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317 lines
11 KiB
Python
317 lines
11 KiB
Python
# pylint: disable=W0611
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#
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# Copyright (c) 2003-2010 LOGILAB S.A. (Paris, FRANCE).
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# http://www.logilab.fr/ -- mailto:contact@logilab.fr
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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"""some functions that may be useful for various checkers
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"""
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import string
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from logilab import astng
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from logilab.common.compat import builtins
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BUILTINS_NAME = builtins.__name__
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COMP_NODE_TYPES = astng.ListComp, astng.SetComp, astng.DictComp, astng.GenExpr
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def is_inside_except(node):
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"""Returns true if node is directly inside an exception handler"""
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return isinstance(node.parent, astng.ExceptHandler)
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def clobber_in_except(node):
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"""Checks if an assignment node in an except handler clobbers an existing
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variable.
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Returns (True, args for W0623) if assignment clobbers an existing variable,
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(False, None) otherwise.
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"""
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if isinstance(node, astng.AssAttr):
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return (True, (node.attrname, 'object %r' % (node.expr.name,)))
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elif node is not None:
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name = node.name
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if is_builtin(name):
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return (True, (name, 'builtins'))
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else:
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scope, stmts = node.lookup(name)
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if (stmts and
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not isinstance(stmts[0].ass_type(),
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(astng.Assign, astng.AugAssign, astng.ExceptHandler))):
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return (True, (name, 'outer scope (line %i)' % (stmts[0].lineno,)))
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return (False, None)
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def safe_infer(node):
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"""return the inferred value for the given node.
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Return None if inference failed or if there is some ambiguity (more than
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one node has been inferred)
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"""
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try:
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inferit = node.infer()
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value = inferit.next()
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except astng.InferenceError:
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return
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try:
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inferit.next()
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return # None if there is ambiguity on the inferred node
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except StopIteration:
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return value
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def is_super(node):
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"""return True if the node is referencing the "super" builtin function
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"""
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if getattr(node, 'name', None) == 'super' and \
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node.root().name == BUILTINS_NAME:
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return True
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return False
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def is_error(node):
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"""return true if the function does nothing but raising an exception"""
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for child_node in node.get_children():
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if isinstance(child_node, astng.Raise):
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return True
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return False
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def is_raising(body):
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"""return true if the given statement node raise an exception"""
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for node in body:
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if isinstance(node, astng.Raise):
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return True
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return False
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def is_empty(body):
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"""return true if the given node does nothing but 'pass'"""
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return len(body) == 1 and isinstance(body[0], astng.Pass)
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builtins = __builtins__.copy()
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SPECIAL_BUILTINS = ('__builtins__',) # '__path__', '__file__')
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def is_builtin(name): # was is_native_builtin
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"""return true if <name> could be considered as a builtin defined by python
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"""
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if name in builtins:
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return True
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if name in SPECIAL_BUILTINS:
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return True
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return False
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def is_defined_before(var_node):
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"""return True if the variable node is defined by a parent node (list,
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set, dict, or generator comprehension, lambda) or in a previous sibling
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node on the same line (statement_defining ; statement_using)
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"""
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varname = var_node.name
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_node = var_node.parent
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while _node:
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if isinstance(_node, COMP_NODE_TYPES):
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for ass_node in _node.nodes_of_class(astng.AssName):
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if ass_node.name == varname:
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return True
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elif isinstance(_node, astng.For):
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for ass_node in _node.target.nodes_of_class(astng.AssName):
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if ass_node.name == varname:
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return True
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elif isinstance(_node, astng.With):
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if _node.vars is None:
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# quickfix : case in which 'with' is used without 'as'
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return False
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if _node.vars.name == varname:
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return True
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elif isinstance(_node, (astng.Lambda, astng.Function)):
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if _node.args.is_argument(varname):
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return True
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if getattr(_node, 'name', None) == varname:
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return True
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break
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_node = _node.parent
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# possibly multiple statements on the same line using semi colon separator
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stmt = var_node.statement()
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_node = stmt.previous_sibling()
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lineno = stmt.fromlineno
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while _node and _node.fromlineno == lineno:
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for ass_node in _node.nodes_of_class(astng.AssName):
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if ass_node.name == varname:
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return True
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for imp_node in _node.nodes_of_class( (astng.From, astng.Import)):
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if varname in [name[1] or name[0] for name in imp_node.names]:
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return True
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_node = _node.previous_sibling()
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return False
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def is_func_default(node):
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"""return true if the given Name node is used in function default argument's
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value
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"""
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parent = node.scope()
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if isinstance(parent, astng.Function):
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for default_node in parent.args.defaults:
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for default_name_node in default_node.nodes_of_class(astng.Name):
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if default_name_node is node:
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return True
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return False
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def is_func_decorator(node):
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"""return true if the name is used in function decorator"""
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parent = node.parent
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while parent is not None:
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if isinstance(parent, astng.Decorators):
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return True
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if parent.is_statement or isinstance(parent, astng.Lambda):
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break
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parent = parent.parent
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return False
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def is_ancestor_name(frame, node):
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"""return True if `frame` is a astng.Class node with `node` in the
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subtree of its bases attribute
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"""
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try:
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bases = frame.bases
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except AttributeError:
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return False
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for base in bases:
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if node in base.nodes_of_class(astng.Name):
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return True
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return False
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def assign_parent(node):
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"""return the higher parent which is not an AssName, Tuple or List node
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"""
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while node and isinstance(node, (astng.AssName,
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astng.Tuple,
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astng.List)):
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node = node.parent
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return node
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def overrides_an_abstract_method(class_node, name):
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"""return True if pnode is a parent of node"""
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for ancestor in class_node.ancestors():
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if name in ancestor and isinstance(ancestor[name], astng.Function) and \
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ancestor[name].is_abstract(pass_is_abstract=False):
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return True
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return False
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def overrides_a_method(class_node, name):
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"""return True if <name> is a method overridden from an ancestor"""
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for ancestor in class_node.ancestors():
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if name in ancestor and isinstance(ancestor[name], astng.Function):
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return True
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return False
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PYMETHODS = set(('__new__', '__init__', '__del__', '__hash__',
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'__str__', '__repr__',
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'__len__', '__iter__',
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'__delete__', '__get__', '__set__',
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'__getitem__', '__setitem__', '__delitem__', '__contains__',
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'__getattribute__', '__getattr__', '__setattr__', '__delattr__',
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'__call__',
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'__enter__', '__exit__',
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'__cmp__', '__ge__', '__gt__', '__le__', '__lt__', '__eq__',
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'__nonzero__', '__neg__', '__invert__',
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'__mul__', '__imul__', '__rmul__',
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'__div__', '__idiv__', '__rdiv__',
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'__add__', '__iadd__', '__radd__',
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'__sub__', '__isub__', '__rsub__',
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'__pow__', '__ipow__', '__rpow__',
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'__mod__', '__imod__', '__rmod__',
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'__and__', '__iand__', '__rand__',
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'__or__', '__ior__', '__ror__',
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'__xor__', '__ixor__', '__rxor__',
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# XXX To be continued
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))
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def check_messages(*messages):
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"""decorator to store messages that are handled by a checker method"""
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def store_messages(func):
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func.checks_msgs = messages
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return func
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return store_messages
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class IncompleteFormatString(Exception):
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"""A format string ended in the middle of a format specifier."""
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pass
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class UnsupportedFormatCharacter(Exception):
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"""A format character in a format string is not one of the supported
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format characters."""
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def __init__(self, index):
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Exception.__init__(self, index)
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self.index = index
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def parse_format_string(format_string):
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"""Parses a format string, returning a tuple of (keys, num_args), where keys
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is the set of mapping keys in the format string, and num_args is the number
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of arguments required by the format string. Raises
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IncompleteFormatString or UnsupportedFormatCharacter if a
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parse error occurs."""
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keys = set()
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num_args = 0
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def next_char(i):
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i += 1
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if i == len(format_string):
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raise IncompleteFormatString
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return (i, format_string[i])
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i = 0
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while i < len(format_string):
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c = format_string[i]
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if c == '%':
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i, c = next_char(i)
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# Parse the mapping key (optional).
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key = None
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if c == '(':
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depth = 1
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i, c = next_char(i)
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key_start = i
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while depth != 0:
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if c == '(':
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depth += 1
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elif c == ')':
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depth -= 1
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i, c = next_char(i)
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key_end = i - 1
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key = format_string[key_start:key_end]
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# Parse the conversion flags (optional).
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while c in '#0- +':
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i, c = next_char(i)
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# Parse the minimum field width (optional).
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if c == '*':
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num_args += 1
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i, c = next_char(i)
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else:
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while c in string.digits:
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i, c = next_char(i)
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# Parse the precision (optional).
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if c == '.':
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i, c = next_char(i)
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if c == '*':
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num_args += 1
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i, c = next_char(i)
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else:
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while c in string.digits:
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i, c = next_char(i)
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# Parse the length modifier (optional).
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if c in 'hlL':
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i, c = next_char(i)
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# Parse the conversion type (mandatory).
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if c not in 'diouxXeEfFgGcrs%':
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raise UnsupportedFormatCharacter(i)
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if key:
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keys.add(key)
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elif c != '%':
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num_args += 1
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i += 1
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return keys, num_args
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