Class Span

rich/text.py:47–115

A marked up region in some text.

class Span(NamedTuple):
    """A marked up region in some text."""

    start: int
    """Span start index."""
    end: int
    """Span end index."""
    style: Union[str, Style]
    """Style associated with the span."""

    def __repr__(self) -> str:
        return f"Span({self.start}, {self.end}, {self.style!r})"

    def __bool__(self) -> bool:
        return self.end > self.start

    def split(self, offset: int) -> Tuple["Span", Optional["Span"]]:
        """Split a span in to 2 from a given offset."""

        if offset < self.start:
            return self, None
        if offset >= self.end:
            return self, None

        start, end, style = self
        span1 = Span(start, min(end, offset), style)
        span2 = Span(span1.end, end, style)
        return span1, span2

    def move(self, offset: int) -> "Span":
        """Move start and end by a given offset.

        Args:
            offset (int): Number of characters to add to start and end.

        Returns:
            TextSpan: A new TextSpan with adjusted position.
        """
        start, end, style = self
        return Span(start + offset, end + offset, style)

    def right_crop(self, offset: int) -> "Span":
        """Crop the span at the given offset.

        Args:
            offset (int): A value between start and end.

        Returns:
            Span: A new (possibly smaller) span.
        """
        start, end, style = self
        if offset >= end:
            return self
        return Span(start, min(offset, end), style)

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