def __post_init__(self) -> None: """You are in a twisty little maze of passages.""" self.current_line = Line(mode=self.mode) v = self.visit_stmt Ø: Set[str] = set() self.visit_assert_stmt = partial(v, keywords={"assert"}, parens={"assert", ","}) self.visit_if_stmt = partial( v, keywords={"if", "else", "elif"}, parens={"if", "elif"} ) self.visit_while_stmt = partial(v, keywords={"while", "else"}, parens={"while"}) self.visit_for_stmt = partial(v, keywords={"for", "else"}, parens={"for", "in"}) self.visit_try_stmt = partial( v, keywords={"try", "except", "else", "finally"}, parens=Ø ) self.visit_except_clause = partial(v, keywords={"except"}, parens=Ø) self.visit_with_stmt = partial(v, keywords={"with"}, parens=Ø) self.visit_funcdef = partial(v, keywords={"def"}, parens=Ø) self.visit_classdef = partial(v, keywords={"class"}, parens=Ø) self.visit_expr_stmt = partial(v, keywords=Ø, parens=ASSIGNMENTS) self.visit_return_stmt = partial(v, keywords={"return"}, parens={"return"}) self.visit_import_from = partial(v, keywords=Ø, parens={"import"}) self.visit_del_stmt = partial(v, keywords=Ø, parens={"del"}) self.visit_async_funcdef = self.visit_async_stmt self.visit_decorated = self.visit_decorators # PEP 634 self.visit_match_stmt = self.visit_match_case self.visit_case_block = self.visit_match_case
def _format_str_once(src_contents: str, *, mode: Mode) -> str: src_node = lib2to3_parse(src_contents.lstrip(), mode.target_versions) dst_contents = [] future_imports = get_future_imports(src_node) if mode.target_versions: versions = mode.target_versions else: versions = detect_target_versions(src_node, future_imports=future_imports) normalize_fmt_off(src_node, preview=mode.preview) lines = LineGenerator(mode=mode) elt = EmptyLineTracker(is_pyi=mode.is_pyi) empty_line = Line(mode=mode) after = 0 split_line_features = { feature for feature in {Feature.TRAILING_COMMA_IN_CALL, Feature.TRAILING_COMMA_IN_DEF} if supports_feature(versions, feature) } for current_line in lines.visit(src_node): dst_contents.append(str(empty_line) * after) before, after = elt.maybe_empty_lines(current_line) dst_contents.append(str(empty_line) * before) for line in transform_line(current_line, mode=mode, features=split_line_features): dst_contents.append(str(line)) return "".join(dst_contents)
def standalone_comment_split( line: Line, features: Collection[Feature] = () ) -> Iterator[Line]: """Split standalone comments from the rest of the line.""" if not line.contains_standalone_comments(0): raise CannotSplit("Line does not have any standalone comments") current_line = Line( mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets ) def append_to_line(leaf: Leaf) -> Iterator[Line]: """Append `leaf` to current line or to new line if appending impossible.""" nonlocal current_line try: current_line.append_safe(leaf, preformatted=True) except ValueError: yield current_line current_line = Line( line.mode, depth=line.depth, inside_brackets=line.inside_brackets ) current_line.append(leaf) for leaf in line.leaves: yield from append_to_line(leaf) for comment_after in line.comments_after(leaf): yield from append_to_line(comment_after) if current_line: yield current_line
def format_str(src_contents: str, *, mode: Mode) -> FileContent: """Reformat a string and return new contents. `mode` determines formatting options, such as how many characters per line are allowed. Example: >>> import black >>> print(black.format_str("def f(arg:str='')->None:...", mode=black.Mode())) def f(arg: str = "") -> None: ... A more complex example: >>> print( ... black.format_str( ... "def f(arg:str='')->None: hey", ... mode=black.Mode( ... target_versions={black.TargetVersion.PY36}, ... line_length=10, ... string_normalization=False, ... is_pyi=False, ... ), ... ), ... ) def f( arg: str = '', ) -> None: hey """ src_node = lib2to3_parse(src_contents.lstrip(), mode.target_versions) dst_contents = [] future_imports = get_future_imports(src_node) if mode.target_versions: versions = mode.target_versions else: versions = detect_target_versions(src_node) normalize_fmt_off(src_node) lines = LineGenerator( mode=mode, remove_u_prefix="unicode_literals" in future_imports or supports_feature(versions, Feature.UNICODE_LITERALS), ) elt = EmptyLineTracker(is_pyi=mode.is_pyi) empty_line = Line(mode=mode) after = 0 split_line_features = { feature for feature in {Feature.TRAILING_COMMA_IN_CALL, Feature.TRAILING_COMMA_IN_DEF} if supports_feature(versions, feature) } for current_line in lines.visit(src_node): dst_contents.append(str(empty_line) * after) before, after = elt.maybe_empty_lines(current_line) dst_contents.append(str(empty_line) * before) for line in transform_line( current_line, mode=mode, features=split_line_features ): dst_contents.append(str(line)) return "".join(dst_contents)
def bracket_split_build_line( leaves: List[Leaf], original: Line, opening_bracket: Leaf, *, is_body: bool = False ) -> Line: """Return a new line with given `leaves` and respective comments from `original`. If `is_body` is True, the result line is one-indented inside brackets and as such has its first leaf's prefix normalized and a trailing comma added when expected. """ result = Line(mode=original.mode, depth=original.depth) if is_body: result.inside_brackets = True result.depth += 1 if leaves: # Since body is a new indent level, remove spurious leading whitespace. normalize_prefix(leaves[0], inside_brackets=True) # Ensure a trailing comma for imports and standalone function arguments, but # be careful not to add one after any comments or within type annotations. no_commas = ( original.is_def and opening_bracket.value == "(" and not any(leaf.type == token.COMMA for leaf in leaves) # In particular, don't add one within a parenthesized return annotation. # Unfortunately the indicator we're in a return annotation (RARROW) may # be defined directly in the parent node, the parent of the parent ... # and so on depending on how complex the return annotation is. # This isn't perfect and there's some false negatives but they are in # contexts were a comma is actually fine. and not any( node.prev_sibling.type == RARROW for node in ( leaves[0].parent, getattr(leaves[0].parent, "parent", None), ) if isinstance(node, Node) and isinstance(node.prev_sibling, Leaf) ) ) if original.is_import or no_commas: for i in range(len(leaves) - 1, -1, -1): if leaves[i].type == STANDALONE_COMMENT: continue if leaves[i].type != token.COMMA: new_comma = Leaf(token.COMMA, ",") leaves.insert(i + 1, new_comma) break # Populate the line for leaf in leaves: result.append(leaf, preformatted=True) for comment_after in original.comments_after(leaf): result.append(comment_after, preformatted=True) if is_body and should_split_line(result, opening_bracket): result.should_split_rhs = True return result
def append_to_line(leaf: Leaf) -> Iterator[Line]: """Append `leaf` to current line or to new line if appending impossible.""" nonlocal current_line try: current_line.append_safe(leaf, preformatted=True) except ValueError: yield current_line current_line = Line( line.mode, depth=line.depth, inside_brackets=line.inside_brackets ) current_line.append(leaf)
def line(self, indent: int = 0) -> Iterator[Line]: """Generate a line. If the line is empty, only emit if it makes sense. If the line is too long, split it first and then generate. If any lines were generated, set up a new current_line. """ if not self.current_line: self.current_line.depth += indent return # Line is empty, don't emit. Creating a new one unnecessary. complete_line = self.current_line self.current_line = Line(mode=self.mode, depth=complete_line.depth + indent) yield complete_line
def bracket_split_build_line(leaves: List[Leaf], original: Line, opening_bracket: Leaf, *, is_body: bool = False) -> Line: """Return a new line with given `leaves` and respective comments from `original`. If `is_body` is True, the result line is one-indented inside brackets and as such has its first leaf's prefix normalized and a trailing comma added when expected. """ result = Line(mode=original.mode, depth=original.depth) if is_body: result.inside_brackets = True result.depth += 1 if leaves: # Since body is a new indent level, remove spurious leading whitespace. normalize_prefix(leaves[0], inside_brackets=True) # Ensure a trailing comma for imports and standalone function arguments, but # be careful not to add one after any comments or within type annotations. no_commas = (original.is_def and opening_bracket.value == "(" and not any(leaf.type == token.COMMA for leaf in leaves)) if original.is_import or no_commas: for i in range(len(leaves) - 1, -1, -1): if leaves[i].type == STANDALONE_COMMENT: continue if leaves[i].type != token.COMMA and not original.is_import: new_comma = Leaf(token.COMMA, ",") leaves.insert(i + 1, new_comma) break # Populate the line for leaf in leaves: result.append(leaf, preformatted=True) for comment_after in original.comments_after(leaf): result.append(comment_after, preformatted=True) if is_body and should_split_line(result, opening_bracket): result.should_split_rhs = True return result
def delimiter_split(line: Line, features: Collection[Feature] = ()) -> Iterator[Line]: """Split according to delimiters of the highest priority. If the appropriate Features are given, the split will add trailing commas also in function signatures and calls that contain `*` and `**`. """ try: last_leaf = line.leaves[-1] except IndexError: raise CannotSplit("Line empty") from None bt = line.bracket_tracker try: delimiter_priority = bt.max_delimiter_priority(exclude={id(last_leaf)}) except ValueError: raise CannotSplit("No delimiters found") from None if delimiter_priority == DOT_PRIORITY: if bt.delimiter_count_with_priority(delimiter_priority) == 1: raise CannotSplit("Splitting a single attribute from its owner looks wrong") current_line = Line( mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets ) lowest_depth = sys.maxsize trailing_comma_safe = True def append_to_line(leaf: Leaf) -> Iterator[Line]: """Append `leaf` to current line or to new line if appending impossible.""" nonlocal current_line try: current_line.append_safe(leaf, preformatted=True) except ValueError: yield current_line current_line = Line( mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets ) current_line.append(leaf) for leaf in line.leaves: yield from append_to_line(leaf) for comment_after in line.comments_after(leaf): yield from append_to_line(comment_after) lowest_depth = min(lowest_depth, leaf.bracket_depth) if leaf.bracket_depth == lowest_depth: if is_vararg(leaf, within={syms.typedargslist}): trailing_comma_safe = ( trailing_comma_safe and Feature.TRAILING_COMMA_IN_DEF in features ) elif is_vararg(leaf, within={syms.arglist, syms.argument}): trailing_comma_safe = ( trailing_comma_safe and Feature.TRAILING_COMMA_IN_CALL in features ) leaf_priority = bt.delimiters.get(id(leaf)) if leaf_priority == delimiter_priority: yield current_line current_line = Line( mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets ) if current_line: if ( trailing_comma_safe and delimiter_priority == COMMA_PRIORITY and current_line.leaves[-1].type != token.COMMA and current_line.leaves[-1].type != STANDALONE_COMMENT ): new_comma = Leaf(token.COMMA, ",") current_line.append(new_comma) yield current_line