def __init__(self, text):
"""Create expression from text.
:param text: Input text
:type text: str
:raise: ValueError if not a valid expression
"""
parts = text.split()
if len(parts) != 3:
raise ValueError(self._op_errmsg.format(text))
self._field = parts[0]
oper_str = parts[1]
self._val = parts[2]
# if val is a date, then parse it and optionally modify operator
_, mdate = parse.guess(self._val, try_num=False)
if mdate is not None:
self._val = mdate
if self._field != common.Keyword.TIME:
# time will have the value itself pre-parsed, but other
# fields will not, so we indicate this in the operator
oper_str = Oper.DATE_VALUE_PREFIX + oper_str
elif self._field == common.Keyword.TIME:
raise ValueError(
"Cannot compare non-date to timestamp field ({}): {}".format(
self._field, self._val))
self._op = Oper(oper_str)
def compare(self, lhs, rhs):
"""Compare two values with this operator.
:return: Boolean result of comparison
:rtype: bool
"""
if self._rhs_date:
_, rhs_d = parse.guess(rhs)
if rhs_d is None:
return False # Not a date; exception?
rhs = rhs_d
elif self._must_be_numeric:
lhs = self._number(lhs)
rhs = self._number(rhs)
if lhs is None or rhs is None:
return False # Not a number; exception?
return self._opfn(lhs, rhs)