from black.comments import contains_pragma_comment
from black.lines import Line, append_leaves
-from black.mode import Feature
+from black.mode import Feature, Mode
from black.nodes import (
CLOSING_BRACKETS,
OPENING_BRACKETS,
from black.rusty import Err, Ok, Result
from black.strings import (
assert_is_leaf_string,
+ count_chars_in_width,
get_string_prefix,
has_triple_quotes,
normalize_string_quotes,
+ str_width,
)
from blib2to3.pgen2 import token
from blib2to3.pytree import Leaf, Node
# types
T = TypeVar("T")
LN = Union[Leaf, Node]
-Transformer = Callable[[Line, Collection[Feature]], Iterator[Line]]
+Transformer = Callable[[Line, Collection[Feature], Mode], Iterator[Line]]
Index = int
NodeType = int
ParserState = int
TResult = Result[T, CannotTransform] # (T)ransform Result
TMatchResult = TResult[List[Index]]
+SPLIT_SAFE_CHARS = frozenset(["\u3001", "\u3002", "\uff0c"]) # East Asian stops
+
def TErr(err_msg: str) -> Err[CannotTransform]:
"""(T)ransform Err
return Err(cant_transform)
-def hug_power_op(line: Line, features: Collection[Feature]) -> Iterator[Line]:
+def hug_power_op(
+ line: Line, features: Collection[Feature], mode: Mode
+) -> Iterator[Line]:
"""A transformer which normalizes spacing around power operators."""
# Performance optimization to avoid unnecessary Leaf clones and other ops.
yield an CannotTransform after that point.)
"""
- def __call__(self, line: Line, _features: Collection[Feature]) -> Iterator[Line]:
+ def __call__(
+ self, line: Line, _features: Collection[Feature], _mode: Mode
+ ) -> Iterator[Line]:
"""
StringTransformer instances have a call signature that mirrors that of
the Transformer type.
characters have been escaped.
"""
assert_is_leaf_string(string)
+ if "f" in string_prefix:
+ string = _toggle_fexpr_quotes(string, QUOTE)
+ # After quotes toggling, quotes in expressions won't be escaped
+ # because quotes can't be reused in f-strings. So we can simply
+ # let the escaping logic below run without knowing f-string
+ # expressions.
RE_EVEN_BACKSLASHES = r"(?:(?<!\\)(?:\\\\)*)"
naked_string = string[len(string_prefix) + 1 : -1]
# WMA4 the length of the inline comment.
offset += len(comment_leaf.value)
- max_string_length = self.line_length - offset
+ max_string_length = count_chars_in_width(str(line), self.line_length - offset)
return max_string_length
@staticmethod
return any(iter_fexpr_spans(s))
+def _toggle_fexpr_quotes(fstring: str, old_quote: str) -> str:
+ """
+ Toggles quotes used in f-string expressions that are `old_quote`.
+
+ f-string expressions can't contain backslashes, so we need to toggle the
+ quotes if the f-string itself will end up using the same quote. We can
+ simply toggle without escaping because, quotes can't be reused in f-string
+ expressions. They will fail to parse.
+
+ NOTE: If PEP 701 is accepted, above statement will no longer be true.
+ Though if quotes can be reused, we can simply reuse them without updates or
+ escaping, once Black figures out how to parse the new grammar.
+ """
+ new_quote = "'" if old_quote == '"' else '"'
+ parts = []
+ previous_index = 0
+ for start, end in iter_fexpr_spans(fstring):
+ parts.append(fstring[previous_index:start])
+ parts.append(fstring[start:end].replace(old_quote, new_quote))
+ previous_index = end
+ parts.append(fstring[previous_index:])
+ return "".join(parts)
+
+
class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
"""
StringTransformer that splits "atom" strings (i.e. strings which exist on
is_valid_index(string_idx + 1) and LL[string_idx + 1].type == token.COMMA
)
- def max_last_string() -> int:
+ def max_last_string_column() -> int:
"""
Returns:
- The max allowed length of the string value used for the last
- line we will construct.
+ The max allowed width of the string value used for the last
+ line we will construct. Note that this value means the width
+ rather than the number of characters (e.g., many East Asian
+ characters expand to two columns).
"""
result = self.line_length
result -= line.depth * 4
result -= string_op_leaves_length
return result
- # --- Calculate Max Break Index (for string value)
+ # --- Calculate Max Break Width (for string value)
# We start with the line length limit
- max_break_idx = self.line_length
+ max_break_width = self.line_length
# The last index of a string of length N is N-1.
- max_break_idx -= 1
+ max_break_width -= 1
# Leading whitespace is not present in the string value (e.g. Leaf.value).
- max_break_idx -= line.depth * 4
- if max_break_idx < 0:
+ max_break_width -= line.depth * 4
+ if max_break_width < 0:
yield TErr(
f"Unable to split {LL[string_idx].value} at such high of a line depth:"
f" {line.depth}"
# line limit.
use_custom_breakpoints = bool(
custom_splits
- and all(csplit.break_idx <= max_break_idx for csplit in custom_splits)
+ and all(csplit.break_idx <= max_break_width for csplit in custom_splits)
)
# Temporary storage for the remaining chunk of the string line that
if use_custom_breakpoints:
return len(custom_splits) > 1
else:
- return len(rest_value) > max_last_string()
+ return str_width(rest_value) > max_last_string_column()
string_line_results: List[Ok[Line]] = []
while more_splits_should_be_made():
break_idx = csplit.break_idx
else:
# Algorithmic Split (automatic)
- max_bidx = max_break_idx - string_op_leaves_length
+ max_bidx = (
+ count_chars_in_width(rest_value, max_break_width)
+ - string_op_leaves_length
+ )
maybe_break_idx = self._get_break_idx(rest_value, max_bidx)
if maybe_break_idx is None:
# If we are unable to algorithmically determine a good split
# Try to fit them all on the same line with the last substring...
if (
- len(temp_value) <= max_last_string()
+ str_width(temp_value) <= max_last_string_column()
or LL[string_idx + 1].type == token.COMMA
):
last_line.append(rest_leaf)
section of this classes' docstring would be be met by returning @i.
"""
is_space = string[i] == " "
+ is_split_safe = is_valid_index(i - 1) and string[i - 1] in SPLIT_SAFE_CHARS
is_not_escaped = True
j = i - 1
and len(string[:i]) >= self.MIN_SUBSTR_SIZE
)
return (
- is_space
+ (is_space or is_split_safe)
and is_not_escaped
and is_big_enough
and not breaks_unsplittable_expression(i)
if string_idx is not None:
string_value = line.leaves[string_idx].value
- # If the string has no spaces...
- if " " not in string_value:
+ # If the string has neither spaces nor East Asian stops...
+ if not any(
+ char == " " or char in SPLIT_SAFE_CHARS for char in string_value
+ ):
# And will still violate the line length limit when split...
- max_string_length = self.line_length - ((line.depth + 1) * 4)
- if len(string_value) > max_string_length:
+ max_string_width = self.line_length - ((line.depth + 1) * 4)
+ if str_width(string_value) > max_string_width:
# And has no associated custom splits...
if not self.has_custom_splits(string_value):
# Then we should NOT put this string on its own line.