mirror of
https://github.com/python/cpython.git
synced 2024-12-18 06:14:00 +08:00
8baef8ae36
It was never really safe and this claim conflicts directly with the big warning in the docs about it being able to crash the interpreter.
1732 lines
59 KiB
Python
1732 lines
59 KiB
Python
"""
|
|
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, _simple_enum
|
|
|
|
|
|
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 feature_version is None:
|
|
feature_version = -1
|
|
elif isinstance(feature_version, tuple):
|
|
major, minor = feature_version # Should be a 2-tuple.
|
|
if major != 3:
|
|
raise ValueError(f"Unsupported major version: {major}")
|
|
feature_version = minor
|
|
# 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):
|
|
"""
|
|
Evaluate an expression node or a string containing only 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.
|
|
|
|
Caution: A complex expression can overflow the C stack and cause a crash.
|
|
"""
|
|
if isinstance(node_or_string, str):
|
|
node_or_string = parse(node_or_string.lstrip(" \t"), mode='eval')
|
|
if isinstance(node_or_string, Expression):
|
|
node_or_string = node_or_string.body
|
|
def _raise_malformed_node(node):
|
|
msg = "malformed node or string"
|
|
if lno := getattr(node, 'lineno', None):
|
|
msg += f' on line {lno}'
|
|
raise ValueError(msg + f': {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)
|
|
|
|
@_simple_enum(IntEnum)
|
|
class _Precedence:
|
|
"""Precedence table that originated from python grammar."""
|
|
|
|
NAMED_EXPR = auto() # <target> := <expr1>
|
|
TUPLE = auto() # <expr1>, <expr2>
|
|
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._precedences = {}
|
|
self._type_ignores = {}
|
|
self._indent = 0
|
|
self._avoid_backslashes = _avoid_backslashes
|
|
self._in_try_star = False
|
|
|
|
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):
|
|
"""Add new source parts"""
|
|
self._source.extend(text)
|
|
|
|
@contextmanager
|
|
def buffered(self, buffer = None):
|
|
if buffer is None:
|
|
buffer = []
|
|
|
|
original_source = self._source
|
|
self._source = buffer
|
|
yield buffer
|
|
self._source = original_source
|
|
|
|
@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)
|
|
|
|
# Note: as visit() resets the output text, do NOT rely on
|
|
# NodeVisitor.generic_visit to handle any nodes (as it calls back in to
|
|
# the subclass visit() method, which resets self._source to an empty list)
|
|
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.NAMED_EXPR, 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 or 0))
|
|
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.set_precedence(_Precedence.TUPLE, target)
|
|
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 do_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_Try(self, node):
|
|
prev_in_try_star = self._in_try_star
|
|
try:
|
|
self._in_try_star = False
|
|
self.do_visit_try(node)
|
|
finally:
|
|
self._in_try_star = prev_in_try_star
|
|
|
|
def visit_TryStar(self, node):
|
|
prev_in_try_star = self._in_try_star
|
|
try:
|
|
self._in_try_star = True
|
|
self.do_visit_try(node)
|
|
finally:
|
|
self._in_try_star = prev_in_try_star
|
|
|
|
def visit_ExceptHandler(self, node):
|
|
self.fill("except*" if self._in_try_star else "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.set_precedence(_Precedence.TUPLE, node.target)
|
|
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:
|
|
with self.buffered() as buffer:
|
|
self._write_fstring_inner(node)
|
|
return self._write_str_avoiding_backslashes("".join(buffer))
|
|
|
|
# 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.
|
|
fstring_parts = []
|
|
for value in node.values:
|
|
with self.buffered() as buffer:
|
|
self._write_fstring_inner(value)
|
|
fstring_parts.append(
|
|
("".join(buffer), isinstance(value, Constant))
|
|
)
|
|
|
|
new_fstring_parts = []
|
|
quote_types = list(_ALL_QUOTES)
|
|
for value, is_constant in fstring_parts:
|
|
value, quote_types = self._str_literal_helper(
|
|
value,
|
|
quote_types=quote_types,
|
|
escape_special_whitespace=is_constant,
|
|
)
|
|
new_fstring_parts.append(value)
|
|
|
|
value = "".join(new_fstring_parts)
|
|
quote_type = quote_types[0]
|
|
self.write(f"{quote_type}{value}{quote_type}")
|
|
|
|
def _write_fstring_inner(self, node):
|
|
if isinstance(node, JoinedStr):
|
|
# for both the f-string itself, and format_spec
|
|
for value in node.values:
|
|
self._write_fstring_inner(value)
|
|
elif isinstance(node, Constant) and isinstance(node.value, str):
|
|
value = node.value.replace("{", "{{").replace("}", "}}")
|
|
self.write(value)
|
|
elif isinstance(node, FormattedValue):
|
|
self.visit_FormattedValue(node)
|
|
else:
|
|
raise ValueError(f"Unexpected node inside JoinedStr, {node!r}")
|
|
|
|
def visit_FormattedValue(self, node):
|
|
def unparse_inner(inner):
|
|
unparser = type(self)(_avoid_backslashes=True)
|
|
unparser.set_precedence(_Precedence.TEST.next(), inner)
|
|
return unparser.visit(inner)
|
|
|
|
with self.delimit("{", "}"):
|
|
expr = unparse_inner(node.value)
|
|
if "\\" in expr:
|
|
raise ValueError(
|
|
"Unable to avoid backslash in f-string expression part"
|
|
)
|
|
if expr.startswith("{"):
|
|
# Separate pair of opening brackets as "{ {"
|
|
self.write(" ")
|
|
self.write(expr)
|
|
if node.conversion != -1:
|
|
self.write(f"!{chr(node.conversion)}")
|
|
if node.format_spec:
|
|
self.write(":")
|
|
self._write_fstring_inner(node.format_spec)
|
|
|
|
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,
|
|
# and inf - inf for NaNs.
|
|
self.write(
|
|
repr(value)
|
|
.replace("inf", _INFSTR)
|
|
.replace("nan", f"({_INFSTR}-{_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 node.elts:
|
|
with self.delimit("{", "}"):
|
|
self.interleave(lambda: self.write(", "), self.traverse, node.elts)
|
|
else:
|
|
# `{}` would be interpreted as a dictionary literal, and
|
|
# `set` might be shadowed. Thus:
|
|
self.write('{*()}')
|
|
|
|
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_if(
|
|
"(",
|
|
")",
|
|
len(node.elts) == 0 or self.get_precedence(node) > _Precedence.TUPLE
|
|
):
|
|
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 separated
|
|
# 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_non_empty_tuple(slice_value):
|
|
return (
|
|
isinstance(slice_value, Tuple)
|
|
and slice_value.elts
|
|
)
|
|
|
|
self.set_precedence(_Precedence.ATOM, node.value)
|
|
self.traverse(node.value)
|
|
with self.delimit("[", "]"):
|
|
if is_non_empty_tuple(node.slice):
|
|
# parentheses can be omitted if the tuple isn't empty
|
|
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_Match(self, node):
|
|
self.fill("match ")
|
|
self.traverse(node.subject)
|
|
with self.block():
|
|
for case in node.cases:
|
|
self.traverse(case)
|
|
|
|
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")
|
|
with self.buffered() as buffer:
|
|
self.traverse(node.args)
|
|
if buffer:
|
|
self.write(" ", *buffer)
|
|
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 visit_match_case(self, node):
|
|
self.fill("case ")
|
|
self.traverse(node.pattern)
|
|
if node.guard:
|
|
self.write(" if ")
|
|
self.traverse(node.guard)
|
|
with self.block():
|
|
self.traverse(node.body)
|
|
|
|
def visit_MatchValue(self, node):
|
|
self.traverse(node.value)
|
|
|
|
def visit_MatchSingleton(self, node):
|
|
self._write_constant(node.value)
|
|
|
|
def visit_MatchSequence(self, node):
|
|
with self.delimit("[", "]"):
|
|
self.interleave(
|
|
lambda: self.write(", "), self.traverse, node.patterns
|
|
)
|
|
|
|
def visit_MatchStar(self, node):
|
|
name = node.name
|
|
if name is None:
|
|
name = "_"
|
|
self.write(f"*{name}")
|
|
|
|
def visit_MatchMapping(self, node):
|
|
def write_key_pattern_pair(pair):
|
|
k, p = pair
|
|
self.traverse(k)
|
|
self.write(": ")
|
|
self.traverse(p)
|
|
|
|
with self.delimit("{", "}"):
|
|
keys = node.keys
|
|
self.interleave(
|
|
lambda: self.write(", "),
|
|
write_key_pattern_pair,
|
|
zip(keys, node.patterns, strict=True),
|
|
)
|
|
rest = node.rest
|
|
if rest is not None:
|
|
if keys:
|
|
self.write(", ")
|
|
self.write(f"**{rest}")
|
|
|
|
def visit_MatchClass(self, node):
|
|
self.set_precedence(_Precedence.ATOM, node.cls)
|
|
self.traverse(node.cls)
|
|
with self.delimit("(", ")"):
|
|
patterns = node.patterns
|
|
self.interleave(
|
|
lambda: self.write(", "), self.traverse, patterns
|
|
)
|
|
attrs = node.kwd_attrs
|
|
if attrs:
|
|
def write_attr_pattern(pair):
|
|
attr, pattern = pair
|
|
self.write(f"{attr}=")
|
|
self.traverse(pattern)
|
|
|
|
if patterns:
|
|
self.write(", ")
|
|
self.interleave(
|
|
lambda: self.write(", "),
|
|
write_attr_pattern,
|
|
zip(attrs, node.kwd_patterns, strict=True),
|
|
)
|
|
|
|
def visit_MatchAs(self, node):
|
|
name = node.name
|
|
pattern = node.pattern
|
|
if name is None:
|
|
self.write("_")
|
|
elif pattern is None:
|
|
self.write(node.name)
|
|
else:
|
|
with self.require_parens(_Precedence.TEST, node):
|
|
self.set_precedence(_Precedence.BOR, node.pattern)
|
|
self.traverse(node.pattern)
|
|
self.write(f" as {node.name}")
|
|
|
|
def visit_MatchOr(self, node):
|
|
with self.require_parens(_Precedence.BOR, node):
|
|
self.set_precedence(_Precedence.BOR.next(), *node.patterns)
|
|
self.interleave(lambda: self.write(" | "), self.traverse, node.patterns)
|
|
|
|
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()
|