def transform_line(
line: Line, mode: Mode, features: Collection[Feature] = ()
) -> Iterator[Line]:
"""Transform a `line`, potentially splitting it into many lines.
They should fit in the allotted `line_length` but might not be able to.
`features` are syntactical features that may be used in the output.
"""
if line.is_comment:
yield line
return
line_str = line_to_string(line)
ll = mode.line_length
sn = mode.string_normalization
string_merge = StringMerger(ll, sn)
string_paren_strip = StringParenStripper(ll, sn)
string_split = StringSplitter(ll, sn)
string_paren_wrap = StringParenWrapper(ll, sn)
transformers: List[Transformer]
if (
not line.contains_uncollapsable_type_comments()
and not line.should_split_rhs
and not line.magic_trailing_comma
and (
is_line_short_enough(line, line_length=mode.line_length, line_str=line_str)
or line.contains_unsplittable_type_ignore()
)
and not (line.inside_brackets and line.contains_standalone_comments())
):
# Only apply basic string preprocessing, since lines shouldn't be split here.
if Preview.string_processing in mode:
transformers = [string_merge, string_paren_strip]
else:
transformers = []
elif line.is_def:
transformers = [left_hand_split]
else:
def _rhs(
self: object, line: Line, features: Collection[Feature]
) -> Iterator[Line]:
"""Wraps calls to `right_hand_split`.
The calls increasingly `omit` right-hand trailers (bracket pairs with
content), meaning the trailers get glued together to split on another
bracket pair instead.
"""
for omit in generate_trailers_to_omit(line, mode.line_length):
lines = list(
right_hand_split(line, mode.line_length, features, omit=omit)
)
# Note: this check is only able to figure out if the first line of the
# *current* transformation fits in the line length. This is true only
# for simple cases. All others require running more transforms via
# `transform_line()`. This check doesn't know if those would succeed.
if is_line_short_enough(lines[0], line_length=mode.line_length):
yield from lines
return
# All splits failed, best effort split with no omits.
# This mostly happens to multiline strings that are by definition
# reported as not fitting a single line, as well as lines that contain
# trailing commas (those have to be exploded).
yield from right_hand_split(
line, line_length=mode.line_length, features=features
)
# HACK: nested functions (like _rhs) compiled by mypyc don't retain their
# __name__ attribute which is needed in `run_transformer` further down.
# Unfortunately a nested class breaks mypyc too. So a class must be created
# via type ... https://github.com/mypyc/mypyc/issues/884
rhs = type("rhs", (), {"__call__": _rhs})()
if Preview.string_processing in mode:
if line.inside_brackets:
transformers = [
string_merge,
string_paren_strip,
string_split,
delimiter_split,
standalone_comment_split,
string_paren_wrap,
rhs,
]
else:
transformers = [
string_merge,
string_paren_strip,
string_split,
string_paren_wrap,
rhs,
]
else:
if line.inside_brackets:
transformers = [delimiter_split, standalone_comment_split, rhs]
else:
transformers = [rhs]
# It's always safe to attempt hugging of power operations and pretty much every line
# could match.
transformers.append(hug_power_op)
for transform in transformers:
# We are accumulating lines in `result` because we might want to abort
# mission and return the original line in the end, or attempt a different
# split altogether.
try:
result = run_transformer(line, transform, mode, features, line_str=line_str)
except CannotTransform:
continue
else:
yield from result
break
else:
yield line
def transform_line(
line: Line, mode: Mode,
features: Collection[Feature] = ()) -> Iterator[Line]:
"""Transform a `line`, potentially splitting it into many lines.
They should fit in the allotted `line_length` but might not be able to.
`features` are syntactical features that may be used in the output.
"""
if line.is_comment:
yield line
return
line_str = line_to_string(line)
ll = mode.line_length
sn = mode.string_normalization
string_merge = StringMerger(ll, sn)
string_paren_strip = StringParenStripper(ll, sn)
string_split = StringSplitter(ll, sn)
string_paren_wrap = StringParenWrapper(ll, sn)
transformers: List[Transformer]
if (not line.contains_uncollapsable_type_comments()
and not line.should_split_rhs and not line.magic_trailing_comma
and (is_line_short_enough(
line, line_length=mode.line_length, line_str=line_str)
or line.contains_unsplittable_type_ignore())
and not (line.inside_brackets
and line.contains_standalone_comments())):
# Only apply basic string preprocessing, since lines shouldn't be split here.
if mode.experimental_string_processing:
transformers = [string_merge, string_paren_strip]
else:
transformers = []
elif line.is_def:
transformers = [left_hand_split]
else:
def rhs(line: Line, features: Collection[Feature]) -> Iterator[Line]:
"""Wraps calls to `right_hand_split`.
The calls increasingly `omit` right-hand trailers (bracket pairs with
content), meaning the trailers get glued together to split on another
bracket pair instead.
"""
for omit in generate_trailers_to_omit(line, mode.line_length):
lines = list(
right_hand_split(line,
mode.line_length,
features,
omit=omit))
# Note: this check is only able to figure out if the first line of the
# *current* transformation fits in the line length. This is true only
# for simple cases. All others require running more transforms via
# `transform_line()`. This check doesn't know if those would succeed.
if is_line_short_enough(lines[0],
line_length=mode.line_length):
yield from lines
return
# All splits failed, best effort split with no omits.
# This mostly happens to multiline strings that are by definition
# reported as not fitting a single line, as well as lines that contain
# trailing commas (those have to be exploded).
yield from right_hand_split(line,
line_length=mode.line_length,
features=features)
if mode.experimental_string_processing:
if line.inside_brackets:
transformers = [
string_merge,
string_paren_strip,
string_split,
delimiter_split,
standalone_comment_split,
string_paren_wrap,
rhs,
]
else:
transformers = [
string_merge,
string_paren_strip,
string_split,
string_paren_wrap,
rhs,
]
else:
if line.inside_brackets:
transformers = [delimiter_split, standalone_comment_split, rhs]
else:
transformers = [rhs]
for transform in transformers:
# We are accumulating lines in `result` because we might want to abort
# mission and return the original line in the end, or attempt a different
# split altogether.
try:
result = run_transformer(line,
transform,
mode,
features,
line_str=line_str)
except CannotTransform:
continue
else:
yield from result
break
else:
yield line