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# copyright 2003-2013 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact --
# This file is part of astroid.
# astroid is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation, either version 2.1 of the License, or (at your
# option) any later version.
# astroid is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
# for more details.
# You should have received a copy of the GNU Lesser General Public License along
# with astroid. If not, see <>.
"""Module for some node classes. More nodes in
import sys
import six
import logilab
from logilab.common.decorators import cachedproperty
from astroid.exceptions import NoDefault
from astroid.bases import (NodeNG, Statement, Instance, InferenceContext,
_infer_stmts, YES, BUILTINS)
from astroid.mixins import (BlockRangeMixIn, AssignTypeMixin,
ParentAssignTypeMixin, FromImportMixIn)
PY3K = sys.version_info >= (3, 0)
def unpack_infer(stmt, context=None):
"""recursively generate nodes inferred by the given statement.
If the inferred value is a list or a tuple, recurse on the elements
if isinstance(stmt, (List, Tuple)):
for elt in stmt.elts:
for infered_elt in unpack_infer(elt, context):
yield infered_elt
# if infered is a final node, return it and stop
infered = next(stmt.infer(context))
if infered is stmt:
yield infered
# else, infer recursivly, except YES object that should be returned as is
for infered in stmt.infer(context):
if infered is YES:
yield infered
for inf_inf in unpack_infer(infered, context):
yield inf_inf
def are_exclusive(stmt1, stmt2, exceptions=None):
"""return true if the two given statements are mutually exclusive
`exceptions` may be a list of exception names. If specified, discard If
branches and check one of the statement is in an exception handler catching
one of the given exceptions.
algorithm :
1) index stmt1's parents
2) climb among stmt2's parents until we find a common parent
3) if the common parent is a If or TryExcept statement, look if nodes are
in exclusive branches
# index stmt1's parents
stmt1_parents = {}
children = {}
node = stmt1.parent
previous = stmt1
while node:
stmt1_parents[node] = 1
children[node] = previous
previous = node
node = node.parent
# climb among stmt2's parents until we find a common parent
node = stmt2.parent
previous = stmt2
while node:
if node in stmt1_parents:
# if the common parent is a If or TryExcept statement, look if
# nodes are in exclusive branches
if isinstance(node, If) and exceptions is None:
if (node.locate_child(previous)[1]
is not node.locate_child(children[node])[1]):
return True
elif isinstance(node, TryExcept):
c2attr, c2node = node.locate_child(previous)
c1attr, c1node = node.locate_child(children[node])
if c1node is not c2node:
if ((c2attr == 'body' and c1attr == 'handlers' and children[node].catch(exceptions)) or
(c2attr == 'handlers' and c1attr == 'body' and previous.catch(exceptions)) or
(c2attr == 'handlers' and c1attr == 'orelse') or
(c2attr == 'orelse' and c1attr == 'handlers')):
return True
elif c2attr == 'handlers' and c1attr == 'handlers':
return previous is not children[node]
return False
previous = node
node = node.parent
return False
class LookupMixIn(object):
"""Mixin looking up a name in the right scope
def lookup(self, name):
"""lookup a variable name
return the scope node and the list of assignments associated to the
given name according to the scope where it has been found (locals,
globals or builtin)
The lookup is starting from self's scope. If self is not a frame itself
and the name is found in the inner frame locals, statements will be
filtered to remove ignorable statements according to self's location
return self.scope().scope_lookup(self, name)
def ilookup(self, name):
"""infered lookup
return an iterator on infered values of the statements returned by
the lookup method
frame, stmts = self.lookup(name)
return _infer_stmts(stmts, None, frame)
def _filter_stmts(self, stmts, frame, offset):
"""filter statements to remove ignorable statements.
If self is not a frame itself and the name is found in the inner
frame locals, statements will be filtered to remove ignorable
statements according to self's location
# if offset == -1, my actual frame is not the inner frame but its parent
# class A(B): pass
# we need this to resolve B correctly
if offset == -1:
myframe = self.frame().parent.frame()
myframe = self.frame()
# If the frame of this node is the same as the statement
# of this node, then the node is part of a class or
# a function definition and the frame of this node should be the
# the upper frame, not the frame of the definition.
# For more information why this is important,
# see Pylint issue #295.
# For example, for 'b', the statement is the same
# as the frame / scope:
# def test(b=1):
# ...
if self.statement() is myframe and myframe.parent:
myframe = myframe.parent.frame()
if not myframe is frame or self is frame:
return stmts
mystmt = self.statement()
# line filtering if we are in the same frame
# take care node may be missing lineno information (this is the case for
# nodes inserted for living objects)
if myframe is frame and mystmt.fromlineno is not None:
assert mystmt.fromlineno is not None, mystmt
mylineno = mystmt.fromlineno + offset
# disabling lineno filtering
mylineno = 0
_stmts = []
_stmt_parents = []
for node in stmts:
stmt = node.statement()
# line filtering is on and we have reached our location, break
if mylineno > 0 and stmt.fromlineno > mylineno:
assert hasattr(node, 'ass_type'), (node, node.scope(),
ass_type = node.ass_type()
if node.has_base(self):
_stmts, done = ass_type._get_filtered_stmts(self, node, _stmts, mystmt)
if done:
optional_assign = ass_type.optional_assign
if optional_assign and ass_type.parent_of(self):
# we are inside a loop, loop var assigment is hidding previous
# assigment
_stmts = [node]
_stmt_parents = [stmt.parent]
# XXX comment various branches below!!!
pindex = _stmt_parents.index(stmt.parent)
except ValueError:
# we got a parent index, this means the currently visited node
# is at the same block level as a previously visited node
if _stmts[pindex].ass_type().parent_of(ass_type):
# both statements are not at the same block level
# if currently visited node is following previously considered
# assignement and both are not exclusive, we can drop the
# previous one. For instance in the following code ::
# if a:
# x = 1
# else:
# x = 2
# print x
# we can't remove neither x = 1 nor x = 2 when looking for 'x'
# of 'print x'; while in the following ::
# x = 1
# x = 2
# print x
# we can remove x = 1 when we see x = 2
# moreover, on loop assignment types, assignment won't
# necessarily be done if the loop has no iteration, so we don't
# want to clear previous assigments if any (hence the test on
# optional_assign)
if not (optional_assign or are_exclusive(_stmts[pindex], node)):
del _stmt_parents[pindex]
del _stmts[pindex]
if isinstance(node, AssName):
if not optional_assign and stmt.parent is mystmt.parent:
_stmts = []
_stmt_parents = []
elif isinstance(node, DelName):
_stmts = []
_stmt_parents = []
if not are_exclusive(self, node):
return _stmts
# Name classes
class AssName(LookupMixIn, ParentAssignTypeMixin, NodeNG):
"""class representing an AssName node"""
class DelName(LookupMixIn, ParentAssignTypeMixin, NodeNG):
"""class representing a DelName node"""
class Name(LookupMixIn, NodeNG):
"""class representing a Name node"""
##################### node classes ########################################
class Arguments(NodeNG, AssignTypeMixin):
"""class representing an Arguments node"""
if PY3K:
# Python 3.4+ uses a different approach regarding annotations,
# each argument is a new class, _ast.arg, which exposes an
# 'annotation' attribute. In astroid though, arguments are exposed
# as is in the Arguments node and the only way to expose annotations
# is by using something similar with Python 3.3:
# - we expose 'varargannotation' and 'kwargannotation' of annotations
# of varargs and kwargs.
# - we expose 'annotation', a list with annotations for
# for each normal argument. If an argument doesn't have an
# annotation, its value will be None.
_astroid_fields = ('args', 'defaults', 'kwonlyargs',
'kw_defaults', 'annotations',
'varargannotation', 'kwargannotation')
annotations = None
varargannotation = None
kwargannotation = None
_astroid_fields = ('args', 'defaults', 'kwonlyargs', 'kw_defaults')
args = None
defaults = None
kwonlyargs = None
kw_defaults = None
def __init__(self, vararg=None, kwarg=None):
self.vararg = vararg
self.kwarg = kwarg
def _infer_name(self, frame, name):
if self.parent is frame:
return name
return None
def fromlineno(self):
lineno = super(Arguments, self).fromlineno
return max(lineno, self.parent.fromlineno)
def format_args(self):
"""return arguments formatted as string"""
result = []
if self.args:
result.append(_format_args(self.args, self.defaults))
if self.vararg:
result.append('*%s' % self.vararg)
if self.kwarg:
result.append('**%s' % self.kwarg)
if self.kwonlyargs:
if not self.vararg:
result.append(_format_args(self.kwonlyargs, self.kw_defaults))
return ', '.join(result)
def default_value(self, argname):
"""return the default value for an argument
:raise `NoDefault`: if there is no default value defined
i = _find_arg(argname, self.args)[0]
if i is not None:
idx = i - (len(self.args) - len(self.defaults))
if idx >= 0:
return self.defaults[idx]
i = _find_arg(argname, self.kwonlyargs)[0]
if i is not None and self.kw_defaults[i] is not None:
return self.kw_defaults[i]
raise NoDefault()
def is_argument(self, name):
"""return True if the name is defined in arguments"""
if name == self.vararg:
return True
if name == self.kwarg:
return True
return self.find_argname(name, True)[1] is not None
def find_argname(self, argname, rec=False):
"""return index and Name node with given name"""
if self.args: # self.args may be None in some cases (builtin function)
return _find_arg(argname, self.args, rec)
return None, None
def get_children(self):
"""override get_children to skip over None elements in kw_defaults"""
for child in super(Arguments, self).get_children():
if child is not None:
yield child
def _find_arg(argname, args, rec=False):
for i, arg in enumerate(args):
if isinstance(arg, Tuple):
if rec:
found = _find_arg(argname, arg.elts)
if found[0] is not None:
return found
elif == argname:
return i, arg
return None, None
def _format_args(args, defaults=None):
values = []
if args is None:
return ''
if defaults is not None:
default_offset = len(args) - len(defaults)
for i, arg in enumerate(args):
if isinstance(arg, Tuple):
values.append('(%s)' % _format_args(arg.elts))
if defaults is not None and i >= default_offset:
if defaults[i-default_offset] is not None:
values[-1] += '=' + defaults[i-default_offset].as_string()
return ', '.join(values)
class AssAttr(NodeNG, ParentAssignTypeMixin):
"""class representing an AssAttr node"""
_astroid_fields = ('expr',)
expr = None
class Assert(Statement):
"""class representing an Assert node"""
_astroid_fields = ('test', 'fail',)
test = None
fail = None
class Assign(Statement, AssignTypeMixin):
"""class representing an Assign node"""
_astroid_fields = ('targets', 'value',)
targets = None
value = None
class AugAssign(Statement, AssignTypeMixin):
"""class representing an AugAssign node"""
_astroid_fields = ('target', 'value',)
target = None
value = None
class Backquote(NodeNG):
"""class representing a Backquote node"""
_astroid_fields = ('value',)
value = None
class BinOp(NodeNG):
"""class representing a BinOp node"""
_astroid_fields = ('left', 'right',)
left = None
right = None
class BoolOp(NodeNG):
"""class representing a BoolOp node"""
_astroid_fields = ('values',)
values = None
class Break(Statement):
"""class representing a Break node"""
class CallFunc(NodeNG):
"""class representing a CallFunc node"""
_astroid_fields = ('func', 'args', 'starargs', 'kwargs')
func = None
args = None
starargs = None
kwargs = None
def __init__(self):
self.starargs = None
self.kwargs = None
class Compare(NodeNG):
"""class representing a Compare node"""
_astroid_fields = ('left', 'ops',)
left = None
ops = None
def get_children(self):
"""override get_children for tuple fields"""
yield self.left
for _, comparator in self.ops:
yield comparator # we don't want the 'op'
def last_child(self):
"""override last_child"""
# XXX maybe if self.ops:
return self.ops[-1][1]
#return self.left
class Comprehension(NodeNG):
"""class representing a Comprehension node"""
_astroid_fields = ('target', 'iter', 'ifs')
target = None
iter = None
ifs = None
optional_assign = True
def ass_type(self):
return self
def _get_filtered_stmts(self, lookup_node, node, stmts, mystmt):
"""method used in filter_stmts"""
if self is mystmt:
if isinstance(lookup_node, (Const, Name)):
return [lookup_node], True
elif self.statement() is mystmt:
# original node's statement is the assignment, only keeps
# current node (gen exp, list comp)
return [node], True
return stmts, False
class Const(NodeNG, Instance):
"""represent a constant node like num, str, bool, None, bytes"""
def __init__(self, value=None):
self.value = value
def getitem(self, index, context=None):
if isinstance(self.value, six.string_types):
return Const(self.value[index])
raise TypeError('%r (value=%s)' % (self, self.value))
def has_dynamic_getattr(self):
return False
def itered(self):
if isinstance(self.value, six.string_types):
return self.value
raise TypeError()
def pytype(self):
return self._proxied.qname()
class Continue(Statement):
"""class representing a Continue node"""
class Decorators(NodeNG):
"""class representing a Decorators node"""
_astroid_fields = ('nodes',)
nodes = None
def __init__(self, nodes=None):
self.nodes = nodes
def scope(self):
# skip the function node to go directly to the upper level scope
return self.parent.parent.scope()
class DelAttr(NodeNG, ParentAssignTypeMixin):
"""class representing a DelAttr node"""
_astroid_fields = ('expr',)
expr = None
class Delete(Statement, AssignTypeMixin):
"""class representing a Delete node"""
_astroid_fields = ('targets',)
targets = None
class Dict(NodeNG, Instance):
"""class representing a Dict node"""
_astroid_fields = ('items',)
def __init__(self, items=None):
if items is None:
self.items = []
self.items = [(const_factory(k), const_factory(v))
for k, v in items.items()]
def pytype(self):
return '%s.dict' % BUILTINS
def get_children(self):
"""get children of a Dict node"""
# overrides get_children
for key, value in self.items:
yield key
yield value
def last_child(self):
"""override last_child"""
if self.items:
return self.items[-1][1]
return None
def itered(self):
return self.items[::2]
def getitem(self, lookup_key, context=None):
for key, value in self.items:
for inferedkey in key.infer(context):
if inferedkey is YES:
if isinstance(inferedkey, Const) \
and inferedkey.value == lookup_key:
return value
# This should raise KeyError, but all call sites only catch
# IndexError. Let's leave it like that for now.
raise IndexError(lookup_key)
class Discard(Statement):
"""class representing a Discard node"""
_astroid_fields = ('value',)
value = None
class Ellipsis(NodeNG):
"""class representing an Ellipsis node"""
class EmptyNode(NodeNG):
"""class representing an EmptyNode node"""
class ExceptHandler(Statement, AssignTypeMixin):
"""class representing an ExceptHandler node"""
_astroid_fields = ('type', 'name', 'body',)
type = None
name = None
body = None
def blockstart_tolineno(self):
elif self.type:
return self.type.tolineno
return self.lineno
def catch(self, exceptions):
if self.type is None or exceptions is None:
return True
for node in self.type.nodes_of_class(Name):
if in exceptions:
return True
class Exec(Statement):
"""class representing an Exec node"""
_astroid_fields = ('expr', 'globals', 'locals',)
expr = None
globals = None
locals = None
class ExtSlice(NodeNG):
"""class representing an ExtSlice node"""
_astroid_fields = ('dims',)
dims = None
class For(BlockRangeMixIn, AssignTypeMixin, Statement):
"""class representing a For node"""
_astroid_fields = ('target', 'iter', 'body', 'orelse',)
target = None
iter = None
body = None
orelse = None
optional_assign = True
def blockstart_tolineno(self):
return self.iter.tolineno
class From(FromImportMixIn, Statement):
"""class representing a From node"""
def __init__(self, fromname, names, level=0):
self.modname = fromname
self.names = names
self.level = level
class Getattr(NodeNG):
"""class representing a Getattr node"""
_astroid_fields = ('expr',)
expr = None
class Global(Statement):
"""class representing a Global node"""
def __init__(self, names):
self.names = names
def _infer_name(self, frame, name):
return name
class If(BlockRangeMixIn, Statement):
"""class representing an If node"""
_astroid_fields = ('test', 'body', 'orelse')
test = None
body = None
orelse = None
def blockstart_tolineno(self):
return self.test.tolineno
def block_range(self, lineno):
"""handle block line numbers range for if statements"""
if lineno == self.body[0].fromlineno:
return lineno, lineno
if lineno <= self.body[-1].tolineno:
return lineno, self.body[-1].tolineno
return self._elsed_block_range(lineno, self.orelse,
self.body[0].fromlineno - 1)
class IfExp(NodeNG):
"""class representing an IfExp node"""
_astroid_fields = ('test', 'body', 'orelse')
test = None
body = None
orelse = None
class Import(FromImportMixIn, Statement):
"""class representing an Import node"""
class Index(NodeNG):
"""class representing an Index node"""
_astroid_fields = ('value',)
value = None
class Keyword(NodeNG):
"""class representing a Keyword node"""
_astroid_fields = ('value',)
value = None
class List(NodeNG, Instance, ParentAssignTypeMixin):
"""class representing a List node"""
_astroid_fields = ('elts',)
def __init__(self, elts=None):
if elts is None:
self.elts = []
self.elts = [const_factory(e) for e in elts]
def pytype(self):
return '%s.list' % BUILTINS
def getitem(self, index, context=None):
return self.elts[index]
def itered(self):
return self.elts
class Nonlocal(Statement):
"""class representing a Nonlocal node"""
def __init__(self, names):
self.names = names
def _infer_name(self, frame, name):
return name
class Pass(Statement):
"""class representing a Pass node"""
class Print(Statement):
"""class representing a Print node"""
_astroid_fields = ('dest', 'values',)
dest = None
values = None
class Raise(Statement):
"""class representing a Raise node"""
exc = None
if sys.version_info < (3, 0):
_astroid_fields = ('exc', 'inst', 'tback')
inst = None
tback = None
_astroid_fields = ('exc', 'cause')
exc = None
cause = None
def raises_not_implemented(self):
if not self.exc:
for name in self.exc.nodes_of_class(Name):
if == 'NotImplementedError':
return True
class Return(Statement):
"""class representing a Return node"""
_astroid_fields = ('value',)
value = None
class Set(NodeNG, Instance, ParentAssignTypeMixin):
"""class representing a Set node"""
_astroid_fields = ('elts',)
def __init__(self, elts=None):
if elts is None:
self.elts = []
self.elts = [const_factory(e) for e in elts]
def pytype(self):
return '%s.set' % BUILTINS
def itered(self):
return self.elts
class Slice(NodeNG):
"""class representing a Slice node"""
_astroid_fields = ('lower', 'upper', 'step')
lower = None
upper = None
step = None
class Starred(NodeNG, ParentAssignTypeMixin):
"""class representing a Starred node"""
_astroid_fields = ('value',)
value = None
class Subscript(NodeNG):
"""class representing a Subscript node"""
_astroid_fields = ('value', 'slice')
value = None
slice = None
class TryExcept(BlockRangeMixIn, Statement):
"""class representing a TryExcept node"""
_astroid_fields = ('body', 'handlers', 'orelse',)
body = None
handlers = None
orelse = None
def _infer_name(self, frame, name):
return name
def block_range(self, lineno):
"""handle block line numbers range for try/except statements"""
last = None
for exhandler in self.handlers:
if exhandler.type and lineno == exhandler.type.fromlineno:
return lineno, lineno
if exhandler.body[0].fromlineno <= lineno <= exhandler.body[-1].tolineno:
return lineno, exhandler.body[-1].tolineno
if last is None:
last = exhandler.body[0].fromlineno - 1
return self._elsed_block_range(lineno, self.orelse, last)
class TryFinally(BlockRangeMixIn, Statement):
"""class representing a TryFinally node"""
_astroid_fields = ('body', 'finalbody',)
body = None
finalbody = None
def block_range(self, lineno):
"""handle block line numbers range for try/finally statements"""
child = self.body[0]
# py2.5 try: except: finally:
if (isinstance(child, TryExcept) and child.fromlineno == self.fromlineno
and lineno > self.fromlineno and lineno <= child.tolineno):
return child.block_range(lineno)
return self._elsed_block_range(lineno, self.finalbody)
class Tuple(NodeNG, Instance, ParentAssignTypeMixin):
"""class representing a Tuple node"""
_astroid_fields = ('elts',)
def __init__(self, elts=None):
if elts is None:
self.elts = []
self.elts = [const_factory(e) for e in elts]
def pytype(self):
return '%s.tuple' % BUILTINS
def getitem(self, index, context=None):
return self.elts[index]
def itered(self):
return self.elts
class UnaryOp(NodeNG):
"""class representing an UnaryOp node"""
_astroid_fields = ('operand',)
operand = None
class While(BlockRangeMixIn, Statement):
"""class representing a While node"""
_astroid_fields = ('test', 'body', 'orelse',)
test = None
body = None
orelse = None
def blockstart_tolineno(self):
return self.test.tolineno
def block_range(self, lineno):
"""handle block line numbers range for for and while statements"""
return self. _elsed_block_range(lineno, self.orelse)
class With(BlockRangeMixIn, AssignTypeMixin, Statement):
"""class representing a With node"""
_astroid_fields = ('items', 'body')
items = None
body = None
def blockstart_tolineno(self):
return self.items[-1][0].tolineno
def get_children(self):
for expr, var in self.items:
yield expr
if var:
yield var
for elt in self.body:
yield elt
class Yield(NodeNG):
"""class representing a Yield node"""
_astroid_fields = ('value',)
value = None
class YieldFrom(Yield):
""" Class representing a YieldFrom node. """
# constants ##############################################################
list: List,
tuple: Tuple,
dict: Dict,
set: Set,
type(None): Const,
def _update_const_classes():
"""update constant classes, so the keys of CONST_CLS can be reused"""
klasses = (bool, int, float, complex, str)
if sys.version_info < (3, 0):
klasses += (unicode, long)
if sys.version_info >= (2, 6):
klasses += (bytes,)
for kls in klasses:
CONST_CLS[kls] = Const
def const_factory(value):
"""return an astroid node for a python value"""
# XXX we should probably be stricter here and only consider stuff in
# CONST_CLS or do better treatment: in case where value is not in CONST_CLS,
# we should rather recall the builder on this value than returning an empty
# node (another option being that const_factory shouldn't be called with something
# not in CONST_CLS)
assert not isinstance(value, NodeNG)
return CONST_CLS[value.__class__](value)
except (KeyError, AttributeError):
node = EmptyNode()
node.object = value
return node