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jedi-fork/jedi/evaluate/pep0484.py

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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)
v Local variable type hints
v Assigned types: `Url = str\ndef get(url:Url) -> str:`
v Type hints in `with` statements
x Stub files support
x support `@no_type_check` and `@no_type_check_decorator`
x support for typing.cast() operator
x support for type hint comments for functions, `# type: (int, str) -> int`.
See comment from Guido https://github.com/davidhalter/jedi/issues/662
"""
import itertools
import os
import re
from parso import ParserSyntaxError
from parso.python import tree
from jedi.common import unite
from jedi.evaluate.cache import memoize_default
from jedi.evaluate import compiled
from jedi.evaluate.context import LazyTreeContext
from jedi import debug
from jedi import _compatibility
from jedi import parser_utils
def _evaluate_for_annotation(context, annotation, index=None):
"""
Evaluates a string-node, looking for an annotation
If index is not None, the annotation is expected to be a tuple
and we're interested in that index
"""
if annotation is not None:
definitions = context.eval_node(
_fix_forward_reference(context, annotation))
if index is not None:
definitions = list(itertools.chain.from_iterable(
definition.py__getitem__(index) for definition in definitions
if definition.array_type == 'tuple' and
len(list(definition.py__iter__())) >= index))
return unite(d.execute_evaluated() for d in definitions)
else:
return set()
def _fix_forward_reference(context, node):
evaled_nodes = context.eval_node(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:
new_node = context.evaluator.grammar.parse(
_compatibility.unicode(evaled_node.obj),
start_symbol='eval_input',
error_recovery=False
)
except ParserSyntaxError:
debug.warning('Annotation not parsed: %s' % evaled_node.obj)
return node
else:
module = node.get_root_node()
parser_utils.move(new_node, module.end_pos[0])
new_node.parent = context.tree_node
return new_node
else:
return node
@memoize_default()
def infer_param(execution_context, param):
annotation = param.annotation
module_context = execution_context.get_root_context()
return _evaluate_for_annotation(module_context, annotation)
def py__annotations__(funcdef):
return_annotation = funcdef.annotation
if return_annotation:
dct = {'return': return_annotation}
else:
dct = {}
for function_param in funcdef.params:
param_annotation = function_param.annotation
if param_annotation is not None:
dct[function_param.name.value] = param_annotation
return dct
@memoize_default()
def infer_return_types(function_context):
annotation = py__annotations__(function_context.tree_node).get("return", None)
module_context = function_context.get_root_context()
return _evaluate_for_annotation(module_context, annotation)
_typing_module = None
def _get_typing_replacement_module(grammar):
"""
The idea is to return our jedi replacement for the PEP-0484 typing module
as discussed at https://github.com/davidhalter/jedi/issues/663
"""
global _typing_module
if _typing_module is None:
typing_path = \
os.path.abspath(os.path.join(__file__, "../jedi_typing.py"))
with open(typing_path) as f:
code = _compatibility.unicode(f.read())
_typing_module = grammar.parse(code)
return _typing_module
def py__getitem__(context, typ, node):
if not typ.get_root_context().name.string_name == "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 node.type == "subscriptlist":
nodes = node.children[::2] # skip the commas
else:
nodes = [node]
del node
nodes = [_fix_forward_reference(context, node) for node in nodes]
type_name = typ.name.string_name
# hacked in Union and Optional, since it's hard to do nicely in parsed code
if type_name in ("Union", '_Union'):
# In Python 3.6 it's still called typing.Union but it's an instance
# called _Union.
return unite(context.eval_node(node) for node in nodes)
if type_name in ("Optional", '_Optional'):
# Here we have the same issue like in Union. Therefore we also need to
# check for the instance typing._Optional (Python 3.6).
return context.eval_node(nodes[0])
from jedi.evaluate.representation import ModuleContext
typing = ModuleContext(
context.evaluator,
module_node=_get_typing_replacement_module(context.evaluator.latest_grammar),
path=None
)
factories = typing.py__getattribute__("factory")
assert len(factories) == 1
factory = list(factories)[0]
assert factory
function_body_nodes = factory.tree_node.children[4].children
valid_classnames = set(child.name.value
for child in function_body_nodes
if isinstance(child, tree.Class))
if type_name not in valid_classnames:
return None
compiled_classname = compiled.create(context.evaluator, type_name)
from jedi.evaluate.iterable import FakeSequence
args = FakeSequence(
context.evaluator,
"tuple",
[LazyTreeContext(context, n) for n in nodes]
)
result = factory.execute_evaluated(compiled_classname, args)
return result
def find_type_from_comment_hint_for(context, node, name):
return _find_type_from_comment_hint(context, node, node.children[1], name)
def find_type_from_comment_hint_with(context, node, name):
assert len(node.children[1].children) == 3, \
"Can only be here when children[1] is 'foo() as f'"
varlist = node.children[1].children[2]
return _find_type_from_comment_hint(context, node, varlist, name)
def find_type_from_comment_hint_assign(context, node, name):
return _find_type_from_comment_hint(context, node, node.children[0], name)
def _find_type_from_comment_hint(context, node, varlist, name):
index = None
if varlist.type in ("testlist_star_expr", "exprlist"):
# something like "a, b = 1, 2"
index = 0
for child in varlist.children:
if child == name:
break
if child.type == "operator":
continue
index += 1
else:
return []
comment = parser_utils.get_following_comment_same_line(node)
if comment is None:
return []
match = re.match(r"^#\s*type:\s*([^#]*)", comment)
if not match:
return []
annotation = tree.String(
repr(str(match.group(1).strip())),
node.start_pos)
annotation.parent = node.parent
return _evaluate_for_annotation(context, annotation, index)