use JSON for serialization rather than rolling own

[scpubgit/stemmatology.git] / lib / Text / Tradition / Collation / Reading.pm

package Text::Tradition::Collation::Reading;

use Moose;
use JSON qw/ from_json /;
use Module::Load;
use Text::Tradition::Error;
use YAML::XS;
use overload '""' => \&_stringify, 'fallback' => 1;

=head1 NAME

Text::Tradition::Collation::Reading - represents a reading (usually a word)
in a collation.

=head1 DESCRIPTION

Text::Tradition is a library for representation and analysis of collated
texts, particularly medieval ones.  A 'reading' refers to a unit of text,
usually a word, that appears in one or more witnesses (manuscripts) of the
tradition; the text of a given witness is composed of a set of readings in
a particular sequence

=head1 METHODS

=head2 new

Creates a new reading in the given collation with the given attributes.
Options include:

=over 4

=item collation - The Text::Tradition::Collation object to which this
reading belongs.  Required.

=item id - A unique identifier for this reading. Required.

=item text - The word or other text of the reading.

=item is_start - The reading is the starting point for the collation.

=item is_end - The reading is the ending point for the collation.

=item is_lacuna - The 'reading' represents a known gap in the text.

=item is_ph - A temporary placeholder for apparatus parsing purposes.  Do
not use unless you know what you are doing.

=item rank - The sequence number of the reading. This should probably not
be set manually.

=back

One of 'text', 'is_start', 'is_end', or 'is_lacuna' is required.

=head2 collation

=head2 id

=head2 text

=head2 is_start

=head2 is_end

=head2 is_lacuna

=head2 rank

Accessor methods for the given attributes.

=cut

has 'collation' => (
	is => 'ro',
	isa => 'Text::Tradition::Collation',
	# required => 1,
	weak_ref => 1,
	);

has 'id' => (
	is => 'ro',
	isa => 'Str',
	required => 1,
	);

has 'text' => (
	is => 'ro',
	isa => 'Str',
	required => 1,
	writer => 'alter_text',
	);
	
has 'language' => (
	is => 'ro',
	isa => 'Str',
	predicate => 'has_language',
	);
	
has 'is_start' => (
	is => 'ro',
	isa => 'Bool',
	default => undef,
	);

has 'is_end' => (
	is => 'ro',
	isa => 'Bool',
	default => undef,
	);
    
has 'is_lacuna' => (
    is => 'ro',
    isa => 'Bool',
	default => undef,
    );
    
has 'is_ph' => (
	is => 'ro',
	isa => 'Bool',
	default => undef,
	);
	
has 'is_common' => (
	is => 'rw',
	isa => 'Bool',
	default => undef,
	);

has 'rank' => (
    is => 'rw',
    isa => 'Int',
    predicate => 'has_rank',
    clearer => 'clear_rank',
    );
    
## For morphological analysis

has 'normal_form' => (
	is => 'rw',
	isa => 'Str',
	predicate => 'has_normal_form',
	);

# Holds the lexemes for the reading.
has 'reading_lexemes' => (
	traits => ['Array'],
	isa => 'ArrayRef[Text::Tradition::Collation::Reading::Lexeme]',
	handles => {
		lexemes => 'elements',
		has_lexemes => 'count',
		clear_lexemes => 'clear',
		add_lexeme => 'push',
		},
	default => sub { [] },
	);
	
## For prefix/suffix readings

has 'join_prior' => (
	is => 'ro',
	isa => 'Bool',
	default => undef,
	);
	
has 'join_next' => (
	is => 'ro',
	isa => 'Bool',
	default => undef,
	);


around BUILDARGS => sub {
	my $orig = shift;
	my $class = shift;
	my $args;
	if( @_ == 1 ) {
		$args = shift;
	} else {
		$args = { @_ };
	}
			
	# If one of our special booleans is set, we change the text and the
	# ID to match.
	if( exists $args->{'is_lacuna'} && !exists $args->{'text'} ) {
		$args->{'text'} = '#LACUNA#';
	} elsif( exists $args->{'is_start'} ) {
		$args->{'id'} = '#START#';  # Change the ID to ensure we have only one
		$args->{'text'} = '#START#';
		$args->{'rank'} = 0;
	} elsif( exists $args->{'is_end'} ) {
		$args->{'id'} = '#END#';	# Change the ID to ensure we have only one
		$args->{'text'} = '#END#';
	} elsif( exists $args->{'is_ph'} ) {
		$args->{'text'} = $args->{'id'};
	}
	
	$class->$orig( $args );
};

# Look for a lexeme-string argument in the build args.
sub BUILD {
	my( $self, $args ) = @_;
	if( exists $args->{'lexemes'} ) {
		$self->_deserialize_lexemes( $args->{'lexemes'} );
	}
}

=head2 is_meta

A meta attribute (ha ha), which should be true if any of our 'special'
booleans are true.  Implies that the reading does not represent a bit 
of text found in a witness.

=cut

sub is_meta {
	my $self = shift;
	return $self->is_start || $self->is_end || $self->is_lacuna || $self->is_ph;	
}

=head1 Convenience methods

=head2 related_readings

Calls Collation's related_readings with $self as the first argument.

=cut

sub related_readings {
	my $self = shift;
	return $self->collation->related_readings( $self, @_ );
}

=head2 witnesses 

Calls Collation's reading_witnesses with $self as the first argument.

=cut

sub witnesses {
	my $self = shift;
	return $self->collation->reading_witnesses( $self, @_ );
}

=head2 predecessors

Returns a list of Reading objects that immediately precede $self in the collation.

=cut

sub predecessors {
	my $self = shift;
	my @pred = $self->collation->sequence->predecessors( $self->id );
	return map { $self->collation->reading( $_ ) } @pred;
}

=head2 successors

Returns a list of Reading objects that immediately follow $self in the collation.

=cut

sub successors {
	my $self = shift;
	my @succ = $self->collation->sequence->successors( $self->id );
	return map { $self->collation->reading( $_ ) } @succ;
}

=head2 set_identical( $other_reading)

Backwards compatibility method, to add a transposition relationship
between $self and $other_reading.  Don't use this.

=cut

sub set_identical {
	my( $self, $other ) = @_;
	return $self->collation->add_relationship( $self, $other, 
		{ 'type' => 'transposition' } );
}

sub _stringify {
	my $self = shift;
	return $self->id;
}

=head1 MORPHOLOGY

Methods for the morphological information (if any) attached to readings.
A reading may be made up of multiple lexemes; the concatenated lexeme
strings ought to match the reading's normalized form.
 
See L<Text::Tradition::Collation::Reading::Lexeme> for more information
on Lexeme objects and their attributes.

=head2 has_lexemes

Returns a true value if the reading has any attached lexemes.

=head2 lexemes

Returns the Lexeme objects (if any) attached to the reading.

=head2 clear_lexemes

Wipes any associated Lexeme objects out of the reading.

=head2 add_lexeme( $lexobj )

Adds the Lexeme in $lexobj to the list of lexemes.

=head2 lemmatize

If the language of the reading is set, this method will use the appropriate
Language model to determine the lexemes that belong to this reading.  See
L<Text::Tradition::lemmatize> if you wish to lemmatize an entire tradition.

=cut

sub lemmatize {
	my $self = shift;
	unless( $self->has_language ) {
		warn "Please set a language to lemmatize a tradition";
		return;
	}
	my $mod = "Text::Tradition::Language::" . $self->language;
	load( $mod );
	$mod->can( 'reading_lookup' )->( $self );

}

# For graph serialization. Return a JSON representation of the associated
# reading lexemes.
sub _serialize_lexemes {
	my $self = shift;
	my $json = JSON->new->allow_blessed(1)->convert_blessed(1);
	return $json->encode( [ $self->lexemes ] );
}

# Given a JSON representation of the lexemes, instantiate them and add
# them to the reading.
sub _deserialize_lexemes {
	my( $self, $json ) = @_;
	my $data = from_json( $json );
	return unless @$data;
	
	# Need to have the lexeme module in order to have lexemes.
	eval { use Text::Tradition::Collation::Reading::Lexeme; };
	throw( $@ ) if $@;
	
	# Good to go - add the lexemes.
	my @lexemes;
	foreach my $lexhash ( @$data ) {
		push( @lexemes, Text::Tradition::Collation::Reading::Lexeme->new(
			'JSON' => $lexhash ) );
	}
	$self->clear_lexemes;
	$self->add_lexeme( @lexemes );
}

## Utility methods

sub TO_JSON {
	my $self = shift;
	return $self->text;
}

sub throw {
	Text::Tradition::Error->throw( 
		'ident' => 'Reading error',
		'message' => $_[0],
		);
}

no Moose;
__PACKAGE__->meta->make_immutable;

1;