| """ |
| 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. |
| """ |
| import sys |
| from _ast import * |
| from contextlib import contextmanager, nullcontext |
| from enum import IntEnum, auto |
| |
| |
| def parse(source, filename='<unknown>', mode='exec', *, |
| type_comments=False, feature_version=None): |
| """ |
| Parse the source into an AST node. |
| Equivalent to compile(source, filename, mode, PyCF_ONLY_AST). |
| Pass type_comments=True to get back type comments where the syntax allows. |
| """ |
| flags = PyCF_ONLY_AST |
| if type_comments: |
| flags |= PyCF_TYPE_COMMENTS |
| if isinstance(feature_version, tuple): |
| major, minor = feature_version # Should be a 2-tuple. |
| assert major == 3 |
| feature_version = minor |
| elif feature_version is None: |
| feature_version = -1 |
| # Else it should be an int giving the minor version for 3.x. |
| return compile(source, filename, mode, flags, |
| _feature_version=feature_version) |
| |
| |
| 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, bytes, numbers, tuples, lists, dicts, |
| sets, booleans, and None. |
| """ |
| if isinstance(node_or_string, str): |
| node_or_string = parse(node_or_string, mode='eval') |
| if isinstance(node_or_string, Expression): |
| node_or_string = node_or_string.body |
| def _raise_malformed_node(node): |
| raise ValueError(f'malformed node or string: {node!r}') |
| def _convert_num(node): |
| if not isinstance(node, Constant) or type(node.value) not in (int, float, complex): |
| _raise_malformed_node(node) |
| return node.value |
| def _convert_signed_num(node): |
| if isinstance(node, UnaryOp) and isinstance(node.op, (UAdd, USub)): |
| operand = _convert_num(node.operand) |
| if isinstance(node.op, UAdd): |
| return + operand |
| else: |
| return - operand |
| return _convert_num(node) |
| def _convert(node): |
| if isinstance(node, Constant): |
| return node.value |
| elif isinstance(node, Tuple): |
| return tuple(map(_convert, node.elts)) |
| elif isinstance(node, List): |
| return list(map(_convert, node.elts)) |
| elif isinstance(node, Set): |
| return set(map(_convert, node.elts)) |
| elif (isinstance(node, Call) and isinstance(node.func, Name) and |
| node.func.id == 'set' and node.args == node.keywords == []): |
| return set() |
| elif isinstance(node, Dict): |
| if len(node.keys) != len(node.values): |
| _raise_malformed_node(node) |
| return dict(zip(map(_convert, node.keys), |
| map(_convert, node.values))) |
| elif isinstance(node, BinOp) and isinstance(node.op, (Add, Sub)): |
| left = _convert_signed_num(node.left) |
| right = _convert_num(node.right) |
| if isinstance(left, (int, float)) and isinstance(right, complex): |
| if isinstance(node.op, Add): |
| return left + right |
| else: |
| return left - right |
| return _convert_signed_num(node) |
| return _convert(node_or_string) |
| |
| |
| def dump(node, annotate_fields=True, include_attributes=False, *, indent=None): |
| """ |
| Return a formatted dump of the tree in node. This is mainly useful for |
| debugging purposes. If annotate_fields is true (by default), |
| the returned string will show the names and the values for fields. |
| If annotate_fields is false, the result string will be more compact by |
| omitting unambiguous field names. Attributes such as line |
| numbers and column offsets are not dumped by default. If this is wanted, |
| include_attributes can be set to true. If indent is a non-negative |
| integer or string, then the tree will be pretty-printed with that indent |
| level. None (the default) selects the single line representation. |
| """ |
| def _format(node, level=0): |
| if indent is not None: |
| level += 1 |
| prefix = '\n' + indent * level |
| sep = ',\n' + indent * level |
| else: |
| prefix = '' |
| sep = ', ' |
| if isinstance(node, AST): |
| cls = type(node) |
| args = [] |
| allsimple = True |
| keywords = annotate_fields |
| for name in node._fields: |
| try: |
| value = getattr(node, name) |
| except AttributeError: |
| keywords = True |
| continue |
| if value is None and getattr(cls, name, ...) is None: |
| keywords = True |
| continue |
| value, simple = _format(value, level) |
| allsimple = allsimple and simple |
| if keywords: |
| args.append('%s=%s' % (name, value)) |
| else: |
| args.append(value) |
| if include_attributes and node._attributes: |
| for name in node._attributes: |
| try: |
| value = getattr(node, name) |
| except AttributeError: |
| continue |
| if value is None and getattr(cls, name, ...) is None: |
| continue |
| value, simple = _format(value, level) |
| allsimple = allsimple and simple |
| args.append('%s=%s' % (name, value)) |
| if allsimple and len(args) <= 3: |
| return '%s(%s)' % (node.__class__.__name__, ', '.join(args)), not args |
| return '%s(%s%s)' % (node.__class__.__name__, prefix, sep.join(args)), False |
| elif isinstance(node, list): |
| if not node: |
| return '[]', True |
| return '[%s%s]' % (prefix, sep.join(_format(x, level)[0] for x in node)), False |
| return repr(node), True |
| |
| if not isinstance(node, AST): |
| raise TypeError('expected AST, got %r' % node.__class__.__name__) |
| if indent is not None and not isinstance(indent, str): |
| indent = ' ' * indent |
| return _format(node)[0] |
| |
| |
| def copy_location(new_node, old_node): |
| """ |
| Copy source location (`lineno`, `col_offset`, `end_lineno`, and `end_col_offset` |
| attributes) from *old_node* to *new_node* if possible, and return *new_node*. |
| """ |
| for attr in 'lineno', 'col_offset', 'end_lineno', 'end_col_offset': |
| if attr in old_node._attributes and attr in new_node._attributes: |
| value = getattr(old_node, attr, None) |
| # end_lineno and end_col_offset are optional attributes, and they |
| # should be copied whether the value is None or not. |
| if value is not None or ( |
| hasattr(old_node, attr) and attr.startswith("end_") |
| ): |
| setattr(new_node, attr, value) |
| 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, end_lineno, end_col_offset): |
| if 'lineno' in node._attributes: |
| if not hasattr(node, 'lineno'): |
| node.lineno = lineno |
| else: |
| lineno = node.lineno |
| if 'end_lineno' in node._attributes: |
| if getattr(node, 'end_lineno', None) is None: |
| node.end_lineno = end_lineno |
| else: |
| end_lineno = node.end_lineno |
| if 'col_offset' in node._attributes: |
| if not hasattr(node, 'col_offset'): |
| node.col_offset = col_offset |
| else: |
| col_offset = node.col_offset |
| if 'end_col_offset' in node._attributes: |
| if getattr(node, 'end_col_offset', None) is None: |
| node.end_col_offset = end_col_offset |
| else: |
| end_col_offset = node.end_col_offset |
| for child in iter_child_nodes(node): |
| _fix(child, lineno, col_offset, end_lineno, end_col_offset) |
| _fix(node, 1, 0, 1, 0) |
| return node |
| |
| |
| def increment_lineno(node, n=1): |
| """ |
| Increment the line number and end 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 |
| if ( |
| "end_lineno" in child._attributes |
| and (end_lineno := getattr(child, "end_lineno", 0)) is not None |
| ): |
| child.end_lineno = end_lineno + 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 *clean* is `True`, all tabs are expanded to spaces and any whitespace |
| that can be uniformly removed from the second line onwards is removed. |
| """ |
| if not isinstance(node, (AsyncFunctionDef, FunctionDef, ClassDef, Module)): |
| raise TypeError("%r can't have docstrings" % node.__class__.__name__) |
| if not(node.body and isinstance(node.body[0], Expr)): |
| return None |
| node = node.body[0].value |
| if isinstance(node, Str): |
| text = node.s |
| elif isinstance(node, Constant) and isinstance(node.value, str): |
| text = node.value |
| else: |
| return None |
| if clean: |
| import inspect |
| text = inspect.cleandoc(text) |
| return text |
| |
| |
| def _splitlines_no_ff(source): |
| """Split a string into lines ignoring form feed and other chars. |
| |
| This mimics how the Python parser splits source code. |
| """ |
| idx = 0 |
| lines = [] |
| next_line = '' |
| while idx < len(source): |
| c = source[idx] |
| next_line += c |
| idx += 1 |
| # Keep \r\n together |
| if c == '\r' and idx < len(source) and source[idx] == '\n': |
| next_line += '\n' |
| idx += 1 |
| if c in '\r\n': |
| lines.append(next_line) |
| next_line = '' |
| |
| if next_line: |
| lines.append(next_line) |
| return lines |
| |
| |
| def _pad_whitespace(source): |
| r"""Replace all chars except '\f\t' in a line with spaces.""" |
| result = '' |
| for c in source: |
| if c in '\f\t': |
| result += c |
| else: |
| result += ' ' |
| return result |
| |
| |
| def get_source_segment(source, node, *, padded=False): |
| """Get source code segment of the *source* that generated *node*. |
| |
| If some location information (`lineno`, `end_lineno`, `col_offset`, |
| or `end_col_offset`) is missing, return None. |
| |
| If *padded* is `True`, the first line of a multi-line statement will |
| be padded with spaces to match its original position. |
| """ |
| try: |
| if node.end_lineno is None or node.end_col_offset is None: |
| return None |
| lineno = node.lineno - 1 |
| end_lineno = node.end_lineno - 1 |
| col_offset = node.col_offset |
| end_col_offset = node.end_col_offset |
| except AttributeError: |
| return None |
| |
| lines = _splitlines_no_ff(source) |
| if end_lineno == lineno: |
| return lines[lineno].encode()[col_offset:end_col_offset].decode() |
| |
| if padded: |
| padding = _pad_whitespace(lines[lineno].encode()[:col_offset].decode()) |
| else: |
| padding = '' |
| |
| first = padding + lines[lineno].encode()[col_offset:].decode() |
| last = lines[end_lineno].encode()[:end_col_offset].decode() |
| lines = lines[lineno+1:end_lineno] |
| |
| lines.insert(0, first) |
| lines.append(last) |
| return ''.join(lines) |
| |
| |
| 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) |
| |
| def visit_Constant(self, node): |
| value = node.value |
| type_name = _const_node_type_names.get(type(value)) |
| if type_name is None: |
| for cls, name in _const_node_type_names.items(): |
| if isinstance(value, cls): |
| type_name = name |
| break |
| if type_name is not None: |
| method = 'visit_' + type_name |
| try: |
| visitor = getattr(self, method) |
| except AttributeError: |
| pass |
| else: |
| import warnings |
| warnings.warn(f"{method} is deprecated; add visit_Constant", |
| DeprecationWarning, 2) |
| return visitor(node) |
| return self.generic_visit(node) |
| |
| |
| 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 Subscript( |
| value=Name(id='data', ctx=Load()), |
| slice=Constant(value=node.id), |
| ctx=node.ctx |
| ) |
| |
| 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): |
| 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 |
| |
| |
| # If the ast module is loaded more than once, only add deprecated methods once |
| if not hasattr(Constant, 'n'): |
| # The following code is for backward compatibility. |
| # It will be removed in future. |
| |
| def _getter(self): |
| """Deprecated. Use value instead.""" |
| return self.value |
| |
| def _setter(self, value): |
| self.value = value |
| |
| Constant.n = property(_getter, _setter) |
| Constant.s = property(_getter, _setter) |
| |
| class _ABC(type): |
| |
| def __init__(cls, *args): |
| cls.__doc__ = """Deprecated AST node class. Use ast.Constant instead""" |
| |
| def __instancecheck__(cls, inst): |
| if not isinstance(inst, Constant): |
| return False |
| if cls in _const_types: |
| try: |
| value = inst.value |
| except AttributeError: |
| return False |
| else: |
| return ( |
| isinstance(value, _const_types[cls]) and |
| not isinstance(value, _const_types_not.get(cls, ())) |
| ) |
| return type.__instancecheck__(cls, inst) |
| |
| def _new(cls, *args, **kwargs): |
| for key in kwargs: |
| if key not in cls._fields: |
| # arbitrary keyword arguments are accepted |
| continue |
| pos = cls._fields.index(key) |
| if pos < len(args): |
| raise TypeError(f"{cls.__name__} got multiple values for argument {key!r}") |
| if cls in _const_types: |
| return Constant(*args, **kwargs) |
| return Constant.__new__(cls, *args, **kwargs) |
| |
| class Num(Constant, metaclass=_ABC): |
| _fields = ('n',) |
| __new__ = _new |
| |
| class Str(Constant, metaclass=_ABC): |
| _fields = ('s',) |
| __new__ = _new |
| |
| class Bytes(Constant, metaclass=_ABC): |
| _fields = ('s',) |
| __new__ = _new |
| |
| class NameConstant(Constant, metaclass=_ABC): |
| __new__ = _new |
| |
| class Ellipsis(Constant, metaclass=_ABC): |
| _fields = () |
| |
| def __new__(cls, *args, **kwargs): |
| if cls is Ellipsis: |
| return Constant(..., *args, **kwargs) |
| return Constant.__new__(cls, *args, **kwargs) |
| |
| _const_types = { |
| Num: (int, float, complex), |
| Str: (str,), |
| Bytes: (bytes,), |
| NameConstant: (type(None), bool), |
| Ellipsis: (type(...),), |
| } |
| _const_types_not = { |
| Num: (bool,), |
| } |
| |
| _const_node_type_names = { |
| bool: 'NameConstant', # should be before int |
| type(None): 'NameConstant', |
| int: 'Num', |
| float: 'Num', |
| complex: 'Num', |
| str: 'Str', |
| bytes: 'Bytes', |
| type(...): 'Ellipsis', |
| } |
| |
| class slice(AST): |
| """Deprecated AST node class.""" |
| |
| class Index(slice): |
| """Deprecated AST node class. Use the index value directly instead.""" |
| def __new__(cls, value, **kwargs): |
| return value |
| |
| class ExtSlice(slice): |
| """Deprecated AST node class. Use ast.Tuple instead.""" |
| def __new__(cls, dims=(), **kwargs): |
| return Tuple(list(dims), Load(), **kwargs) |
| |
| # If the ast module is loaded more than once, only add deprecated methods once |
| if not hasattr(Tuple, 'dims'): |
| # The following code is for backward compatibility. |
| # It will be removed in future. |
| |
| def _dims_getter(self): |
| """Deprecated. Use elts instead.""" |
| return self.elts |
| |
| def _dims_setter(self, value): |
| self.elts = value |
| |
| Tuple.dims = property(_dims_getter, _dims_setter) |
| |
| class Suite(mod): |
| """Deprecated AST node class. Unused in Python 3.""" |
| |
| class AugLoad(expr_context): |
| """Deprecated AST node class. Unused in Python 3.""" |
| |
| class AugStore(expr_context): |
| """Deprecated AST node class. Unused in Python 3.""" |
| |
| class Param(expr_context): |
| """Deprecated AST node class. Unused in Python 3.""" |
| |
| |
| # Large float and imaginary literals get turned into infinities in the AST. |
| # We unparse those infinities to INFSTR. |
| _INFSTR = "1e" + repr(sys.float_info.max_10_exp + 1) |
| |
| class _Precedence(IntEnum): |
| """Precedence table that originated from python grammar.""" |
| |
| TUPLE = auto() |
| YIELD = auto() # 'yield', 'yield from' |
| TEST = auto() # 'if'-'else', 'lambda' |
| OR = auto() # 'or' |
| AND = auto() # 'and' |
| NOT = auto() # 'not' |
| CMP = auto() # '<', '>', '==', '>=', '<=', '!=', |
| # 'in', 'not in', 'is', 'is not' |
| EXPR = auto() |
| BOR = EXPR # '|' |
| BXOR = auto() # '^' |
| BAND = auto() # '&' |
| SHIFT = auto() # '<<', '>>' |
| ARITH = auto() # '+', '-' |
| TERM = auto() # '*', '@', '/', '%', '//' |
| FACTOR = auto() # unary '+', '-', '~' |
| POWER = auto() # '**' |
| AWAIT = auto() # 'await' |
| ATOM = auto() |
| |
| def next(self): |
| try: |
| return self.__class__(self + 1) |
| except ValueError: |
| return self |
| |
| |
| _SINGLE_QUOTES = ("'", '"') |
| _MULTI_QUOTES = ('"""', "'''") |
| _ALL_QUOTES = (*_SINGLE_QUOTES, *_MULTI_QUOTES) |
| |
| class _Unparser(NodeVisitor): |
| """Methods in this class recursively traverse an AST and |
| output source code for the abstract syntax; original formatting |
| is disregarded.""" |
| |
| def __init__(self, *, _avoid_backslashes=False): |
| self._source = [] |
| self._buffer = [] |
| self._precedences = {} |
| self._type_ignores = {} |
| self._indent = 0 |
| self._avoid_backslashes = _avoid_backslashes |
| |
| def interleave(self, inter, f, seq): |
| """Call f on each item in seq, calling inter() in between.""" |
| seq = iter(seq) |
| try: |
| f(next(seq)) |
| except StopIteration: |
| pass |
| else: |
| for x in seq: |
| inter() |
| f(x) |
| |
| def items_view(self, traverser, items): |
| """Traverse and separate the given *items* with a comma and append it to |
| the buffer. If *items* is a single item sequence, a trailing comma |
| will be added.""" |
| if len(items) == 1: |
| traverser(items[0]) |
| self.write(",") |
| else: |
| self.interleave(lambda: self.write(", "), traverser, items) |
| |
| def maybe_newline(self): |
| """Adds a newline if it isn't the start of generated source""" |
| if self._source: |
| self.write("\n") |
| |
| def fill(self, text=""): |
| """Indent a piece of text and append it, according to the current |
| indentation level""" |
| self.maybe_newline() |
| self.write(" " * self._indent + text) |
| |
| def write(self, text): |
| """Append a piece of text""" |
| self._source.append(text) |
| |
| def buffer_writer(self, text): |
| self._buffer.append(text) |
| |
| @property |
| def buffer(self): |
| value = "".join(self._buffer) |
| self._buffer.clear() |
| return value |
| |
| @contextmanager |
| def block(self, *, extra = None): |
| """A context manager for preparing the source for blocks. It adds |
| the character':', increases the indentation on enter and decreases |
| the indentation on exit. If *extra* is given, it will be directly |
| appended after the colon character. |
| """ |
| self.write(":") |
| if extra: |
| self.write(extra) |
| self._indent += 1 |
| yield |
| self._indent -= 1 |
| |
| @contextmanager |
| def delimit(self, start, end): |
| """A context manager for preparing the source for expressions. It adds |
| *start* to the buffer and enters, after exit it adds *end*.""" |
| |
| self.write(start) |
| yield |
| self.write(end) |
| |
| def delimit_if(self, start, end, condition): |
| if condition: |
| return self.delimit(start, end) |
| else: |
| return nullcontext() |
| |
| def require_parens(self, precedence, node): |
| """Shortcut to adding precedence related parens""" |
| return self.delimit_if("(", ")", self.get_precedence(node) > precedence) |
| |
| def get_precedence(self, node): |
| return self._precedences.get(node, _Precedence.TEST) |
| |
| def set_precedence(self, precedence, *nodes): |
| for node in nodes: |
| self._precedences[node] = precedence |
| |
| def get_raw_docstring(self, node): |
| """If a docstring node is found in the body of the *node* parameter, |
| return that docstring node, None otherwise. |
| |
| Logic mirrored from ``_PyAST_GetDocString``.""" |
| if not isinstance( |
| node, (AsyncFunctionDef, FunctionDef, ClassDef, Module) |
| ) or len(node.body) < 1: |
| return None |
| node = node.body[0] |
| if not isinstance(node, Expr): |
| return None |
| node = node.value |
| if isinstance(node, Constant) and isinstance(node.value, str): |
| return node |
| |
| def get_type_comment(self, node): |
| comment = self._type_ignores.get(node.lineno) or node.type_comment |
| if comment is not None: |
| return f" # type: {comment}" |
| |
| def traverse(self, node): |
| if isinstance(node, list): |
| for item in node: |
| self.traverse(item) |
| else: |
| super().visit(node) |
| |
| def visit(self, node): |
| """Outputs a source code string that, if converted back to an ast |
| (using ast.parse) will generate an AST equivalent to *node*""" |
| self._source = [] |
| self.traverse(node) |
| return "".join(self._source) |
| |
| def _write_docstring_and_traverse_body(self, node): |
| if (docstring := self.get_raw_docstring(node)): |
| self._write_docstring(docstring) |
| self.traverse(node.body[1:]) |
| else: |
| self.traverse(node.body) |
| |
| def visit_Module(self, node): |
| self._type_ignores = { |
| ignore.lineno: f"ignore{ignore.tag}" |
| for ignore in node.type_ignores |
| } |
| self._write_docstring_and_traverse_body(node) |
| self._type_ignores.clear() |
| |
| def visit_FunctionType(self, node): |
| with self.delimit("(", ")"): |
| self.interleave( |
| lambda: self.write(", "), self.traverse, node.argtypes |
| ) |
| |
| self.write(" -> ") |
| self.traverse(node.returns) |
| |
| def visit_Expr(self, node): |
| self.fill() |
| self.set_precedence(_Precedence.YIELD, node.value) |
| self.traverse(node.value) |
| |
| def visit_NamedExpr(self, node): |
| with self.require_parens(_Precedence.TUPLE, node): |
| self.set_precedence(_Precedence.ATOM, node.target, node.value) |
| self.traverse(node.target) |
| self.write(" := ") |
| self.traverse(node.value) |
| |
| def visit_Import(self, node): |
| self.fill("import ") |
| self.interleave(lambda: self.write(", "), self.traverse, node.names) |
| |
| def visit_ImportFrom(self, node): |
| self.fill("from ") |
| self.write("." * node.level) |
| if node.module: |
| self.write(node.module) |
| self.write(" import ") |
| self.interleave(lambda: self.write(", "), self.traverse, node.names) |
| |
| def visit_Assign(self, node): |
| self.fill() |
| for target in node.targets: |
| self.traverse(target) |
| self.write(" = ") |
| self.traverse(node.value) |
| if type_comment := self.get_type_comment(node): |
| self.write(type_comment) |
| |
| def visit_AugAssign(self, node): |
| self.fill() |
| self.traverse(node.target) |
| self.write(" " + self.binop[node.op.__class__.__name__] + "= ") |
| self.traverse(node.value) |
| |
| def visit_AnnAssign(self, node): |
| self.fill() |
| with self.delimit_if("(", ")", not node.simple and isinstance(node.target, Name)): |
| self.traverse(node.target) |
| self.write(": ") |
| self.traverse(node.annotation) |
| if node.value: |
| self.write(" = ") |
| self.traverse(node.value) |
| |
| def visit_Return(self, node): |
| self.fill("return") |
| if node.value: |
| self.write(" ") |
| self.traverse(node.value) |
| |
| def visit_Pass(self, node): |
| self.fill("pass") |
| |
| def visit_Break(self, node): |
| self.fill("break") |
| |
| def visit_Continue(self, node): |
| self.fill("continue") |
| |
| def visit_Delete(self, node): |
| self.fill("del ") |
| self.interleave(lambda: self.write(", "), self.traverse, node.targets) |
| |
| def visit_Assert(self, node): |
| self.fill("assert ") |
| self.traverse(node.test) |
| if node.msg: |
| self.write(", ") |
| self.traverse(node.msg) |
| |
| def visit_Global(self, node): |
| self.fill("global ") |
| self.interleave(lambda: self.write(", "), self.write, node.names) |
| |
| def visit_Nonlocal(self, node): |
| self.fill("nonlocal ") |
| self.interleave(lambda: self.write(", "), self.write, node.names) |
| |
| def visit_Await(self, node): |
| with self.require_parens(_Precedence.AWAIT, node): |
| self.write("await") |
| if node.value: |
| self.write(" ") |
| self.set_precedence(_Precedence.ATOM, node.value) |
| self.traverse(node.value) |
| |
| def visit_Yield(self, node): |
| with self.require_parens(_Precedence.YIELD, node): |
| self.write("yield") |
| if node.value: |
| self.write(" ") |
| self.set_precedence(_Precedence.ATOM, node.value) |
| self.traverse(node.value) |
| |
| def visit_YieldFrom(self, node): |
| with self.require_parens(_Precedence.YIELD, node): |
| self.write("yield from ") |
| if not node.value: |
| raise ValueError("Node can't be used without a value attribute.") |
| self.set_precedence(_Precedence.ATOM, node.value) |
| self.traverse(node.value) |
| |
| def visit_Raise(self, node): |
| self.fill("raise") |
| if not node.exc: |
| if node.cause: |
| raise ValueError(f"Node can't use cause without an exception.") |
| return |
| self.write(" ") |
| self.traverse(node.exc) |
| if node.cause: |
| self.write(" from ") |
| self.traverse(node.cause) |
| |
| def visit_Try(self, node): |
| self.fill("try") |
| with self.block(): |
| self.traverse(node.body) |
| for ex in node.handlers: |
| self.traverse(ex) |
| if node.orelse: |
| self.fill("else") |
| with self.block(): |
| self.traverse(node.orelse) |
| if node.finalbody: |
| self.fill("finally") |
| with self.block(): |
| self.traverse(node.finalbody) |
| |
| def visit_ExceptHandler(self, node): |
| self.fill("except") |
| if node.type: |
| self.write(" ") |
| self.traverse(node.type) |
| if node.name: |
| self.write(" as ") |
| self.write(node.name) |
| with self.block(): |
| self.traverse(node.body) |
| |
| def visit_ClassDef(self, node): |
| self.maybe_newline() |
| for deco in node.decorator_list: |
| self.fill("@") |
| self.traverse(deco) |
| self.fill("class " + node.name) |
| with self.delimit_if("(", ")", condition = node.bases or node.keywords): |
| comma = False |
| for e in node.bases: |
| if comma: |
| self.write(", ") |
| else: |
| comma = True |
| self.traverse(e) |
| for e in node.keywords: |
| if comma: |
| self.write(", ") |
| else: |
| comma = True |
| self.traverse(e) |
| |
| with self.block(): |
| self._write_docstring_and_traverse_body(node) |
| |
| def visit_FunctionDef(self, node): |
| self._function_helper(node, "def") |
| |
| def visit_AsyncFunctionDef(self, node): |
| self._function_helper(node, "async def") |
| |
| def _function_helper(self, node, fill_suffix): |
| self.maybe_newline() |
| for deco in node.decorator_list: |
| self.fill("@") |
| self.traverse(deco) |
| def_str = fill_suffix + " " + node.name |
| self.fill(def_str) |
| with self.delimit("(", ")"): |
| self.traverse(node.args) |
| if node.returns: |
| self.write(" -> ") |
| self.traverse(node.returns) |
| with self.block(extra=self.get_type_comment(node)): |
| self._write_docstring_and_traverse_body(node) |
| |
| def visit_For(self, node): |
| self._for_helper("for ", node) |
| |
| def visit_AsyncFor(self, node): |
| self._for_helper("async for ", node) |
| |
| def _for_helper(self, fill, node): |
| self.fill(fill) |
| self.traverse(node.target) |
| self.write(" in ") |
| self.traverse(node.iter) |
| with self.block(extra=self.get_type_comment(node)): |
| self.traverse(node.body) |
| if node.orelse: |
| self.fill("else") |
| with self.block(): |
| self.traverse(node.orelse) |
| |
| def visit_If(self, node): |
| self.fill("if ") |
| self.traverse(node.test) |
| with self.block(): |
| self.traverse(node.body) |
| # collapse nested ifs into equivalent elifs. |
| while node.orelse and len(node.orelse) == 1 and isinstance(node.orelse[0], If): |
| node = node.orelse[0] |
| self.fill("elif ") |
| self.traverse(node.test) |
| with self.block(): |
| self.traverse(node.body) |
| # final else |
| if node.orelse: |
| self.fill("else") |
| with self.block(): |
| self.traverse(node.orelse) |
| |
| def visit_While(self, node): |
| self.fill("while ") |
| self.traverse(node.test) |
| with self.block(): |
| self.traverse(node.body) |
| if node.orelse: |
| self.fill("else") |
| with self.block(): |
| self.traverse(node.orelse) |
| |
| def visit_With(self, node): |
| self.fill("with ") |
| self.interleave(lambda: self.write(", "), self.traverse, node.items) |
| with self.block(extra=self.get_type_comment(node)): |
| self.traverse(node.body) |
| |
| def visit_AsyncWith(self, node): |
| self.fill("async with ") |
| self.interleave(lambda: self.write(", "), self.traverse, node.items) |
| with self.block(extra=self.get_type_comment(node)): |
| self.traverse(node.body) |
| |
| def _str_literal_helper( |
| self, string, *, quote_types=_ALL_QUOTES, escape_special_whitespace=False |
| ): |
| """Helper for writing string literals, minimizing escapes. |
| Returns the tuple (string literal to write, possible quote types). |
| """ |
| def escape_char(c): |
| # \n and \t are non-printable, but we only escape them if |
| # escape_special_whitespace is True |
| if not escape_special_whitespace and c in "\n\t": |
| return c |
| # Always escape backslashes and other non-printable characters |
| if c == "\\" or not c.isprintable(): |
| return c.encode("unicode_escape").decode("ascii") |
| return c |
| |
| escaped_string = "".join(map(escape_char, string)) |
| possible_quotes = quote_types |
| if "\n" in escaped_string: |
| possible_quotes = [q for q in possible_quotes if q in _MULTI_QUOTES] |
| possible_quotes = [q for q in possible_quotes if q not in escaped_string] |
| if not possible_quotes: |
| # If there aren't any possible_quotes, fallback to using repr |
| # on the original string. Try to use a quote from quote_types, |
| # e.g., so that we use triple quotes for docstrings. |
| string = repr(string) |
| quote = next((q for q in quote_types if string[0] in q), string[0]) |
| return string[1:-1], [quote] |
| if escaped_string: |
| # Sort so that we prefer '''"''' over """\"""" |
| possible_quotes.sort(key=lambda q: q[0] == escaped_string[-1]) |
| # If we're using triple quotes and we'd need to escape a final |
| # quote, escape it |
| if possible_quotes[0][0] == escaped_string[-1]: |
| assert len(possible_quotes[0]) == 3 |
| escaped_string = escaped_string[:-1] + "\\" + escaped_string[-1] |
| return escaped_string, possible_quotes |
| |
| def _write_str_avoiding_backslashes(self, string, *, quote_types=_ALL_QUOTES): |
| """Write string literal value with a best effort attempt to avoid backslashes.""" |
| string, quote_types = self._str_literal_helper(string, quote_types=quote_types) |
| quote_type = quote_types[0] |
| self.write(f"{quote_type}{string}{quote_type}") |
| |
| def visit_JoinedStr(self, node): |
| self.write("f") |
| if self._avoid_backslashes: |
| self._fstring_JoinedStr(node, self.buffer_writer) |
| self._write_str_avoiding_backslashes(self.buffer) |
| return |
| |
| # If we don't need to avoid backslashes globally (i.e., we only need |
| # to avoid them inside FormattedValues), it's cosmetically preferred |
| # to use escaped whitespace. That is, it's preferred to use backslashes |
| # for cases like: f"{x}\n". To accomplish this, we keep track of what |
| # in our buffer corresponds to FormattedValues and what corresponds to |
| # Constant parts of the f-string, and allow escapes accordingly. |
| buffer = [] |
| for value in node.values: |
| meth = getattr(self, "_fstring_" + type(value).__name__) |
| meth(value, self.buffer_writer) |
| buffer.append((self.buffer, isinstance(value, Constant))) |
| new_buffer = [] |
| quote_types = _ALL_QUOTES |
| for value, is_constant in buffer: |
| # Repeatedly narrow down the list of possible quote_types |
| value, quote_types = self._str_literal_helper( |
| value, quote_types=quote_types, |
| escape_special_whitespace=is_constant |
| ) |
| new_buffer.append(value) |
| value = "".join(new_buffer) |
| quote_type = quote_types[0] |
| self.write(f"{quote_type}{value}{quote_type}") |
| |
| def visit_FormattedValue(self, node): |
| self.write("f") |
| self._fstring_FormattedValue(node, self.buffer_writer) |
| self._write_str_avoiding_backslashes(self.buffer) |
| |
| def _fstring_JoinedStr(self, node, write): |
| for value in node.values: |
| meth = getattr(self, "_fstring_" + type(value).__name__) |
| meth(value, write) |
| |
| def _fstring_Constant(self, node, write): |
| if not isinstance(node.value, str): |
| raise ValueError("Constants inside JoinedStr should be a string.") |
| value = node.value.replace("{", "{{").replace("}", "}}") |
| write(value) |
| |
| def _fstring_FormattedValue(self, node, write): |
| write("{") |
| unparser = type(self)(_avoid_backslashes=True) |
| unparser.set_precedence(_Precedence.TEST.next(), node.value) |
| expr = unparser.visit(node.value) |
| if expr.startswith("{"): |
| write(" ") # Separate pair of opening brackets as "{ {" |
| if "\\" in expr: |
| raise ValueError("Unable to avoid backslash in f-string expression part") |
| write(expr) |
| if node.conversion != -1: |
| conversion = chr(node.conversion) |
| if conversion not in "sra": |
| raise ValueError("Unknown f-string conversion.") |
| write(f"!{conversion}") |
| if node.format_spec: |
| write(":") |
| meth = getattr(self, "_fstring_" + type(node.format_spec).__name__) |
| meth(node.format_spec, write) |
| write("}") |
| |
| def visit_Name(self, node): |
| self.write(node.id) |
| |
| def _write_docstring(self, node): |
| self.fill() |
| if node.kind == "u": |
| self.write("u") |
| self._write_str_avoiding_backslashes(node.value, quote_types=_MULTI_QUOTES) |
| |
| def _write_constant(self, value): |
| if isinstance(value, (float, complex)): |
| # Substitute overflowing decimal literal for AST infinities. |
| self.write(repr(value).replace("inf", _INFSTR)) |
| elif self._avoid_backslashes and isinstance(value, str): |
| self._write_str_avoiding_backslashes(value) |
| else: |
| self.write(repr(value)) |
| |
| def visit_Constant(self, node): |
| value = node.value |
| if isinstance(value, tuple): |
| with self.delimit("(", ")"): |
| self.items_view(self._write_constant, value) |
| elif value is ...: |
| self.write("...") |
| else: |
| if node.kind == "u": |
| self.write("u") |
| self._write_constant(node.value) |
| |
| def visit_List(self, node): |
| with self.delimit("[", "]"): |
| self.interleave(lambda: self.write(", "), self.traverse, node.elts) |
| |
| def visit_ListComp(self, node): |
| with self.delimit("[", "]"): |
| self.traverse(node.elt) |
| for gen in node.generators: |
| self.traverse(gen) |
| |
| def visit_GeneratorExp(self, node): |
| with self.delimit("(", ")"): |
| self.traverse(node.elt) |
| for gen in node.generators: |
| self.traverse(gen) |
| |
| def visit_SetComp(self, node): |
| with self.delimit("{", "}"): |
| self.traverse(node.elt) |
| for gen in node.generators: |
| self.traverse(gen) |
| |
| def visit_DictComp(self, node): |
| with self.delimit("{", "}"): |
| self.traverse(node.key) |
| self.write(": ") |
| self.traverse(node.value) |
| for gen in node.generators: |
| self.traverse(gen) |
| |
| def visit_comprehension(self, node): |
| if node.is_async: |
| self.write(" async for ") |
| else: |
| self.write(" for ") |
| self.set_precedence(_Precedence.TUPLE, node.target) |
| self.traverse(node.target) |
| self.write(" in ") |
| self.set_precedence(_Precedence.TEST.next(), node.iter, *node.ifs) |
| self.traverse(node.iter) |
| for if_clause in node.ifs: |
| self.write(" if ") |
| self.traverse(if_clause) |
| |
| def visit_IfExp(self, node): |
| with self.require_parens(_Precedence.TEST, node): |
| self.set_precedence(_Precedence.TEST.next(), node.body, node.test) |
| self.traverse(node.body) |
| self.write(" if ") |
| self.traverse(node.test) |
| self.write(" else ") |
| self.set_precedence(_Precedence.TEST, node.orelse) |
| self.traverse(node.orelse) |
| |
| def visit_Set(self, node): |
| if not node.elts: |
| raise ValueError("Set node should have at least one item") |
| with self.delimit("{", "}"): |
| self.interleave(lambda: self.write(", "), self.traverse, node.elts) |
| |
| def visit_Dict(self, node): |
| def write_key_value_pair(k, v): |
| self.traverse(k) |
| self.write(": ") |
| self.traverse(v) |
| |
| def write_item(item): |
| k, v = item |
| if k is None: |
| # for dictionary unpacking operator in dicts {**{'y': 2}} |
| # see PEP 448 for details |
| self.write("**") |
| self.set_precedence(_Precedence.EXPR, v) |
| self.traverse(v) |
| else: |
| write_key_value_pair(k, v) |
| |
| with self.delimit("{", "}"): |
| self.interleave( |
| lambda: self.write(", "), write_item, zip(node.keys, node.values) |
| ) |
| |
| def visit_Tuple(self, node): |
| with self.delimit("(", ")"): |
| self.items_view(self.traverse, node.elts) |
| |
| unop = {"Invert": "~", "Not": "not", "UAdd": "+", "USub": "-"} |
| unop_precedence = { |
| "not": _Precedence.NOT, |
| "~": _Precedence.FACTOR, |
| "+": _Precedence.FACTOR, |
| "-": _Precedence.FACTOR, |
| } |
| |
| def visit_UnaryOp(self, node): |
| operator = self.unop[node.op.__class__.__name__] |
| operator_precedence = self.unop_precedence[operator] |
| with self.require_parens(operator_precedence, node): |
| self.write(operator) |
| # factor prefixes (+, -, ~) shouldn't be seperated |
| # from the value they belong, (e.g: +1 instead of + 1) |
| if operator_precedence is not _Precedence.FACTOR: |
| self.write(" ") |
| self.set_precedence(operator_precedence, node.operand) |
| self.traverse(node.operand) |
| |
| binop = { |
| "Add": "+", |
| "Sub": "-", |
| "Mult": "*", |
| "MatMult": "@", |
| "Div": "/", |
| "Mod": "%", |
| "LShift": "<<", |
| "RShift": ">>", |
| "BitOr": "|", |
| "BitXor": "^", |
| "BitAnd": "&", |
| "FloorDiv": "//", |
| "Pow": "**", |
| } |
| |
| binop_precedence = { |
| "+": _Precedence.ARITH, |
| "-": _Precedence.ARITH, |
| "*": _Precedence.TERM, |
| "@": _Precedence.TERM, |
| "/": _Precedence.TERM, |
| "%": _Precedence.TERM, |
| "<<": _Precedence.SHIFT, |
| ">>": _Precedence.SHIFT, |
| "|": _Precedence.BOR, |
| "^": _Precedence.BXOR, |
| "&": _Precedence.BAND, |
| "//": _Precedence.TERM, |
| "**": _Precedence.POWER, |
| } |
| |
| binop_rassoc = frozenset(("**",)) |
| def visit_BinOp(self, node): |
| operator = self.binop[node.op.__class__.__name__] |
| operator_precedence = self.binop_precedence[operator] |
| with self.require_parens(operator_precedence, node): |
| if operator in self.binop_rassoc: |
| left_precedence = operator_precedence.next() |
| right_precedence = operator_precedence |
| else: |
| left_precedence = operator_precedence |
| right_precedence = operator_precedence.next() |
| |
| self.set_precedence(left_precedence, node.left) |
| self.traverse(node.left) |
| self.write(f" {operator} ") |
| self.set_precedence(right_precedence, node.right) |
| self.traverse(node.right) |
| |
| cmpops = { |
| "Eq": "==", |
| "NotEq": "!=", |
| "Lt": "<", |
| "LtE": "<=", |
| "Gt": ">", |
| "GtE": ">=", |
| "Is": "is", |
| "IsNot": "is not", |
| "In": "in", |
| "NotIn": "not in", |
| } |
| |
| def visit_Compare(self, node): |
| with self.require_parens(_Precedence.CMP, node): |
| self.set_precedence(_Precedence.CMP.next(), node.left, *node.comparators) |
| self.traverse(node.left) |
| for o, e in zip(node.ops, node.comparators): |
| self.write(" " + self.cmpops[o.__class__.__name__] + " ") |
| self.traverse(e) |
| |
| boolops = {"And": "and", "Or": "or"} |
| boolop_precedence = {"and": _Precedence.AND, "or": _Precedence.OR} |
| |
| def visit_BoolOp(self, node): |
| operator = self.boolops[node.op.__class__.__name__] |
| operator_precedence = self.boolop_precedence[operator] |
| |
| def increasing_level_traverse(node): |
| nonlocal operator_precedence |
| operator_precedence = operator_precedence.next() |
| self.set_precedence(operator_precedence, node) |
| self.traverse(node) |
| |
| with self.require_parens(operator_precedence, node): |
| s = f" {operator} " |
| self.interleave(lambda: self.write(s), increasing_level_traverse, node.values) |
| |
| def visit_Attribute(self, node): |
| self.set_precedence(_Precedence.ATOM, node.value) |
| self.traverse(node.value) |
| # Special case: 3.__abs__() is a syntax error, so if node.value |
| # is an integer literal then we need to either parenthesize |
| # it or add an extra space to get 3 .__abs__(). |
| if isinstance(node.value, Constant) and isinstance(node.value.value, int): |
| self.write(" ") |
| self.write(".") |
| self.write(node.attr) |
| |
| def visit_Call(self, node): |
| self.set_precedence(_Precedence.ATOM, node.func) |
| self.traverse(node.func) |
| with self.delimit("(", ")"): |
| comma = False |
| for e in node.args: |
| if comma: |
| self.write(", ") |
| else: |
| comma = True |
| self.traverse(e) |
| for e in node.keywords: |
| if comma: |
| self.write(", ") |
| else: |
| comma = True |
| self.traverse(e) |
| |
| def visit_Subscript(self, node): |
| def is_simple_tuple(slice_value): |
| # when unparsing a non-empty tuple, the parantheses can be safely |
| # omitted if there aren't any elements that explicitly requires |
| # parantheses (such as starred expressions). |
| return ( |
| isinstance(slice_value, Tuple) |
| and slice_value.elts |
| and not any(isinstance(elt, Starred) for elt in slice_value.elts) |
| ) |
| |
| self.set_precedence(_Precedence.ATOM, node.value) |
| self.traverse(node.value) |
| with self.delimit("[", "]"): |
| if is_simple_tuple(node.slice): |
| self.items_view(self.traverse, node.slice.elts) |
| else: |
| self.traverse(node.slice) |
| |
| def visit_Starred(self, node): |
| self.write("*") |
| self.set_precedence(_Precedence.EXPR, node.value) |
| self.traverse(node.value) |
| |
| def visit_Ellipsis(self, node): |
| self.write("...") |
| |
| def visit_Slice(self, node): |
| if node.lower: |
| self.traverse(node.lower) |
| self.write(":") |
| if node.upper: |
| self.traverse(node.upper) |
| if node.step: |
| self.write(":") |
| self.traverse(node.step) |
| |
| def visit_arg(self, node): |
| self.write(node.arg) |
| if node.annotation: |
| self.write(": ") |
| self.traverse(node.annotation) |
| |
| def visit_arguments(self, node): |
| first = True |
| # normal arguments |
| all_args = node.posonlyargs + node.args |
| defaults = [None] * (len(all_args) - len(node.defaults)) + node.defaults |
| for index, elements in enumerate(zip(all_args, defaults), 1): |
| a, d = elements |
| if first: |
| first = False |
| else: |
| self.write(", ") |
| self.traverse(a) |
| if d: |
| self.write("=") |
| self.traverse(d) |
| if index == len(node.posonlyargs): |
| self.write(", /") |
| |
| # varargs, or bare '*' if no varargs but keyword-only arguments present |
| if node.vararg or node.kwonlyargs: |
| if first: |
| first = False |
| else: |
| self.write(", ") |
| self.write("*") |
| if node.vararg: |
| self.write(node.vararg.arg) |
| if node.vararg.annotation: |
| self.write(": ") |
| self.traverse(node.vararg.annotation) |
| |
| # keyword-only arguments |
| if node.kwonlyargs: |
| for a, d in zip(node.kwonlyargs, node.kw_defaults): |
| self.write(", ") |
| self.traverse(a) |
| if d: |
| self.write("=") |
| self.traverse(d) |
| |
| # kwargs |
| if node.kwarg: |
| if first: |
| first = False |
| else: |
| self.write(", ") |
| self.write("**" + node.kwarg.arg) |
| if node.kwarg.annotation: |
| self.write(": ") |
| self.traverse(node.kwarg.annotation) |
| |
| def visit_keyword(self, node): |
| if node.arg is None: |
| self.write("**") |
| else: |
| self.write(node.arg) |
| self.write("=") |
| self.traverse(node.value) |
| |
| def visit_Lambda(self, node): |
| with self.require_parens(_Precedence.TEST, node): |
| self.write("lambda ") |
| self.traverse(node.args) |
| self.write(": ") |
| self.set_precedence(_Precedence.TEST, node.body) |
| self.traverse(node.body) |
| |
| def visit_alias(self, node): |
| self.write(node.name) |
| if node.asname: |
| self.write(" as " + node.asname) |
| |
| def visit_withitem(self, node): |
| self.traverse(node.context_expr) |
| if node.optional_vars: |
| self.write(" as ") |
| self.traverse(node.optional_vars) |
| |
| def unparse(ast_obj): |
| unparser = _Unparser() |
| return unparser.visit(ast_obj) |
| |
| |
| def main(): |
| import argparse |
| |
| parser = argparse.ArgumentParser(prog='python -m ast') |
| parser.add_argument('infile', type=argparse.FileType(mode='rb'), nargs='?', |
| default='-', |
| help='the file to parse; defaults to stdin') |
| parser.add_argument('-m', '--mode', default='exec', |
| choices=('exec', 'single', 'eval', 'func_type'), |
| help='specify what kind of code must be parsed') |
| parser.add_argument('--no-type-comments', default=True, action='store_false', |
| help="don't add information about type comments") |
| parser.add_argument('-a', '--include-attributes', action='store_true', |
| help='include attributes such as line numbers and ' |
| 'column offsets') |
| parser.add_argument('-i', '--indent', type=int, default=3, |
| help='indentation of nodes (number of spaces)') |
| args = parser.parse_args() |
| |
| with args.infile as infile: |
| source = infile.read() |
| tree = parse(source, args.infile.name, args.mode, type_comments=args.no_type_comments) |
| print(dump(tree, include_attributes=args.include_attributes, indent=args.indent)) |
| |
| if __name__ == '__main__': |
| main() |
