forked from VimPlug/jedi
656 lines
26 KiB
Python
656 lines
26 KiB
Python
"""
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The ``Parser`` tries to convert the available Python code in an easy to read
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format, something like an abstract syntax tree. The classes who represent this
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tree, are sitting in the :mod:`parsing_representation` module.
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The Python module ``tokenize`` is a very important part in the ``Parser``,
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because it splits the code into different words (tokens). Sometimes it looks a
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bit messy. Sorry for that! You might ask now: "Why didn't you use the ``ast``
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module for this? Well, ``ast`` does a very good job understanding proper Python
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code, but fails to work as soon as there's a single line of broken code.
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There's one important optimization that needs to be known: Statements are not
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being parsed completely. ``Statement`` is just a representation of the tokens
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within the statement. This lowers memory usage and cpu time and reduces the
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complexity of the ``Parser`` (there's another parser sitting inside
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``Statement``, which produces ``Array`` and ``Call``).
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"""
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from _compatibility import next, StringIO
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import tokenize
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import keyword
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import debug
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import common
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import parsing_representation as pr
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class ParserError(Exception):
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pass
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class Parser(object):
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"""
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This class is used to parse a Python file, it then divides them into a
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class structure of different scopes.
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:param source: The codebase for the parser.
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:type source: str
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:param module_path: The path of the module in the file system, may be None.
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:type module_path: str
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:param user_position: The line/column, the user is currently on.
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:type user_position: tuple(int, int)
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:param no_docstr: If True, a string at the beginning is not a docstr.
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:param stop_on_scope: Stop if a scope appears -> for fast_parser
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:param top_module: Use this module as a parent instead of `self.module`.
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"""
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def __init__(self, source, module_path=None, user_position=None,
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no_docstr=False, offset=(0, 0), stop_on_scope=None,
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top_module=None):
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self.user_position = user_position
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self.user_scope = None
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self.user_stmt = None
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self.no_docstr = no_docstr
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# initialize global Scope
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self.module = pr.SubModule(module_path, (offset[0] + 1, offset[1]),
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top_module)
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self.scope = self.module
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self.current = (None, None)
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self.start_pos = 1, 0
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self.end_pos = 1, 0
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source = source + '\n' # end with \n, because the parser needs it
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buf = StringIO(source)
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self._gen = common.NoErrorTokenizer(buf.readline, offset,
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stop_on_scope)
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self.top_module = top_module or self.module
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try:
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self._parse()
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except (common.MultiLevelStopIteration, StopIteration):
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# StopIteration needs to be added as well, because python 2 has a
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# strange way of handling StopIterations.
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# sometimes StopIteration isn't catched. Just ignore it.
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pass
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# clean up unused decorators
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for d in self._decorators:
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# set a parent for unused decorators, avoid NullPointerException
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# because of `self.module.used_names`.
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d.parent = self.module
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self.start_pos = self.module.start_pos
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self.module.end_pos = self.end_pos
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del self._gen
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def __repr__(self):
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return "<%s: %s>" % (type(self).__name__, self.module)
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def _check_user_stmt(self, simple):
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# this is not user checking, just update the used_names
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for tok_name in self.module.temp_used_names:
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try:
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self.module.used_names[tok_name].add(simple)
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except KeyError:
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self.module.used_names[tok_name] = set([simple])
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self.module.temp_used_names = []
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if not self.user_position:
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return
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# the position is right
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if simple.start_pos <= self.user_position <= simple.end_pos:
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if self.user_stmt is not None:
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# if there is already a user position (another import, because
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# imports are splitted) the names are checked.
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for n in simple.get_set_vars():
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if n.start_pos < self.user_position <= n.end_pos:
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self.user_stmt = simple
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else:
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self.user_stmt = simple
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def _parse_dot_name(self, pre_used_token=None):
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"""
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The dot name parser parses a name, variable or function and returns
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their names.
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:return: Tuple of Name, token_type, nexttoken.
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:rtype: tuple(Name, int, str)
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"""
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def append(el):
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names.append(el)
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self.module.temp_used_names.append(el[0])
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names = []
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if pre_used_token is None:
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token_type, tok = self.next()
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if token_type != tokenize.NAME and tok != '*':
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return [], token_type, tok
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else:
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token_type, tok = pre_used_token
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if token_type != tokenize.NAME and tok != '*':
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# token maybe a name or star
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return None, token_type, tok
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append((tok, self.start_pos))
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first_pos = self.start_pos
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while True:
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token_type, tok = self.next()
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if tok != '.':
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break
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token_type, tok = self.next()
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if token_type != tokenize.NAME:
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break
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append((tok, self.start_pos))
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n = pr.Name(self.module, names, first_pos, self.end_pos) if names \
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else None
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return n, token_type, tok
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def _parse_import_list(self):
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"""
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The parser for the imports. Unlike the class and function parse
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function, this returns no Import class, but rather an import list,
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which is then added later on.
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The reason, why this is not done in the same class lies in the nature
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of imports. There are two ways to write them:
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- from ... import ...
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- import ...
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To distinguish, this has to be processed after the parser.
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:return: List of imports.
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:rtype: list
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"""
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imports = []
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brackets = False
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continue_kw = [",", ";", "\n", ')'] \
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+ list(set(keyword.kwlist) - set(['as']))
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while True:
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defunct = False
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token_type, tok = self.next()
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if token_type == tokenize.ENDMARKER:
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break
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if brackets and tok == '\n':
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self.next()
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if tok == '(': # python allows only one `(` in the statement.
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brackets = True
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self.next()
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i, token_type, tok = self._parse_dot_name(self.current)
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if not i:
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defunct = True
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name2 = None
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if tok == 'as':
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name2, token_type, tok = self._parse_dot_name()
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imports.append((i, name2, defunct))
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while tok not in continue_kw:
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token_type, tok = self.next()
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if not (tok == "," or brackets and tok == '\n'):
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break
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return imports
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def _parse_parentheses(self):
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"""
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Functions and Classes have params (which means for classes
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super-classes). They are parsed here and returned as Statements.
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:return: List of Statements
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:rtype: list
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"""
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names = []
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tok = None
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pos = 0
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breaks = [',', ':']
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while tok not in [')', ':']:
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param, tok = self._parse_statement(added_breaks=breaks,
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stmt_class=pr.Param)
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if param and tok == ':':
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# parse annotations
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annotation, tok = self._parse_statement(added_breaks=breaks)
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if annotation:
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param.add_annotation(annotation)
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# params without vars are usually syntax errors.
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if param and (param.set_vars or param.used_vars):
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param.position_nr = pos
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names.append(param)
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pos += 1
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return names
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def _parse_function(self):
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"""
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The parser for a text functions. Process the tokens, which follow a
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function definition.
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:return: Return a Scope representation of the tokens.
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:rtype: Function
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"""
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first_pos = self.start_pos
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token_type, fname = self.next()
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if token_type != tokenize.NAME:
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return None
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fname = pr.Name(self.module, [(fname, self.start_pos)], self.start_pos,
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self.end_pos)
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token_type, open = self.next()
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if open != '(':
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return None
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params = self._parse_parentheses()
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token_type, colon = self.next()
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annotation = None
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if colon in ['-', '->']:
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# parse annotations
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if colon == '-':
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# The Python 2 tokenizer doesn't understand this
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token_type, colon = self.next()
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if colon != '>':
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return None
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annotation, colon = self._parse_statement(added_breaks=[':'])
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if colon != ':':
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return None
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# because of 2 line func param definitions
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scope = pr.Function(self.module, fname, params, first_pos, annotation)
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if self.user_scope and scope != self.user_scope \
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and self.user_position > first_pos:
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self.user_scope = scope
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return scope
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def _parse_class(self):
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"""
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The parser for a text class. Process the tokens, which follow a
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class definition.
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:return: Return a Scope representation of the tokens.
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:rtype: Class
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"""
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first_pos = self.start_pos
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token_type, cname = self.next()
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if token_type != tokenize.NAME:
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debug.warning("class: syntax err, token is not a name@%s (%s: %s)"
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% (self.start_pos[0], tokenize.tok_name[token_type], cname))
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return None
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cname = pr.Name(self.module, [(cname, self.start_pos)], self.start_pos,
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self.end_pos)
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super = []
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token_type, _next = self.next()
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if _next == '(':
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super = self._parse_parentheses()
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token_type, _next = self.next()
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if _next != ':':
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debug.warning("class syntax: %s@%s" % (cname, self.start_pos[0]))
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return None
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# because of 2 line class initializations
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scope = pr.Class(self.module, cname, super, first_pos)
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if self.user_scope and scope != self.user_scope \
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and self.user_position > first_pos:
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self.user_scope = scope
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return scope
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def _parse_statement(self, pre_used_token=None, added_breaks=None,
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stmt_class=pr.Statement):
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"""
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Parses statements like:
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>>> a = test(b)
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>>> a += 3 - 2 or b
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and so on. One line at a time.
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:param pre_used_token: The pre parsed token.
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:type pre_used_token: set
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:return: Statement + last parsed token.
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:rtype: (Statement, str)
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"""
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set_vars = []
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used_vars = []
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level = 0 # The level of parentheses
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if pre_used_token:
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token_type, tok = pre_used_token
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else:
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token_type, tok = self.next()
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while token_type == tokenize.COMMENT:
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# remove newline and comment
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self.next()
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token_type, tok = self.next()
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first_pos = self.start_pos
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opening_brackets = ['{', '(', '[']
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closing_brackets = ['}', ')', ']']
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# the difference between "break" and "always break" is that the latter
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# will even break in parentheses. This is true for typical flow
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# commands like def and class and the imports, which will never be used
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# in a statement.
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breaks = set(['\n', ':', ')'])
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always_break = [';', 'import', 'from', 'class', 'def', 'try', 'except',
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'finally', 'while', 'return', 'yield']
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not_first_break = ['del', 'raise']
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if added_breaks:
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breaks |= set(added_breaks)
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tok_list = []
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while not (tok in always_break
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or tok in not_first_break and not tok_list
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or tok in breaks and level <= 0):
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try:
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#print 'parse_stmt', tok, tokenize.tok_name[token_type]
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tok_list.append(self.current + (self.start_pos,))
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if tok == 'as':
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token_type, tok = self.next()
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if token_type == tokenize.NAME:
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n, token_type, tok = self._parse_dot_name(self.current)
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if n:
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set_vars.append(n)
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tok_list.append(n)
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continue
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elif tok in ['lambda', 'for', 'in']:
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# don't parse these keywords, parse later in stmt.
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if tok == 'lambda':
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breaks.discard(':')
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elif token_type == tokenize.NAME:
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n, token_type, tok = self._parse_dot_name(self.current)
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# removed last entry, because we add Name
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tok_list.pop()
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if n:
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tok_list.append(n)
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used_vars.append(n)
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continue
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elif tok.endswith('=') and tok not in ['>=', '<=', '==', '!=']:
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# there has been an assignement -> change vars
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if level == 0:
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set_vars += used_vars
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used_vars = []
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elif tok in opening_brackets:
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level += 1
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elif tok in closing_brackets:
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level -= 1
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token_type, tok = self.next()
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except (StopIteration, common.MultiLevelStopIteration):
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# comes from tokenizer
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break
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if not tok_list:
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return None, tok
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#print 'new_stat', set_vars, used_vars
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if self.freshscope and not self.no_docstr and len(tok_list) == 1 \
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and self.last_token[0] == tokenize.STRING:
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self.scope.add_docstr(self.last_token[1])
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return None, tok
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else:
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stmt = stmt_class(self.module, set_vars, used_vars, tok_list,
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first_pos, self.end_pos)
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self._check_user_stmt(stmt)
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if tok in always_break + not_first_break:
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self._gen.push_last_back()
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return stmt, tok
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def next(self):
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return self.__next__()
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def __iter__(self):
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return self
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def __next__(self):
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""" Generate the next tokenize pattern. """
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try:
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typ, tok, self.start_pos, self.end_pos, \
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self.parserline = next(self._gen)
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except (StopIteration, common.MultiLevelStopIteration):
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# on finish, set end_pos correctly
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s = self.scope
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while s is not None:
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s.end_pos = self.end_pos
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s = s.parent
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raise
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if self.user_position and (self.start_pos[0] == self.user_position[0]
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or self.user_scope is None
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and self.start_pos[0] >= self.user_position[0]):
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debug.dbg('user scope found [%s] = %s' % \
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(self.parserline.replace('\n', ''), repr(self.scope)))
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self.user_scope = self.scope
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self.last_token = self.current
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self.current = (typ, tok)
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return self.current
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def _parse(self):
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"""
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The main part of the program. It analyzes the given code-text and
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returns a tree-like scope. For a more detailed description, see the
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class description.
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:param text: The code which should be parsed.
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:param type: str
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:raises: IndentationError
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"""
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extended_flow = ['else', 'elif', 'except', 'finally']
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statement_toks = ['{', '[', '(', '`']
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self._decorators = []
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self.freshscope = True
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self.iterator = iter(self)
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# This iterator stuff is not intentional. It grew historically.
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for token_type, tok in self.iterator:
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self.module.temp_used_names = []
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#debug.dbg('main: tok=[%s] type=[%s] indent=[%s]'\
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# % (tok, tokenize.tok_name[token_type], start_position[0]))
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while token_type == tokenize.DEDENT and self.scope != self.module:
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token_type, tok = self.next()
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if self.start_pos[1] <= self.scope.start_pos[1]:
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self.scope.end_pos = self.start_pos
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self.scope = self.scope.parent
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if isinstance(self.scope, pr.Module) \
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and not isinstance(self.scope, pr.SubModule):
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self.scope = self.module
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# check again for unindented stuff. this is true for syntax
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# errors. only check for names, because thats relevant here. If
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# some docstrings are not indented, I don't care.
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while self.start_pos[1] <= self.scope.start_pos[1] \
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and (token_type == tokenize.NAME or tok in ['(', '['])\
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and self.scope != self.module:
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self.scope.end_pos = self.start_pos
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self.scope = self.scope.parent
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if isinstance(self.scope, pr.Module) \
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and not isinstance(self.scope, pr.SubModule):
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self.scope = self.module
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use_as_parent_scope = self.top_module if isinstance(self.scope,
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pr.SubModule) else self.scope
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first_pos = self.start_pos
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if tok == 'def':
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func = self._parse_function()
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if func is None:
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debug.warning("function: syntax error@%s" %
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self.start_pos[0])
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continue
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self.freshscope = True
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self.scope = self.scope.add_scope(func, self._decorators)
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self._decorators = []
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elif tok == 'class':
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cls = self._parse_class()
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if cls is None:
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debug.warning("class: syntax error@%s" % self.start_pos[0])
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continue
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self.freshscope = True
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self.scope = self.scope.add_scope(cls, self._decorators)
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self._decorators = []
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# import stuff
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elif tok == 'import':
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imports = self._parse_import_list()
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for m, alias, defunct in imports:
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i = pr.Import(self.module, first_pos, self.end_pos, m,
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alias, defunct=defunct)
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self._check_user_stmt(i)
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self.scope.add_import(i)
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if not imports:
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i = pr.Import(self.module, first_pos, self.end_pos, None,
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defunct=True)
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self._check_user_stmt(i)
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self.freshscope = False
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elif tok == 'from':
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defunct = False
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# take care for relative imports
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relative_count = 0
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|
while 1:
|
|
token_type, tok = self.next()
|
|
if tok != '.':
|
|
break
|
|
relative_count += 1
|
|
# the from import
|
|
mod, token_type, tok = self._parse_dot_name(self.current)
|
|
if str(mod) == 'import' and relative_count:
|
|
self._gen.push_last_back()
|
|
tok = 'import'
|
|
mod = None
|
|
if not mod and not relative_count or tok != "import":
|
|
debug.warning("from: syntax error@%s" % self.start_pos[0])
|
|
defunct = True
|
|
if tok != 'import':
|
|
self._gen.push_last_back()
|
|
names = self._parse_import_list()
|
|
for name, alias, defunct2 in names:
|
|
star = name is not None and name.names[0] == '*'
|
|
if star:
|
|
name = None
|
|
i = pr.Import(self.module, first_pos, self.end_pos, name,
|
|
alias, mod, star, relative_count,
|
|
defunct=defunct or defunct2)
|
|
self._check_user_stmt(i)
|
|
self.scope.add_import(i)
|
|
self.freshscope = False
|
|
#loops
|
|
elif tok == 'for':
|
|
set_stmt, tok = self._parse_statement(added_breaks=['in'])
|
|
if tok == 'in':
|
|
statement, tok = self._parse_statement()
|
|
if tok == ':':
|
|
s = [] if statement is None else [statement]
|
|
f = pr.ForFlow(self.module, s, first_pos, set_stmt)
|
|
self.scope = self.scope.add_statement(f)
|
|
else:
|
|
debug.warning('syntax err, for flow started @%s',
|
|
self.start_pos[0])
|
|
if statement is not None:
|
|
statement.parent = use_as_parent_scope
|
|
if set_stmt is not None:
|
|
set_stmt.parent = use_as_parent_scope
|
|
else:
|
|
debug.warning('syntax err, for flow incomplete @%s',
|
|
self.start_pos[0])
|
|
if set_stmt is not None:
|
|
set_stmt.parent = use_as_parent_scope
|
|
|
|
elif tok in ['if', 'while', 'try', 'with'] + extended_flow:
|
|
added_breaks = []
|
|
command = tok
|
|
if command in ['except', 'with']:
|
|
added_breaks.append(',')
|
|
# multiple inputs because of with
|
|
inputs = []
|
|
first = True
|
|
while first or command == 'with' \
|
|
and tok not in [':', '\n']:
|
|
statement, tok = \
|
|
self._parse_statement(added_breaks=added_breaks)
|
|
if command == 'except' and tok in added_breaks:
|
|
# the except statement defines a var
|
|
# this is only true for python 2
|
|
n, token_type, tok = self._parse_dot_name()
|
|
if n:
|
|
statement.set_vars.append(n)
|
|
if statement:
|
|
inputs.append(statement)
|
|
first = False
|
|
|
|
if tok == ':':
|
|
f = pr.Flow(self.module, command, inputs, first_pos)
|
|
if command in extended_flow:
|
|
# the last statement has to be another part of
|
|
# the flow statement, because a dedent releases the
|
|
# main scope, so just take the last statement.
|
|
try:
|
|
s = self.scope.statements[-1].set_next(f)
|
|
except (AttributeError, IndexError):
|
|
# If set_next doesn't exist, just add it.
|
|
s = self.scope.add_statement(f)
|
|
else:
|
|
s = self.scope.add_statement(f)
|
|
self.scope = s
|
|
else:
|
|
for i in inputs:
|
|
i.parent = use_as_parent_scope
|
|
debug.warning('syntax err, flow started @%s',
|
|
self.start_pos[0])
|
|
# returns
|
|
elif tok in ['return', 'yield']:
|
|
s = self.start_pos
|
|
self.freshscope = False
|
|
# add returns to the scope
|
|
func = self.scope.get_parent_until(pr.Function)
|
|
if tok == 'yield':
|
|
func.is_generator = True
|
|
|
|
stmt, tok = self._parse_statement()
|
|
if stmt is not None:
|
|
stmt.parent = use_as_parent_scope
|
|
try:
|
|
func.returns.append(stmt)
|
|
# start_pos is the one of the return statement
|
|
stmt.start_pos = s
|
|
except AttributeError:
|
|
debug.warning('return in non-function')
|
|
# globals
|
|
elif tok == 'global':
|
|
stmt, tok = self._parse_statement(self.current)
|
|
if stmt:
|
|
self.scope.add_statement(stmt)
|
|
for name in stmt.used_vars:
|
|
# add the global to the top, because there it is
|
|
# important.
|
|
self.module.add_global(name)
|
|
# decorator
|
|
elif tok == '@':
|
|
stmt, tok = self._parse_statement()
|
|
self._decorators.append(stmt)
|
|
elif tok == 'pass':
|
|
continue
|
|
elif tok == 'assert':
|
|
stmt, tok = self._parse_statement()
|
|
stmt.parent = use_as_parent_scope
|
|
self.scope.asserts.append(stmt)
|
|
# default
|
|
elif token_type in [tokenize.NAME, tokenize.STRING,
|
|
tokenize.NUMBER] \
|
|
or tok in statement_toks:
|
|
# this is the main part - a name can be a function or a
|
|
# normal var, which can follow anything. but this is done
|
|
# by the statement parser.
|
|
stmt, tok = self._parse_statement(self.current)
|
|
if stmt:
|
|
self.scope.add_statement(stmt)
|
|
self.freshscope = False
|
|
else:
|
|
if token_type not in [tokenize.COMMENT, tokenize.INDENT,
|
|
tokenize.NEWLINE, tokenize.NL,
|
|
tokenize.ENDMARKER]:
|
|
debug.warning('token not classified', tok, token_type,
|
|
self.start_pos[0])
|