[scpubgit/stemmatology.git] / lib / Text / Tradition / Parser / TEI.pm

package Text::Tradition::Parser::TEI;

use strict;
use warnings;
use Text::Tradition::Parser::Util qw( collate_variants );
use XML::LibXML;
use XML::LibXML::XPathContext;

=head1 NAME

Text::Tradition::Parser::TEI

=head1 SYNOPSIS

  use Text::Tradition;
  
  my $t_from_file = Text::Tradition->new( 
    'name' => 'my text',
    'input' => 'TEI',
    'file' => '/path/to/parallel_seg_file.xml'
    );
    
  my $t_from_string = Text::Tradition->new( 
    'name' => 'my text',
    'input' => 'TEI',
    'string' => $parallel_seg_xml,
    );


=head1 DESCRIPTION

Parser module for Text::Tradition, given a TEI parallel-segmentation file
that describes a text and its variants.  Normally called upon
initialization of Text::Tradition.

The witnesses for the tradition are taken from the <listWit/> element
within the TEI header; the readings are taken from any <p/> element that
appears in the text body (including <head/> elements therein.)

=head1 METHODS

=over

=item B<parse>( $tradition, $option_hash )

Takes an initialized tradition and a set of options; creates the
appropriate nodes and edges on the graph, as well as the appropriate
witness objects.  The $option_hash must contain either a 'file' or a
'string' argument with the XML to be parsed.

=begin testing

use Text::Tradition;
binmode STDOUT, ":utf8";
binmode STDERR, ":utf8";
eval { no warnings; binmode $DB::OUT, ":utf8"; };

my $par_seg = 't/data/florilegium_tei_ps.xml';
my $t = Text::Tradition->new( 
    'name'  => 'inline', 
    'input' => 'TEI',
    'file'  => $par_seg,
    );

is( ref( $t ), 'Text::Tradition', "Parsed parallel-segmentation TEI" );
if( $t ) {
    is( scalar $t->collation->readings, 319, "Collation has all readings" );
    is( scalar $t->collation->paths, 2854, "Collation has all paths" );
}

=end testing

=cut

my $text = {}; # Hash of arrays, one per eventual witness we find.
my $substitutions = {}; # Keep track of merged readings
my $app_anchors = {};   # Track apparatus references
my $app_ac = {};        # Save a.c. readings
my $app_count;          # Keep track of how many apps we have

# Create the package variables for tag names.

# Would really like to do this with varname variables, but apparently this
# is considered a bad idea.  The long way round then.
my( $LISTWIT, $WITNESS, $TEXT, $W, $SEG, $APP, $RDG, $LEM ) 
    = ( 'listWit', 'witness', 'text', 'w', 'seg', 'app', 'rdg', 'lem' );
sub _make_tagnames {
    my( $ns ) = @_;
    if( $ns ) {
        $LISTWIT = "$ns:$LISTWIT";
        $WITNESS = "$ns:$WITNESS";
        $TEXT = "$ns:$TEXT";
        $W = "$ns:$W";
        $SEG = "$ns:$SEG";
        $APP = "$ns:$APP";
        $RDG = "$ns:$RDG";
        $LEM = "$ns:$LEM";
    }
}

# Parse the TEI file.
sub parse {
    my( $tradition, $opts ) = @_;
    
    # First, parse the XML.
    my $parser = XML::LibXML->new();
    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 $tei = $doc->documentElement();
    my $xpc = XML::LibXML::XPathContext->new( $tei );
    my $ns;
    if( $tei->namespaceURI ) {
        $ns = 'tei';
        $xpc->registerNs( $ns, $tei->namespaceURI );
    }
    _make_tagnames( $ns );

    # Then get the witnesses and create the witness objects.
    foreach my $wit_el ( $xpc->findnodes( "//$LISTWIT/$WITNESS" ) ) {
        my $sig = $wit_el->getAttribute( 'xml:id' );
        my $source = $wit_el->toString();
        $tradition->add_witness( sigil => $sig, source => $source );
    }
    map { $text->{$_->sigil} = [] } $tradition->witnesses;

    # Look for all word/seg node IDs and note their pre-existence.
    my @attrs = $xpc->findnodes( "//$W|$SEG/attribute::xml:id" );
    _save_preexisting_nodeids( @attrs );

    # Count up how many apps we have.
    my @apps = $xpc->findnodes( "//$APP" );
    $app_count = scalar( @apps );

    # Now go through the children of the text element and pull out the
    # actual text.
    foreach my $xml_el ( $xpc->findnodes( "//$TEXT" ) ) {
        foreach my $xn ( $xml_el->childNodes ) {
            _get_readings( $tradition, $xn );
        }
    }
    # Our $text global now has lists of readings, one per witness.
    # Join them up.
    my $c = $tradition->collation;
    foreach my $sig ( keys %$text ) {
        next if $sig eq 'base';  # Skip base text readings with no witnesses.
        # Determine the list of readings for 
        my $sequence = $text->{$sig};
        my @real_sequence = ( $c->start );
        push( @$sequence, $c->end );
        my $source = $c->start;
        foreach( _clean_sequence( $sig, $sequence ) ) {
            my $rdg = _return_rdg( $_ );
            push( @real_sequence, $rdg );
            $c->add_path( $source, $rdg, $sig );
            $source = $rdg;
        }
        $tradition->witness( $sig )->path( \@real_sequence );
        # See if we need to make an a.c. version of the witness.
        if( exists $app_ac->{$sig} ) {
            my @uncorrected;
            push( @uncorrected, @real_sequence );
            foreach my $app ( keys %{$app_ac->{$sig}} ) {
                my $start = _return_rdg( $app_anchors->{$app}->{$sig}->{'start'} ); 
                my $end = _return_rdg( $app_anchors->{$app}->{$sig}->{'end'} );
                my @new = map { _return_rdg( $_ ) } @{$app_ac->{$sig}->{$app}};
                _replace_sequence( \@uncorrected, $start, $end, @new );
            }
            my $source = $c->start;
            foreach my $rdg ( @uncorrected ) {
                my $has_base = grep { $_->label eq $sig } $source->edges_to( $rdg );
                if( $rdg ne $c->start && !$has_base ) {
                    print STDERR sprintf( "Adding path %s from %s -> %s\n",
                        $sig.$c->ac_label, $source->name, $rdg->name );
                    $c->add_path( $source, $rdg, $sig.$c->ac_label );
                }
                $source = $rdg;
            }
            print STDERR "Adding a.c. version for witness $sig\n";
            $tradition->witness( $sig )->uncorrected_path( \@uncorrected );
        }
    }
    
    # Calculate the ranks for the nodes.
    $tradition->collation->calculate_ranks();
    
    # Now that we have ranks, see if we have distinct nodes with identical
    # text and identical rank that can be merged.
    $tradition->collation->flatten_ranks();
}

sub _clean_sequence {
    my( $wit, $sequence ) = @_;
    my @clean_sequence;
    foreach my $rdg ( @$sequence ) {
        if( $rdg =~ /^PH-(.*)$/ ) {
            # It is a placeholder.  Keep it only if we need it.
            my $app_id = $1;
            if( exists $app_ac->{$wit} &&
                exists $app_ac->{$wit}->{$app_id} ) {
                print STDERR "Retaining empty placeholder for $app_id\n";
                push( @clean_sequence, $rdg );
            }
        } else {
            push( @clean_sequence, $rdg );
        }
    }
    return @clean_sequence;
}

sub _replace_sequence {
    my( $arr, $start, $end, @new ) = @_;
    my( $start_idx, $end_idx );
    foreach my $i ( 0 .. $#{$arr} ) {
        $start_idx = $i if( $arr->[$i]->name eq $start );
        if( $arr->[$i]->name eq $end ) {
            $end_idx = $i;
            last;
        }
    }
    unless( $start_idx && $end_idx ) {
        warn "Could not find start and end";
        return;
    }
    my $length = $end_idx - $start_idx + 1;
    splice( @$arr, $start_idx, $length, @new );
}

sub _return_rdg {
    my( $rdg ) = @_;
    # If we were passed a reading name, return the name.  If we were
    # passed a reading object, return the object.
    my $wantobj = ref( $rdg ) eq 'Text::Tradition::Collation::Reading';
    my $real = $rdg;
    if( exists $substitutions->{ $wantobj ? $rdg->name : $rdg } ) {
        $real = $substitutions->{ $wantobj ? $rdg->name : $rdg };
        $real = $real->name unless $wantobj;
    }
    return $real;
}

=begin testing

## TODO test specific sorts of nodes of the parallel-seg XML.

=end testing

## Recursive helper function to help us navigate through nested XML,
## picking out the text.  $tradition is the tradition, needed for
## making readings; $xn is the XML node currently being looked at,
## $in_var is a flag to say that we are inside a variant, $ac is a
## flag to say that we are inside an ante-correctionem reading, and
## @cur_wits is the list of witnesses to which this XML node applies.
## Returns the list of readings, if any, created on the run.

{
    my %active_wits;
    my $current_app;
    my $seen_apps;

    sub _get_readings {
        my( $tradition, $xn, $in_var, $ac, @cur_wits ) = @_;
        @cur_wits = grep { $active_wits{$_} } keys %active_wits unless $in_var;

        my @new_readings;
        if( $xn->nodeType == XML_TEXT_NODE ) {
            # Some words, thus make some readings.
            my $str = $xn->data;
            return unless $str =~ /\S/; # skip whitespace-only text nodes
            #print STDERR "Handling text node " . $str . "\n";
            # Check that all the witnesses we have are active.
            foreach my $c ( @cur_wits ) {
                warn "$c is not among active wits" unless $active_wits{$c};
            }
            $str =~ s/^\s+//;
            my $final = $str =~ s/\s+$//;
            foreach my $w ( split( /\s+/, $str ) ) {
                # For now, skip punctuation.
                next if $w !~ /[[:alnum:]]/;
                my $rdg = _make_reading( $tradition->collation, $w );
                push( @new_readings, $rdg );
                unless( $in_var ) {
                    $rdg->make_common;
                }
                foreach ( @cur_wits ) {
                    warn "Empty wit!" unless $_;
                    warn "Empty reading!" unless $rdg;
                    push( @{$text->{$_}}, $rdg ) unless $ac;
                }
            }
        } elsif( $xn->nodeName eq 'w' ) {
            # Everything in this tag is one word.  Also save any original XML ID.
            #print STDERR "Handling word " . $xn->toString . "\n";
            # Check that all the witnesses we have are active.
            foreach my $c ( @cur_wits ) {
                warn "$c is not among active wits" unless $active_wits{$c};
            }
            my $xml_id = $xn->getAttribute( 'xml:id' );
            my $rdg = _make_reading( $tradition->collation, $xn->textContent, $xml_id );
            push( @new_readings, $rdg );
            unless( $in_var ) {
                $rdg->make_common;
            }
            foreach( @cur_wits ) {
                warn "Empty wit!" unless $_;
                warn "Empty reading!" unless $rdg;
                push( @{$text->{$_}}, $rdg ) unless $ac;
            }
        } elsif ( $xn->nodeName eq 'app' ) {
            $seen_apps++;
            $current_app = $xn->getAttribute( 'xml:id' );
            # print STDERR "Handling app $current_app\n";
            # Keep the reading sets in this app.
            my @sets;
            # Recurse through all children (i.e. rdgs) for sets of words.
            foreach ( $xn->childNodes ) {
                my @rdg_set = _get_readings( $tradition, $_, $in_var, $ac, @cur_wits );
                push( @sets, \@rdg_set ) if @rdg_set;
            }
            # Now collate these sets if we have more than one.
            my $subs = collate_variants( $tradition->collation, @sets ) if @sets > 1;
            map { $substitutions->{$_} = $subs->{$_} } keys %$subs;
            # TODO Look through substitutions to see if we can make anything common now.
            # Return the entire set of unique readings.
            my %unique;
            foreach my $s ( @sets ) {
                map { $unique{$_->name} = $_ } @$s;
            }
            push( @new_readings, values( %unique ) );
            # Exit the current app.
            $current_app = '';
        } elsif ( $xn->nodeName eq 'lem' || $xn->nodeName eq 'rdg' ) {
            # Alter the current witnesses and recurse.
            #print STDERR "Handling reading for " . $xn->getAttribute( 'wit' ) . "\n";
            # TODO handle p.c. and s.l. designations too
            $ac = $xn->getAttribute( 'type' ) && $xn->getAttribute( 'type' ) eq 'a.c.';
            my @rdg_wits = _get_sigla( $xn );
            @rdg_wits = ( 'base' ) unless @rdg_wits;  # Allow for editorially-supplied readings
            my @words;
            foreach ( $xn->childNodes ) {
                my @rdg_set = _get_readings( $tradition, $_, 1, $ac, @rdg_wits );
                push( @words, @rdg_set ) if @rdg_set;
            }
            # If we have more than one word in a reading, it should become a segment.
            # $tradition->collation->add_segment( @words ) if @words > 1;
            
            if( $ac ) {
                # Add the reading set to the a.c. readings.
                foreach ( @rdg_wits ) {
                    $app_ac->{$_}->{$current_app} = \@words;
                }
            } else {
                # Add the reading set to the app anchors for each witness
                # or put in placeholders for empty p.c. readings
                foreach ( @rdg_wits ) {
                    my $start = @words ? $words[0]->name : "PH-$current_app";
                    my $end = @words ? $words[-1]->name : "PH-$current_app";
                    $app_anchors->{$current_app}->{$_}->{'start'} = $start;
                    $app_anchors->{$current_app}->{$_}->{'end'} = $end;
                    push( @{$text->{$_}}, $start ) unless @words;
                }
            }
            push( @new_readings, @words );
        } elsif( $xn->nodeName eq 'witStart' ) {
            # Add the relevant wit(s) to the active list.
            #print STDERR "Handling witStart\n";
            map { $active_wits{$_} = 1 } @cur_wits;
            # Record a lacuna in all non-active witnesses if this is
            # the first app. Get the full list from $text.
            if( $seen_apps == 1 ) {
                my $i = 0;
                foreach my $sig ( keys %$text ) {
                    next if $active_wits{$sig};
                    my $l = $tradition->collation->add_lacuna( $current_app . "_$i" );
                    $i++;
                    push( @{$text->{$sig}}, $l );
                }
            }
        } elsif( $xn->nodeName eq 'witEnd' ) {
            # Take the relevant wit(s) out of the list.
            #print STDERR "Handling witEnd\n";
            map { $active_wits{$_} = undef } @cur_wits;
            # Record a lacuna, unless this is the last app.
            unless( $seen_apps == $app_count ) {
                foreach my $i ( 0 .. $#cur_wits ) {
                    my $w = $cur_wits[$i];
                    my $l = $tradition->collation->add_lacuna( $current_app . "_$i" );
                    push( @{$text->{$w}}, $l );
                }
            }
        } elsif( $xn->nodeName eq 'witDetail' ) {
            # Ignore these for now.
            return;
        } else {
            # Recurse as if this tag weren't there.
            #print STDERR "Recursing on tag " . $xn->nodeName . "\n";
            foreach( $xn->childNodes ) {
                push( @new_readings, _get_readings( $tradition, $_, $in_var, $ac, @cur_wits ) );
            }
        }
        return @new_readings;
    }

}

=begin testing

use XML::LibXML;
use XML::LibXML::XPathContext;
use Text::Tradition::Parser::TEI;

my $xml_str = '<tei><rdg wit="#A #B #C #D">some text</rdg></tei>';
my $el = XML::LibXML->new()->parse_string( $xml_str )->documentElement;
my $xpc = XML::LibXML::XPathContext->new( $el );
my $obj = $xpc->find( '//rdg' );

my @wits = Text::Tradition::Parser::TEI::_get_sigla( $obj );
is( join( ' ', @wits) , "A B C D", "correctly parsed reading wit string" );

=end testing

=cut

# Helper to extract a list of witness sigla from a reading element.
sub _get_sigla {
    my( $rdg ) = @_;
    # Cope if we have been handed a NodeList.  There is only
    # one reading here.
    if( ref( $rdg ) eq 'XML::LibXML::NodeList' ) {
        $rdg = $rdg->shift;
    }

    my @wits;
    if( ref( $rdg ) eq 'XML::LibXML::Element' ) {
        my $witstr = $rdg->getAttribute( 'wit' );
        $witstr =~ s/^\s+//;
        $witstr =~ s/\s+$//;
        @wits = split( /\s+/, $witstr );
        map { $_ =~ s/^\#// } @wits;
    }
    return @wits;
}

# Helper with its counters to actually make the readings.
{
    my $word_ctr = 0;
    my %used_nodeids;

    sub _save_preexisting_nodeids {
        foreach( @_ ) {
            $used_nodeids{$_->getValue()} = 1;
        }
    }

    sub _make_reading {
        my( $graph, $word, $xml_id ) = @_;
        if( $xml_id ) {
            if( exists $used_nodeids{$xml_id} ) {
                if( $used_nodeids{$xml_id} != 1 ) {
                    warn "Already used assigned XML ID somewhere else!";
                    $xml_id = undef;
                }
            } else {
                warn "Undetected pre-existing XML ID";
            }
        }
        if( !$xml_id ) {
            until( $xml_id ) {
                my $try_id = 'w'.$word_ctr++;
                next if exists $used_nodeids{$try_id};
                $xml_id = $try_id;
            }
        }
        my $rdg = $graph->add_reading( $xml_id );
        $rdg->text( $word );
        $used_nodeids{$xml_id} = $rdg;
        return $rdg;
    }
}

1;

=head1 BUGS / TODO

=over

=item * More unit testing

=back

=head1 LICENSE

This package is free software and is provided "as is" without express
or implied warranty.  You can redistribute it and/or modify it under
the same terms as Perl itself.

=head1 AUTHOR

Tara L Andrews E<lt>aurum@cpan.orgE<gt>
Commit	Line	Data
f6066bac	1	package Text::Tradition::Parser::TEI;
	2
	3	use strict;
	4	use warnings;
910a0a6d	5	use Text::Tradition::Parser::Util qw( collate_variants );
f6066bac	6	use XML::LibXML;
	7	use XML::LibXML::XPathContext;
	8
	9	=head1 NAME
	10
	11	Text::Tradition::Parser::TEI
	12
3b853983	13	=head1 SYNOPSIS
	14
	15	use Text::Tradition;
	16
	17	my $t_from_file = Text::Tradition->new(
	18	'name' => 'my text',
	19	'input' => 'TEI',
	20	'file' => '/path/to/parallel_seg_file.xml'
	21	);
	22
	23	my $t_from_string = Text::Tradition->new(
	24	'name' => 'my text',
	25	'input' => 'TEI',
	26	'string' => $parallel_seg_xml,
	27	);
	28
	29
f6066bac	30	=head1 DESCRIPTION
f6066bac	31
3b853983	32	Parser module for Text::Tradition, given a TEI parallel-segmentation file
	33	that describes a text and its variants. Normally called upon
	34	initialization of Text::Tradition.
	35
	36	The witnesses for the tradition are taken from the <listWit/> element
	37	within the TEI header; the readings are taken from any <p/> element that
	38	appears in the text body (including <head/> elements therein.)
f6066bac	39
	40	=head1 METHODS
	41
	42	=over
	43
3b853983	44	=item B<parse>( $tradition, $option_hash )
	45
	46	Takes an initialized tradition and a set of options; creates the
	47	appropriate nodes and edges on the graph, as well as the appropriate
	48	witness objects. The $option_hash must contain either a 'file' or a
	49	'string' argument with the XML to be parsed.
	50
	51	=begin testing
	52
	53	use Text::Tradition;
	54	binmode STDOUT, ":utf8";
	55	binmode STDERR, ":utf8";
	56	eval { no warnings; binmode $DB::OUT, ":utf8"; };
	57
	58	my $par_seg = 't/data/florilegium_tei_ps.xml';
	59	my $t = Text::Tradition->new(
	60	'name' => 'inline',
	61	'input' => 'TEI',
	62	'file' => $par_seg,
	63	);
f6066bac	64
3b853983	65	is( ref( $t ), 'Text::Tradition', "Parsed parallel-segmentation TEI" );
	66	if( $t ) {
	67	is( scalar $t->collation->readings, 319, "Collation has all readings" );
	68	is( scalar $t->collation->paths, 2854, "Collation has all paths" );
	69	}
f6066bac	70
3b853983	71	=end testing
f6066bac	72
	73	=cut
	74
910a0a6d	75	my $text = {}; # Hash of arrays, one per eventual witness we find.
910a0a6d	76	my $substitutions = {}; # Keep track of merged readings
	77	my $app_anchors = {}; # Track apparatus references
	78	my $app_ac = {}; # Save a.c. readings
eca16057	79	my $app_count; # Keep track of how many apps we have
910a0a6d	80
	81	# Create the package variables for tag names.
	82
	83	# Would really like to do this with varname variables, but apparently this
	84	# is considered a bad idea. The long way round then.
	85	my( $LISTWIT, $WITNESS, $TEXT, $W, $SEG, $APP, $RDG, $LEM )
	86	= ( 'listWit', 'witness', 'text', 'w', 'seg', 'app', 'rdg', 'lem' );
3b853983	87	sub _make_tagnames {
910a0a6d	88	my( $ns ) = @_;
	89	if( $ns ) {
	90	$LISTWIT = "$ns:$LISTWIT";
	91	$WITNESS = "$ns:$WITNESS";
	92	$TEXT = "$ns:$TEXT";
	93	$W = "$ns:$W";
	94	$SEG = "$ns:$SEG";
	95	$APP = "$ns:$APP";
	96	$RDG = "$ns:$RDG";
	97	$LEM = "$ns:$LEM";
	98	}
	99	}
	100
	101	# Parse the TEI file.
f6066bac	102	sub parse {
dfc37e38	103	my( $tradition, $opts ) = @_;
f6066bac	104
	105	# First, parse the XML.
	106	my $parser = XML::LibXML->new();
dfc37e38	107	my $doc;
	108	if( exists $opts->{'string'} ) {
	109	$doc = $parser->parse_string( $opts->{'string'} );
	110	} elsif ( exists $opts->{'file'} ) {
	111	$doc = $parser->parse_file( $opts->{'file'} );
	112	} else {
	113	warn "Could not find string or file option to parse";
	114	return;
	115	}
f6066bac	116	my $tei = $doc->documentElement();
f2b9605f	117	my $xpc = XML::LibXML::XPathContext->new( $tei );
910a0a6d	118	my $ns;
	119	if( $tei->namespaceURI ) {
	120	$ns = 'tei';
	121	$xpc->registerNs( $ns, $tei->namespaceURI );
	122	}
3b853983	123	_make_tagnames( $ns );
910a0a6d	124
f6066bac	125	# Then get the witnesses and create the witness objects.
910a0a6d	126	foreach my $wit_el ( $xpc->findnodes( "//$LISTWIT/$WITNESS" ) ) {
	127	my $sig = $wit_el->getAttribute( 'xml:id' );
	128	my $source = $wit_el->toString();
	129	$tradition->add_witness( sigil => $sig, source => $source );
f6066bac	130	}
910a0a6d	131	map { $text->{$_->sigil} = [] } $tradition->witnesses;
eca16057	132
910a0a6d	133	# Look for all word/seg node IDs and note their pre-existence.
910a0a6d	134	my @attrs = $xpc->findnodes( "//$W\|$SEG/attribute::xml:id" );
3b853983	135	_save_preexisting_nodeids( @attrs );
910a0a6d	136
eca16057	137	# Count up how many apps we have.
	138	my @apps = $xpc->findnodes( "//$APP" );
	139	$app_count = scalar( @apps );
	140
910a0a6d	141	# Now go through the children of the text element and pull out the
	142	# actual text.
	143	foreach my $xml_el ( $xpc->findnodes( "//$TEXT" ) ) {
	144	foreach my $xn ( $xml_el->childNodes ) {
	145	_get_readings( $tradition, $xn );
	146	}
	147	}
	148	# Our $text global now has lists of readings, one per witness.
	149	# Join them up.
	150	my $c = $tradition->collation;
	151	foreach my $sig ( keys %$text ) {
	152	next if $sig eq 'base'; # Skip base text readings with no witnesses.
	153	# Determine the list of readings for
	154	my $sequence = $text->{$sig};
	155	my @real_sequence = ( $c->start );
	156	push( @$sequence, $c->end );
	157	my $source = $c->start;
	158	foreach( _clean_sequence( $sig, $sequence ) ) {
	159	my $rdg = _return_rdg( $_ );
	160	push( @real_sequence, $rdg );
	161	$c->add_path( $source, $rdg, $sig );
	162	$source = $rdg;
	163	}
	164	$tradition->witness( $sig )->path( \@real_sequence );
	165	# See if we need to make an a.c. version of the witness.
	166	if( exists $app_ac->{$sig} ) {
	167	my @uncorrected;
	168	push( @uncorrected, @real_sequence );
	169	foreach my $app ( keys %{$app_ac->{$sig}} ) {
	170	my $start = _return_rdg( $app_anchors->{$app}->{$sig}->{'start'} );
	171	my $end = _return_rdg( $app_anchors->{$app}->{$sig}->{'end'} );
	172	my @new = map { _return_rdg( $_ ) } @{$app_ac->{$sig}->{$app}};
	173	_replace_sequence( \@uncorrected, $start, $end, @new );
	174	}
	175	my $source = $c->start;
	176	foreach my $rdg ( @uncorrected ) {
	177	my $has_base = grep { $_->label eq $sig } $source->edges_to( $rdg );
	178	if( $rdg ne $c->start && !$has_base ) {
	179	print STDERR sprintf( "Adding path %s from %s -> %s\n",
	180	$sig.$c->ac_label, $source->name, $rdg->name );
	181	$c->add_path( $source, $rdg, $sig.$c->ac_label );
	182	}
	183	$source = $rdg;
	184	}
78fab1cf	185	print STDERR "Adding a.c. version for witness $sig\n";
910a0a6d	186	$tradition->witness( $sig )->uncorrected_path( \@uncorrected );
	187	}
	188	}
3b853983	189
3b853983	190	# Calculate the ranks for the nodes.
c9bf3dbf	191	$tradition->collation->calculate_ranks();
3bc0cd18	192
	193	# Now that we have ranks, see if we have distinct nodes with identical
	194	# text and identical rank that can be merged.
0e476982	195	$tradition->collation->flatten_ranks();
910a0a6d	196	}
	197
	198	sub _clean_sequence {
	199	my( $wit, $sequence ) = @_;
	200	my @clean_sequence;
	201	foreach my $rdg ( @$sequence ) {
	202	if( $rdg =~ /^PH-(.*)$/ ) {
	203	# It is a placeholder. Keep it only if we need it.
	204	my $app_id = $1;
78fab1cf	205	if( exists $app_ac->{$wit} &&
78fab1cf	206	exists $app_ac->{$wit}->{$app_id} ) {
910a0a6d	207	print STDERR "Retaining empty placeholder for $app_id\n";
	208	push( @clean_sequence, $rdg );
	209	}
	210	} else {
	211	push( @clean_sequence, $rdg );
	212	}
f6066bac	213	}
910a0a6d	214	return @clean_sequence;
910a0a6d	215	}
f6066bac	216
910a0a6d	217	sub _replace_sequence {
	218	my( $arr, $start, $end, @new ) = @_;
	219	my( $start_idx, $end_idx );
	220	foreach my $i ( 0 .. $#{$arr} ) {
	221	$start_idx = $i if( $arr->[$i]->name eq $start );
	222	if( $arr->[$i]->name eq $end ) {
	223	$end_idx = $i;
	224	last;
	225	}
	226	}
	227	unless( $start_idx && $end_idx ) {
	228	warn "Could not find start and end";
	229	return;
f2b9605f	230	}
910a0a6d	231	my $length = $end_idx - $start_idx + 1;
	232	splice( @$arr, $start_idx, $length, @new );
	233	}
f6066bac	234
910a0a6d	235	sub _return_rdg {
	236	my( $rdg ) = @_;
	237	# If we were passed a reading name, return the name. If we were
	238	# passed a reading object, return the object.
	239	my $wantobj = ref( $rdg ) eq 'Text::Tradition::Collation::Reading';
	240	my $real = $rdg;
	241	if( exists $substitutions->{ $wantobj ? $rdg->name : $rdg } ) {
	242	$real = $substitutions->{ $wantobj ? $rdg->name : $rdg };
	243	$real = $real->name unless $wantobj;
	244	}
	245	return $real;
f6066bac	246	}
f6066bac	247
3b853983	248	=begin testing
	249
	250	## TODO test specific sorts of nodes of the parallel-seg XML.
	251
	252	=end testing
	253
910a0a6d	254	## Recursive helper function to help us navigate through nested XML,
	255	## picking out the text. $tradition is the tradition, needed for
	256	## making readings; $xn is the XML node currently being looked at,
	257	## $in_var is a flag to say that we are inside a variant, $ac is a
	258	## flag to say that we are inside an ante-correctionem reading, and
	259	## @cur_wits is the list of witnesses to which this XML node applies.
	260	## Returns the list of readings, if any, created on the run.
	261
	262	{
3bc0cd18	263	my %active_wits;
910a0a6d	264	my $current_app;
eca16057	265	my $seen_apps;
910a0a6d	266
	267	sub _get_readings {
	268	my( $tradition, $xn, $in_var, $ac, @cur_wits ) = @_;
3bc0cd18	269	@cur_wits = grep { $active_wits{$_} } keys %active_wits unless $in_var;
910a0a6d	270
	271	my @new_readings;
	272	if( $xn->nodeType == XML_TEXT_NODE ) {
	273	# Some words, thus make some readings.
	274	my $str = $xn->data;
	275	return unless $str =~ /\S/; # skip whitespace-only text nodes
	276	#print STDERR "Handling text node " . $str . "\n";
	277	# Check that all the witnesses we have are active.
	278	foreach my $c ( @cur_wits ) {
3bc0cd18	279	warn "$c is not among active wits" unless $active_wits{$c};
910a0a6d	280	}
	281	$str =~ s/^\s+//;
	282	my $final = $str =~ s/\s+$//;
	283	foreach my $w ( split( /\s+/, $str ) ) {
	284	# For now, skip punctuation.
	285	next if $w !~ /[[:alnum:]]/;
3b853983	286	my $rdg = _make_reading( $tradition->collation, $w );
910a0a6d	287	push( @new_readings, $rdg );
910a0a6d	288	unless( $in_var ) {
910a0a6d	289	$rdg->make_common;
	290	}
	291	foreach ( @cur_wits ) {
	292	warn "Empty wit!" unless $_;
	293	warn "Empty reading!" unless $rdg;
	294	push( @{$text->{$_}}, $rdg ) unless $ac;
	295	}
	296	}
	297	} elsif( $xn->nodeName eq 'w' ) {
	298	# Everything in this tag is one word. Also save any original XML ID.
	299	#print STDERR "Handling word " . $xn->toString . "\n";
	300	# Check that all the witnesses we have are active.
	301	foreach my $c ( @cur_wits ) {
3bc0cd18	302	warn "$c is not among active wits" unless $active_wits{$c};
910a0a6d	303	}
910a0a6d	304	my $xml_id = $xn->getAttribute( 'xml:id' );
3b853983	305	my $rdg = _make_reading( $tradition->collation, $xn->textContent, $xml_id );
910a0a6d	306	push( @new_readings, $rdg );
910a0a6d	307	unless( $in_var ) {
910a0a6d	308	$rdg->make_common;
	309	}
	310	foreach( @cur_wits ) {
	311	warn "Empty wit!" unless $_;
	312	warn "Empty reading!" unless $rdg;
	313	push( @{$text->{$_}}, $rdg ) unless $ac;
	314	}
	315	} elsif ( $xn->nodeName eq 'app' ) {
eca16057	316	$seen_apps++;
910a0a6d	317	$current_app = $xn->getAttribute( 'xml:id' );
	318	# print STDERR "Handling app $current_app\n";
	319	# Keep the reading sets in this app.
	320	my @sets;
	321	# Recurse through all children (i.e. rdgs) for sets of words.
	322	foreach ( $xn->childNodes ) {
	323	my @rdg_set = _get_readings( $tradition, $_, $in_var, $ac, @cur_wits );
	324	push( @sets, \@rdg_set ) if @rdg_set;
	325	}
	326	# Now collate these sets if we have more than one.
	327	my $subs = collate_variants( $tradition->collation, @sets ) if @sets > 1;
	328	map { $substitutions->{$_} = $subs->{$_} } keys %$subs;
	329	# TODO Look through substitutions to see if we can make anything common now.
	330	# Return the entire set of unique readings.
	331	my %unique;
	332	foreach my $s ( @sets ) {
	333	map { $unique{$_->name} = $_ } @$s;
	334	}
	335	push( @new_readings, values( %unique ) );
	336	# Exit the current app.
	337	$current_app = '';
	338	} elsif ( $xn->nodeName eq 'lem' \|\| $xn->nodeName eq 'rdg' ) {
	339	# Alter the current witnesses and recurse.
	340	#print STDERR "Handling reading for " . $xn->getAttribute( 'wit' ) . "\n";
3bc0cd18	341	# TODO handle p.c. and s.l. designations too
910a0a6d	342	$ac = $xn->getAttribute( 'type' ) && $xn->getAttribute( 'type' ) eq 'a.c.';
3b853983	343	my @rdg_wits = _get_sigla( $xn );
910a0a6d	344	@rdg_wits = ( 'base' ) unless @rdg_wits; # Allow for editorially-supplied readings
	345	my @words;
	346	foreach ( $xn->childNodes ) {
	347	my @rdg_set = _get_readings( $tradition, $_, 1, $ac, @rdg_wits );
	348	push( @words, @rdg_set ) if @rdg_set;
	349	}
	350	# If we have more than one word in a reading, it should become a segment.
	351	# $tradition->collation->add_segment( @words ) if @words > 1;
	352
	353	if( $ac ) {
	354	# Add the reading set to the a.c. readings.
	355	foreach ( @rdg_wits ) {
	356	$app_ac->{$_}->{$current_app} = \@words;
	357	}
	358	} else {
	359	# Add the reading set to the app anchors for each witness
	360	# or put in placeholders for empty p.c. readings
	361	foreach ( @rdg_wits ) {
	362	my $start = @words ? $words[0]->name : "PH-$current_app";
	363	my $end = @words ? $words[-1]->name : "PH-$current_app";
	364	$app_anchors->{$current_app}->{$_}->{'start'} = $start;
	365	$app_anchors->{$current_app}->{$_}->{'end'} = $end;
	366	push( @{$text->{$_}}, $start ) unless @words;
	367	}
	368	}
	369	push( @new_readings, @words );
	370	} elsif( $xn->nodeName eq 'witStart' ) {
	371	# Add the relevant wit(s) to the active list.
	372	#print STDERR "Handling witStart\n";
3bc0cd18	373	map { $active_wits{$_} = 1 } @cur_wits;
	374	# Record a lacuna in all non-active witnesses if this is
	375	# the first app. Get the full list from $text.
	376	if( $seen_apps == 1 ) {
	377	my $i = 0;
	378	foreach my $sig ( keys %$text ) {
	379	next if $active_wits{$sig};
	380	my $l = $tradition->collation->add_lacuna( $current_app . "_$i" );
	381	$i++;
	382	push( @{$text->{$sig}}, $l );
	383	}
	384	}
910a0a6d	385	} elsif( $xn->nodeName eq 'witEnd' ) {
	386	# Take the relevant wit(s) out of the list.
	387	#print STDERR "Handling witEnd\n";
3bc0cd18	388	map { $active_wits{$_} = undef } @cur_wits;
eca16057	389	# Record a lacuna, unless this is the last app.
	390	unless( $seen_apps == $app_count ) {
	391	foreach my $i ( 0 .. $#cur_wits ) {
	392	my $w = $cur_wits[$i];
	393	my $l = $tradition->collation->add_lacuna( $current_app . "_$i" );
	394	push( @{$text->{$w}}, $l );
	395	}
	396	}
910a0a6d	397	} elsif( $xn->nodeName eq 'witDetail' ) {
	398	# Ignore these for now.
	399	return;
	400	} else {
	401	# Recurse as if this tag weren't there.
	402	#print STDERR "Recursing on tag " . $xn->nodeName . "\n";
	403	foreach( $xn->childNodes ) {
	404	push( @new_readings, _get_readings( $tradition, $_, $in_var, $ac, @cur_wits ) );
	405	}
	406	}
	407	return @new_readings;
	408	}
	409
	410	}
	411
3b853983	412	=begin testing
	413
	414	use XML::LibXML;
	415	use XML::LibXML::XPathContext;
	416	use Text::Tradition::Parser::TEI;
	417
	418	my $xml_str = '<tei><rdg wit="#A #B #C #D">some text</rdg></tei>';
	419	my $el = XML::LibXML->new()->parse_string( $xml_str )->documentElement;
	420	my $xpc = XML::LibXML::XPathContext->new( $el );
	421	my $obj = $xpc->find( '//rdg' );
	422
	423	my @wits = Text::Tradition::Parser::TEI::_get_sigla( $obj );
	424	is( join( ' ', @wits) , "A B C D", "correctly parsed reading wit string" );
	425
	426	=end testing
	427
	428	=cut
	429
910a0a6d	430	# Helper to extract a list of witness sigla from a reading element.
3b853983	431	sub _get_sigla {
f6066bac	432	my( $rdg ) = @_;
	433	# Cope if we have been handed a NodeList. There is only
	434	# one reading here.
	435	if( ref( $rdg ) eq 'XML::LibXML::NodeList' ) {
910a0a6d	436	$rdg = $rdg->shift;
f6066bac	437	}
	438
	439	my @wits;
	440	if( ref( $rdg ) eq 'XML::LibXML::Element' ) {
910a0a6d	441	my $witstr = $rdg->getAttribute( 'wit' );
	442	$witstr =~ s/^\s+//;
	443	$witstr =~ s/\s+$//;
	444	@wits = split( /\s+/, $witstr );
	445	map { $_ =~ s/^\#// } @wits;
f6066bac	446	}
	447	return @wits;
	448	}
	449
910a0a6d	450	# Helper with its counters to actually make the readings.
f2b9605f	451	{
	452	my $word_ctr = 0;
	453	my %used_nodeids;
	454
3b853983	455	sub _save_preexisting_nodeids {
910a0a6d	456	foreach( @_ ) {
	457	$used_nodeids{$_->getValue()} = 1;
	458	}
	459	}
	460
3b853983	461	sub _make_reading {
910a0a6d	462	my( $graph, $word, $xml_id ) = @_;
	463	if( $xml_id ) {
	464	if( exists $used_nodeids{$xml_id} ) {
	465	if( $used_nodeids{$xml_id} != 1 ) {
	466	warn "Already used assigned XML ID somewhere else!";
	467	$xml_id = undef;
	468	}
	469	} else {
	470	warn "Undetected pre-existing XML ID";
	471	}
	472	}
	473	if( !$xml_id ) {
	474	until( $xml_id ) {
	475	my $try_id = 'w'.$word_ctr++;
	476	next if exists $used_nodeids{$try_id};
	477	$xml_id = $try_id;
	478	}
	479	}
	480	my $rdg = $graph->add_reading( $xml_id );
	481	$rdg->text( $word );
	482	$used_nodeids{$xml_id} = $rdg;
	483	return $rdg;
f2b9605f	484	}
	485	}
	486
f6066bac	487	1;
3b853983	488
	489	=head1 BUGS / TODO
	490
	491	=over
	492
	493	=item * More unit testing
	494
	495	=back
	496
	497	=head1 LICENSE
	498
	499	This package is free software and is provided "as is" without express
	500	or implied warranty. You can redistribute it and/or modify it under
	501	the same terms as Perl itself.
	502
	503	=head1 AUTHOR
	504
	505	Tara L Andrews E<lt>aurum@cpan.orgE<gt>