Function changeLine

static/js/codemirror/codemirror.js:2510–2518

(cm, handle, op)

  }

  function changeLine(cm, handle, op) {
    var no = handle, line = handle, doc = cm.doc;
    if (typeof handle == "number") line = getLine(doc, clipLine(doc, handle));
    else no = lineNo(handle);
    if (no == null) return null;
    if (op(line, no)) regChange(cm, no, no + 1);
    else return null;
    return line;
  }

  function findPosH(doc, pos, dir, unit, visually) {
    var line = pos.line, ch = pos.ch;