def parse_type(string, expect=None):
"""Convert a string into a type expression
Parameters
----------
string : str
The string type expression to convert into a TypeExpression
expect : {'semantic', 'primitive', 'visualization'}, optional
Will raise a TypeError if the resulting TypeExpression is not a member
of `expect`.
Returns
-------
type expression
"""
if expect is not None and expect not in {'semantic', 'primitive',
'visualization'}:
raise ValueError("`expect` got %r, must be 'semantic', 'primitive',"
" 'visualization', or None." % (expect,))
type_expr = _parse.ast_to_type(_parse.string_to_ast(string))
if expect is None:
pass
elif expect == 'semantic' and qtype.is_semantic_type(type_expr):
pass
elif expect == 'primitive' and qtype.is_primitive_type(type_expr):
pass
elif expect == 'visualization' and type_expr == qtype.Visualization:
pass
else:
raise TypeError("Type expression %r is not a %s type."
% (type_expr, expect))
return type_expr
def assert_roundtrip(self, type):
ast = string_to_ast(repr(type))
type1 = ast_to_type(ast)
type2 = ast_to_type(type1.to_ast())
self.assertEqual(type, type1)
self.assertEqual(ast, type1.to_ast())
self.assertEqual(type1, type2)
def test_weird(self):
with self.assertRaisesRegex(ValueError, "Unknown literal"):
string_to_ast('FeatureTable(Foo + Bar)')
def test_more_bad(self):
with self.assertRaisesRegex(ValueError, "Unknown expression"):
string_to_ast('lambda x: x')
def test_bad_juju(self):
with self.assertRaisesRegex(ValueError, "one type expression"):
string_to_ast('import os; os.rmdir("something-important")')
def test_syntax_error(self):
with self.assertRaisesRegex(ValueError, "could not be parsed"):
string_to_ast('$')
