Method format

marimo/_utils/formatter.py:144–186

(
        self, codes: CellCodes, stdin_filename: str | None = None
    )

class RuffFormatter(Formatter):
    async def format(
        self, codes: CellCodes, stdin_filename: str | None = None
    ) -> CellCodes:
        # Wrap each cell in a dummy function so ruff applies function-scope
        # blank-line rules (1 blank line around nested defs) instead of
        # file-scope rules (2 blank lines). Cells with no executable
        # statements (whitespace-only or comment-only) are left unwrapped
        # since an empty or comment-only function body is invalid Python.
        skip_wrap = {
            key
            for key, code in codes.items()
            if all(
                not line.strip() or line.strip().startswith("#")
                for line in code.splitlines()
            )
        }
        wrapped: CellCodes = {}
        for key, code in codes.items():
            if key not in skip_wrap:
                wrapped[key] = "\n".join(
                    ["def _():", textwrap.indent(code, "    ")]
                )
            else:
                wrapped[key] = code

        wrapped_result = await ruff(
            wrapped,
            "format",
            "--line-length",
            str(self.line_length),
            stdin_filename=stdin_filename,
        )

        # Unwrap: use the AST to extract the function body, mirroring the
        # parse mechanism in marimo/_ast/parse.py (Extractor + fixed_dedent).
        result: CellCodes = {}
        for key, code in codes.items():
            if key in skip_wrap:
                result[key] = wrapped_result.get(key, code)
            elif key in wrapped_result:
                result[key] = unwrap_cell_body(wrapped_result[key])

        return result


class BlackFormatter(Formatter):