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jedi-fork/jedi/evaluate/pep0484.py
2016-01-23 22:10:52 +01:00

132 lines
4.8 KiB
Python

"""
PEP 0484 ( https://www.python.org/dev/peps/pep-0484/ ) describes type hints
through function annotations. There is a strong suggestion in this document
that only the type of type hinting defined in PEP0484 should be allowed
as annotations in future python versions.
The (initial / probably incomplete) implementation todo list for pep-0484:
v Function parameter annotations with builtin/custom type classes
v Function returntype annotations with builtin/custom type classes
v Function parameter annotations with strings (forward reference)
v Function return type annotations with strings (forward reference)
x Local variable type hints
v Assigned types: `Url = str\ndef get(url:Url) -> str:`
x Type hints in `with` statements
x Stub files support
x support `@no_type_check` and `@no_type_check_decorator`
x support for type hint comments `# type: (int, str) -> int`. See comment from
Guido https://github.com/davidhalter/jedi/issues/662
"""
import itertools
import os
from jedi.parser import \
Parser, load_grammar, ParseError, ParserWithRecovery, tree
from jedi.evaluate.cache import memoize_default
from jedi.common import unite
from jedi.evaluate import compiled
from jedi import debug
def _evaluate_for_annotation(evaluator, annotation):
if annotation is not None:
definitions = evaluator.eval_element(
_fix_forward_reference(evaluator, annotation))
return list(itertools.chain.from_iterable(
evaluator.execute(d) for d in definitions))
else:
return []
def _fix_forward_reference(evaluator, node):
evaled_nodes = evaluator.eval_element(node)
if len(evaled_nodes) != 1:
debug.warning("Eval'ed typing index %s should lead to 1 object, "
" not %s" % (node, evaled_nodes))
return node
evaled_node = list(evaled_nodes)[0]
if isinstance(evaled_node, compiled.CompiledObject) and \
isinstance(evaled_node.obj, str):
try:
p = Parser(load_grammar(), evaled_node.obj, start='eval_input')
newnode = p.get_parsed_node()
except ParseError:
debug.warning('Annotation not parsed: %s' % evaled_node.obj)
return node
else:
module = node.get_parent_until()
p.position_modifier.line = module.end_pos[0]
newnode.parent = module
return newnode
else:
return node
@memoize_default(None, evaluator_is_first_arg=True)
def follow_param(evaluator, param):
annotation = param.annotation()
return _evaluate_for_annotation(evaluator, annotation)
@memoize_default(None, evaluator_is_first_arg=True)
def find_return_types(evaluator, func):
annotation = func.py__annotations__().get("return", None)
return _evaluate_for_annotation(evaluator, annotation)
# TODO: Memoize
def _get_typing_replacement_module():
"""
The idea is to return our jedi replacement for the PEP-0484 typing module
as discussed at https://github.com/davidhalter/jedi/issues/663
"""
typing_path = os.path.abspath(os.path.join(__file__, "../jedi_typing.py"))
with open(typing_path) as f:
code = f.read()
p = ParserWithRecovery(load_grammar(), code)
return p.module
def get_types_for_typing_module(evaluator, typ, node):
from jedi.evaluate.iterable import FakeSequence
if not typ.base.get_parent_until().name.value == "typing":
return None
# we assume that any class using [] in a module called
# "typing" with a name for which we have a replacement
# should be replaced by that class. This is not 100%
# airtight but I don't have a better idea to check that it's
# actually the PEP-0484 typing module and not some other
if tree.is_node(node, "subscriptlist"):
nodes = node.children[::2] # skip the commas
else:
nodes = [node]
del node
nodes = [_fix_forward_reference(evaluator, node) for node in nodes]
# hacked in Union and Optional, since it's hard to do nicely in parsed code
if typ.name.value == "Union":
return unite(evaluator.eval_element(node) for node in nodes)
if typ.name.value == "Optional":
return evaluator.eval_element(nodes[0])
typing = _get_typing_replacement_module()
factories = evaluator.find_types(typing, "factory")
assert len(factories) == 1
factory = list(factories)[0]
assert factory
function_body_nodes = factory.children[4].children
valid_classnames = set(child.name.value
for child in function_body_nodes
if isinstance(child, tree.Class))
if typ.name.value not in valid_classnames:
return None
compiled_classname = compiled.create(evaluator, typ.name.value)
args = FakeSequence(evaluator, nodes, "tuple")
result = evaluator.execute_evaluated(factory, compiled_classname, args)
return result