func NewIndexJoin(keyspace datastore.Keyspace, join *algebra.IndexJoin, index datastore.Index, covers expression.Covers) *IndexJoin { rv := &IndexJoin{ keyspace: keyspace, term: join.Right(), outer: join.Outer(), keyFor: join.For(), index: index, covers: covers, } rv.idExpr = expression.NewField( expression.NewMeta(expression.NewIdentifier(rv.keyFor)), expression.NewFieldName("id", false)) return rv }