public T visitIntervalTypeSpecifier(IntervalTypeSpecifier elm, C context) {
        visitElement(elm.getPointType(), context);
        return null;
    }
public T visitIntervalTypeSpecifier ( IntervalTypeSpecifier elm , C context ) { visitElement ( elm . getPointType ( ) , context ) ; return null ; }
Visit a IntervalTypeSpecifier. This method will be called for
every node in the tree that is a IntervalTypeSpecifier.

@param elm     the ELM tree
@param context the context passed to the visitor
@return the visitor result