Pre-conditions: * On the first call to this function, @leaf MUST be the leaf that was directly after the string leaf

Pre-Conditions: * assert_is_leaf_string(@string) Returns: * If @string is an f-string that contains no f-exp

Returns whether we should prefer the result from a split omitting optional parens.

Helper to recursively yield the matches.

Merge strings that were split across multiple lines using line-continuation backslashes. Returns: Ok(new_line),

Returns: string_idx such that @LL[string_idx] is equal to our target (i.e. matched) string, if this line matches the

Toggles quotes used in f-string expressions that are `old_quote`. f-string expressions can't contain backslashes, so we need to toggle the

Checks that @line meets all of the requirements listed in this classes' docstring. Refer to `help(BaseStringSplitter)` for a detailed

Validate (M)erge (S)tring (G)roup Transform-time string validation logic for _merge_string_group(...). Returns: * Ok(Non

Custom Split Map Setter Method Side Effects: Adds a mapping from @string to the custom splits @custom_splits.

Add a token; return True iff this is the end of the program.

Add an inline or standalone comment to the line.

Like :func:`append()` but disallow invalid standalone comment structure. Raises ValueError when any `leaf` is appended after a standalone com

Raise AssertionError if `src` and `dst` aren't equivalent.

Raise AssertionError if `dst` reformats differently the second time.

Use the node-level invariant ones for basic parsing operations (push/pop/shift). These still will operate on the stack; but they won'

This is another docstring with more lines of text

Return False if the line cannot be split *for sure*. This is not an exhaustive search but a cheap heuristic that we can use to avoid some unf

Does `rhs.body` have a shape safe to reformat without optional parens around it? Returns True for only a subset of potentially nice looking forma

Return the width of a single character as it would be displayed in a terminal or editor (which respects Unicode East Asian Width). Full width

Return the child of `ancestor` that contains `descendant`.

Determine if children have formatting switched on.

Turn a token into a label. (Internal) Depending on whether the value is a soft-keyword or not, this function may return multiple lab

Return `leaf` or one of its ancestors that is the topmost container of it. By "container" we mean a node where `leaf` is the very first child.

Convert content of a single `# fmt: off`/`# fmt: on` into a standalone comment. Returns True if a pair was converted.

Detect the version to target based on the nodes used.

Returns: * Ok(string_indices) such that for each index, `line.leaves[index]` is our target string if a match was able

BaseStringSplitter asks its clients to override this method instead of `StringTransformer.do_match(...)`. Follows the same p

Yields: * Ok(new_line) where new_line is the new transformed line. OR * Err(CannotTransform) if the t

Split an iterable of paths in `sources` into two sets. The first contains paths of files that modified on disk or are not in the cache. The o

Find the absolute filepath to a pyproject.toml if it exists

Create additional useful structures. (Internal).

Map ast nodes deprecated in 3.8 to Constant.

Formats a complex string like `10j`

Formats a hexadecimal string like "0x12B3"

Format Jupyter notebook. Operate cell-by-cell, only on code cells, only for Python notebooks. If the ``.ipynb`` originally had a trailing new

Formats a numeric string utilizing scentific notation

Docstring comes first. Possibly many lines.

Generate all files under `path` whose paths are not excluded by the `exclude_regex`, `extend_exclude`, or `force_exclude` regexes, but are inc

Clean the prefix of the `leaf` and generate comments from it, if any. Comments in lib2to3 are shoved into the whitespace prefix. This happens

Starting from the container of `leaf`, generate all leaves until `# fmt: on`. If comment is skip, returns leaf only. Stops at the end of the

Generator yielding matches for a sequence of nodes. Args: nodes: sequence of nodes Yields: (count,

The generate_tokens() generator requires one argument, readline, which must be a callable object which provides the same interface as the

Generate sets of closing bracket IDs that should be omitted in a RHS. Brackets can be omitted if the entire trailer up to and including a pre

Return a set of (relatively) new Python features used in this file. Currently looking for: - f-strings; - self-documenting expressions in

Return a set of __future__ imports in the file.

Return leaves that are inside matching brackets. The input `leaves` can have non-matching brackets at the head or tail parts. Matching bracke

Return the most recent opening square bracket (if any).

Compute the set of files to be formatted.

Returns: True iff @string is associated with a set of custom splits.

Return True if we have a magic trailing comma, that is when: - there's a trailing comma here - it's not a one-tuple - it's not

Infer Black's target version from the project metadata in pyproject.toml. Supports the PyPA standard format (PEP 621): https://packaging.pyth