liurenjie1024 commented on code in PR #320: URL: https://github.com/apache/iceberg-rust/pull/320#discussion_r1553279624
########## crates/iceberg/src/expr/visitors/bound_predicate_visitor.rs: ########## @@ -0,0 +1,366 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use crate::expr::{BoundPredicate, BoundReference, PredicateOperator}; +use crate::spec::Datum; +use crate::Result; +use fnv::FnvHashSet; + +pub trait BoundPredicateVisitor { + type T; + + fn always_true(&mut self) -> Result<Self::T>; + fn always_false(&mut self) -> Result<Self::T>; + + fn and(&mut self, lhs: Self::T, rhs: Self::T) -> Result<Self::T>; + fn or(&mut self, lhs: Self::T, rhs: Self::T) -> Result<Self::T>; + fn not(&mut self, inner: Self::T) -> Result<Self::T>; + + fn is_null(&mut self, reference: &BoundReference) -> Result<Self::T>; Review Comment: > If we add default implementations that return something like Err(OperatorNotImplemented), then if we add an operator, wouldn't existing code work for existing operators and only break if users then try to use the new operator without having updated any visitors they have to use the new operator? Yes, I agree with that. Another option is to use following method: ```rust trait BoundPredicateVisitor { fn visitor_op(&mut self, op: &PredicateOperator, reference: &BoundReference, results: Vec<Self::T>) -> Result<Self::T> {} } ``` This way we can force user to think about added new operator, otherwise it will throw compiler error, but this may break things when we add new operator. I think the two approaches have different pros and cons, let's wait to see others's comments. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
