def import_library(libfilepointer):
"""
Import a units library, replacing any existing definitions.
Parameters
----------
libfilepointer : file
new library file to work with
Returns
-------
ConfigParser
newly updated units library for the module
"""
global _UNIT_LIB
global _UNIT_CACHE
_UNIT_CACHE = {}
_UNIT_LIB = ConfigParser()
_UNIT_LIB.optionxform = _do_nothing
# New in Python 3.2: read_file() replaces readfp().
if sys.version_info >= (3, 2):
_UNIT_LIB.read_file(libfilepointer)
else:
_UNIT_LIB.readfp(libfilepointer)
required_base_types = ['length', 'mass', 'time', 'temperature', 'angle']
_UNIT_LIB.base_names = list()
# used to is_angle() and other base type checking
_UNIT_LIB.base_types = dict()
_UNIT_LIB.unit_table = dict()
_UNIT_LIB.prefixes = dict()
_UNIT_LIB.help = list()
for prefix, factor in _UNIT_LIB.items('prefixes'):
factor, comma, comment = factor.partition(',')
_UNIT_LIB.prefixes[prefix] = float(factor)
base_list = [0] * len(_UNIT_LIB.items('base_units'))
for i, (unit_type, name) in enumerate(_UNIT_LIB.items('base_units')):
_UNIT_LIB.base_types[unit_type] = i
powers = list(base_list)
powers[i] = 1
# print '%20s'%unit_type, powers
# cant use add_unit because no base units exist yet
_new_unit(name, 1, powers)
_UNIT_LIB.base_names.append(name)
# test for required base types
missing = [utype for utype in required_base_types
if utype not in _UNIT_LIB.base_types]
if missing:
raise ValueError('Not all required base type were present in the'
' config file. missing: %s, at least %s required'
% (missing, required_base_types))
_update_library(_UNIT_LIB)
return _UNIT_LIB
