (a.c.)',
+    );
+
 
 # The collation can be created two ways:
 # 1. Collate a set of witnesses (with CollateX I guess) and process
@@ -80,13 +100,56 @@ has 'wit_list_separator' => (
 sub BUILD {
     my( $self, $args ) = @_;
     $self->graph->use_class('node', 'Text::Tradition::Collation::Reading');
+    $self->graph->use_class('edge', 'Text::Tradition::Collation::Path');
 
     # Pass through any graph-specific options.
     my $shape = exists( $args->{'shape'} ) ? $args->{'shape'} : 'ellipse';
     $self->graph->set_attribute( 'node', 'shape', $shape );
 }
 
-# Wrappes around merge_nodes
+# Wrapper around add_path 
+
+around add_path => sub {
+    my $orig = shift;
+    my $self = shift;
+
+    # Make sure there are three arguments
+    unless( @_ == 3 ) {
+	warn "Call add_path with args source, target, witness";
+	return;
+    }
+    # Make sure the proposed path does not yet exist
+    my( $source, $target, $wit ) = @_;
+    $source = $self->reading( $source )
+	unless ref( $source ) eq 'Text::Tradition::Collation::Reading';
+    $target = $self->reading( $target )
+	unless ref( $target ) eq 'Text::Tradition::Collation::Reading';
+    foreach my $path ( $source->edges_to( $target ) ) {
+	if( $path->label eq $wit && $path->class eq 'edge.path' ) {
+	    return;
+	}
+    }
+    # Do the deed
+    $self->$orig( @_ );
+};
+
+# Wrapper around paths
+around paths => sub {
+    my $orig = shift;
+    my $self = shift;
+
+    my @result = grep { $_->class eq 'edge.path' } $self->$orig( @_ );
+    return @result;
+};
+
+around relationships => sub {
+    my $orig = shift;
+    my $self = shift;
+    my @result = grep { $_->class eq 'edge.relationship' } $self->$orig( @_ );
+    return @result;
+};
+
+# Wrapper around merge_nodes
 
 sub merge_readings {
     my $self = shift;
@@ -97,6 +160,63 @@ sub merge_readings {
     return $self->graph->merge_nodes( @_ );
 }
 
+# Extra graph-alike utility
+sub has_path {
+    my( $self, $source, $target, $label ) = @_;
+    my @paths = $source->edges_to( $target );
+    my @relevant = grep { $_->label eq $label } @paths;
+    return scalar @paths;
+}
+
+## Dealing with relationships between readings.  This is a different
+## sort of graph edge.
+
+sub add_relationship {
+    my( $self, $type, $source, $target, $global ) = @_;
+
+    # Make sure there is not another relationship between these two
+    # readings already
+    $source = $self->reading( $source )
+	unless ref( $source ) eq 'Text::Tradition::Collation::Reading';
+    $target = $self->reading( $target )
+	unless ref( $target ) eq 'Text::Tradition::Collation::Reading';
+    foreach my $rel ( $source->edges_to( $target ) ) {
+	if( $rel->label eq $type && $rel->class eq 'edge.relationship' ) {
+	    return;
+	}
+    }
+
+    my $rel = Text::Tradition::Collation::Relationship->new(
+	    'sort' => $type,
+	    'global' => $global,
+	    'orig_relation' => [ $source, $target ],
+    );
+    print STDERR sprintf( "Setting relationship %s between readings %s (%s)"
+			  . " and %s (%s)\n", $type, 
+			  $source->label, $source->name,
+			  $target->label, $target->name );
+    $self->graph->add_edge( $source, $target, $rel );
+    if( $global ) {
+	# Look for all readings with the source label, and if there are
+	# colocated readings with the target label, join them too.
+	foreach my $r ( $self->readings() ) {
+	    next unless $r->label eq $source->label;
+	    my @colocated = grep { $_->label eq $target->label }
+	        $self->same_position_as( $r );
+	    if( @colocated ) {
+		warn "Multiple readings with same label at same position!"
+		    if @colocated > 1;
+		my $dup_rel = Text::Tradition::Collation::Relationship->new(
+		    'sort' => $type,
+		    'global' => $global,
+		    'orig_relation' => [ $source, $target ],
+		    );
+		$self->graph->add_edge( $r, $colocated[0], $dup_rel );
+	    }
+	}
+    }
+}
+
 =head2 Output method(s)
 
 =over
@@ -116,17 +236,55 @@ sub as_svg {
     my( $self, $recalc ) = @_;
     return $self->svg if $self->has_svg;
     
-    $self->_save_graphviz( $self->graph->as_graphviz() )
-	unless( $self->has_graphviz && !$recalc );
+    $self->collapse_graph_paths();
     
     my @cmd = qw/dot -Tsvg/;
     my( $svg, $err );
-    my $in = $self->graphviz;
+    my $in = $self->as_dot();
     run( \@cmd, \$in, ">", binary(), \$svg );
-    $self->{'svg'} = $svg;
+    $self->_save_svg( $svg );
+    $self->expand_graph_paths();
     return $svg;
 }
 
+=item B<as_dot>
+
+print $graph->as_dot( $view, $recalculate );
+
+Returns a string that is the collation graph expressed in dot
+(i.e. GraphViz) format.  The 'view' argument determines what kind of
+graph is produced.
+    * 'path': a graph of witness paths through the collation (DEFAULT)
+    * 'relationship': a graph of how collation readings relate to 
+      each other
+
+=cut
+
+sub as_dot {
+    my( $self, $view ) = @_;
+    $view = 'path' unless $view;
+    # TODO consider making some of these things configurable
+    my $dot = sprintf( "digraph %s {\n", $self->tradition->name );
+    $dot .= "\tedge [ arrowhead=open ];\n";
+    $dot .= "\tgraph [ rankdir=LR ];\n";
+    $dot .= sprintf( "\tnode [ fontsize=%d, fillcolor=%s, style=%s, shape=%s ];\n",
+		     11, "white", "filled", $self->graph->get_attribute( 'node', 'shape' ) );
+
+    foreach my $reading ( $self->readings ) {
+	next if $reading->name eq $reading->label;
+	$dot .= sprintf( "\t\"%s\" [ label=\"%s\" ]\n", $reading->name, $reading->label );
+    }
+
+    my @edges = $view eq 'relationship' ? $self->relationships : $self->paths;
+    foreach my $edge ( @edges ) {
+	$dot .= sprintf( "\t\"%s\" -> \"%s\" [ color=\"%s\", fontcolor=\"%s\", label=\"%s\" ]\n",
+			 $edge->from->name, $edge->to->name, '#000000', '#000000', $edge->label );
+    }
+
+    $dot .= "}\n";
+    return $dot;
+}
+
 =item B<as_graphml>
 
 print $graph->as_graphml( $recalculate )
@@ -156,51 +314,56 @@ sub as_graphml {
     $root->setAttributeNS( $xsi_ns, 'schemaLocation', $graphml_schema );
 
     # Add the data keys for nodes
-    my @node_data = ( 'name', 'token', 'identical', 'position' );
-    foreach my $ndi ( 0 .. $#node_data ) {
+    my @node_data = ( 'name', 'reading', 'identical', 'position' );
+    # HACKY HACKY HACK Relationship data
+    my %node_data_keys;
+    my $ndi = 0;
+    foreach my $datum ( @node_data ) {
+	$node_data_keys{$datum} = 'dn'.$ndi++;
 	my $key = $root->addNewChild( $graphml_ns, 'key' );
-	$key->setAttribute( 'attr.name', $node_data[$ndi] );
+	$key->setAttribute( 'attr.name', $datum );
 	$key->setAttribute( 'attr.type', 'string' );
 	$key->setAttribute( 'for', 'node' );
-	$key->setAttribute( 'id', 'd'.$ndi );
+	$key->setAttribute( 'id', $node_data_keys{$datum} );
     }
 
-    # Add the data keys for edges
-    my %wit_hash;
-    my $wit_ctr = 0;
-    foreach my $wit ( $self->getWitnessList ) {
-	my $wit_key = 'w' . $wit_ctr++;
-	$wit_hash{$wit} = $wit_key;
+    # Add the data keys for edges, i.e. witnesses
+    my $edi = 0;
+    my %edge_data_keys;
+    foreach my $edge_key( qw/ witness_main witness_ante_corr relationship / ) {
+	$edge_data_keys{$edge_key} = 'de'.$edi++;
 	my $key = $root->addNewChild( $graphml_ns, 'key' );
-	$key->setAttribute( 'attr.name', $wit );
+	$key->setAttribute( 'attr.name', $edge_key );
 	$key->setAttribute( 'attr.type', 'string' );
 	$key->setAttribute( 'for', 'edge' );
-	$key->setAttribute( 'id', $wit_key );
+	$key->setAttribute( 'id', $edge_data_keys{$edge_key} );
     }
-
+    
     # Add the graph, its nodes, and its edges
     my $graph = $root->addNewChild( $graphml_ns, 'graph' );
     $graph->setAttribute( 'edgedefault', 'directed' );
     $graph->setAttribute( 'id', 'g0' ); # TODO make this meaningful
     $graph->setAttribute( 'parse.edgeids', 'canonical' );
-    $graph->setAttribute( 'parse.edges', $self->edges() );
+    $graph->setAttribute( 'parse.edges', scalar($self->paths) );
     $graph->setAttribute( 'parse.nodeids', 'canonical' );
-    $graph->setAttribute( 'parse.nodes', $self->nodes() );
+    $graph->setAttribute( 'parse.nodes', scalar($self->readings) );
     $graph->setAttribute( 'parse.order', 'nodesfirst' );
 
     my $node_ctr = 0;
     my %node_hash;
-    foreach my $n ( $self->readings ) {
+    foreach my $n ( sort { $a->name cmp $b->name } $self->readings ) {
 	my %this_node_data = ();
-	foreach my $ndi ( 0 .. $#node_data ) {
-	    my $value;
-	    $this_node_data{'d'.$ndi} = $n->name if $node_data[$ndi] eq 'name';
-	    $this_node_data{'d'.$ndi} = $n->label 
-		if $node_data[$ndi] eq 'token';
-	    $this_node_data{'d'.$ndi} = $n->primary->name if $n->has_primary;
-	    $this_node_data{'d'.$ndi} = 
-		$self->{'positions'}->node_position( $n )
-		if $node_data[$ndi] eq 'position';
+	foreach my $datum ( @node_data ) {
+	    my $key = $node_data_keys{$datum};
+	    if( $datum eq 'name' ) {
+		$this_node_data{$key} = $n->name;
+	    } elsif( $datum eq 'reading' ) {
+		$this_node_data{$key} = $n->label;
+	    } elsif( $datum eq 'identical' && $n->has_primary ) {
+		$this_node_data{$key} = $n->primary->name;
+	    } elsif( $datum eq 'position' ) {
+		$this_node_data{$key} = $n->position;
+	    }
 	}
 	my $node_el = $graph->addNewChild( $graphml_ns, 'node' );
 	my $node_xmlid = 'n' . $node_ctr++;
@@ -210,24 +373,127 @@ sub as_graphml {
 	foreach my $dk ( keys %this_node_data ) {
 	    my $d_el = $node_el->addNewChild( $graphml_ns, 'data' );
 	    $d_el->setAttribute( 'key', $dk );
-	    $d_el->appendTextChild( $this_node_data{$dk} );
+	    $d_el->appendText( $this_node_data{$dk} );
 	}
     }
 
-    foreach my $e ( $self->edges() ) {
-	my( $name, $from, $to ) = ( $e->name,
-				    $node_hash{ $e->from()->name() },
-				    $node_hash{ $e->to()->name() } );
+    # Add the path edges
+    my $edge_ctr = 0;
+    foreach my $e ( sort { $a->from->name cmp $b->from->name } $self->graph->edges() ) {
+	my( $name, $from, $to ) = ( 'e'.$edge_ctr++,
+				    $node_hash{ $e->from->name() },
+				    $node_hash{ $e->to->name() } );
 	my $edge_el = $graph->addNewChild( $graphml_ns, 'edge' );
 	$edge_el->setAttribute( 'source', $from );
 	$edge_el->setAttribute( 'target', $to );
 	$edge_el->setAttribute( 'id', $name );
-	# TODO Got to add the witnesses
+	if( $e->class() eq 'edge.path' ) {
+	    # It's a witness path, so add the witness
+	    my $base = $e->label;
+	    my $key = $edge_data_keys{'witness_main'};
+	    # TODO kind of hacky
+	    if( $e->label =~ /^(.*?)\s+(\(a\.c\.\))$/ ) {
+		$base = $1;
+		$key = $edge_data_keys{'witness_ante_corr'};
+	    }
+	    my $wit_el = $edge_el->addNewChild( $graphml_ns, 'data' );
+	    $wit_el->setAttribute( 'key', $key );
+	    $wit_el->appendText( $base );
+	} else {
+	    # It's a relationship
+	    my $rel_el = $edge_el->addNewChild( $graphml_ns, 'data' );
+	    $rel_el->setAttribute( 'key', $edge_data_keys{'relationship'} );
+	    $rel_el->appendText( $e->label() );
+	}
     }
 
     # Return the thing
-    $self->_save_graphml( $graphml );
-    return $graphml;
+    $self->_save_graphml( $graphml->toString(1) );
+    return $graphml->toString(1);
+}
+
+sub _make_xml_attr {
+    my $str = shift;
+    $str =~ s/\s/_/g;
+    $str =~ s/\W//g;
+    $str =~ "a$str" if $str =~ /^\d/;
+    return $str;
+}
+
+sub collapse_graph_paths {
+    my $self = shift;
+    # Our collation graph has an path per witness.  This is great for
+    # calculation purposes, but terrible for display.  Thus we want to
+    # display only one path between any two nodes.
+
+    return if $self->collapsed;
+
+    print STDERR "Collapsing witness paths in graph...\n";
+
+    # Don't list out every witness if we have more than half to list.
+    my $majority = int( scalar( @{$self->tradition->witnesses} ) / 2 ) + 1;
+    # But don't compress if there are only a few witnesses.
+    $majority = 4 if $majority < 4;
+    foreach my $node( $self->readings ) {
+	my $newlabels = {};
+	# We will visit each node, so we only look ahead.
+	foreach my $edge ( $node->outgoing() ) {
+	    next unless $edge->class eq 'edge.path';
+	    add_hash_entry( $newlabels, $edge->to->name, $edge->name );
+	    $self->del_path( $edge );
+	}
+
+	foreach my $newdest ( keys %$newlabels ) {
+	    my $label;
+	    my @compressed_wits = ();
+	    if( @{$newlabels->{$newdest}} < $majority ) {
+		$label = join( ', ', sort( @{$newlabels->{$newdest}} ) );
+	    } else {
+		## TODO FIX THIS HACK
+		my @aclabels;
+		foreach my $wit ( @{$newlabels->{$newdest}} ) {
+		    if( $wit =~ /^(.*?)(\s*\(?a\.\s*c\.\)?)$/ ) {
+			push( @aclabels, $wit );
+		    } else {
+			push( @compressed_wits, $wit );
+		    }
+		}
+		$label = join( ', ', 'majority', sort( @aclabels ) );
+	    }
+	    
+	    my $newpath = 
+		$self->add_path( $node, $self->reading( $newdest ), $label );
+	    if( @compressed_wits ) {
+		$newpath->hidden_witnesses( \@compressed_wits );
+	    }
+	}
+    }
+
+    $self->collapsed( 1 );
+}
+
+sub expand_graph_paths {
+    my $self = shift;
+    # Our collation graph has only one path between any two nodes.
+    # This is great for display, but not so great for analysis.
+    # Expand this so that each witness has its own path between any
+    # two reading nodes.
+    return unless $self->collapsed;
+    
+    print STDERR "Expanding witness paths in graph...\n";
+    foreach my $path( $self->paths ) {
+	my $from = $path->from;
+	my $to = $path->to;
+	my @wits = split( /, /, $path->label );
+	if( $path->has_hidden_witnesses ) {
+	    push( @wits, @{$path->hidden_witnesses} );
+	}
+	$self->del_path( $path );
+	foreach ( @wits ) {
+	    $self->add_path( $from, $to, $_ );
+	}
+    }
+    $self->collapsed( 0 );
 }
 
 =back
@@ -268,11 +534,11 @@ assume that the path is that of the base text (if any.)
 sub reading_sequence {
     my( $self, $start, $end, $witness, $backup ) = @_;
 
-    $witness = 'base text' unless $witness;
+    $witness = $self->baselabel unless $witness;
     my @readings = ( $start );
     my %seen;
     my $n = $start;
-    while( $n ne $end ) {
+    while( $n && $n ne $end ) {
 	if( exists( $seen{$n->name()} ) ) {
 	    warn "Detected loop at " . $n->name();
 	    last;
@@ -299,7 +565,7 @@ sub reading_sequence {
 my $next_reading = $graph->next_reading( $reading, $witpath );
 
 Returns the reading that follows the given reading along the given witness
-path.  TODO These are badly named.
+path.  
 
 =cut
 
@@ -314,7 +580,7 @@ sub next_reading {
 my $prior_reading = $graph->prior_reading( $reading, $witpath );
 
 Returns the reading that precedes the given reading along the given witness
-path.  TODO These are badly named.
+path.  
 
 =cut
 
@@ -338,7 +604,7 @@ sub _find_linked_reading {
     my $base_le;
     my $alt_le;
     foreach my $le ( @linked_paths ) {
-	if( $le->name eq 'base text' ) {
+	if( $le->name eq $self->baselabel ) {
 	    $base_le = $le;
 	} else {
 	    my @le_wits = $self->witnesses_of_label( $le->name );
@@ -367,7 +633,7 @@ sub _find_linked_reading {
 # Some set logic.
 sub _is_within {
     my( $set1, $set2 ) = @_;
-    my $ret = 1;
+    my $ret = @$set1; # will be 0, i.e. false, if set1 is empty
     foreach my $el ( @$set1 ) {
 	$ret = 0 unless grep { /^\Q$el\E$/ } @$set2;
     }
@@ -395,16 +661,7 @@ sub walk_witness_paths {
 	$wit->path( \@wit_path );
 
 	# Detect the common readings.
-	if( @common_readings ) {
-	    my @cn;
-	    foreach my $n ( @wit_path ) {
-		push( @cn, $n ) if grep { $_ eq $n } @common_readings;
-	    }
-	    @common_readings = ();
-	    push( @common_readings, @cn );
-	} else {
-	    push( @common_readings, @wit_path );
-	}
+	@common_readings = _find_common( \@common_readings, \@wit_path );
     }
 
     # Mark all the nodes as either common or not.
@@ -420,44 +677,62 @@ sub walk_witness_paths {
     return @common_readings;
 }
 
+sub _find_common {
+    my( $common_readings, $new_path ) = @_;
+    my @cr;
+    if( @$common_readings ) {
+	foreach my $n ( @$new_path ) {
+	    push( @cr, $n ) if grep { $_ eq $n } @$common_readings;
+	}
+    } else {
+	push( @cr, @$new_path );
+    }
+    return @cr;
+}
+
+sub _remove_common {
+    my( $common_readings, $divergence ) = @_;
+    my @cr;
+    my %diverged;
+    map { $diverged{$_->name} = 1 } @$divergence;
+    foreach( @$common_readings ) {
+	push( @cr, $_ ) unless $diverged{$_->name};
+    }
+    return @cr;
+}
+
+
 # An alternative to walk_witness_paths, for use when a collation is
-# constructed from a base text and an apparatus.  Also modifies the
-# collation graph to remove all 'base text' paths and replace them
-# with real witness paths.
+# constructed from a base text and an apparatus.  We have the
+# sequences of readings and just need to add path edges.
 
-sub walk_and_expand_base {
-    my( $self, $end ) = @_;
+sub make_witness_paths {
+    my( $self ) = @_;
 
+    my @common_readings;
     foreach my $wit ( @{$self->tradition->witnesses} ) {
-	my $sig = $wit_sigil;
-	my $post_sig;
-	$post_sig = $wit->post_correctione 
-	    if $wit->has_post_correctione;
-	my @wit_path = ( $self->start );
-	my @wit_pc_path;
-	my $curr_rdg = $self->start;
-	my %seen;
-	while( $curr_rdg ne $end ) {
-	    if( $seen{$curr_reading->name} ) {
-		warn "Detected loop in walk_and_expand_base with witness "
-		    . "$sig on reading " . $curr_reading->name . "\n";
-		last;
-	    }
-	    my $next_rdg = $self->next_reading( $curr_reading, $sig );
-	    unless( $self->has_explicit_path( $curr_reading, 
-					      $next_reading, $sig ) ) {
-		$self->add_path( $curr_reading, $next_reading, $sig );
-	    }
-	    push( @wit_path, $next_reading );
-	    $seen{$curr_reading->name} = 1;
-	}
-	$wit->path( \@wit_path );
+	print STDERR "Making path for " . $wit->sigil . "\n";
+	$self->make_witness_path( $wit );
+	@common_readings = _find_common( \@common_readings, $wit->path );
+	@common_readings = _find_common( \@common_readings, $wit->uncorrected_path );
+    }
+    return @common_readings;
+}
 
-	# Now go through this path and look for p.c. divergences.
-	# TODO decide how to handle p.c. paths
-	# BIG TODO handle case where p.c. follows the base and a.c. doesn't!
-		
-	    
+sub make_witness_path {
+    my( $self, $wit ) = @_;
+    my @chain = @{$wit->path};
+    my $sig = $wit->sigil;
+    foreach my $idx ( 0 .. $#chain-1 ) {
+	$self->add_path( $chain[$idx], $chain[$idx+1], $sig );
+    }
+    @chain = @{$wit->uncorrected_path};
+    foreach my $idx( 0 .. $#chain-1 ) {
+	my $source = $chain[$idx];
+	my $target = $chain[$idx+1];
+	$self->add_path( $source, $target, "$sig (a.c.)" )
+	    unless $self->has_path( $source, $target, $sig );
+    }
 }
 
 sub common_readings {
@@ -479,50 +754,66 @@ sub calculate_positions {
 
     my $node_pos = {};
     foreach my $wit ( @{$self->tradition->witnesses} ) {
-	# First we walk each path, making a matrix for each witness that
-	# corresponds to its eventual position identifier.  Common nodes
-	# always start a new row, and are thus always in the first column.
-
-	my $wit_matrix = [];
-	my $cn = 0;  # We should hit the common readings in order.
-	my $row = [];
-	foreach my $wn ( @{$wit->path} ) {
-	    if( $wn eq $ordered_common[$cn] ) {
-		# Set up to look for the next common node, and
-		# start a new row of words.
-		$cn++;
-		push( @$wit_matrix, $row ) if scalar( @$row );
-		$row = [];
-	    }
-	    push( @$row, $wn );
-	}
-	push( @$wit_matrix, $row );  # Push the last row onto the matrix
-
-	# Now we have a matrix per witness, so that each row in the
-	# matrix begins with a common node, and continues with all the
-	# variant words that appear in the witness.  We turn this into
-	# real positions in row,cell format.  But we need some
-	# trickery in order to make sure that each node gets assigned
-	# to only one position.
-
-	foreach my $li ( 1..scalar(@$wit_matrix) ) {
-	    foreach my $di ( 1..scalar(@{$wit_matrix->[$li-1]}) ) {
-		my $reading = $wit_matrix->[$li-1]->[$di-1];
-		my $position = "$li,$di";
-		# If we have seen this node before, we need to compare
-		# its position with what went before.
-		unless( $reading->has_position &&
-			_cmp_position( $position, $reading->position ) < 1 ) {
-		    # The new position ID replaces the old one.
-		    $reading->position( $position );
-		} # otherwise, the old position needs to stay.
-	    }
-	}
+	print STDERR "Calculating positions in " . $wit->sigil . "\n";
+	_update_positions_from_path( $wit->path, @ordered_common );
+	_update_positions_from_path( $wit->uncorrected_path, @ordered_common )
+	    if $wit->has_ante_corr;
+    }
+    
+    # DEBUG
+    foreach my $r ( $self->readings() ) {
+	print STDERR "Reading " . $r->name . "/" . $r->label . " has no position\n"
+	    unless( $r->has_position );
     }
 
     $self->init_lemmata();
 }
 
+sub _update_positions_from_path {
+    my( $path, @ordered_common ) = @_;
+
+    # First we walk the given path, making a matrix for the witness
+    # that corresponds to its eventual position identifier.  Common
+    # nodes always start a new row, and are thus always in the first
+    # column.
+    my $wit_matrix = [];
+    my $cn = 0;  # We should hit the common readings in order.
+    my $row = [];
+    foreach my $wn ( @{$path} ) {
+	if( $wn eq $ordered_common[$cn] ) {
+	    # Set up to look for the next common node, and
+	    # start a new row of words.
+	    $cn++;
+	    push( @$wit_matrix, $row ) if scalar( @$row );
+	    $row = [];
+	}
+	push( @$row, $wn );
+    }
+    push( @$wit_matrix, $row );  # Push the last row onto the matrix
+
+    # Now we have a matrix per witness, so that each row in the
+    # matrix begins with a common node, and continues with all the
+    # variant words that appear in the witness.  We turn this into
+    # real positions in row,cell format.  But we need some
+    # trickery in order to make sure that each node gets assigned
+    # to only one position.
+    
+    foreach my $li ( 1..scalar(@$wit_matrix) ) {
+	foreach my $di ( 1..scalar(@{$wit_matrix->[$li-1]}) ) {
+	    my $reading = $wit_matrix->[$li-1]->[$di-1];
+	    my $position = "$li,$di";
+
+	    # If we have seen this node before, we need to compare
+	    # its position with what went before.
+	    unless( $reading->has_position &&
+		    _cmp_position( $position, $reading->position ) < 1 ) {
+		# The new position ID replaces the old one.
+		$reading->position( $position );
+	    } # otherwise, the old position needs to stay.
+	}
+    }
+}
+
 sub _cmp_position {
     my( $a, $b ) = @_;
     if ( $a && $b ) {
@@ -726,5 +1017,14 @@ sub unique_list {
     return values( %h );
 }
 
+sub add_hash_entry {
+    my( $hash, $key, $entry ) = @_;
+    if( exists $hash->{$key} ) {
+	push( @{$hash->{$key}}, $entry );
+    } else {
+	$hash->{$key} = [ $entry ];
+    }
+}
+
 no Moose;
 __PACKAGE__->meta->make_immutable;