X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FText%2FTradition%2FCollation.pm;h=bd3b58df878abe0e57ef8262b8c3d1f1d52dface;hb=6771a1b11e560c54e9cb8cbcb7c18200021894cf;hp=82588d7b2b0023f9f766979471e9bbc07154de4b;hpb=bfcbcecb79f1f863779fef01bcf8e81c0bdbe7b1;p=scpubgit%2Fstemmatology.git diff --git a/lib/Text/Tradition/Collation.pm b/lib/Text/Tradition/Collation.pm index 82588d7..bd3b58d 100644 --- a/lib/Text/Tradition/Collation.pm +++ b/lib/Text/Tradition/Collation.pm @@ -1,14 +1,16 @@ package Text::Tradition::Collation; +use feature 'say'; use Encode qw( decode_utf8 ); use File::Temp; use File::Which; use Graph; use IPC::Run qw( run binary ); -use Text::CSV_XS; +use Text::CSV; use Text::Tradition::Collation::Reading; use Text::Tradition::Collation::RelationshipStore; use Text::Tradition::Error; +use XML::Easy::Syntax qw( $xml10_namestartchar_rx $xml10_namechar_rx ); use XML::LibXML; use XML::LibXML::XPathContext; use Moose; @@ -28,7 +30,10 @@ has 'relations' => ( handles => { relationships => 'relationships', related_readings => 'related_readings', + get_relationship => 'get_relationship', del_relationship => 'del_relationship', + equivalence => 'equivalence', + equivalence_graph => 'equivalence_graph', }, writer => '_set_relations', ); @@ -36,6 +41,7 @@ has 'relations' => ( has 'tradition' => ( is => 'ro', isa => 'Text::Tradition', + writer => '_set_tradition', weak_ref => 1, ); @@ -76,6 +82,12 @@ has 'ac_label' => ( default => ' (a.c.)', ); +has 'wordsep' => ( + is => 'rw', + isa => 'Str', + default => ' ', + ); + has 'start' => ( is => 'ro', isa => 'Text::Tradition::Collation::Reading', @@ -103,6 +115,12 @@ has 'cached_table' => ( predicate => 'has_cached_table', clearer => 'wipe_table', ); + +has '_graphcalc_done' => ( + is => 'rw', + isa => 'Bool', + default => undef, + ); =head1 NAME @@ -156,6 +174,9 @@ representing another layer of path for the given witness - that is, when a text has more than one possible reading due to scribal corrections or the like. Defaults to ' (a.c.)'. +=item * wordsep - The string used to separate words in the original text. +Defaults to ' '. + =back =head1 ACCESSORS @@ -170,6 +191,8 @@ the like. Defaults to ' (a.c.)'. =head2 ac_label +=head2 wordsep + Simple accessors for collation attributes. =head2 start @@ -198,10 +221,14 @@ See L for the available arguments. Removes the given reading from the collation, implicitly removing its paths and relationships. -=head2 merge_readings( $main, $second ) +=head2 merge_readings( $main, $second, $concatenate, $with_str ) + +Merges the $second reading into the $main one. If $concatenate is true, then +the merged node will carry the text of both readings, concatenated with either +$with_str (if specified) or a sensible default (the empty string if the +appropriate 'join_*' flag is set on either reading, or else $self->wordsep.) -Merges the $second reading into the $main one. -The arguments may be either readings or reading IDs. +The first two arguments may be either readings or reading IDs. =head2 has_reading( $id ) @@ -248,22 +275,25 @@ See L for the available options. sub BUILD { my $self = shift; $self->_set_relations( Text::Tradition::Collation::RelationshipStore->new( 'collation' => $self ) ); - $self->_set_start( $self->add_reading( { 'collation' => $self, 'is_start' => 1 } ) ); - $self->_set_end( $self->add_reading( { 'collation' => $self, 'is_end' => 1 } ) ); + $self->_set_start( $self->add_reading( + { 'collation' => $self, 'is_start' => 1, 'init' => 1 } ) ); + $self->_set_end( $self->add_reading( + { 'collation' => $self, 'is_end' => 1, 'init' => 1 } ) ); } ### Reading construct/destruct functions -sub _clear_cache { - my $self = shift; - $self->wipe_svg if $self->has_cached_svg; - $self->wipe_table if $self->has_cached_table; -} - sub add_reading { my( $self, $reading ) = @_; unless( ref( $reading ) eq 'Text::Tradition::Collation::Reading' ) { my %args = %$reading; + if( $args{'init'} ) { + # If we are initializing an empty collation, don't assume that we + # have set a tradition. + delete $args{'init'}; + } elsif( $self->tradition->has_language && !exists $args{'language'} ) { + $args{'language'} = $self->tradition->language; + } $reading = Text::Tradition::Collation::Reading->new( 'collation' => $self, %args ); @@ -272,7 +302,7 @@ sub add_reading { if( $self->reading( $reading->id ) ) { throw( "Collation already has a reading with id " . $reading->id ); } - $self->_clear_cache; + $self->_graphcalc_done(0); $self->_add_reading( $reading->id => $reading ); # Once the reading has been added, put it in both graphs. $self->sequence->add_vertex( $reading->id ); @@ -289,7 +319,8 @@ around del_reading => sub { $arg = $arg->id; } # Remove the reading from the graphs. - $self->_clear_cache; + $self->_graphcalc_done(0); + $self->_clear_cache; # Explicitly clear caches to GC the reading $self->sequence->delete_vertex( $arg ); $self->relations->delete_reading( $arg ); @@ -297,16 +328,71 @@ around del_reading => sub { $self->$orig( $arg ); }; -# merge_readings( $main, $to_be_deleted ); +=begin testing + +use Text::Tradition; + +my $cxfile = 't/data/Collatex-16.xml'; +my $t = Text::Tradition->new( + 'name' => 'inline', + 'input' => 'CollateX', + 'file' => $cxfile, + ); +my $c = $t->collation; + +my $rno = scalar $c->readings; +# Split n21 for testing purposes +my $new_r = $c->add_reading( { 'id' => 'n21p0', 'text' => 'un', 'join_next' => 1 } ); +my $old_r = $c->reading( 'n21' ); +$old_r->alter_text( 'to' ); +$c->del_path( 'n20', 'n21', 'A' ); +$c->add_path( 'n20', 'n21p0', 'A' ); +$c->add_path( 'n21p0', 'n21', 'A' ); +$c->flatten_ranks(); +ok( $c->reading( 'n21p0' ), "New reading exists" ); +is( scalar $c->readings, $rno, "Reading add offset by flatten_ranks" ); + +# Combine n3 and n4 ( with his ) +$c->merge_readings( 'n3', 'n4', 1 ); +ok( !$c->reading('n4'), "Reading n4 is gone" ); +is( $c->reading('n3')->text, 'with his', "Reading n3 has both words" ); + +# Collapse n9 and n10 ( rood / root ) +$c->merge_readings( 'n9', 'n10' ); +ok( !$c->reading('n10'), "Reading n10 is gone" ); +is( $c->reading('n9')->text, 'rood', "Reading n9 has an unchanged word" ); + +# Combine n21 and n21p0 +my $remaining = $c->reading('n21'); +$remaining ||= $c->reading('n22'); # one of these should still exist +$c->merge_readings( 'n21p0', $remaining, 1 ); +ok( !$c->reading('n21'), "Reading $remaining is gone" ); +is( $c->reading('n21p0')->text, 'unto', "Reading n21p0 merged correctly" ); + +=end testing + +=cut sub merge_readings { my $self = shift; + # Sanity check + my( $kept_obj, $del_obj, $combine, $combine_char ) = $self->_objectify_args( @_ ); + my $mergemeta = $kept_obj->is_meta; + throw( "Cannot merge meta and non-meta reading" ) + unless ( $mergemeta && $del_obj->is_meta ) + || ( !$mergemeta && !$del_obj->is_meta ); + if( $mergemeta ) { + throw( "Cannot merge with start or end node" ) + if( $kept_obj eq $self->start || $kept_obj eq $self->end + || $del_obj eq $self->start || $del_obj eq $self->end ); + } # We only need the IDs for adding paths to the graph, not the reading # objects themselves. - my( $kept, $deleted, $combine_char ) = $self->_stringify_args( @_ ); - $self->_clear_cache; - + my $kept = $kept_obj->id; + my $deleted = $del_obj->id; + $self->_graphcalc_done(0); + # The kept reading should inherit the paths and the relationships # of the deleted reading. foreach my $path ( $self->sequence->edges_at( $deleted ) ) { @@ -320,27 +406,89 @@ sub merge_readings { @wits{keys %$fwits} = values %$fwits; $self->sequence->set_edge_attributes( @vector, \%wits ); } - $self->relations->merge_readings( $kept, $deleted, $combine_char ); + $self->relations->merge_readings( $kept, $deleted, $combine ); # Do the deletion deed. - if( $combine_char ) { - my $kept_obj = $self->reading( $kept ); - my $new_text = join( $combine_char, $kept_obj->text, - $self->reading( $deleted )->text ); - $kept_obj->alter_text( $new_text ); + if( $combine ) { + # Combine the text of the readings + my $joinstr = $combine_char; + unless( defined $joinstr ) { + $joinstr = '' if $kept_obj->join_next || $del_obj->join_prior; + $joinstr = $self->wordsep unless defined $joinstr; + } + $kept_obj->alter_text( join( $joinstr, $kept_obj->text, $del_obj->text ) ); + $kept_obj->normal_form( + join( $joinstr, $kept_obj->normal_form, $del_obj->normal_form ) ); + # Combine the lexemes present in the readings + if( $kept_obj->has_lexemes && $del_obj->has_lexemes ) { + $kept_obj->add_lexeme( $del_obj->lexemes ); + } } $self->del_reading( $deleted ); } +=head2 compress_readings + +Where possible in the graph, compresses plain sequences of readings into a +single reading. The sequences must consist of readings with no +relationships to other readings, with only a single witness path between +them and no other witness paths from either that would skip the other. The +readings must also not be marked as nonsense or bad grammar. + +WARNING: This operation cannot be undone. + +=cut + +sub compress_readings { + my $self = shift; + # Anywhere in the graph that there is a reading that joins only to a single + # successor, and neither of these have any relationships, just join the two + # readings. + my %gobbled; + foreach my $rdg ( sort { $a->rank <=> $b->rank } $self->readings ) { + next if $rdg->is_meta; + next if $gobbled{$rdg->id}; + next if $rdg->grammar_invalid || $rdg->is_nonsense; + next if $rdg->related_readings(); + my %seen; + while( $self->sequence->successors( $rdg ) == 1 ) { + my( $next ) = $self->reading( $self->sequence->successors( $rdg ) ); + throw( "Infinite loop" ) if $seen{$next->id}; + $seen{$next->id} = 1; + last if $self->sequence->predecessors( $next ) > 1; + last if $next->is_meta; + last if $next->grammar_invalid || $next->is_nonsense; + last if $next->related_readings(); + say "Joining readings $rdg and $next"; + $self->merge_readings( $rdg, $next, 1 ); + } + } + # Make sure we haven't screwed anything up + foreach my $wit ( $self->tradition->witnesses ) { + my $pathtext = $self->path_text( $wit->sigil ); + my $origtext = join( ' ', @{$wit->text} ); + throw( "Text differs for witness " . $wit->sigil ) + unless $pathtext eq $origtext; + if( $wit->is_layered ) { + $pathtext = $self->path_text( $wit->sigil.$self->ac_label ); + $origtext = join( ' ', @{$wit->layertext} ); + throw( "Ante-corr text differs for witness " . $wit->sigil ) + unless $pathtext eq $origtext; + } + } + + $self->relations->rebuild_equivalence(); + $self->calculate_ranks(); +} # Helper function for manipulating the graph. sub _stringify_args { - my( $self, $first, $second, $arg ) = @_; + my( $self, $first, $second, @args ) = @_; $first = $first->id if ref( $first ) eq 'Text::Tradition::Collation::Reading'; $second = $second->id if ref( $second ) eq 'Text::Tradition::Collation::Reading'; - return( $first, $second, $arg ); + return( $first, $second, @args ); } # Helper function for manipulating the graph. @@ -361,12 +509,15 @@ sub add_path { # objects themselves. my( $source, $target, $wit ) = $self->_stringify_args( @_ ); - $self->_clear_cache; + $self->_graphcalc_done(0); # Connect the readings - $self->sequence->add_edge( $source, $target ); + unless( $self->sequence->has_edge( $source, $target ) ) { + $self->sequence->add_edge( $source, $target ); + $self->relations->add_equivalence_edge( $source, $target ); + } # Note the witness in question $self->sequence->set_edge_attribute( $source, $target, $wit, 1 ); -}; +} sub del_path { my $self = shift; @@ -382,12 +533,13 @@ sub del_path { # objects themselves. my( $source, $target, $wit ) = $self->_stringify_args( @args ); - $self->_clear_cache; + $self->_graphcalc_done(0); if( $self->sequence->has_edge_attribute( $source, $target, $wit ) ) { $self->sequence->delete_edge_attribute( $source, $target, $wit ); } unless( keys %{$self->sequence->get_edge_attributes( $source, $target )} ) { $self->sequence->delete_edge( $source, $target ); + $self->relations->delete_equivalence_edge( $source, $target ); } } @@ -411,7 +563,7 @@ be called via $tradition->del_witness. sub clear_witness { my( $self, @sigils ) = @_; - $self->_clear_cache; + $self->_graphcalc_done(0); # Clear the witness(es) out of the paths foreach my $e ( $self->paths ) { foreach my $sig ( @sigils ) { @@ -430,14 +582,22 @@ sub clear_witness { sub add_relationship { my $self = shift; my( $source, $target, $opts ) = $self->_stringify_args( @_ ); - my( @vectors ) = $self->relations->add_relationship( $source, - $self->reading( $source ), $target, $self->reading( $target ), $opts ); - # Force a full rank recalculation every time. Yuck. - $self->calculate_ranks() if $self->end->has_rank; - $self->_clear_cache; + my( @vectors ) = $self->relations->add_relationship( $source, $target, $opts ); + $self->_graphcalc_done(0); return @vectors; } +around qw/ get_relationship del_relationship / => sub { + my $orig = shift; + my $self = shift; + my @args = @_; + if( @args == 1 && ref( $args[0] ) eq 'ARRAY' ) { + @args = @{$_[0]}; + } + my( $source, $target ) = $self->_stringify_args( @args ); + $self->$orig( $source, $target ); +}; + =head2 reading_witnesses( $reading ) Return a list of sigils corresponding to the witnesses in which the reading appears. @@ -477,6 +637,8 @@ sub as_svg { throw( "Need GraphViz installed to output SVG" ) unless File::Which::which( 'dot' ); my $want_subgraph = exists $opts->{'from'} || exists $opts->{'to'}; + $self->calculate_ranks() + unless( $self->_graphcalc_done || $opts->{'nocalc'} || !$self->linear ); if( !$self->has_cached_svg || $opts->{'recalc'} || $want_subgraph ) { my @cmd = qw/dot -Tsvg/; my( $svg, $err ); @@ -520,6 +682,7 @@ sub as_dot { my $color_common = $opts->{'color_common'} if $opts; my $STRAIGHTENHACK = !$startrank && !$endrank && $self->end->rank && $self->end->rank > 100; + $STRAIGHTENHACK = 1 if $opts->{'straight'}; # even for subgraphs or small graphs # Check the arguments if( $startrank ) { @@ -557,14 +720,15 @@ sub as_dot { # Output substitute start/end readings if necessary if( $startrank ) { - $dot .= "\t\"#SUBSTART#\" [ label=\"...\" ];\n"; + $dot .= "\t\"__SUBSTART__\" [ label=\"...\",id=\"__START__\" ];\n"; } if( $endrank ) { - $dot .= "\t\"#SUBEND#\" [ label=\"...\" ];\n"; + $dot .= "\t\"__SUBEND__\" [ label=\"...\",id=\"__END__\" ];\n"; } if( $STRAIGHTENHACK ) { ## HACK part 1 - $dot .= "\tsubgraph { rank=same \"#START#\" \"#SILENT#\" }\n"; + my $startlabel = $startrank ? '__SUBSTART__' : '__START__'; + $dot .= "\tsubgraph { rank=same \"$startlabel\" \"#SILENT#\" }\n"; $dot .= "\t\"#SILENT#\" [ shape=diamond,color=white,penwidth=0,label=\"\" ];" } my %used; # Keep track of the readings that actually appear in the graph @@ -582,8 +746,11 @@ sub as_dot { next if $reading->id eq $reading->text; my $rattrs; my $label = $reading->text; + $label .= '-' if $reading->join_next; + $label = "-$label" if $reading->join_prior; $label =~ s/\"/\\\"/g; $rattrs->{'label'} = $label; + $rattrs->{'id'} = $reading->id; $rattrs->{'fillcolor'} = '#b3f36d' if $reading->is_common && $color_common; $dot .= sprintf( "\t\"%s\" %s;\n", $reading->id, _dot_attr_string( $rattrs ) ); } @@ -623,27 +790,33 @@ sub as_dot { $dot .= sprintf( "\t\"%s\" -> \"%s\" %s;\n", $edge->[0], $edge->[1], $varopts ); } elsif( $used{$edge->[0]} ) { - $subend{$edge->[0]} = 1; + $subend{$edge->[0]} = $edge->[1]; } elsif( $used{$edge->[1]} ) { - $substart{$edge->[1]} = 1; + $substart{$edge->[1]} = $edge->[0]; } } # Add substitute start and end edges if necessary foreach my $node ( keys %substart ) { - my $witstr = $self->_path_display_label ( $self->reading_witnesses( $self->reading( $node ) ) ); + my $witstr = $self->_path_display_label ( $self->path_witnesses( $substart{$node}, $node ) ); my $variables = { %edge_attrs, 'label' => $witstr }; + my $nrdg = $self->reading( $node ); + if( $nrdg->has_rank && $nrdg->rank > $startrank ) { + # Substart is actually one lower than $startrank + $variables->{'minlen'} = $nrdg->rank - ( $startrank - 1 ); + } my $varopts = _dot_attr_string( $variables ); - $dot .= "\t\"#SUBSTART#\" -> \"$node\" $varopts;"; + $dot .= "\t\"__SUBSTART__\" -> \"$node\" $varopts;\n"; } foreach my $node ( keys %subend ) { - my $witstr = $self->_path_display_label ( $self->reading_witnesses( $self->reading( $node ) ) ); + my $witstr = $self->_path_display_label ( $self->path_witnesses( $node, $subend{$node} ) ); my $variables = { %edge_attrs, 'label' => $witstr }; my $varopts = _dot_attr_string( $variables ); - $dot .= "\t\"$node\" -> \"#SUBEND#\" $varopts;"; + $dot .= "\t\"$node\" -> \"__SUBEND__\" $varopts;\n"; } # HACK part 2 if( $STRAIGHTENHACK ) { - $dot .= "\t\"#END#\" -> \"#SILENT#\" [ color=white,penwidth=0 ];\n"; + my $endlabel = $endrank ? '__SUBEND__' : '__END__'; + $dot .= "\t\"$endlabel\" -> \"#SILENT#\" [ color=white,penwidth=0 ];\n"; } $dot .= "}\n"; @@ -704,26 +877,56 @@ sub path_witnesses { return @wits; } +# Helper function. Make a display label for the given witnesses, showing a.c. +# witnesses only where the main witness is not also in the list. sub _path_display_label { my $self = shift; - my @wits = sort @_; + my %wits; + map { $wits{$_} = 1 } @_; + + # If an a.c. wit is listed, remove it if the main wit is also listed. + # Otherwise keep it for explicit listing. + my $aclabel = $self->ac_label; + my @disp_ac; + foreach my $w ( sort keys %wits ) { + if( $w =~ /^(.*)\Q$aclabel\E$/ ) { + if( exists $wits{$1} ) { + delete $wits{$w}; + } else { + push( @disp_ac, $w ); + } + } + } + + # See if we are in a majority situation. my $maj = scalar( $self->tradition->witnesses ) * 0.6; - if( scalar @wits > $maj ) { - # TODO break out a.c. wits - return 'majority'; + $maj = $maj > 5 ? $maj : 5; + if( scalar keys %wits > $maj ) { + unshift( @disp_ac, 'majority' ); + return join( ', ', @disp_ac ); } else { - return join( ', ', @wits ); + return join( ', ', sort keys %wits ); } } -=head2 witnesses_at_rank +=head2 readings_at_rank( $rank ) -Returns a list of witnesses that are not lacunose, for a given rank. +Returns a list of readings at a given rank, taken from the alignment table. =cut -sub witnesses_at_rank { +sub readings_at_rank { my( $self, $rank ) = @_; + my $table = $self->alignment_table; + # Table rank is real rank - 1. + my @elements = map { $_->{'tokens'}->[$rank-1] } @{$table->{'alignment'}}; + my %readings; + foreach my $e ( @elements ) { + next unless ref( $e ) eq 'HASH'; + next unless exists $e->{'t'}; + $readings{$e->{'t'}->id} = $e->{'t'}; + } + return values %readings; } =head2 as_graphml @@ -768,13 +971,37 @@ is( scalar $st->collation->readings, $READINGS, "Reparsed collation has all read is( scalar $st->collation->paths, $PATHS, "Reparsed collation has all paths" ); is( scalar $st->collation->relationships, 3, "Reparsed collation has new relationships" ); +# Now add a stemma, write to GraphML, and parse again. +my $stemma = $tradition->add_stemma( 'dotfile' => 't/data/florilegium.dot' ); +is( ref( $stemma ), 'Text::Tradition::Stemma', "Parsed dotfile into stemma" ); +is( $tradition->stemmata, 1, "Tradition now has the stemma" ); +$graphml = $c->as_graphml; +like( $graphml, qr/digraph/, "Digraph declaration exists in GraphML" ); + =end testing =cut sub as_graphml { - my( $self ) = @_; - + my( $self, $options ) = @_; + $self->calculate_ranks unless $self->_graphcalc_done; + + my $start = $options->{'from'} + ? $self->reading( $options->{'from'} ) : $self->start; + my $end = $options->{'to'} + ? $self->reading( $options->{'to'} ) : $self->end; + if( $start->has_rank && $end->has_rank && $end->rank < $start->rank ) { + throw( 'Start node must be before end node' ); + } + # The readings need to be ranked for this to work. + $start = $self->start unless $start->has_rank; + $end = $self->end unless $end->has_rank; + my $rankoffset = 0; + unless( $start eq $self->start ) { + $rankoffset = $start->rank - 1; + } + my %use_readings; + # Some namespaces my $graphml_ns = 'http://graphml.graphdrawing.org/xmlns'; my $xsi_ns = 'http://www.w3.org/2001/XMLSchema-instance'; @@ -787,74 +1014,130 @@ sub as_graphml { $graphml->setDocumentElement( $root ); $root->setNamespace( $xsi_ns, 'xsi', 0 ); $root->setAttributeNS( $xsi_ns, 'schemaLocation', $graphml_schema ); + + # List of attribute types to save on our objects and their corresponding + # GraphML types + my %save_types = ( + 'Str' => 'string', + 'Int' => 'int', + 'Bool' => 'boolean', + 'ReadingID' => 'string', + 'RelationshipType' => 'string', + 'RelationshipScope' => 'string', + ); + + # List of attribute names *not* to save on our objects. + # We will also not save any attribute beginning with _. + my %skipsave; + map { $skipsave{$_} = 1 } qw/ cached_svg /; - # Add the data keys for the graph + # Add the data keys for the graph. Include an extra key 'version' for the + # GraphML output version. my %graph_data_keys; my $gdi = 0; - my @graph_attributes = qw/ version wit_list_separator baselabel linear ac_label /; - foreach my $datum ( @graph_attributes ) { + my %graph_attributes = ( 'version' => 'string' ); + # Graph attributes include those of Tradition and those of Collation. + my %gattr_from; + my $tmeta = $self->tradition->meta; + my $cmeta = $self->meta; + map { $gattr_from{$_->name} = 'Tradition' } $tmeta->get_all_attributes; + map { $gattr_from{$_->name} = 'Collation' } $cmeta->get_all_attributes; + foreach my $attr ( ( $tmeta->get_all_attributes, $cmeta->get_all_attributes ) ) { + next if $attr->name =~ /^_/; + next if $skipsave{$attr->name}; + next unless $save_types{$attr->type_constraint->name}; + $graph_attributes{$attr->name} = $save_types{$attr->type_constraint->name}; + } + # Extra custom key for the tradition stemma(ta) + $graph_attributes{'stemmata'} = 'string'; + + foreach my $datum ( sort keys %graph_attributes ) { $graph_data_keys{$datum} = 'dg'.$gdi++; my $key = $root->addNewChild( $graphml_ns, 'key' ); $key->setAttribute( 'attr.name', $datum ); - $key->setAttribute( 'attr.type', $key eq 'linear' ? 'boolean' : 'string' ); + $key->setAttribute( 'attr.type', $graph_attributes{$datum} ); $key->setAttribute( 'for', 'graph' ); $key->setAttribute( 'id', $graph_data_keys{$datum} ); } - # Add the data keys for nodes + # Add the data keys for reading nodes + my %reading_attributes; + my $rmeta = Text::Tradition::Collation::Reading->meta; + foreach my $attr( $rmeta->get_all_attributes ) { + next if $attr->name =~ /^_/; + next if $skipsave{$attr->name}; + next unless $save_types{$attr->type_constraint->name}; + $reading_attributes{$attr->name} = $save_types{$attr->type_constraint->name}; + } + # Extra custom key for the reading morphology + $reading_attributes{'lexemes'} = 'string'; + my %node_data_keys; my $ndi = 0; - my %node_data = ( - id => 'string', - text => 'string', - rank => 'string', - is_start => 'boolean', - is_end => 'boolean', - is_lacuna => 'boolean', - ); - foreach my $datum ( keys %node_data ) { + foreach my $datum ( sort keys %reading_attributes ) { $node_data_keys{$datum} = 'dn'.$ndi++; my $key = $root->addNewChild( $graphml_ns, 'key' ); $key->setAttribute( 'attr.name', $datum ); - $key->setAttribute( 'attr.type', $node_data{$datum} ); + $key->setAttribute( 'attr.type', $reading_attributes{$datum} ); $key->setAttribute( 'for', 'node' ); $key->setAttribute( 'id', $node_data_keys{$datum} ); } - # Add the data keys for edges, i.e. witnesses + # Add the data keys for edges, that is, paths and relationships. Path + # data does not come from a Moose class so is here manually. my $edi = 0; my %edge_data_keys; - my %edge_data = ( - class => 'string', # Class, deprecated soon + my %edge_attributes = ( witness => 'string', # ID/label for a path - relationship => 'string', # ID/label for a relationship extra => 'boolean', # Path key - scope => 'string', # Relationship key - non_correctable => 'boolean', # Relationship key - non_independent => 'boolean', # Relationship key ); - foreach my $datum ( keys %edge_data ) { + my @path_attributes = keys %edge_attributes; # track our manual additions + my $pmeta = Text::Tradition::Collation::Relationship->meta; + foreach my $attr( $pmeta->get_all_attributes ) { + next if $attr->name =~ /^_/; + next if $skipsave{$attr->name}; + next unless $save_types{$attr->type_constraint->name}; + $edge_attributes{$attr->name} = $save_types{$attr->type_constraint->name}; + } + foreach my $datum ( sort keys %edge_attributes ) { $edge_data_keys{$datum} = 'de'.$edi++; my $key = $root->addNewChild( $graphml_ns, 'key' ); $key->setAttribute( 'attr.name', $datum ); - $key->setAttribute( 'attr.type', $edge_data{$datum} ); + $key->setAttribute( 'attr.type', $edge_attributes{$datum} ); $key->setAttribute( 'for', 'edge' ); $key->setAttribute( 'id', $edge_data_keys{$datum} ); } - # Add the collation graph itself + # Add the collation graph itself. First, sanitize the name to a valid XML ID. + my $xmlidname = $self->tradition->name; + $xmlidname =~ s/(?!$xml10_namechar_rx)./_/g; + if( $xmlidname !~ /^$xml10_namestartchar_rx/ ) { + $xmlidname = '_'.$xmlidname; + } my $sgraph = $root->addNewChild( $graphml_ns, 'graph' ); $sgraph->setAttribute( 'edgedefault', 'directed' ); - $sgraph->setAttribute( 'id', $self->tradition->name ); + $sgraph->setAttribute( 'id', $xmlidname ); $sgraph->setAttribute( 'parse.edgeids', 'canonical' ); - $sgraph->setAttribute( 'parse.edges', scalar($self->paths) ); + $sgraph->setAttribute( 'parse.edges', 0 ); # fill in later $sgraph->setAttribute( 'parse.nodeids', 'canonical' ); - $sgraph->setAttribute( 'parse.nodes', scalar($self->readings) ); + $sgraph->setAttribute( 'parse.nodes', 0 ); # fill in later $sgraph->setAttribute( 'parse.order', 'nodesfirst' ); - # Collation attribute data - foreach my $datum ( @graph_attributes ) { - my $value = $datum eq 'version' ? '3.0' : $self->$datum; + # Tradition/collation attribute data + foreach my $datum ( keys %graph_attributes ) { + my $value; + if( $datum eq 'version' ) { + $value = '3.2'; + } elsif( $datum eq 'stemmata' ) { + my @stemstrs; + map { push( @stemstrs, $_->editable( {linesep => ''} ) ) } + $self->tradition->stemmata; + $value = join( "\n", @stemstrs ); + } elsif( $gattr_from{$datum} eq 'Tradition' ) { + $value = $self->tradition->$datum; + } else { + $value = $self->$datum; + } _add_graphml_data( $sgraph, $graph_data_keys{$datum}, $value ); } @@ -862,13 +1145,30 @@ sub as_graphml { my %node_hash; # Add our readings to the graph foreach my $n ( sort { $a->id cmp $b->id } $self->readings ) { + next if $n->has_rank && $n ne $self->start && $n ne $self->end && + ( $n->rank < $start->rank || $n->rank > $end->rank ); + $use_readings{$n->id} = 1; # Add to the main graph my $node_el = $sgraph->addNewChild( $graphml_ns, 'node' ); my $node_xmlid = 'n' . $node_ctr++; $node_hash{ $n->id } = $node_xmlid; $node_el->setAttribute( 'id', $node_xmlid ); - foreach my $d ( keys %node_data ) { + foreach my $d ( keys %reading_attributes ) { my $nval = $n->$d; + # Custom serialization + if( $d eq 'lexemes' ) { + # If nval is a true value, we have lexemes so we need to + # serialize them. Otherwise set nval to undef so that the + # key is excluded from this reading. + $nval = $nval ? $n->_serialize_lexemes : undef; + } elsif( $d eq 'normal_form' && $n->normal_form eq $n->text ) { + $nval = undef; + } + if( $rankoffset && $d eq 'rank' && $n ne $self->start ) { + # Adjust the ranks within the subgraph. + $nval = $n eq $self->end ? $end->rank - $rankoffset + 1 + : $nval - $rankoffset; + } _add_graphml_data( $node_el, $node_data_keys{$d}, $nval ) if defined $nval; } @@ -878,7 +1178,13 @@ sub as_graphml { my $edge_ctr = 0; foreach my $e ( sort { $a->[0] cmp $b->[0] } $self->sequence->edges() ) { # We add an edge in the graphml for every witness in $e. - foreach my $wit ( sort $self->path_witnesses( $e ) ) { + next unless( $use_readings{$e->[0]} || $use_readings{$e->[1]} ); + my @edge_wits = sort $self->path_witnesses( $e ); + $e->[0] = $self->start->id unless $use_readings{$e->[0]}; + $e->[1] = $self->end->id unless $use_readings{$e->[1]}; + # Skip any path from start to end; that witness is not in the subgraph. + next if ( $e->[0] eq $self->start->id && $e->[1] eq $self->end->id ); + foreach my $wit ( @edge_wits ) { my( $id, $from, $to ) = ( 'e'.$edge_ctr++, $node_hash{ $e->[0] }, $node_hash{ $e->[1] } ); @@ -899,11 +1205,15 @@ sub as_graphml { _add_graphml_data( $edge_el, $edge_data_keys{'extra'}, $aclabel ); } _add_graphml_data( $edge_el, $edge_data_keys{'witness'}, $base ); - _add_graphml_data( $edge_el, $edge_data_keys{'class'}, 'path' ); } } + # Report the actual number of nodes and edges that went in + $sgraph->setAttribute( 'parse.edges', $edge_ctr ); + $sgraph->setAttribute( 'parse.nodes', $node_ctr ); + # Add the relationship graph to the XML + map { delete $edge_data_keys{$_} } @path_attributes; $self->relations->_as_graphml( $graphml_ns, $root, \%node_hash, $node_data_keys{'id'}, \%edge_data_keys ); @@ -930,7 +1240,7 @@ row per witness (or witness uncorrected.) sub as_csv { my( $self ) = @_; my $table = $self->alignment_table; - my $csv = Text::CSV_XS->new( { binary => 1, quote_null => 0 } ); + my $csv = Text::CSV->new( { binary => 1, quote_null => 0 } ); my @result; # Make the header row $csv->combine( map { $_->{'witness'} } @{$table->{'alignment'}} ); @@ -967,7 +1277,7 @@ keys have a true hash value will be included. sub alignment_table { my( $self ) = @_; - my $include; # see if we can ditch this + $self->calculate_ranks() unless $self->_graphcalc_done; return $self->cached_table if $self->has_cached_table; # Make sure we can do this @@ -978,10 +1288,7 @@ sub alignment_table { my $table = { 'alignment' => [], 'length' => $self->end->rank - 1 }; my @all_pos = ( 1 .. $self->end->rank - 1 ); foreach my $wit ( sort { $a->sigil cmp $b->sigil } $self->tradition->witnesses ) { - if( $include ) { - next unless $include->{$wit->sigil}; - } - # print STDERR "Making witness row(s) for " . $wit->sigil . "\n"; + # say STDERR "Making witness row(s) for " . $wit->sigil; my @wit_path = $self->reading_sequence( $self->start, $self->end, $wit->sigil ); my @row = _make_witness_row( \@wit_path, \@all_pos ); push( @{$table->{'alignment'}}, @@ -1006,8 +1313,8 @@ sub _make_witness_row { foreach my $rdg ( @$path ) { my $rtext = $rdg->text; $rtext = '#LACUNA#' if $rdg->is_lacuna; - print STDERR "rank " . $rdg->rank . "\n" if $debug; - # print STDERR "No rank for " . $rdg->id . "\n" unless defined $rdg->rank; + say STDERR "rank " . $rdg->rank if $debug; + # say STDERR "No rank for " . $rdg->id unless defined $rdg->rank; $char_hash{$rdg->rank} = { 't' => $rdg }; } my @row = map { $char_hash{$_} } @$positions; @@ -1179,7 +1486,7 @@ sub common_readings { return @common; } -=head2 path_text( $sigil, $mainsigil [, $start, $end ] ) +=head2 path_text( $sigil, [, $start, $end ] ) Returns the text of a witness (plus its backup, if we are using a layer) as stored in the collation. The text is returned as a string, where the @@ -1194,7 +1501,16 @@ sub path_text { $start = $self->start unless $start; $end = $self->end unless $end; my @path = grep { !$_->is_meta } $self->reading_sequence( $start, $end, $wit ); - return join( ' ', map { $_->text } @path ); + my $pathtext = ''; + my $last; + foreach my $r ( @path ) { + unless ( $r->join_prior || !$last || $last->join_next ) { + $pathtext .= ' '; + } + $pathtext .= $r->text; + $last = $r; + } + return $pathtext; } =head1 INITIALIZATION METHODS @@ -1222,7 +1538,7 @@ Call make_witness_path for all witnesses in the tradition. sub make_witness_paths { my( $self ) = @_; foreach my $wit ( $self->tradition->witnesses ) { - # print STDERR "Making path for " . $wit->sigil . "\n"; + # say STDERR "Making path for " . $wit->sigil; $self->make_witness_path( $wit ); } } @@ -1231,11 +1547,16 @@ sub make_witness_path { my( $self, $wit ) = @_; my @chain = @{$wit->path}; my $sig = $wit->sigil; + # Add start and end if necessary + unshift( @chain, $self->start ) unless $chain[0] eq $self->start; + push( @chain, $self->end ) unless $chain[-1] eq $self->end; foreach my $idx ( 0 .. $#chain-1 ) { $self->add_path( $chain[$idx], $chain[$idx+1], $sig ); } if( $wit->is_layered ) { @chain = @{$wit->uncorrected_path}; + unshift( @chain, $self->start ) unless $chain[0] eq $self->start; + push( @chain, $self->end ) unless $chain[-1] eq $self->end; foreach my $idx( 0 .. $#chain-1 ) { my $source = $chain[$idx]; my $target = $chain[$idx+1]; @@ -1270,7 +1591,7 @@ ok( $c->has_cached_table, "Alignment table was cached" ); is( $c->alignment_table, $table, "Cached table returned upon second call" ); $c->calculate_ranks; is( $c->alignment_table, $table, "Cached table retained with no rank change" ); -$c->add_relationship( 'n9', 'n23', { 'type' => 'spelling' } ); +$c->add_relationship( 'n24', 'n23', { 'type' => 'spelling' } ); isnt( $c->alignment_table, $table, "Alignment table changed after relationship add" ); =end testing @@ -1281,58 +1602,20 @@ sub calculate_ranks { my $self = shift; # Save the existing ranks, in case we need to invalidate the cached SVG. my %existing_ranks; - # Walk a version of the graph where every node linked by a relationship - # edge is fundamentally the same node, and do a topological ranking on - # the nodes in this graph. - my $topo_graph = Graph->new(); - my %rel_containers; - my $rel_ctr = 0; - # Add the nodes - foreach my $r ( $self->readings ) { - next if exists $rel_containers{$r->id}; - my @rels = $r->related_readings( 'colocated' ); - if( @rels ) { - # Make a relationship container. - push( @rels, $r ); - my $rn = 'rel_container_' . $rel_ctr++; - $topo_graph->add_vertex( $rn ); - foreach( @rels ) { - $rel_containers{$_->id} = $rn; - } - } else { - # Add a new node to mirror the old node. - $rel_containers{$r->id} = $r->id; - $topo_graph->add_vertex( $r->id ); - } - } + map { $existing_ranks{$_} = $_->rank } $self->readings; + + # Do the rankings based on the relationship equivalence graph, starting + # with the start node. + my ( $node_ranks, $rank_nodes ) = $self->relations->equivalence_ranks(); - # Add the edges. - foreach my $r ( $self->readings ) { - $existing_ranks{$r} = $r->rank; - foreach my $n ( $self->sequence->successors( $r->id ) ) { - my( $tfrom, $tto ) = ( $rel_containers{$r->id}, - $rel_containers{$n} ); - # $DB::single = 1 unless $tfrom && $tto; - $topo_graph->add_edge( $tfrom, $tto ); - } - } - - # Now do the rankings, starting with the start node. - my $topo_start = $rel_containers{$self->start->id}; - my $node_ranks = { $topo_start => 0 }; - my @curr_origin = ( $topo_start ); - # A little iterative function. - while( @curr_origin ) { - @curr_origin = _assign_rank( $topo_graph, $node_ranks, @curr_origin ); - } # Transfer our rankings from the topological graph to the real one. foreach my $r ( $self->readings ) { - if( defined $node_ranks->{$rel_containers{$r->id}} ) { - $r->rank( $node_ranks->{$rel_containers{$r->id}} ); + if( defined $node_ranks->{$self->equivalence( $r->id )} ) { + $r->rank( $node_ranks->{$self->equivalence( $r->id )} ); } else { # Die. Find the last rank we calculated. - my @all_defined = sort { $node_ranks->{$rel_containers{$a->id}} - <=> $node_ranks->{$rel_containers{$b->id}} } + my @all_defined = sort { ( $node_ranks->{$self->equivalence( $a->id )}||-1 ) + <=> ( $node_ranks->{$self->equivalence( $b->id )}||-1 ) } $self->readings; my $last = pop @all_defined; throw( "Ranks not calculated after $last - do you have a cycle in the graph?" ); @@ -1341,47 +1624,25 @@ sub calculate_ranks { # Do we need to invalidate the cached data? if( $self->has_cached_svg || $self->has_cached_table ) { foreach my $r ( $self->readings ) { - next if $existing_ranks{$r} == $r->rank; + next if defined( $existing_ranks{$r} ) + && $existing_ranks{$r} == $r->rank; + # Something has changed, so clear the cache $self->_clear_cache; + # ...and recalculate the common readings. + $self->calculate_common_readings(); last; } } + # The graph calculation information is now up to date. + $self->_graphcalc_done(1); } -sub _assign_rank { - my( $graph, $node_ranks, @current_nodes ) = @_; - # Look at each of the children of @current_nodes. If all the child's - # parents have a rank, assign it the highest rank + 1 and add it to - # @next_nodes. Otherwise skip it; we will return when the highest-ranked - # parent gets a rank. - my @next_nodes; - foreach my $c ( @current_nodes ) { - warn "Current reading $c has no rank!" - unless exists $node_ranks->{$c}; - # print STDERR "Looking at child of node $c, rank " - # . $node_ranks->{$c} . "\n"; - foreach my $child ( $graph->successors( $c ) ) { - next if exists $node_ranks->{$child}; - my $highest_rank = -1; - my $skip = 0; - foreach my $parent ( $graph->predecessors( $child ) ) { - if( exists $node_ranks->{$parent} ) { - $highest_rank = $node_ranks->{$parent} - if $highest_rank <= $node_ranks->{$parent}; - } else { - $skip = 1; - last; - } - } - next if $skip; - my $c_rank = $highest_rank + 1; - # print STDERR "Assigning rank $c_rank to node $child \n"; - $node_ranks->{$child} = $c_rank; - push( @next_nodes, $child ); - } - } - return @next_nodes; -} +sub _clear_cache { + my $self = shift; + $self->wipe_svg if $self->has_cached_svg; + $self->wipe_table if $self->has_cached_table; +} + =head2 flatten_ranks @@ -1393,56 +1654,32 @@ with the same text at the same rank, and merges any that are found. sub flatten_ranks { my $self = shift; my %unique_rank_rdg; + my $changed; foreach my $rdg ( $self->readings ) { next unless $rdg->has_rank; my $key = $rdg->rank . "||" . $rdg->text; if( exists $unique_rank_rdg{$key} ) { + # Make sure they don't have different grammatical forms + my $ur = $unique_rank_rdg{$key}; + if( $rdg->disambiguated && $ur->disambiguated ) { + my $rform = join( '//', map { $_->form->to_string } $rdg->lexemes ); + my $uform = join( '//', map { $_->form->to_string } $ur->lexemes ); + next unless $rform eq $uform; + } elsif( $rdg->disambiguated xor $ur->disambiguated ) { + next; + } # Combine! - # print STDERR "Combining readings at same rank: $key\n"; + #say STDERR "Combining readings at same rank: $key"; + $changed = 1; $self->merge_readings( $unique_rank_rdg{$key}, $rdg ); # TODO see if this now makes a common point. } else { $unique_rank_rdg{$key} = $rdg; } } -} - -=head2 remove_collations - -Another convenience method for parsing. Removes all 'collation' relationships -that were defined in order to get the reading ranks to be correct. - -=begin testing - -use Text::Tradition; - -my $cxfile = 't/data/Collatex-16.xml'; -my $t = Text::Tradition->new( - 'name' => 'inline', - 'input' => 'CollateX', - 'file' => $cxfile, - ); -my $c = $t->collation; - -isnt( $c->reading('n23')->rank, $c->reading('n9')->rank, "Rank skew exists" ); -$c->add_relationship( 'n23', 'n9', { 'type' => 'collated', 'scope' => 'local' } ); -is( scalar $c->relationships, 4, "Found all expected relationships" ); -$c->remove_collations; -is( scalar $c->relationships, 3, "Collated relationships now gone" ); -is( $c->reading('n23')->rank, $c->reading('n9')->rank, "Aligned ranks were preserved" ); - -=end testing - -=cut - -sub remove_collations { - my $self = shift; - foreach my $reledge ( $self->relationships ) { - my $relobj = $self->relations->get_relationship( $reledge ); - if( $relobj && $relobj->type eq 'collated' ) { - $self->relations->delete_relationship( $reledge ); - } - } + # If we merged readings, the ranks are still fine but the alignment + # table is wrong. Wipe it. + $self->wipe_table() if $changed; } @@ -1468,7 +1705,7 @@ my @common = $c->calculate_common_readings(); is( scalar @common, 8, "Found correct number of common readings" ); my @marked = sort $c->common_readings(); is( scalar @common, 8, "All common readings got marked as such" ); -my @expected = qw/ n1 n12 n16 n19 n20 n5 n6 n7 /; +my @expected = qw/ n1 n11 n16 n19 n20 n5 n6 n7 /; is_deeply( \@marked, \@expected, "Found correct list of common readings" ); =end testing @@ -1478,6 +1715,8 @@ is_deeply( \@marked, \@expected, "Found correct list of common readings" ); sub calculate_common_readings { my $self = shift; my @common; + map { $_->is_common( 0 ) } $self->readings; + # Implicitly calls calculate_ranks my $table = $self->alignment_table; foreach my $idx ( 0 .. $table->{'length'} - 1 ) { my @row = map { $_->{'tokens'}->[$idx] @@ -1511,14 +1750,22 @@ original texts. sub text_from_paths { my $self = shift; foreach my $wit ( $self->tradition->witnesses ) { - my @text = split( /\s+/, - $self->reading_sequence( $self->start, $self->end, $wit->sigil ) ); + my @readings = $self->reading_sequence( $self->start, $self->end, $wit->sigil ); + my @text; + foreach my $r ( @readings ) { + next if $r->is_meta; + push( @text, $r->text ); + } $wit->text( \@text ); if( $wit->is_layered ) { - my @uctext = split( /\s+/, - $self->reading_sequence( $self->start, $self->end, - $wit->sigil.$self->ac_label ) ); - $wit->text( \@uctext ); + my @ucrdgs = $self->reading_sequence( $self->start, $self->end, + $wit->sigil.$self->ac_label ); + my @uctext; + foreach my $r ( @ucrdgs ) { + next if $r->is_meta; + push( @uctext, $r->text ); + } + $wit->layertext( \@uctext ); } } } @@ -1528,10 +1775,12 @@ sub text_from_paths { =head2 common_predecessor( $reading_a, $reading_b ) Find the last reading that occurs in sequence before both the given readings. +At the very least this should be $self->start. =head2 common_successor( $reading_a, $reading_b ) Find the first reading that occurs in sequence after both the given readings. +At the very least this should be $self->end. =begin testing @@ -1545,15 +1794,15 @@ my $t = Text::Tradition->new( ); my $c = $t->collation; -is( $c->common_predecessor( 'n9', 'n23' )->id, +is( $c->common_predecessor( 'n24', 'n23' )->id, 'n20', "Found correct common predecessor" ); -is( $c->common_successor( 'n9', 'n23' )->id, - '#END#', "Found correct common successor" ); +is( $c->common_successor( 'n24', 'n23' )->id, + '__END__', "Found correct common successor" ); is( $c->common_predecessor( 'n19', 'n17' )->id, 'n16', "Found correct common predecessor for readings on same path" ); -is( $c->common_successor( 'n21', 'n26' )->id, - '#END#', "Found correct common successor for readings on same path" ); +is( $c->common_successor( 'n21', 'n10' )->id, + '__END__', "Found correct common successor for readings on same path" ); =end testing @@ -1572,26 +1821,45 @@ sub common_successor { return $self->_common_in_path( $r1, $r2, 'successors' ); } + +# TODO think about how to do this without ranks... sub _common_in_path { my( $self, $r1, $r2, $dir ) = @_; - my $iter = $r1->rank > $r2->rank ? $r1->rank : $r2->rank; - $iter = $self->end->rank - $iter if $dir eq 'successors'; + my $iter = $self->end->rank; my @candidates; - my @last_checked = ( $r1, $r2 ); + my @last_r1 = ( $r1 ); + my @last_r2 = ( $r2 ); + # my %all_seen = ( $r1 => 'r1', $r2 => 'r2' ); my %all_seen; + # say STDERR "Finding common $dir for $r1, $r2"; while( !@candidates ) { - my @new_lc; - foreach my $lc ( @last_checked ) { + last unless $iter--; # Avoid looping infinitely + # Iterate separately down the graph from r1 and r2 + my( @new_lc1, @new_lc2 ); + foreach my $lc ( @last_r1 ) { + foreach my $p ( $lc->$dir ) { + if( $all_seen{$p->id} && $all_seen{$p->id} ne 'r1' ) { + # say STDERR "Path candidate $p from $lc"; + push( @candidates, $p ); + } elsif( !$all_seen{$p->id} ) { + $all_seen{$p->id} = 'r1'; + push( @new_lc1, $p ); + } + } + } + foreach my $lc ( @last_r2 ) { foreach my $p ( $lc->$dir ) { - if( $all_seen{$p->id} ) { + if( $all_seen{$p->id} && $all_seen{$p->id} ne 'r2' ) { + # say STDERR "Path candidate $p from $lc"; push( @candidates, $p ); - } else { - $all_seen{$p->id} = 1; - push( @new_lc, $p ); + } elsif( !$all_seen{$p->id} ) { + $all_seen{$p->id} = 'r2'; + push( @new_lc2, $p ); } } } - @last_checked = @new_lc; + @last_r1 = @new_lc1; + @last_r2 = @new_lc2; } my @answer = sort { $a->rank <=> $b->rank } @candidates; return $dir eq 'predecessors' ? pop( @answer ) : shift ( @answer );