Function attachMarkedSpans

static/editor.md/lib/codemirror/lib/codemirror.js:6300–6305

(line, spans)

    line.markedSpans = null;
  }
  function attachMarkedSpans(line, spans) {
    if (!spans) return;
    for (var i = 0; i < spans.length; ++i)
      spans[i].marker.attachLine(line);
    line.markedSpans = spans;
  }

  // Helpers used when computing which overlapping collapsed span
  // counts as the larger one.