Class Emitter

mypyc/codegen/emit.py:203–1448

Helper for C code generation.

class Emitter:
    """Helper for C code generation."""

    def __init__(
        self,
        context: EmitterContext,
        value_names: dict[Value, str] | None = None,
        capi_version: tuple[int, int] | None = None,
        filepath: str | None = None,
    ) -> None:
        self.context = context
        self.capi_version = capi_version or sys.version_info[:2]
        self.names = context.names
        self.value_names = value_names or {}
        self.fragments: list[str] = []
        self._indent = 0
        self.filepath = filepath

    # Low-level operations

    def indent(self) -> None:
        self._indent += 4

    def dedent(self) -> None:
        self._indent -= 4
        assert self._indent >= 0

    def label(self, label: BasicBlock) -> str:
        return "CPyL%s" % label.label

    def reg(self, reg: Value) -> str:
        return REG_PREFIX + self.value_names[reg]

    def attr(self, name: str) -> str:
        return ATTR_PREFIX + name

    def object_annotation(self, obj: object, line: str) -> str:
        """Build a C comment with an object's string representation.

        If the comment exceeds the line length limit, it's wrapped into a
        multiline string (with the extra lines indented to be aligned with
        the first line's comment).

        If it contains illegal characters, an empty string is returned."""
        line_width = self._indent + len(line)
        formatted = pprint.pformat(obj, compact=True, width=max(90 - line_width, 20))
        if any(x in formatted for x in ("/*", "*/", "\0")):
            return ""

        if "\n" in formatted:
            first_line, rest = formatted.split("\n", maxsplit=1)
            comment_continued = textwrap.indent(rest, (line_width + 3) * " ")
            return f" /* {first_line}\n{comment_continued} */"
        else:
            return f" /* {formatted} */"

    def emit_line(self, line: str = "", *, ann: object = None) -> None:
        if line.startswith("}"):