marc::file::usmarc(3pm) [debian man page]

MARC::File::USMARC(3pm) 				User Contributed Perl Documentation				   MARC::File::USMARC(3pm)

NAME

       MARC::File::USMARC - USMARC-specific file handling

SYNOPSIS

	   use MARC::File::USMARC;

	   my $file = MARC::File::USMARC->in( $filename );

	   while ( my $marc = $file->next() ) {
	       # Do something
	   }
	   $file->close();
	   undef $file;

EXPORT

       None.

METHODS

   decode( $string [, &filter_func ] )
       Constructor for handling data from a USMARC file.  This function takes care of all the tag directory parsing & mangling.

       Any warnings or coercions can be checked in the "warnings()" function.

       The $filter_func is an optional reference to a user-supplied function that determines on a tag-by-tag basis if you want the tag passed to
       it to be put into the MARC record.  The function is passed the tag number and the raw tag data, and must return a boolean.  The return of a
       true value tells MARC::File::USMARC::decode that the tag should get put into the resulting MARC record.

       For example, if you only want title and subject tags in your MARC record, try this:

	   sub filter {
	       my ($tagno,$tagdata) = @_;

	       return ($tagno == 245) || ($tagno >= 600 && $tagno <= 699);
	   }

	   my $marc = MARC::File::USMARC->decode( $string, &filter );

       Why would you want to do such a thing?  The big reason is that creating fields is processor-intensive, and if your program is doing read-
       only data analysis and needs to be as fast as possible, you can save time by not creating fields that you'll be ignoring anyway.

       Another possible use is if you're only interested in printing certain tags from the record, then you can filter them when you read from
       disc and not have to delete unwanted tags yourself.

   update_leader()
       If any changes get made to the MARC record, the first 5 bytes of the leader (the length) will be invalid.  This function updates the leader
       with the correct length of the record as it would be if written out to a file.

   _build_tag_directory()
       Function for internal use only: Builds the tag directory that gets put in front of the data in a MARC record.

       Returns two array references, and two lengths: The tag directory, and the data fields themselves, the length of all data (including the
       Leader that we expect will be added), and the size of the Leader and tag directory.

   encode()
       Returns a string of characters suitable for writing out to a USMARC file, including the leader, directory and all the fields.

RELATED MODULES

       MARC::Record

TODO

       Make some sort of autodispatch so that you don't have to explicitly specify the MARC::File::X subclass, sort of like how DBI knows to use
       DBD::Oracle or DBD::Mysql.

       Create a toggle-able option to check inside the field data for end of field characters.	Presumably it would be good to have it turned on
       all the time, but it's nice to be able to opt out if you don't want to take the performance hit.

LICENSE

       This code may be distributed under the same terms as Perl itself.

       Please note that these modules are not products of or supported by the employers of the various contributors to the code.

AUTHOR

       Andy Lester, "<andy@petdance.com>"

perl v5.10.1							    2010-03-29						   MARC::File::USMARC(3pm)

MARC::Batch(3pm)					User Contributed Perl Documentation					  MARC::Batch(3pm)

NAME

       MARC::Batch - Perl module for handling files of MARC::Record objects

SYNOPSIS

       MARC::Batch hides all the file handling of files of "MARC::Record"s.  "MARC::Record" still does the file I/O, but "MARC::Batch" handles the
       multiple-file aspects.

	   use MARC::Batch;

	   # If you have werid control fields...
	   use MARC::Field;
	   MARC::Field->allow_controlfield_tags('FMT', 'LDX');

	   my $batch = MARC::Batch->new( 'USMARC', @files );
	   while ( my $marc = $batch->next ) {
	       print $marc->subfield(245,"a"), "
";
	   }

EXPORT

       None.  Everything is a class method.

METHODS

   new( $type, @files )
       Create a "MARC::Batch" object that will process @files.

       $type must be either "USMARC" or "MicroLIF".  If you want to specify "MARC::File::USMARC" or "MARC::File::MicroLIF", that's OK, too.
       "new()" returns a new MARC::Batch object.

       @files can be a list of filenames:

	   my $batch = MARC::Batch->new( 'USMARC', 'file1.marc', 'file2.marc' );

       Your @files may also contain filehandles. So if you've got a large file that's gzipped you can open a pipe to gzip and pass it in:

	   my $fh = IO::File->new( 'gunzip -c marc.dat.gz |' );
	   my $batch = MARC::Batch->new( 'USMARC', $fh );

       And you can mix and match if you really want to:

	   my $batch = MARC::Batch->new( 'USMARC', $fh, 'file1.marc' );

   next()
       Read the next record from that batch, and return it as a MARC::Record object.  If the current file is at EOF, close it and open the next
       one. "next()" will return "undef" when there is no more data to be read from any batch files.

       By default, "next()" also will return "undef" if an error is encountered while reading from the batch. If not checked for this can cause
       your iteration to terminate prematurely. To alter this behavior, see "strict_off()". You can retrieve warning messages using the
       "warnings()" method.

       Optionally you can pass in a filter function as a subroutine reference if you are only interested in particular fields from the record.
       This can boost performance.

   strict_off()
       If you would like "MARC::Batch" to continue after it has encountered what it believes to be bad MARC data then use this method to turn
       strict OFF.  A call to "strict_off()" always returns true(1).

       "strict_off()" can be handy when you don't care about the quality of your MARC data, and just want to plow through it. For safety,
       "MARC::Batch" strict is ON by default.

   strict_on()
       The opposite of "strict_off()", and the default state. You shouldn't have to use this method unless you've previously used "strict_off()",
       and want it back on again.  When strict is ON calls to next() will return undef when an error is encountered while reading MARC data.
       strict_on() always returns true(1).

   warnings()
       Returns a list of warnings that have accumulated while processing a particular batch file. As a side effect the warning buffer will be
       cleared.

	   my @warnings = $batch->warnings();

       This method is also used internally to set warnings, so you probably don't want to be passing in anything as this will set warnings on your
       batch object.

       "warnings()" will return the empty list when there are no warnings.

   warnings_off()
       Turns off the default behavior of printing warnings to STDERR. However, even with warnings off the messages can still be retrieved using
       the warnings() method if you wish to check for them.

       "warnings_off()" always returns true(1).

   warnings_on()
       Turns on warnings so that diagnostic information is printed to STDERR. This is on by default so you shouldn't have to use it unless you've
       previously turned off warnings using warnings_off().

       warnings_on() always returns true(1).

   filename()
       Returns the currently open filename or "undef" if there is not currently a file open on this batch object.

RELATED MODULES

       MARC::Record, MARC::Lint

TODO

       None yet.  Send me your ideas and needs.

LICENSE

       This code may be distributed under the same terms as Perl itself.

       Please note that these modules are not products of or supported by the employers of the various contributors to the code.

AUTHOR

       Andy Lester, "<andy@petdance.com>"

perl v5.10.1							    2010-03-29							  MARC::Batch(3pm)