// converts single cell to string
docstring asString(MathData const & ar);
// converts single inset to string
docstring asString(InsetMath const &);
docstring asString(MathAtom const &);
// converts string to single cell
// converts single cell to string
docstring asString(MathData const & ar);
// converts single inset to string
docstring asString(InsetMath const &);
docstring asString(MathAtom const &);
// converts string to single cell