Fokko commented on code in PR #320: URL: https://github.com/apache/iceberg-rust/pull/320#discussion_r1567138774
########## crates/iceberg/src/expr/visitors/bound_predicate_visitor.rs: ########## @@ -0,0 +1,317 @@ +// 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(crate) enum OpLiteral<'a> { + Single(&'a Datum), + Set(&'a FnvHashSet<Datum>), +} + +/// A visitor for [`BoundPredicate`]s. Visits in post-order. +pub trait BoundPredicateVisitor { + /// The return type of this visitor + type T; + + /// Called after an `AlwaysTrue` predicate is visited + fn always_true(&mut self) -> Result<Self::T>; + + /// Called after an `AlwaysFalse` predicate is visited + fn always_false(&mut self) -> Result<Self::T>; + + /// Called after an `And` predicate is visited + fn and(&mut self, lhs: Self::T, rhs: Self::T) -> Result<Self::T>; + + /// Called after an `Or` predicate is visited + fn or(&mut self, lhs: Self::T, rhs: Self::T) -> Result<Self::T>; + + /// Called after a `Not` predicate is visited + fn not(&mut self, inner: Self::T) -> Result<Self::T>; + + /// Called after visiting a UnaryPredicate, BinaryPredicate, + /// or SetPredicate. Passes the predicate's operator in all cases, + /// as well as the term and literals in the case of binary and aet + /// predicates. + fn op( Review Comment: I'm not sold on the iterator idea either, it looks very fancy, but iterating over a set feels awkward to me. > If you're not happy with this approach @Fokko, I'll wait until the three of you are in agreement and fix up to whatever you all decide on. I'm happy with the approach as-is after switching my original design to the approach proposed by @liurenjie1024 and @marvinlanhenke. Well, I'm not the one to decide here, just weighing in my opinion :D I have a strong preference for the original approach as suggested in https://github.com/apache/iceberg-rust/pull/334 I think this leverages the visitor as much as possible, and also makes sure that all the operations are covered. -- 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
