OutliningTagger_ReparseFile_SingleSpan.cs

void ReparseFile(object sender, EventArgs args)
{
    ITextSnapshot snapshot = _buffer.CurrentSnapshot;

    List<MarkdownSection> newSections = new List<MarkdownSection>(
        MarkdownParser.ParseMarkdownSections(snapshot)
                      .Select(t => new MarkdownSection()
                      {
                          TokenType = t.TokenType,
                          Span = snapshot.CreateTrackingSpan(t.Span, SpanTrackingMode.EdgeExclusive)
                      }));

    NormalizedSnapshotSpanCollection oldSectionSpans = new NormalizedSnapshotSpanCollection(
        _sections.Select(s => s.Span.GetSpan(snapshot)));
    NormalizedSnapshotSpanCollection newSectionSpans = new NormalizedSnapshotSpanCollection(
        newSections.Select(s => s.Span.GetSpan(snapshot)));

    NormalizedSnapshotSpanCollection difference = NormalizedSnapshotSpanCollection.Difference(oldSectionSpans, newSectionSpans);

    _sections = newSections;

    var temp = TagsChanged;
    if (temp != null && difference.Count > 0)
    {
        temp(this, new SnapshotSpanEventArgs(new SnapshotSpan(difference[0].Start, difference[difference.Count - 1].End)));
    }
}