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This is a helper method used by .scan()
and .scanFlat(). It is a static
method.
# - - - B i r d I d . s c a n A b b r - - -
def scanAbbr ( txny, scan ):
"""Scan one bird code.
"""
We use the regular expression RE_ABBR
to match any leading characters in the scan instance. If it matches, it returns a
Match instance whose .group() method returns the matching text. If it
returns None, there is no match.
#-- 1 --
# [ if scan starts with characters matching RE_ABBR ->
# scan := scan advanced past matching characters
# m := a Match instance representing the matched text
# else ->
# m := None ]
m = scan.tabReMatch ( RE_ABBR )
#-- 2 --
# [ if m is None ->
# scan +:= error message
# raise ValueError
# else ->
# abbr := m.group()
if m is None:
scan.error ( "Expecting a bird code." )
raise ValueError, "Expecting a bird code."
else:
abbr = m.group()
#-- 3 --
# [ if abbr is defined in txny ->
# return abbr
# else -> raise ValueError ]
try:
taxon = txny.lookupAbbr ( abbr )
return abbr
except KeyError, detail:
message = "Unknown bird code '%s'" % abbr
scan.error ( message )
raise ValueError, message
Finally, make this a static method.
scanAbbr = staticmethod ( scanAbbr )