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- import ast
-
- class _CachedWalker(ast.NodeVisitor):
- """
- Local node visitor for python abstract syntax trees.
-
- :ivar accum: (dict) Information on variables, functions, and classes
- accumulated from an abstract syntax tree.
-
- :ivar cache: (dict or None) Information stored about parent nodes. Added
- to accum when node reaches the lowest possible level.
-
- .. todo::
- Add visit funciton for ast.Name to record all uses of a variable.
-
- Use self.cache to store extra information about nodes.
- """
-
- def __init__(self):
- """
- Create a _TreeCutter instance.
- """
-
- self.accum = {'vars': {}, 'functions': {}, 'classes': {}}
- self.cache = []
-
- def block_position(self, node):
- """
- Helper function to get the start and end lines of an AST node.
-
- :param node: The node.
-
- :type node: ast.FunctionDef or ast.ClassDef or ast.Module
- """
-
- start_line, start_col = node.lineno, node.col_offset
-
- temp_node = node
- while 'body' in temp_node.__dict__:
- temp_node = temp_node.body[-1]
-
- end_line, end_col = temp_node.lineno, temp_node.col_offset
- return (start_line, start_col, end_line, end_col)
-
- def visit_Assign(self, node):
- """
- Visits Assign nodes in a tree. Adds relevant data about them to accum.
-
- :param node: The current node.
-
- :type node: ast.Assign
-
- .. todo::
- Add value and type metadata to accum.
- """
-
- line, col = node.lineno, node.col_offset
- pos = (line, col, -1, -1)
-
- self.cache.append({'nodes': []})
- self.generic_visit(node)
- last = self.cache.pop()
-
- for name in last['nodes']:
- if not self.accum['vars'].has_key(name):
- self.accum['vars'][name] = {'assignments': [], 'uses': []}
-
- self.accum['vars'][name]['assignments'].append(pos)
-
-
- def visit_FunctionDef(self, node):
- """
- Visits FunctionDef nodes in a tree. Adds relevant data about them to accum.
-
- :param node: The current node.
-
- :type node: ast.FunctionDef
-
- .. todo::
- Add arguments and decorators metadata to accum.
- """
-
- start_line, start_col, end_line, end_col = self.block_position(node)
-
- if not self.accum['functions'].has_key(node.name):
- self.accum['functions'][node.name] = {'assignments': [], 'uses': []}
-
- pos = (start_line, start_col, end_line, end_col)
- self.accum['functions'][node.name]['assignments'].append(pos)
-
- self.generic_visit(node)
-
- def visit_Call(self, node):
- """
- Visits Function Call nodes in a tree. Adds relevant data about them
- in the functions section for accum.
-
- :param node: The current node.
-
- :type node: ast.Call
-
- .. todo::
- Add arguments and decorators metadata to accum.
- """
-
- line, col = node.lineno, node.col_offset
- pos = (line, col, -1, -1)
-
- if isinstance(node.func, ast.Name):
- name = node.func.id
- else:
- name = node.func.attr
-
- if not self.accum['functions'].has_key(name):
- self.accum['functions'][name] = {'assignments': [], 'uses': []}
-
- self.accum['functions'][name]['uses'].append(pos)
-
- def visit_ClassDef(self, node):
- """
- Visits ClassDef nodes in a tree. Adds relevant data about them to accum.
-
- :param node: The current node.
-
- :type node: ast.ClassDef
-
- .. todo::
- Add arguments, inherits, and decorators metadata to accum.
- """
-
- start_line, start_col, end_line, end_col = self.block_position(node)
-
- pos = (start_line, start_col, end_line, end_col)
- self.accum['classes'][node.name] = pos
-
- self.generic_visit(node)
-
- def visit_Name(self, node):
- if self.cache:
- last = self.cache[-1]
- last['nodes'].append(node.id)
-
- def visit_Attribute(self, node):
- if self.cache:
- last = self.cache[-1]
- last['nodes'].append(node.attr)
-
- def parse_py(codelet):
- """
- Adds 'symbols' field to the codelet after parsing the python code.
-
- :param codelet: The codelet object to parsed.
-
- :type code: Codelet
- """
-
- tree = ast.parse(codelet.code)
- cutter = _CachedWalker()
- cutter.visit(tree)
- codelet.symbols = cutter.accum
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