|  |
| |
If the argument s is a fixed time zone offset
of the form “±hhmm”, this
function returns an instance of class FixedZone
representing that offset.
# - - - p a r s e F i x e d Z o n e
HHMM_PAT = re.compile (
r'\d{4}' # Matches exactly four digits
r'$' ) # Be sure everything is matched
def parseFixedZone ( s ):
"""Convert a +hhmm or -hhmm zone suffix.
[ s is a string ->
if s is a time zone suffix of the form "+hhmm" or "-hhmm" ->
return that zone information as an instance of a class
that inherits from datetime.tzinfo
else -> raise SyntaxError ]
"""
The first character must be “+”
or “-”; we set sign to +1 or -1, respectively.
#-- 1 --
if s.startswith('+'): sign = 1
elif s.startswith('-'): sign = -1
else:
raise SyntaxError, ( "Expecting zone modifier as %shhmm: "
"'%s'" % (s[0], s) )
Use a regular expression to check the length and
content of the hours and minutes. Then return an
instance of the FixedZone class representing
that number of hours and minutes.
#-- 2 --
# [ if s[1:] matches HHMM_PAT ->
# hours := the HH part as an int
# minutes := the MM part as an int
# else -> raise SyntaxError ]
rawHHMM = s[1:]
m = HHMM_PAT.match ( rawHHMM )
if m is None:
raise SyntaxError, ( "Expecting zone modifier as %sHHMM: "
"'%s'" % (s[0], s) )
else:
hours = int ( rawHHMM[:2] )
minutes = int ( rawHHMM[2:] )
#-- 3 --
return FixedZone ( sign*hours, sign*minutes, s )