Function linesFor

static/editor.md/lib/codemirror/lib/codemirror.js:6951–6955

(start, end)

      signalLater(line, "change", line, change);
    }
    function linesFor(start, end) {
      for (var i = start, result = []; i < end; ++i)
        result.push(new Line(text[i], spansFor(i), estimateHeight));
      return result;
    }

    var from = change.from, to = change.to, text = change.text;
    var firstLine = getLine(doc, from.line), lastLine = getLine(doc, to.line);