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Diffstat (limited to 'lib/python2.7/ast.py')
| -rw-r--r-- | lib/python2.7/ast.py | 311 |
1 files changed, 0 insertions, 311 deletions
diff --git a/lib/python2.7/ast.py b/lib/python2.7/ast.py deleted file mode 100644 index fd5dfdb..0000000 --- a/lib/python2.7/ast.py +++ /dev/null @@ -1,311 +0,0 @@ -# -*- coding: utf-8 -*- -""" - ast - ~~~ - - The `ast` module helps Python applications to process trees of the Python - abstract syntax grammar. The abstract syntax itself might change with - each Python release; this module helps to find out programmatically what - the current grammar looks like and allows modifications of it. - - An abstract syntax tree can be generated by passing `ast.PyCF_ONLY_AST` as - a flag to the `compile()` builtin function or by using the `parse()` - function from this module. The result will be a tree of objects whose - classes all inherit from `ast.AST`. - - A modified abstract syntax tree can be compiled into a Python code object - using the built-in `compile()` function. - - Additionally various helper functions are provided that make working with - the trees simpler. The main intention of the helper functions and this - module in general is to provide an easy to use interface for libraries - that work tightly with the python syntax (template engines for example). - - - :copyright: Copyright 2008 by Armin Ronacher. - :license: Python License. -""" -from _ast import * -from _ast import __version__ - - -def parse(source, filename='<unknown>', mode='exec'): - """ - Parse the source into an AST node. - Equivalent to compile(source, filename, mode, PyCF_ONLY_AST). - """ - return compile(source, filename, mode, PyCF_ONLY_AST) - - -def literal_eval(node_or_string): - """ - Safely evaluate an expression node or a string containing a Python - expression. The string or node provided may only consist of the following - Python literal structures: strings, numbers, tuples, lists, dicts, booleans, - and None. - """ - _safe_names = {'None': None, 'True': True, 'False': False} - if isinstance(node_or_string, basestring): - node_or_string = parse(node_or_string, mode='eval') - if isinstance(node_or_string, Expression): - node_or_string = node_or_string.body - def _convert(node): - if isinstance(node, Str): - return node.s - elif isinstance(node, Num): - return node.n - elif isinstance(node, Tuple): - return tuple(map(_convert, node.elts)) - elif isinstance(node, List): - return list(map(_convert, node.elts)) - elif isinstance(node, Dict): - return dict((_convert(k), _convert(v)) for k, v - in zip(node.keys, node.values)) - elif isinstance(node, Name): - if node.id in _safe_names: - return _safe_names[node.id] - elif isinstance(node, BinOp) and \ - isinstance(node.op, (Add, Sub)) and \ - isinstance(node.right, Num) and \ - isinstance(node.right.n, complex) and \ - isinstance(node.left, Num) and \ - isinstance(node.left.n, (int, long, float)): - left = node.left.n - right = node.right.n - if isinstance(node.op, Add): - return left + right - else: - return left - right - raise ValueError('malformed string') - return _convert(node_or_string) - - -def dump(node, annotate_fields=True, include_attributes=False): - """ - Return a formatted dump of the tree in *node*. This is mainly useful for - debugging purposes. The returned string will show the names and the values - for fields. This makes the code impossible to evaluate, so if evaluation is - wanted *annotate_fields* must be set to False. Attributes such as line - numbers and column offsets are not dumped by default. If this is wanted, - *include_attributes* can be set to True. - """ - def _format(node): - if isinstance(node, AST): - fields = [(a, _format(b)) for a, b in iter_fields(node)] - rv = '%s(%s' % (node.__class__.__name__, ', '.join( - ('%s=%s' % field for field in fields) - if annotate_fields else - (b for a, b in fields) - )) - if include_attributes and node._attributes: - rv += fields and ', ' or ' ' - rv += ', '.join('%s=%s' % (a, _format(getattr(node, a))) - for a in node._attributes) - return rv + ')' - elif isinstance(node, list): - return '[%s]' % ', '.join(_format(x) for x in node) - return repr(node) - if not isinstance(node, AST): - raise TypeError('expected AST, got %r' % node.__class__.__name__) - return _format(node) - - -def copy_location(new_node, old_node): - """ - Copy source location (`lineno` and `col_offset` attributes) from - *old_node* to *new_node* if possible, and return *new_node*. - """ - for attr in 'lineno', 'col_offset': - if attr in old_node._attributes and attr in new_node._attributes \ - and hasattr(old_node, attr): - setattr(new_node, attr, getattr(old_node, attr)) - return new_node - - -def fix_missing_locations(node): - """ - When you compile a node tree with compile(), the compiler expects lineno and - col_offset attributes for every node that supports them. This is rather - tedious to fill in for generated nodes, so this helper adds these attributes - recursively where not already set, by setting them to the values of the - parent node. It works recursively starting at *node*. - """ - def _fix(node, lineno, col_offset): - if 'lineno' in node._attributes: - if not hasattr(node, 'lineno'): - node.lineno = lineno - else: - lineno = node.lineno - if 'col_offset' in node._attributes: - if not hasattr(node, 'col_offset'): - node.col_offset = col_offset - else: - col_offset = node.col_offset - for child in iter_child_nodes(node): - _fix(child, lineno, col_offset) - _fix(node, 1, 0) - return node - - -def increment_lineno(node, n=1): - """ - Increment the line number of each node in the tree starting at *node* by *n*. - This is useful to "move code" to a different location in a file. - """ - for child in walk(node): - if 'lineno' in child._attributes: - child.lineno = getattr(child, 'lineno', 0) + n - return node - - -def iter_fields(node): - """ - Yield a tuple of ``(fieldname, value)`` for each field in ``node._fields`` - that is present on *node*. - """ - for field in node._fields: - try: - yield field, getattr(node, field) - except AttributeError: - pass - - -def iter_child_nodes(node): - """ - Yield all direct child nodes of *node*, that is, all fields that are nodes - and all items of fields that are lists of nodes. - """ - for name, field in iter_fields(node): - if isinstance(field, AST): - yield field - elif isinstance(field, list): - for item in field: - if isinstance(item, AST): - yield item - - -def get_docstring(node, clean=True): - """ - Return the docstring for the given node or None if no docstring can - be found. If the node provided does not have docstrings a TypeError - will be raised. - """ - if not isinstance(node, (FunctionDef, ClassDef, Module)): - raise TypeError("%r can't have docstrings" % node.__class__.__name__) - if node.body and isinstance(node.body[0], Expr) and \ - isinstance(node.body[0].value, Str): - if clean: - import inspect - return inspect.cleandoc(node.body[0].value.s) - return node.body[0].value.s - - -def walk(node): - """ - Recursively yield all descendant nodes in the tree starting at *node* - (including *node* itself), in no specified order. This is useful if you - only want to modify nodes in place and don't care about the context. - """ - from collections import deque - todo = deque([node]) - while todo: - node = todo.popleft() - todo.extend(iter_child_nodes(node)) - yield node - - -class NodeVisitor(object): - """ - A node visitor base class that walks the abstract syntax tree and calls a - visitor function for every node found. This function may return a value - which is forwarded by the `visit` method. - - This class is meant to be subclassed, with the subclass adding visitor - methods. - - Per default the visitor functions for the nodes are ``'visit_'`` + - class name of the node. So a `TryFinally` node visit function would - be `visit_TryFinally`. This behavior can be changed by overriding - the `visit` method. If no visitor function exists for a node - (return value `None`) the `generic_visit` visitor is used instead. - - Don't use the `NodeVisitor` if you want to apply changes to nodes during - traversing. For this a special visitor exists (`NodeTransformer`) that - allows modifications. - """ - - def visit(self, node): - """Visit a node.""" - method = 'visit_' + node.__class__.__name__ - visitor = getattr(self, method, self.generic_visit) - return visitor(node) - - def generic_visit(self, node): - """Called if no explicit visitor function exists for a node.""" - for field, value in iter_fields(node): - if isinstance(value, list): - for item in value: - if isinstance(item, AST): - self.visit(item) - elif isinstance(value, AST): - self.visit(value) - - -class NodeTransformer(NodeVisitor): - """ - A :class:`NodeVisitor` subclass that walks the abstract syntax tree and - allows modification of nodes. - - The `NodeTransformer` will walk the AST and use the return value of the - visitor methods to replace or remove the old node. If the return value of - the visitor method is ``None``, the node will be removed from its location, - otherwise it is replaced with the return value. The return value may be the - original node in which case no replacement takes place. - - Here is an example transformer that rewrites all occurrences of name lookups - (``foo``) to ``data['foo']``:: - - class RewriteName(NodeTransformer): - - def visit_Name(self, node): - return copy_location(Subscript( - value=Name(id='data', ctx=Load()), - slice=Index(value=Str(s=node.id)), - ctx=node.ctx - ), node) - - Keep in mind that if the node you're operating on has child nodes you must - either transform the child nodes yourself or call the :meth:`generic_visit` - method for the node first. - - For nodes that were part of a collection of statements (that applies to all - statement nodes), the visitor may also return a list of nodes rather than - just a single node. - - Usually you use the transformer like this:: - - node = YourTransformer().visit(node) - """ - - def generic_visit(self, node): - for field, old_value in iter_fields(node): - old_value = getattr(node, field, None) - if isinstance(old_value, list): - new_values = [] - for value in old_value: - if isinstance(value, AST): - value = self.visit(value) - if value is None: - continue - elif not isinstance(value, AST): - new_values.extend(value) - continue - new_values.append(value) - old_value[:] = new_values - elif isinstance(old_value, AST): - new_node = self.visit(old_value) - if new_node is None: - delattr(node, field) - else: - setattr(node, field, new_node) - return node |