Class Span

src/textual/content.py:83–128

A style applied to a range of character offsets.

@rich.repr.auto
class Span(NamedTuple):
    """A style applied to a range of character offsets."""

    start: int
    end: int
    style: Style | str

    def __rich_repr__(self) -> rich.repr.Result:
        yield self.start
        yield self.end
        yield "style", self.style

    def extend(self, cells: int) -> "Span":
        """Extend the span by the given number of cells.

        Args:
            cells (int): Additional space to add to end of span.

        Returns:
            Span: A span.
        """
        if cells:
            start, end, style = self
            return Span(start, end + cells, style)
        return self

    def _shift(self, distance: int) -> "Span":
        """Shift a span a given distance.

        Note that the start offset is clamped to 0.
        The end offset is not clamped, as it is assumed this has already been checked by the caller.

        Args:
            distance: Number of characters to move.

        Returns:
            New Span.
        """
        if distance < 0:
            start, end, style = self
            return Span(
                offset if (offset := start + distance) > 0 else 0, end + distance, style
            )
        else:
            start, end, style = self
            return Span(start + distance, end + distance, style)


@rich.repr.auto