VERSION

Version 0.23;

SYNOPSIS

Utility functions to deal with Library of Congress Call Numbers

use Library::CallNumber::LC;
my $a = Library::CallNumber::LC->new('A 123.4 .c11');
print $a->normalize; # normalizes for string comparisons.
# gives 'A01234 C11'
print $a->start_of_range; # same as "normalize"
my $b = Library::CallNumber::LC->new('B11 .c13 .d11');
print $b->normalize;
# gives 'B0011 C13 D11'
my @range = ($a->start_of_range, $b->end_of_range);
# end of range is 'B0011 C13 D11~'

# Get components suitable for printing (e.g., number and decimal joined, leading dot on first cutter)
@comps = Library::CallNumber::LC->new('A 123.4 .c11')->components()

# Same thing, but return empty strings for missing components (e.g., the cutters)
@comps = Library::CallNumber::LC->new('A 123.4 .c11')->components('true');

ABSTRACT

Library::CallNumber::LC is mostly designed to do call number normalization, with the following goals:

• The normalized call numbers are comparable with each other, for proper sorting
• The normalized call number is a short as possible, so left-anchored wildcard searches are possible (e.g., searching on ``A11*'' should give you all the A11 call numbers)
• A range defined by start_of_range and end_of_range should be correct, assuming that the string given for the end of the range is, in fact, a left prefix.

That last point needs some explanation. The idea is that if someone gives a range of, say, A-AZ, what they really mean is A - AZ9999.99. The end_of_range method generates a key which lies immediately beyond the last possible key for a given starting point. There is no attempt to make end_of_range normalization correspond to anything in real life.

CONSTRUCTORS

new([call_number_text, [topper_character, [bottomer_character]]]) --- create a new object, optionally passing in the initial string, a topper, and a bottomer (explained below)

BASIC ACCESSORS

call_number([call_number_text])

The text of the call number we are dealing with.

topper([character])

Specify which character occupies the 'always-sort-to-the-top' slots in the sort keys. Defaults to the SPACE character, but can reasonably be anything with an ASCII value lower than 48 (i.e. the 'zero' character, '0'). This can function as either a class or instance method depending on need.

bottomer([character])

Specify which character occupies the 'always-sort-to-the-bottom' slots in the sort keys. Defaults to the TILDE character, but can reasonably be anything with an ASCII value higher than 90 (i.e. 'Z'). This can function as either a class or instance method depending on need.

OTHER METHODS

components(boolean returnAll = false)

  @comps = Library::CallNumber::LC->new('A 123.4 .c11')->components($returnAll)

Returns an array of the individual components of the call number (or undef if it doesn't look like a call number). Components are:

• alpha
• number (numeric.decimal)
• cutter1
• cutter2
• cutter3
• ``extra'' (anything after the cutters)

The optional argument <I returnAll> (false by default) determines whether or not empty components (e.g., extra cutters) get a slot in the returned list.

_normalize(call_number_text)

Base function to perform normalization.

normalize([call_number_text])

Normalize the stored or passed call number as a sortable string

start_of_range([call_number_text])

Alias for normalize

end_of_range([call_number_text])

Downshift an lc number so it represents the end of a range

toLongInt(call_number_text, num_digits)

Attempt to turn a call number into an integer value. Possibly useful for fast range checks, although obviously not perfectly accurate. Optional argument $num_digits can be used to control the number of digits used, and therefore the precision of the results.

AUTHOR

Current Maintainer: Dan Wells, "<dbw2 at calvin.edu>" Original Author: Bill Dueber, "<dueberb at umich.edu>"

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Library::CallNumber::LC

You can also look for information at the Google Code page:

  http://code.google.com/p/library-callnumber-lc/

COPYRIGHT & LICENSE

Copyright 2009 Bill Dueber, all rights reserved. Copyright 2011 Dan Wells, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself and also under the new BSD license as described at http://www.opensource.org/licenses/bsd-license.php