mirror of https://github.com/python/cpython
1732 lines
59 KiB
Python
1732 lines
59 KiB
Python
"""
|
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ast
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~~~
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The `ast` module helps Python applications to process trees of the Python
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abstract syntax grammar. The abstract syntax itself might change with
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each Python release; this module helps to find out programmatically what
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the current grammar looks like and allows modifications of it.
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An abstract syntax tree can be generated by passing `ast.PyCF_ONLY_AST` as
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a flag to the `compile()` builtin function or by using the `parse()`
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function from this module. The result will be a tree of objects whose
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classes all inherit from `ast.AST`.
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A modified abstract syntax tree can be compiled into a Python code object
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using the built-in `compile()` function.
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Additionally various helper functions are provided that make working with
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the trees simpler. The main intention of the helper functions and this
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module in general is to provide an easy to use interface for libraries
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that work tightly with the python syntax (template engines for example).
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:copyright: Copyright 2008 by Armin Ronacher.
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:license: Python License.
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"""
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import sys
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from _ast import *
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from contextlib import contextmanager, nullcontext
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from enum import IntEnum, auto, _simple_enum
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def parse(source, filename='<unknown>', mode='exec', *,
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type_comments=False, feature_version=None):
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"""
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Parse the source into an AST node.
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Equivalent to compile(source, filename, mode, PyCF_ONLY_AST).
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Pass type_comments=True to get back type comments where the syntax allows.
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"""
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flags = PyCF_ONLY_AST
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if type_comments:
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flags |= PyCF_TYPE_COMMENTS
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if feature_version is None:
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feature_version = -1
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elif isinstance(feature_version, tuple):
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major, minor = feature_version # Should be a 2-tuple.
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if major != 3:
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raise ValueError(f"Unsupported major version: {major}")
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feature_version = minor
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# Else it should be an int giving the minor version for 3.x.
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return compile(source, filename, mode, flags,
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_feature_version=feature_version)
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def literal_eval(node_or_string):
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"""
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Evaluate an expression node or a string containing only a Python
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expression. The string or node provided may only consist of the following
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Python literal structures: strings, bytes, numbers, tuples, lists, dicts,
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sets, booleans, and None.
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Caution: A complex expression can overflow the C stack and cause a crash.
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"""
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if isinstance(node_or_string, str):
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node_or_string = parse(node_or_string.lstrip(" \t"), mode='eval')
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if isinstance(node_or_string, Expression):
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node_or_string = node_or_string.body
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def _raise_malformed_node(node):
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msg = "malformed node or string"
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if lno := getattr(node, 'lineno', None):
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msg += f' on line {lno}'
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raise ValueError(msg + f': {node!r}')
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def _convert_num(node):
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if not isinstance(node, Constant) or type(node.value) not in (int, float, complex):
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_raise_malformed_node(node)
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return node.value
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def _convert_signed_num(node):
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if isinstance(node, UnaryOp) and isinstance(node.op, (UAdd, USub)):
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operand = _convert_num(node.operand)
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if isinstance(node.op, UAdd):
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return + operand
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else:
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return - operand
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return _convert_num(node)
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def _convert(node):
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if isinstance(node, Constant):
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return node.value
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elif isinstance(node, Tuple):
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return tuple(map(_convert, node.elts))
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elif isinstance(node, List):
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return list(map(_convert, node.elts))
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elif isinstance(node, Set):
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return set(map(_convert, node.elts))
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elif (isinstance(node, Call) and isinstance(node.func, Name) and
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node.func.id == 'set' and node.args == node.keywords == []):
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return set()
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elif isinstance(node, Dict):
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if len(node.keys) != len(node.values):
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_raise_malformed_node(node)
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return dict(zip(map(_convert, node.keys),
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map(_convert, node.values)))
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elif isinstance(node, BinOp) and isinstance(node.op, (Add, Sub)):
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left = _convert_signed_num(node.left)
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right = _convert_num(node.right)
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if isinstance(left, (int, float)) and isinstance(right, complex):
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if isinstance(node.op, Add):
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return left + right
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else:
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return left - right
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return _convert_signed_num(node)
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return _convert(node_or_string)
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def dump(node, annotate_fields=True, include_attributes=False, *, indent=None):
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"""
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Return a formatted dump of the tree in node. This is mainly useful for
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debugging purposes. If annotate_fields is true (by default),
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the returned string will show the names and the values for fields.
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If annotate_fields is false, the result string will be more compact by
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omitting unambiguous field names. Attributes such as line
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numbers and column offsets are not dumped by default. If this is wanted,
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include_attributes can be set to true. If indent is a non-negative
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integer or string, then the tree will be pretty-printed with that indent
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level. None (the default) selects the single line representation.
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"""
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def _format(node, level=0):
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if indent is not None:
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level += 1
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prefix = '\n' + indent * level
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sep = ',\n' + indent * level
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else:
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prefix = ''
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sep = ', '
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if isinstance(node, AST):
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cls = type(node)
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args = []
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allsimple = True
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keywords = annotate_fields
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for name in node._fields:
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try:
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value = getattr(node, name)
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except AttributeError:
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keywords = True
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continue
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if value is None and getattr(cls, name, ...) is None:
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keywords = True
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continue
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value, simple = _format(value, level)
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allsimple = allsimple and simple
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if keywords:
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args.append('%s=%s' % (name, value))
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else:
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args.append(value)
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if include_attributes and node._attributes:
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for name in node._attributes:
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try:
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value = getattr(node, name)
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except AttributeError:
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continue
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if value is None and getattr(cls, name, ...) is None:
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continue
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value, simple = _format(value, level)
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allsimple = allsimple and simple
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args.append('%s=%s' % (name, value))
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if allsimple and len(args) <= 3:
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return '%s(%s)' % (node.__class__.__name__, ', '.join(args)), not args
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return '%s(%s%s)' % (node.__class__.__name__, prefix, sep.join(args)), False
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elif isinstance(node, list):
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if not node:
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return '[]', True
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return '[%s%s]' % (prefix, sep.join(_format(x, level)[0] for x in node)), False
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return repr(node), True
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if not isinstance(node, AST):
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raise TypeError('expected AST, got %r' % node.__class__.__name__)
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if indent is not None and not isinstance(indent, str):
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indent = ' ' * indent
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return _format(node)[0]
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def copy_location(new_node, old_node):
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"""
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Copy source location (`lineno`, `col_offset`, `end_lineno`, and `end_col_offset`
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attributes) from *old_node* to *new_node* if possible, and return *new_node*.
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"""
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for attr in 'lineno', 'col_offset', 'end_lineno', 'end_col_offset':
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if attr in old_node._attributes and attr in new_node._attributes:
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value = getattr(old_node, attr, None)
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# end_lineno and end_col_offset are optional attributes, and they
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# should be copied whether the value is None or not.
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if value is not None or (
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hasattr(old_node, attr) and attr.startswith("end_")
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):
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setattr(new_node, attr, value)
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return new_node
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def fix_missing_locations(node):
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"""
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When you compile a node tree with compile(), the compiler expects lineno and
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col_offset attributes for every node that supports them. This is rather
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tedious to fill in for generated nodes, so this helper adds these attributes
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recursively where not already set, by setting them to the values of the
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parent node. It works recursively starting at *node*.
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"""
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def _fix(node, lineno, col_offset, end_lineno, end_col_offset):
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if 'lineno' in node._attributes:
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if not hasattr(node, 'lineno'):
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node.lineno = lineno
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else:
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lineno = node.lineno
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if 'end_lineno' in node._attributes:
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if getattr(node, 'end_lineno', None) is None:
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node.end_lineno = end_lineno
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else:
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end_lineno = node.end_lineno
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if 'col_offset' in node._attributes:
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if not hasattr(node, 'col_offset'):
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node.col_offset = col_offset
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else:
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col_offset = node.col_offset
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if 'end_col_offset' in node._attributes:
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if getattr(node, 'end_col_offset', None) is None:
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node.end_col_offset = end_col_offset
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else:
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end_col_offset = node.end_col_offset
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for child in iter_child_nodes(node):
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_fix(child, lineno, col_offset, end_lineno, end_col_offset)
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_fix(node, 1, 0, 1, 0)
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return node
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def increment_lineno(node, n=1):
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"""
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Increment the line number and end line number of each node in the tree
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starting at *node* by *n*. This is useful to "move code" to a different
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location in a file.
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"""
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for child in walk(node):
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if 'lineno' in child._attributes:
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child.lineno = getattr(child, 'lineno', 0) + n
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if (
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"end_lineno" in child._attributes
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and (end_lineno := getattr(child, "end_lineno", 0)) is not None
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):
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child.end_lineno = end_lineno + n
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return node
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def iter_fields(node):
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"""
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Yield a tuple of ``(fieldname, value)`` for each field in ``node._fields``
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that is present on *node*.
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"""
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for field in node._fields:
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try:
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yield field, getattr(node, field)
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except AttributeError:
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pass
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def iter_child_nodes(node):
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"""
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Yield all direct child nodes of *node*, that is, all fields that are nodes
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and all items of fields that are lists of nodes.
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"""
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for name, field in iter_fields(node):
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if isinstance(field, AST):
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yield field
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elif isinstance(field, list):
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for item in field:
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if isinstance(item, AST):
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yield item
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|
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def get_docstring(node, clean=True):
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"""
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Return the docstring for the given node or None if no docstring can
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be found. If the node provided does not have docstrings a TypeError
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will be raised.
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If *clean* is `True`, all tabs are expanded to spaces and any whitespace
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that can be uniformly removed from the second line onwards is removed.
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"""
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if not isinstance(node, (AsyncFunctionDef, FunctionDef, ClassDef, Module)):
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raise TypeError("%r can't have docstrings" % node.__class__.__name__)
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if not(node.body and isinstance(node.body[0], Expr)):
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return None
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node = node.body[0].value
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if isinstance(node, Str):
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text = node.s
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elif isinstance(node, Constant) and isinstance(node.value, str):
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text = node.value
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else:
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return None
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if clean:
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import inspect
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text = inspect.cleandoc(text)
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return text
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|
|
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|
def _splitlines_no_ff(source):
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"""Split a string into lines ignoring form feed and other chars.
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|
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|
This mimics how the Python parser splits source code.
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|
"""
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idx = 0
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lines = []
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next_line = ''
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while idx < len(source):
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c = source[idx]
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next_line += c
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idx += 1
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# Keep \r\n together
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if c == '\r' and idx < len(source) and source[idx] == '\n':
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next_line += '\n'
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idx += 1
|
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if c in '\r\n':
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lines.append(next_line)
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next_line = ''
|
|
|
|
if next_line:
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lines.append(next_line)
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return lines
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|
|
|
|
def _pad_whitespace(source):
|
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r"""Replace all chars except '\f\t' in a line with spaces."""
|
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result = ''
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for c in source:
|
|
if c in '\f\t':
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result += c
|
|
else:
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|
result += ' '
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|
return result
|
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|
|
|
|
def get_source_segment(source, node, *, padded=False):
|
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"""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.
|
|
"""
|
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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 = ''
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|
|
|
first = padding + lines[lineno].encode()[col_offset:].decode()
|
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last = lines[end_lineno].encode()[:end_col_offset].decode()
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lines = lines[lineno+1:end_lineno]
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|
|
lines.insert(0, first)
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lines.append(last)
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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()
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|
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()
|