mirror of
https://github.com/thegeeklab/ansible-later.git
synced 2024-11-18 10:50:40 +00:00
654 lines
24 KiB
Python
654 lines
24 KiB
Python
"""Python code parser."""
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import six
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import textwrap
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import tokenize as tk
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from itertools import chain, dropwhile
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from re import compile as re
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from .utils import log
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try:
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from StringIO import StringIO
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except ImportError: # Python 3.0 and later
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from io import StringIO
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try:
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next
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except NameError: # Python 2.5 and earlier
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nothing = object()
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def next(obj, default=nothing):
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if default == nothing:
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return obj.next()
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else:
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try:
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return obj.next()
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except StopIteration:
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return default
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__all__ = ('Parser', 'Definition', 'Module', 'Package', 'Function',
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'NestedFunction', 'Method', 'Class', 'NestedClass', 'AllError',
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'StringIO', 'ParseError')
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class ParseError(Exception):
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def __str__(self):
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return "Cannot parse file."
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class UnexpectedTokenError(ParseError):
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def __init__(self, token, expected_kind):
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self.token = token
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self.expected_kind = expected_kind
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def __str__(self):
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return "Unexpected token {}, expected {}".format(
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self.token, self.expected_kind)
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def humanize(string):
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return re(r'(.)([A-Z]+)').sub(r'\1 \2', string).lower()
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class Value(object):
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"""A generic object with a list of preset fields."""
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def __init__(self, *args):
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if len(self._fields) != len(args):
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raise ValueError('got {} arguments for {} fields for {}: {}'
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.format(len(args), len(self._fields),
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self.__class__.__name__, self._fields))
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vars(self).update(zip(self._fields, args))
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def __hash__(self):
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return hash(repr(self))
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def __eq__(self, other):
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return other and vars(self) == vars(other)
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def __repr__(self):
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kwargs = ', '.join('{}={!r}'.format(field, getattr(self, field))
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for field in self._fields)
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return '{}({})'.format(self.__class__.__name__, kwargs)
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class Definition(Value):
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"""A Python source code definition (could be class, function, etc)."""
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_fields = ('name', '_source', 'start', 'end', 'decorators', 'docstring',
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'children', 'parent', 'skipped_error_codes')
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_human = property(lambda self: humanize(type(self).__name__))
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kind = property(lambda self: self._human.split()[-1])
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module = property(lambda self: self.parent.module)
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dunder_all = property(lambda self: self.module.dunder_all)
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_slice = property(lambda self: slice(self.start - 1, self.end))
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is_class = False
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def __iter__(self):
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return chain([self], *self.children)
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@property
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def error_lineno(self):
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"""Get the line number with which to report violations."""
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if isinstance(self.docstring, Docstring):
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return self.docstring.start
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return self.start
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@property
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def _publicity(self):
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return {True: 'public', False: 'private'}[self.is_public]
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@property
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def source(self):
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"""Return the source code for the definition."""
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full_src = self._source[self._slice]
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def is_empty_or_comment(line):
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return line.strip() == '' or line.strip().startswith('#')
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filtered_src = dropwhile(is_empty_or_comment, reversed(full_src))
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return ''.join(reversed(list(filtered_src)))
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def __str__(self):
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out = 'in {} {} `{}`'.format(self._publicity, self._human, self.name)
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if self.skipped_error_codes:
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out += ' (skipping {})'.format(self.skipped_error_codes)
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return out
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class Module(Definition):
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"""A Python source code module."""
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_fields = ('name', '_source', 'start', 'end', 'decorators', 'docstring',
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'children', 'parent', '_dunder_all', 'dunder_all_error',
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'future_imports', 'skipped_error_codes')
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_nest = staticmethod(lambda s: {'def': Function, 'class': Class}[s])
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module = property(lambda self: self)
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dunder_all = property(lambda self: self._dunder_all)
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@property
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def is_public(self):
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return not self.name.startswith('_') or self.name.startswith('__')
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def __str__(self):
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return 'at module level'
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class Package(Module):
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"""A package is a __init__.py module."""
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class Function(Definition):
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"""A Python source code function."""
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_nest = staticmethod(lambda s: {'def': NestedFunction,
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'class': NestedClass}[s])
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@property
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def is_public(self):
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"""Return True iff this function should be considered public."""
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if self.dunder_all is not None:
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return self.name in self.dunder_all
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else:
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return not self.name.startswith('_')
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@property
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def is_test(self):
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"""Return True if this function is a test function/method.
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We exclude tests from the imperative mood check, because to phrase
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their docstring in the imperative mood, they would have to start with
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a highly redundant "Test that ...".
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"""
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return self.name.startswith('test') or self.name == 'runTest'
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class NestedFunction(Function):
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"""A Python source code nested function."""
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is_public = False
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class Method(Function):
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"""A Python source code method."""
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@property
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def is_magic(self):
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"""Return True iff this method is a magic method (e.g., `__str__`)."""
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return (self.name.startswith('__') and
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self.name.endswith('__') and
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self.name not in VARIADIC_MAGIC_METHODS)
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@property
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def is_init(self):
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"""Return True iff this method is `__init__`."""
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return self.name == '__init__'
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@property
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def is_public(self):
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"""Return True iff this method should be considered public."""
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# Check if we are a setter/deleter method, and mark as private if so.
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for decorator in self.decorators:
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# Given 'foo', match 'foo.bar' but not 'foobar' or 'sfoo'
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if re(r"^{}\.".format(self.name)).match(decorator.name):
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return False
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name_is_public = (not self.name.startswith('_') or
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self.name in VARIADIC_MAGIC_METHODS or
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self.is_magic)
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return self.parent.is_public and name_is_public
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class Class(Definition):
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"""A Python source code class."""
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_nest = staticmethod(lambda s: {'def': Method, 'class': NestedClass}[s])
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is_public = Function.is_public
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is_class = True
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class NestedClass(Class):
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"""A Python source code nested class."""
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@property
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def is_public(self):
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"""Return True iff this class should be considered public."""
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return (not self.name.startswith('_') and
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self.parent.is_class and
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self.parent.is_public)
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class Decorator(Value):
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"""A decorator for function, method or class."""
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_fields = 'name arguments'.split()
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class Docstring(str):
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"""Represent a docstring.
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This is a string, but has additional start/end attributes representing
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the start and end of the token.
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"""
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def __new__(cls, v, start, end):
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return str.__new__(cls, v)
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def __init__(self, v, start, end):
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self.start = start
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self.end = end
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VARIADIC_MAGIC_METHODS = ('__init__', '__call__', '__new__')
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class AllError(Exception):
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"""Raised when there is a problem with __all__ when parsing."""
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def __init__(self, message):
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"""Initialize the error with a more specific message."""
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Exception.__init__(
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self, message + textwrap.dedent("""
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That means pydocstyle cannot decide which definitions are
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public. Variable __all__ should be present at most once in
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each file, in form
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`__all__ = ('a_public_function', 'APublicClass', ...)`.
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More info on __all__: http://stackoverflow.com/q/44834/. ')
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"""))
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class TokenStream(object):
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# A logical newline is where a new expression or statement begins. When
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# there is a physical new line, but not a logical one, for example:
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# (x +
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# y)
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# The token will be tk.NL, not tk.NEWLINE.
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LOGICAL_NEWLINES = {tk.NEWLINE, tk.INDENT, tk.DEDENT}
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def __init__(self, filelike):
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self._generator = tk.generate_tokens(filelike.readline)
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self.current = Token(*next(self._generator, None))
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self.line = self.current.start[0]
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self.log = log
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self.got_logical_newline = True
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def move(self):
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previous = self.current
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current = self._next_from_generator()
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self.current = None if current is None else Token(*current)
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self.line = self.current.start[0] if self.current else self.line
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self.got_logical_newline = (previous.kind in self.LOGICAL_NEWLINES)
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return previous
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def _next_from_generator(self):
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try:
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return next(self._generator, None)
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except (SyntaxError, tk.TokenError):
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self.log.warning('error generating tokens', exc_info=True)
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return None
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def __iter__(self):
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while True:
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if self.current is not None:
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yield self.current
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else:
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return
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self.move()
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class TokenKind(int):
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def __repr__(self):
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return "tk.{}".format(tk.tok_name[self])
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class Token(Value):
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_fields = 'kind value start end source'.split()
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def __init__(self, *args):
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super(Token, self).__init__(*args)
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self.kind = TokenKind(self.kind)
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def __str__(self):
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return "{!r} ({})".format(self.kind, self.value)
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class Parser(object):
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"""A Python source code parser."""
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def parse(self, filelike, filename):
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"""Parse the given file-like object and return its Module object."""
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self.log = log
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self.source = filelike.readlines()
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src = ''.join(self.source)
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try:
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compile(src, filename, 'exec')
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except SyntaxError as error:
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six.raise_from(ParseError(), error)
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self.stream = TokenStream(StringIO(src))
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self.filename = filename
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self.dunder_all = None
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self.dunder_all_error = None
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self.future_imports = set()
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self._accumulated_decorators = []
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return self.parse_module()
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# TODO: remove
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def __call__(self, *args, **kwargs):
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"""Call the parse method."""
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return self.parse(*args, **kwargs)
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current = property(lambda self: self.stream.current)
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line = property(lambda self: self.stream.line)
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def consume(self, kind):
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"""Consume one token and verify it is of the expected kind."""
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next_token = self.stream.move()
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if next_token.kind != kind:
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raise UnexpectedTokenError(token=next_token, expected_kind=kind)
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def leapfrog(self, kind, value=None):
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"""Skip tokens in the stream until a certain token kind is reached.
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If `value` is specified, tokens whose values are different will also
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be skipped.
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"""
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while self.current is not None:
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if (self.current.kind == kind and
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(value is None or self.current.value == value)):
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self.consume(kind)
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return
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self.stream.move()
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def parse_docstring(self):
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"""Parse a single docstring and return its value."""
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self.log.debug("parsing docstring, token is %s", self.current)
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while self.current.kind in (tk.COMMENT, tk.NEWLINE, tk.NL):
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self.stream.move()
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self.log.debug("parsing docstring, token is %r (%s)",
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self.current.kind, self.current.value)
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if self.current.kind == tk.STRING:
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docstring = Docstring(
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self.current.value,
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self.current.start[0],
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self.current.end[0]
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)
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self.stream.move()
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return docstring
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return None
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def parse_decorators(self):
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"""Called after first @ is found.
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Parse decorators into self._accumulated_decorators.
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Continue to do so until encountering the 'def' or 'class' start token.
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"""
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name = []
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arguments = []
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at_arguments = False
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while self.current is not None:
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self.log.debug("parsing decorators, current token is %r (%s)",
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self.current.kind, self.current.value)
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if (self.current.kind == tk.NAME and
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self.current.value in ['def', 'class']):
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# Done with decorators - found function or class proper
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break
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elif self.current.kind == tk.OP and self.current.value == '@':
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# New decorator found. Store the decorator accumulated so far:
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self._accumulated_decorators.append(
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Decorator(''.join(name), ''.join(arguments)))
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# Now reset to begin accumulating the new decorator:
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name = []
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arguments = []
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at_arguments = False
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elif self.current.kind == tk.OP and self.current.value == '(':
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at_arguments = True
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elif self.current.kind == tk.OP and self.current.value == ')':
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# Ignore close parenthesis
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pass
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elif self.current.kind == tk.NEWLINE or self.current.kind == tk.NL:
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# Ignore newlines
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pass
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else:
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# Keep accumulating current decorator's name or argument.
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if not at_arguments:
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name.append(self.current.value)
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else:
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arguments.append(self.current.value)
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self.stream.move()
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# Add decorator accumulated so far
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self._accumulated_decorators.append(
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Decorator(''.join(name), ''.join(arguments)))
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def parse_definitions(self, class_, dunder_all=False):
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"""Parse multiple definitions and yield them."""
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while self.current is not None:
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self.log.debug("parsing definition list, current token is %r (%s)",
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self.current.kind, self.current.value)
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self.log.debug('got_newline: %s', self.stream.got_logical_newline)
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if dunder_all and self.current.value == '__all__':
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self.parse_dunder_all()
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elif (self.current.kind == tk.OP and
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self.current.value == '@' and
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self.stream.got_logical_newline):
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self.consume(tk.OP)
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self.parse_decorators()
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elif self.current.value in ['def', 'class']:
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yield self.parse_definition(class_._nest(self.current.value))
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elif self.current.kind == tk.INDENT:
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self.consume(tk.INDENT)
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for definition in self.parse_definitions(class_):
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yield definition
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elif self.current.kind == tk.DEDENT:
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self.consume(tk.DEDENT)
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return
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elif self.current.value == 'from':
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self.parse_from_import_statement()
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else:
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self.stream.move()
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def parse_dunder_all(self):
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"""Parse the __all__ definition in a module."""
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assert self.current.value == '__all__'
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self.consume(tk.NAME)
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# More than one __all__ definition means we ignore all __all__.
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if self.dunder_all is not None or self.dunder_all_error is not None:
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self.dunder_all = None
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self.dunder_all_error = 'Could not evaluate contents of __all__. '
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return
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if self.current.value != '=':
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self.dunder_all_error = 'Could not evaluate contents of __all__. '
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return
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self.consume(tk.OP)
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if self.current.value not in '([':
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self.dunder_all_error = 'Could not evaluate contents of __all__. '
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return
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self.consume(tk.OP)
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dunder_all_content = "("
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while self.current.kind != tk.OP or self.current.value not in ")]":
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if self.current.kind in (tk.NL, tk.COMMENT):
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pass
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elif (self.current.kind == tk.STRING or
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self.current.value == ','):
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dunder_all_content += self.current.value
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else:
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self.dunder_all_error = (
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'Unexpected token kind in __all__: {!r}. '
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.format(self.current.kind))
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return
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self.stream.move()
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self.consume(tk.OP)
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dunder_all_content += ")"
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try:
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self.dunder_all = eval(dunder_all_content, {})
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except BaseException as e:
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self.dunder_all_error = (
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'Could not evaluate contents of __all__.'
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'\bThe value was {}. The exception was:\n{}'
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.format(dunder_all_content, e))
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while not self.current.kind in self.stream.LOGICAL_NEWLINES:
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if self.current.kind != tk.COMMENT:
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self.dunder_all = None
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self.dunder_all_error = 'Could not evaluate contents of __all__. '
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return
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def parse_module(self):
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"""Parse a module (and its children) and return a Module object."""
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self.log.debug("parsing module.")
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start = self.line
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docstring = self.parse_docstring()
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children = list(self.parse_definitions(Module, dunder_all=True))
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assert self.current is None, self.current
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end = self.line
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cls = Module
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if self.filename.endswith('__init__.py'):
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cls = Package
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module = cls(self.filename, self.source, start, end,
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[], docstring, children, None, self.dunder_all,
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self.dunder_all_error, None, '')
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for child in module.children:
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child.parent = module
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module.future_imports = self.future_imports
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self.log.debug("finished parsing module.")
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return module
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def parse_definition(self, class_):
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"""Parse a definition and return its value in a `class_` object."""
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start = self.line
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self.consume(tk.NAME)
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name = self.current.value
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self.log.debug("parsing %s '%s'", class_.__name__, name)
|
|
self.stream.move()
|
|
if self.current.kind == tk.OP and self.current.value == '(':
|
|
parenthesis_level = 0
|
|
while True:
|
|
if self.current.kind == tk.OP:
|
|
if self.current.value == '(':
|
|
parenthesis_level += 1
|
|
elif self.current.value == ')':
|
|
parenthesis_level -= 1
|
|
if parenthesis_level == 0:
|
|
break
|
|
self.stream.move()
|
|
if self.current.kind != tk.OP or self.current.value != ':':
|
|
self.leapfrog(tk.OP, value=":")
|
|
else:
|
|
self.consume(tk.OP)
|
|
if self.current.kind in (tk.NEWLINE, tk.COMMENT):
|
|
skipped_error_codes = self.parse_skip_comment()
|
|
self.leapfrog(tk.INDENT)
|
|
assert self.current.kind != tk.INDENT
|
|
docstring = self.parse_docstring()
|
|
decorators = self._accumulated_decorators
|
|
self.log.debug("current accumulated decorators: %s", decorators)
|
|
self._accumulated_decorators = []
|
|
self.log.debug("parsing nested definitions.")
|
|
children = list(self.parse_definitions(class_))
|
|
self.log.debug("finished parsing nested definitions for '%s'",
|
|
name)
|
|
end = self.line - 1
|
|
else: # one-liner definition
|
|
skipped_error_codes = ''
|
|
docstring = self.parse_docstring()
|
|
decorators = [] # TODO
|
|
children = []
|
|
end = self.line
|
|
self.leapfrog(tk.NEWLINE)
|
|
definition = class_(name, self.source, start, end,
|
|
decorators, docstring, children, None,
|
|
skipped_error_codes)
|
|
for child in definition.children:
|
|
child.parent = definition
|
|
self.log.debug("finished parsing %s '%s'. Next token is %r",
|
|
class_.__name__, name, self.current)
|
|
return definition
|
|
|
|
def parse_skip_comment(self):
|
|
"""Parse a definition comment for noqa skips."""
|
|
skipped_error_codes = ''
|
|
if self.current.kind == tk.COMMENT:
|
|
if 'noqa: ' in self.current.value:
|
|
skipped_error_codes = ''.join(
|
|
self.current.value.split('noqa: ')[1:])
|
|
elif self.current.value.startswith('# noqa'):
|
|
skipped_error_codes = 'all'
|
|
return skipped_error_codes
|
|
|
|
def check_current(self, kind=None, value=None):
|
|
"""Verify the current token is of type `kind` and equals `value`."""
|
|
msg = textwrap.dedent("""
|
|
Unexpected token at line {self.line}:
|
|
|
|
In file: {self.filename}
|
|
|
|
Got kind {self.current.kind!r}
|
|
Got value {self.current.value}
|
|
""".format(self=self))
|
|
kind_valid = self.current.kind == kind if kind else True
|
|
value_valid = self.current.value == value if value else True
|
|
assert kind_valid and value_valid, msg
|
|
|
|
def parse_from_import_statement(self):
|
|
"""Parse a 'from x import y' statement.
|
|
|
|
The purpose is to find __future__ statements.
|
|
|
|
"""
|
|
self.log.debug('parsing from/import statement.')
|
|
is_future_import = self._parse_from_import_source()
|
|
self._parse_from_import_names(is_future_import)
|
|
|
|
def _parse_from_import_source(self):
|
|
"""Parse the 'from x import' part in a 'from x import y' statement.
|
|
|
|
Return true iff `x` is __future__.
|
|
"""
|
|
assert self.current.value == 'from', self.current.value
|
|
self.stream.move()
|
|
is_future_import = self.current.value == '__future__'
|
|
self.stream.move()
|
|
while (self.current is not None and
|
|
self.current.kind in (tk.DOT, tk.NAME, tk.OP) and
|
|
self.current.value != 'import'):
|
|
self.stream.move()
|
|
if self.current is None or self.current.value != 'import':
|
|
return False
|
|
self.check_current(value='import')
|
|
assert self.current.value == 'import', self.current.value
|
|
self.stream.move()
|
|
return is_future_import
|
|
|
|
def _parse_from_import_names(self, is_future_import):
|
|
"""Parse the 'y' part in a 'from x import y' statement."""
|
|
if self.current.value == '(':
|
|
self.consume(tk.OP)
|
|
expected_end_kinds = (tk.OP, )
|
|
else:
|
|
expected_end_kinds = (tk.NEWLINE, tk.ENDMARKER)
|
|
while self.current.kind not in expected_end_kinds and not (
|
|
self.current.kind == tk.OP and self.current.value == ';'):
|
|
if self.current.kind != tk.NAME:
|
|
self.stream.move()
|
|
continue
|
|
self.log.debug("parsing import, token is %r (%s)",
|
|
self.current.kind, self.current.value)
|
|
if is_future_import:
|
|
self.log.debug('found future import: %s', self.current.value)
|
|
self.future_imports.add(self.current.value)
|
|
self.consume(tk.NAME)
|
|
self.log.debug("parsing import, token is %r (%s)",
|
|
self.current.kind, self.current.value)
|
|
if self.current.kind == tk.NAME and self.current.value == 'as':
|
|
self.consume(tk.NAME) # as
|
|
if self.current.kind == tk.NAME:
|
|
self.consume(tk.NAME) # new name, irrelevant
|
|
if self.current.value == ',':
|
|
self.consume(tk.OP)
|
|
self.log.debug("parsing import, token is %r (%s)",
|
|
self.current.kind, self.current.value)
|