def _infer_subscript_list(context, index):
"""
Handles slices in subscript nodes.
"""
if index == ':':
# Like array[:]
return ValueSet([iterable.Slice(context, None, None, None)])
elif index.type == 'subscript' and not index.children[0] == '.':
# subscript basically implies a slice operation
# e.g. array[:3]
result = []
for el in index.children:
if el == ':':
if not result:
result.append(None)
elif el.type == 'sliceop':
if len(el.children) == 2:
result.append(el.children[1])
else:
result.append(el)
result += [None] * (3 - len(result))
return ValueSet([iterable.Slice(context, *result)])
elif index.type == 'subscriptlist':
return ValueSet([
iterable.SequenceLiteralValue(context.inference_state, context,
index)
])
# No slices
return context.infer_node(index)
def infer_atom(context, atom):
"""
Basically to process ``atom`` nodes. The parser sometimes doesn't
generate the node (because it has just one child). In that case an atom
might be a name or a literal as well.
"""
state = context.inference_state
if atom.type == 'name':
# This is the first global lookup.
stmt = tree.search_ancestor(atom, 'expr_stmt', 'lambdef',
'if_stmt') or atom
if stmt.type == 'if_stmt':
if not any(n.start_pos <= atom.start_pos < n.end_pos
for n in stmt.get_test_nodes()):
stmt = atom
elif stmt.type == 'lambdef':
stmt = atom
position = stmt.start_pos
if _is_annotation_name(atom):
# Since Python 3.7 (with from __future__ import annotations),
# annotations are essentially strings and can reference objects
# that are defined further down in code. Therefore just set the
# position to None, so the finder will not try to stop at a certain
# position in the module.
position = None
return context.py__getattribute__(atom, position=position)
elif atom.type == 'keyword':
# For False/True/None
if atom.value in ('False', 'True', 'None'):
return ValueSet([compiled.builtin_from_name(state, atom.value)])
elif atom.value == 'yield':
# Contrary to yield from, yield can just appear alone to return a
# value when used with `.send()`.
return NO_VALUES
assert False, 'Cannot infer the keyword %s' % atom
elif isinstance(atom, tree.Literal):
string = state.compiled_subprocess.safe_literal_eval(atom.value)
return ValueSet([compiled.create_simple_object(state, string)])
elif atom.type == 'strings':
# Will be multiple string.
value_set = infer_atom(context, atom.children[0])
for string in atom.children[1:]:
right = infer_atom(context, string)
value_set = _infer_comparison(context, value_set, '+', right)
return value_set
elif atom.type == 'fstring':
return compiled.get_string_value_set(state)
else:
c = atom.children
# Parentheses without commas are not tuples.
if c[0] == '(' and not len(c) == 2 \
and not(c[1].type == 'testlist_comp'
and len(c[1].children) > 1):
return context.infer_node(c[1])
try:
comp_for = c[1].children[1]
except (IndexError, AttributeError):
pass
else:
if comp_for == ':':
# Dict comprehensions have a colon at the 3rd index.
try:
comp_for = c[1].children[3]
except IndexError:
pass
if comp_for.type in ('comp_for', 'sync_comp_for'):
return ValueSet(
[iterable.comprehension_from_atom(state, context, atom)])
# It's a dict/list/tuple literal.
array_node = c[1]
try:
array_node_c = array_node.children
except AttributeError:
array_node_c = []
if c[0] == '{' and (array_node == '}' or ':' in array_node_c
or '**' in array_node_c):
new_value = iterable.DictLiteralValue(state, context, atom)
else:
new_value = iterable.SequenceLiteralValue(state, context, atom)
return ValueSet([new_value])
def _infer_node(context, element):
debug.dbg('infer_node %s@%s in %s', element, element.start_pos, context)
inference_state = context.inference_state
typ = element.type
if typ in ('name', 'number', 'string', 'atom', 'strings', 'keyword',
'fstring'):
return infer_atom(context, element)
elif typ == 'lambdef':
return ValueSet([FunctionValue.from_context(context, element)])
elif typ == 'expr_stmt':
return infer_expr_stmt(context, element)
elif typ in ('power', 'atom_expr'):
first_child = element.children[0]
children = element.children[1:]
had_await = False
if first_child.type == 'keyword' and first_child.value == 'await':
had_await = True
first_child = children.pop(0)
value_set = context.infer_node(first_child)
for (i, trailer) in enumerate(children):
if trailer == '**': # has a power operation.
right = context.infer_node(children[i + 1])
value_set = _infer_comparison(context, value_set, trailer,
right)
break
value_set = infer_trailer(context, value_set, trailer)
if had_await:
return value_set.py__await__().py__stop_iteration_returns()
return value_set
elif typ in (
'testlist_star_expr',
'testlist',
):
# The implicit tuple in statements.
return ValueSet(
[iterable.SequenceLiteralValue(inference_state, context, element)])
elif typ in ('not_test', 'factor'):
value_set = context.infer_node(element.children[-1])
for operator in element.children[:-1]:
value_set = infer_factor(value_set, operator)
return value_set
elif typ == 'test':
# `x if foo else y` case.
return (context.infer_node(element.children[0])
| context.infer_node(element.children[-1]))
elif typ == 'operator':
# Must be an ellipsis, other operators are not inferred.
if element.value != '...':
origin = element.parent
raise AssertionError("unhandled operator %s in %s " %
(repr(element.value), origin))
return ValueSet(
[compiled.builtin_from_name(inference_state, 'Ellipsis')])
elif typ == 'dotted_name':
value_set = infer_atom(context, element.children[0])
for next_name in element.children[2::2]:
value_set = value_set.py__getattribute__(next_name,
name_context=context)
return value_set
elif typ == 'eval_input':
return context.infer_node(element.children[0])
elif typ == 'annassign':
return annotation.infer_annotation(context, element.children[1]) \
.execute_annotation()
elif typ == 'yield_expr':
if len(element.children) and element.children[1].type == 'yield_arg':
# Implies that it's a yield from.
element = element.children[1].children[1]
generators = context.infer_node(element) \
.py__getattribute__('__iter__').execute_with_values()
return generators.py__stop_iteration_returns()
# Generator.send() is not implemented.
return NO_VALUES
elif typ == 'namedexpr_test':
return context.infer_node(element.children[2])
else:
return infer_or_test(context, element)