def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
if is_docstring(leaf) and "\\\n" not in leaf.value:
# We're ignoring docstrings with backslash newline escapes because changing
# indentation of those changes the AST representation of the code.
docstring = normalize_string_prefix(leaf.value)
prefix = get_string_prefix(docstring)
docstring = docstring[len(prefix) :] # Remove the prefix
quote_char = docstring[0]
# A natural way to remove the outer quotes is to do:
# docstring = docstring.strip(quote_char)
# but that breaks on """""x""" (which is '""x').
# So we actually need to remove the first character and the next two
# characters but only if they are the same as the first.
quote_len = 1 if docstring[1] != quote_char else 3
docstring = docstring[quote_len:-quote_len]
docstring_started_empty = not docstring
if is_multiline_string(leaf):
indent = " " * 4 * self.current_line.depth
docstring = fix_docstring(docstring, indent)
else:
docstring = docstring.strip()
if docstring:
# Add some padding if the docstring starts / ends with a quote mark.
if docstring[0] == quote_char:
docstring = " " + docstring
if docstring[-1] == quote_char:
docstring += " "
if docstring[-1] == "\\":
backslash_count = len(docstring) - len(docstring.rstrip("\\"))
if backslash_count % 2:
# Odd number of tailing backslashes, add some padding to
# avoid escaping the closing string quote.
docstring += " "
elif not docstring_started_empty:
docstring = " "
# We could enforce triple quotes at this point.
quote = quote_char * quote_len
leaf.value = prefix + quote + docstring + quote
yield from self.visit_default(leaf)
def contains_multiline_strings(self) -> bool:
return any(is_multiline_string(leaf) for leaf in self.leaves)
def can_omit_invisible_parens(
line: Line,
line_length: int,
) -> bool:
"""Does `line` have a shape safe to reformat without optional parens around it?
Returns True for only a subset of potentially nice looking formattings but
the point is to not return false positives that end up producing lines that
are too long.
"""
bt = line.bracket_tracker
if not bt.delimiters:
# Without delimiters the optional parentheses are useless.
return True
max_priority = bt.max_delimiter_priority()
if bt.delimiter_count_with_priority(max_priority) > 1:
# With more than one delimiter of a kind the optional parentheses read better.
return False
if max_priority == DOT_PRIORITY:
# A single stranded method call doesn't require optional parentheses.
return True
assert len(line.leaves) >= 2, "Stranded delimiter"
# With a single delimiter, omit if the expression starts or ends with
# a bracket.
first = line.leaves[0]
second = line.leaves[1]
if first.type in OPENING_BRACKETS and second.type not in CLOSING_BRACKETS:
if _can_omit_opening_paren(line, first=first, line_length=line_length):
return True
# Note: we are not returning False here because a line might have *both*
# a leading opening bracket and a trailing closing bracket. If the
# opening bracket doesn't match our rule, maybe the closing will.
penultimate = line.leaves[-2]
last = line.leaves[-1]
if (
last.type == token.RPAR
or last.type == token.RBRACE
or (
# don't use indexing for omitting optional parentheses;
# it looks weird
last.type == token.RSQB
and last.parent
and last.parent.type != syms.trailer
)
):
if penultimate.type in OPENING_BRACKETS:
# Empty brackets don't help.
return False
if is_multiline_string(first):
# Additional wrapping of a multiline string in this situation is
# unnecessary.
return True
if _can_omit_closing_paren(line, last=last, line_length=line_length):
return True
return False
def normalize_invisible_parens(
node: Node, parens_after: Set[str], *, preview: bool
) -> None:
"""Make existing optional parentheses invisible or create new ones.
`parens_after` is a set of string leaf values immediately after which parens
should be put.
Standardizes on visible parentheses for single-element tuples, and keeps
existing visible parentheses for other tuples and generator expressions.
"""
for pc in list_comments(node.prefix, is_endmarker=False, preview=preview):
if pc.value in FMT_OFF:
# This `node` has a prefix with `# fmt: off`, don't mess with parens.
return
check_lpar = False
for index, child in enumerate(list(node.children)):
# Fixes a bug where invisible parens are not properly stripped from
# assignment statements that contain type annotations.
if isinstance(child, Node) and child.type == syms.annassign:
normalize_invisible_parens(
child, parens_after=parens_after, preview=preview
)
# Add parentheses around long tuple unpacking in assignments.
if (
index == 0
and isinstance(child, Node)
and child.type == syms.testlist_star_expr
):
check_lpar = True
if check_lpar:
if (
preview
and child.type == syms.atom
and node.type == syms.for_stmt
and isinstance(child.prev_sibling, Leaf)
and child.prev_sibling.type == token.NAME
and child.prev_sibling.value == "for"
):
if maybe_make_parens_invisible_in_atom(
child,
parent=node,
remove_brackets_around_comma=True,
):
wrap_in_parentheses(node, child, visible=False)
elif preview and isinstance(child, Node) and node.type == syms.with_stmt:
remove_with_parens(child, node)
elif child.type == syms.atom:
if maybe_make_parens_invisible_in_atom(
child,
parent=node,
):
wrap_in_parentheses(node, child, visible=False)
elif is_one_tuple(child):
wrap_in_parentheses(node, child, visible=True)
elif node.type == syms.import_from:
# "import from" nodes store parentheses directly as part of
# the statement
if is_lpar_token(child):
assert is_rpar_token(node.children[-1])
# make parentheses invisible
child.value = ""
node.children[-1].value = ""
elif child.type != token.STAR:
# insert invisible parentheses
node.insert_child(index, Leaf(token.LPAR, ""))
node.append_child(Leaf(token.RPAR, ""))
break
elif (
index == 1
and child.type == token.STAR
and node.type == syms.except_clause
):
# In except* (PEP 654), the star is actually part of
# of the keyword. So we need to skip the insertion of
# invisible parentheses to work more precisely.
continue
elif not (isinstance(child, Leaf) and is_multiline_string(child)):
wrap_in_parentheses(node, child, visible=False)
comma_check = child.type == token.COMMA if preview else False
check_lpar = isinstance(child, Leaf) and (
child.value in parens_after or comma_check
)