private void delRef ( final int root ) { if ( root < 2 ) return ; if ( root >= this . nodesize ) throw new IllegalStateException ( "Cannot dereference a variable > varnum" ) ; if ( this . low ( root ) == - 1 ) throw new IllegalStateException ( "Cannot dereference variable -1" ) ; if ( ! this . hasref ( root ) ) throw new IllegalStateException ( "Cannot dereference a variable which has no reference" ) ; this . decRef ( root ) ; }
Deletes a reference for a given node .