improved handling for drawing data from fields other than the holdings tag

improved handling for drawing data from fields other than the holdings tag

Suppose the 852 is the main holdings tag, but information is needed
from the 590$a (e.g., as an item note).  The extract_holdings configuration file
can now work as follows:

# to map the subfield contents to the item record
barcode 852 p
note    590 a

# to map, but have the 590$a information be associated
# only with the first item in the bib; if m:first is
# not supplied, the 590$a note will be supplied
# to all items associated with the bib
barcode 852 p
note    590 a m:first

# to put all occurrences of the 590$a into a separate
# file for linking with the appropriate items.  m:multi
# *must* be supplied if the 590 tag occurs more than once
# in the bib records
barcode 852 p
note    590 a m:multi

# to concatenate repeats of $a in the 590 together
barcode 852 p
note    590 a m:concatenate

# to concatenate with a custom separator
barcode 852 p
note    590 a m:concatenate c:' / '

Development sponsored by the Indiana State Library