from abc import abstractmethod, abstractproperty
from typing import List, Optional, Tuple, Union
from parso.utils import split_lines
[docs]
def search_ancestor(node: 'NodeOrLeaf', *node_types: str) -> 'Optional[BaseNode]':
"""
Recursively looks at the parents of a node and returns the first found node
that matches ``node_types``. Returns ``None`` if no matching node is found.
This function is deprecated, use :meth:`NodeOrLeaf.search_ancestor` instead.
:param node: The ancestors of this node will be checked.
:param node_types: type names that are searched for.
"""
n = node.parent
while n is not None:
if n.type in node_types:
return n
n = n.parent
return None
[docs]
class NodeOrLeaf:
"""
The base class for nodes and leaves.
"""
__slots__ = ('parent',)
type: str
'''
The type is a string that typically matches the types of the grammar file.
'''
parent: 'Optional[BaseNode]'
'''
The parent :class:`BaseNode` of this node or leaf.
None if this is the root node.
'''
[docs]
def get_root_node(self):
"""
Returns the root node of a parser tree. The returned node doesn't have
a parent node like all the other nodes/leaves.
"""
scope = self
while scope.parent is not None:
scope = scope.parent
return scope
[docs]
def get_next_sibling(self):
"""
Returns the node immediately following this node in this parent's
children list. If this node does not have a next sibling, it is None
"""
parent = self.parent
if parent is None:
return None
# Can't use index(); we need to test by identity
for i, child in enumerate(parent.children):
if child is self:
try:
return self.parent.children[i + 1]
except IndexError:
return None
[docs]
def get_previous_sibling(self):
"""
Returns the node immediately preceding this node in this parent's
children list. If this node does not have a previous sibling, it is
None.
"""
parent = self.parent
if parent is None:
return None
# Can't use index(); we need to test by identity
for i, child in enumerate(parent.children):
if child is self:
if i == 0:
return None
return self.parent.children[i - 1]
[docs]
def get_previous_leaf(self):
"""
Returns the previous leaf in the parser tree.
Returns `None` if this is the first element in the parser tree.
"""
if self.parent is None:
return None
node = self
while True:
c = node.parent.children
i = c.index(node)
if i == 0:
node = node.parent
if node.parent is None:
return None
else:
node = c[i - 1]
break
while True:
try:
node = node.children[-1]
except AttributeError: # A Leaf doesn't have children.
return node
[docs]
def get_next_leaf(self):
"""
Returns the next leaf in the parser tree.
Returns None if this is the last element in the parser tree.
"""
if self.parent is None:
return None
node = self
while True:
c = node.parent.children
i = c.index(node)
if i == len(c) - 1:
node = node.parent
if node.parent is None:
return None
else:
node = c[i + 1]
break
while True:
try:
node = node.children[0]
except AttributeError: # A Leaf doesn't have children.
return node
@abstractproperty
def start_pos(self) -> Tuple[int, int]:
"""
Returns the starting position of the prefix as a tuple, e.g. `(3, 4)`.
:return tuple of int: (line, column)
"""
@abstractproperty
def end_pos(self) -> Tuple[int, int]:
"""
Returns the end position of the prefix as a tuple, e.g. `(3, 4)`.
:return tuple of int: (line, column)
"""
[docs]
@abstractmethod
def get_start_pos_of_prefix(self):
"""
Returns the start_pos of the prefix. This means basically it returns
the end_pos of the last prefix. The `get_start_pos_of_prefix()` of the
prefix `+` in `2 + 1` would be `(1, 1)`, while the start_pos is
`(1, 2)`.
:return tuple of int: (line, column)
"""
[docs]
@abstractmethod
def get_first_leaf(self):
"""
Returns the first leaf of a node or itself if this is a leaf.
"""
[docs]
@abstractmethod
def get_last_leaf(self):
"""
Returns the last leaf of a node or itself if this is a leaf.
"""
[docs]
@abstractmethod
def get_code(self, include_prefix=True):
"""
Returns the code that was the input for the parser for this node.
:param include_prefix: Removes the prefix (whitespace and comments) of
e.g. a statement.
"""
[docs]
def search_ancestor(self, *node_types: str) -> 'Optional[BaseNode]':
"""
Recursively looks at the parents of this node or leaf and returns the
first found node that matches ``node_types``. Returns ``None`` if no
matching node is found.
:param node_types: type names that are searched for.
"""
node = self.parent
while node is not None:
if node.type in node_types:
return node
node = node.parent
return None
[docs]
def dump(self, *, indent: Optional[Union[int, str]] = 4) -> str:
"""
Returns a formatted dump of the parser tree rooted at this node or leaf. This is
mainly useful for debugging purposes.
The ``indent`` parameter is interpreted in a similar way as :py:func:`ast.dump`.
If ``indent`` is a non-negative integer or string, then the tree will be
pretty-printed with that indent level. An indent level of 0, negative, or ``""``
will only insert newlines. ``None`` selects the single line representation.
Using a positive integer indent indents that many spaces per level. If
``indent`` is a string (such as ``"\\t"``), that string is used to indent each
level.
:param indent: Indentation style as described above. The default indentation is
4 spaces, which yields a pretty-printed dump.
>>> import parso
>>> print(parso.parse("lambda x, y: x + y").dump())
Module([
Lambda([
Keyword('lambda', (1, 0)),
Param([
Name('x', (1, 7), prefix=' '),
Operator(',', (1, 8)),
]),
Param([
Name('y', (1, 10), prefix=' '),
]),
Operator(':', (1, 11)),
PythonNode('arith_expr', [
Name('x', (1, 13), prefix=' '),
Operator('+', (1, 15), prefix=' '),
Name('y', (1, 17), prefix=' '),
]),
]),
EndMarker('', (1, 18)),
])
"""
if indent is None:
newline = False
indent_string = ''
elif isinstance(indent, int):
newline = True
indent_string = ' ' * indent
elif isinstance(indent, str):
newline = True
indent_string = indent
else:
raise TypeError(f"expect 'indent' to be int, str or None, got {indent!r}")
def _format_dump(node: NodeOrLeaf, indent: str = '', top_level: bool = True) -> str:
result = ''
node_type = type(node).__name__
if isinstance(node, Leaf):
result += f'{indent}{node_type}('
if isinstance(node, ErrorLeaf):
result += f'{node.token_type!r}, '
elif isinstance(node, TypedLeaf):
result += f'{node.type!r}, '
result += f'{node.value!r}, {node.start_pos!r}'
if node.prefix:
result += f', prefix={node.prefix!r}'
result += ')'
elif isinstance(node, BaseNode):
result += f'{indent}{node_type}('
if isinstance(node, Node):
result += f'{node.type!r}, '
result += '['
if newline:
result += '\n'
for child in node.children:
result += _format_dump(child, indent=indent + indent_string, top_level=False)
result += f'{indent}])'
else: # pragma: no cover
# We shouldn't ever reach here, unless:
# - `NodeOrLeaf` is incorrectly subclassed else where
# - or a node's children list contains invalid nodes or leafs
# Both are unexpected internal errors.
raise TypeError(f'unsupported node encountered: {node!r}')
if not top_level:
if newline:
result += ',\n'
else:
result += ', '
return result
return _format_dump(self)
[docs]
class Leaf(NodeOrLeaf):
'''
Leafs are basically tokens with a better API. Leafs exactly know where they
were defined and what text preceeds them.
'''
__slots__ = ('value', 'line', 'column', 'prefix')
prefix: str
def __init__(self, value: str, start_pos: Tuple[int, int], prefix: str = '') -> None:
self.value = value
'''
:py:func:`str` The value of the current token.
'''
self.start_pos = start_pos
self.prefix = prefix
'''
:py:func:`str` Typically a mixture of whitespace and comments. Stuff
that is syntactically irrelevant for the syntax tree.
'''
self.parent: Optional[BaseNode] = None
'''
The parent :class:`BaseNode` of this leaf.
'''
@property
def start_pos(self) -> Tuple[int, int]:
return self.line, self.column
@start_pos.setter
def start_pos(self, value: Tuple[int, int]) -> None:
self.line = value[0]
self.column = value[1]
[docs]
def get_start_pos_of_prefix(self):
previous_leaf = self.get_previous_leaf()
if previous_leaf is None:
lines = split_lines(self.prefix)
# + 1 is needed because split_lines always returns at least [''].
return self.line - len(lines) + 1, 0 # It's the first leaf.
return previous_leaf.end_pos
[docs]
def get_first_leaf(self):
return self
[docs]
def get_last_leaf(self):
return self
[docs]
def get_code(self, include_prefix=True):
if include_prefix:
return self.prefix + self.value
else:
return self.value
@property
def end_pos(self) -> Tuple[int, int]:
lines = split_lines(self.value)
end_pos_line = self.line + len(lines) - 1
# Check for multiline token
if self.line == end_pos_line:
end_pos_column = self.column + len(lines[-1])
else:
end_pos_column = len(lines[-1])
return end_pos_line, end_pos_column
def __repr__(self):
value = self.value
if not value:
value = self.type
return "<%s: %s>" % (type(self).__name__, value)
class TypedLeaf(Leaf):
__slots__ = ('type',)
def __init__(self, type, value, start_pos, prefix=''):
super().__init__(value, start_pos, prefix)
self.type = type
[docs]
class BaseNode(NodeOrLeaf):
"""
The super class for all nodes.
A node has children, a type and possibly a parent node.
"""
__slots__ = ('children',)
def __init__(self, children: List[NodeOrLeaf]) -> None:
self.children = children
"""
A list of :class:`NodeOrLeaf` child nodes.
"""
self.parent: Optional[BaseNode] = None
'''
The parent :class:`BaseNode` of this node.
None if this is the root node.
'''
for child in children:
child.parent = self
@property
def start_pos(self) -> Tuple[int, int]:
return self.children[0].start_pos
[docs]
def get_start_pos_of_prefix(self):
return self.children[0].get_start_pos_of_prefix()
@property
def end_pos(self) -> Tuple[int, int]:
return self.children[-1].end_pos
def _get_code_for_children(self, children, include_prefix):
if include_prefix:
return "".join(c.get_code() for c in children)
else:
first = children[0].get_code(include_prefix=False)
return first + "".join(c.get_code() for c in children[1:])
[docs]
def get_code(self, include_prefix=True):
return self._get_code_for_children(self.children, include_prefix)
[docs]
def get_leaf_for_position(self, position, include_prefixes=False):
"""
Get the :py:class:`parso.tree.Leaf` at ``position``
:param tuple position: A position tuple, row, column. Rows start from 1
:param bool include_prefixes: If ``False``, ``None`` will be returned if ``position`` falls
on whitespace or comments before a leaf
:return: :py:class:`parso.tree.Leaf` at ``position``, or ``None``
"""
def binary_search(lower, upper):
if lower == upper:
element = self.children[lower]
if not include_prefixes and position < element.start_pos:
# We're on a prefix.
return None
# In case we have prefixes, a leaf always matches
try:
return element.get_leaf_for_position(position, include_prefixes)
except AttributeError:
return element
index = int((lower + upper) / 2)
element = self.children[index]
if position <= element.end_pos:
return binary_search(lower, index)
else:
return binary_search(index + 1, upper)
if not ((1, 0) <= position <= self.children[-1].end_pos):
raise ValueError('Please provide a position that exists within this node.')
return binary_search(0, len(self.children) - 1)
[docs]
def get_first_leaf(self):
return self.children[0].get_first_leaf()
[docs]
def get_last_leaf(self):
return self.children[-1].get_last_leaf()
def __repr__(self):
code = self.get_code().replace('\n', ' ').replace('\r', ' ').strip()
return "<%s: %s@%s,%s>" % \
(type(self).__name__, code, self.start_pos[0], self.start_pos[1])
class Node(BaseNode):
"""Concrete implementation for interior nodes."""
__slots__ = ('type',)
def __init__(self, type, children):
super().__init__(children)
self.type = type
def __repr__(self):
return "%s(%s, %r)" % (self.__class__.__name__, self.type, self.children)
class ErrorNode(BaseNode):
"""
A node that contains valid nodes/leaves that we're follow by a token that
was invalid. This basically means that the leaf after this node is where
Python would mark a syntax error.
"""
__slots__ = ()
type = 'error_node'
class ErrorLeaf(Leaf):
"""
A leaf that is either completely invalid in a language (like `$` in Python)
or is invalid at that position. Like the star in `1 +* 1`.
"""
__slots__ = ('token_type',)
type = 'error_leaf'
def __init__(self, token_type, value, start_pos, prefix=''):
super().__init__(value, start_pos, prefix)
self.token_type = token_type
def __repr__(self):
return "<%s: %s:%s, %s>" % \
(type(self).__name__, self.token_type, repr(self.value), self.start_pos)
