@Override
    public String toString(ToStringContext<NAMETYPE> context) {
        return "cell_cast(" + argument.toString(context) + ", " + valueType + ")";
    }
The <i>cell_cast</i> tensor function creates a new tensor with the specified cell value type.

@author lesters
vespajlib/src/main/java/com/yahoo/tensor/functions/CellCast.java