def castable(source, target):
"""Return whether source ir type is implicitly castable to target
Based on the underlying datatypes and the value in case of Literals
"""
op = source.op()
value = getattr(op, 'value', None)
return dt.castable(source.type(), target.type(), value=value)
def value(dtype, arg):
"""Validates that the given argument is a Value with a particular datatype
Parameters
----------
dtype : DataType subclass or DataType instance
arg : python literal or an ibis expression
If a python literal is given the validator tries to coerce it to an ibis
literal.
Returns
-------
arg : AnyValue
An ibis value expression with the specified datatype
"""
if not isinstance(arg, ir.Expr):
# coerce python literal to ibis literal
arg = ir.literal(arg)
if not isinstance(arg, ir.AnyValue):
raise com.IbisTypeError(
'Given argument with type {} is not a value '
'expression'.format(type(arg))
)
# retrieve literal values for implicit cast check
value = getattr(arg.op(), 'value', None)
if isinstance(dtype, type) and isinstance(arg.type(), dtype):
# dtype class has been specified like dt.Interval or dt.Decimal
return arg
elif dt.castable(arg.type(), dt.dtype(dtype), value=value):
# dtype instance or string has been specified and arg's dtype is
# implicitly castable to it, like dt.int8 is castable to dt.int64
return arg
else:
raise com.IbisTypeError(
'Given argument with datatype {} is not '
'subtype of {} nor implicitly castable to '
'it'.format(arg.type(), dtype)
)
def test_implicitly_uncastable_values(source, target, value):
assert not dt.castable(source, target, value=value)
def test_implicitly_uncastable(source, target):
assert not dt.castable(source, target)
def test_implicit_castable(source, target):
assert dt.castable(source, target)
def test_implicitly_uncastable(source, target):
assert not dt.castable(source, target)
def test_implicit_castable(source, target):
assert dt.castable(source, target)
def test_implicitly_uncastable_values(source, target, value):
assert not dt.castable(source, target, value=value)
