MARC::Descriptions - MARC metadata looker-upper

 use MARC::Descriptions

 my $TD = MARC::Descriptions->new;

 # hash of all tag data
 my $href = $TD->get("245");

 # string description
 my $s = $TD->get("245", "description");

 # hash of all subfields
 my $href = $TD->get("245", "subfield");

 # hash of subfield 'a'
 my $href = $TD->get("245", "subfield", "a");

 # description of subfield 'a'
 my $s = $TD->get("245", "subfield", "a", "description");

MARC::Description allows you to get either a string of information about a particular bit of a MARC record (eg: the description of the 245 tag, or the flags associated with tag 245 subfield \$a), or a hash of (hashes of) strings of information about a particular subset of a MARC record (eg: all of the 2nd indicators for tag 245, or all of the subfields for tag 245, or even a complete breakdown of tag 245).

Creates the MARC::Descriptions object. You only ever need one of these; all of the fun stuff is done in get().

 Returns information about the MARC structure.

 tag is the MARC tag
    eg: get("010")
    With no other parameters, this returns a hash of all information
    about that tag.

 parm1 can be one of:
    "description","shortname", or "flags" (eg: get("245","description")),
       in which case a string is returned with that information,
   or
    "ind1","ind2","subfield" (eg: get("245","subfield")),
       in which case parm2 will be the indicator/subfield that you're
       interested in, and get() will return a hash of the information
       about all possible indicators or subfields.

 If both parm1 and parm2 are specified, then parm3 can also be specified
    to have get() return a string containing information about that particular
    indicator/subfield.  (eg: get("245","subfield","a"))

If you've asked get() to return a hash, it will look like this (or a subset of this) - the example is for get("010"):

 {
 flags => "",
 shortname => "LCCN",
 description => "Library of Congress Control Number",
 ind1 => {
	"#" => {
		flags => "",
		description => "Unused",
		},
	},
 ind2 => {
	"#" => {
		flags => "",
		description => "Blank",
		},
	},
 subfield => {
	"a" => {
		flags => "",
		description => "LC control number",
		},
	"b" => {
		flags => "aR",
		description => "National Union Catalog of Manuscript Collections Control Number",
		},
	"z" => {
		flags => "R",
		description => "Canceled/invalid LC control number",
		},
	},
 }

* perl4lib (http://www.rice.edu/perl4lib/)

A mailing list devoted to the use of Perl in libraries.

* Library Of Congress MARC pages (http://www.loc.gov/marc/)

The definitive source for all things MARC.

* Understanding MARC Bibliographic (http://lcweb.loc.gov/marc/umb/)

Online version of the free booklet. An excellent overview of the MARC format. Essential.

* Tag Of The Month (http://www.tagofthemonth.com/)

Follett Software Company's (http://www.fsc.follett.com/) monthly discussion of various MARC tags.

* Cataloguer's Reference Shelf (http://www.carl.org/tlc/crs/CRS0000.htm)

The Library Corporation's (L:<http://www.carl.org/tlccarl/index.asp>) free online resource for cataloguers.

David Christensen, <DChristensenSPAMLESS@westman.wave.ca>

Copyright 2003 by David Christensen

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.