notfilippo commented on code in PR #12853: URL: https://github.com/apache/datafusion/pull/12853#discussion_r1800893742
########## datafusion/common/src/types/logical.rs: ########## @@ -0,0 +1,124 @@ +// 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 core::fmt; +use std::{cmp::Ordering, hash::Hash, sync::Arc}; + +use super::NativeType; + +#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)] +pub enum TypeSignature<'a> { + /// Represents a built-in native type. + Native(&'a NativeType), + /// Represents an arrow-compatible extension type. + /// (https://arrow.apache.org/docs/format/Columnar.html#extension-types) + /// + /// The `name` should contain the same value as 'ARROW:extension:name'. + Extension { + name: &'a str, + parameters: &'a [TypeParameter<'a>], + }, +} + +#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)] +pub enum TypeParameter<'a> { + Type(TypeSignature<'a>), + Number(i128), +} + +/// A reference counted [`LogicalType`] +pub type LogicalTypeRef = Arc<dyn LogicalType>; + +pub trait LogicalType: Sync + Send { + fn native(&self) -> &NativeType; + fn signature(&self) -> TypeSignature<'_>; +} + +impl fmt::Debug for dyn LogicalType { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + f.debug_tuple("LogicalType") + .field(&self.signature()) + .field(&self.native()) + .finish() + } +} + +impl PartialEq for dyn LogicalType { + fn eq(&self, other: &Self) -> bool { + self.native().eq(other.native()) && self.signature().eq(&other.signature()) + } +} + +impl Eq for dyn LogicalType {} + +impl PartialOrd for dyn LogicalType { + fn partial_cmp(&self, other: &Self) -> Option<Ordering> { + Some(self.cmp(other)) + } +} + +impl Ord for dyn LogicalType { + fn cmp(&self, other: &Self) -> Ordering { + self.signature() + .cmp(&other.signature()) + .then(self.native().cmp(other.native())) + } +} + +impl Hash for dyn LogicalType { + fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + self.signature().hash(state); + self.native().hash(state); + } +} + +#[cfg(test)] +mod test { + #![allow(dead_code)] + + use super::{LogicalType, TypeParameter, TypeSignature}; + use crate::types::NativeType; + + struct MagicalType {} + + impl LogicalType for MagicalType { + fn native(&self) -> &NativeType { + &NativeType::Utf8 + } + + fn signature(&self) -> TypeSignature<'_> { + TypeSignature::Extension { + name: "MagicalType", + parameters: &[TypeParameter::Type(TypeSignature::Native( + &NativeType::Boolean, + ))], + } + } + } + + fn test(logical_type: &dyn LogicalType) { + match logical_type.signature() { + TypeSignature::Extension { + name: "MagicalType", + parameters: + [TypeParameter::Type(TypeSignature::Native(NativeType::Boolean))], + } => {} + TypeSignature::Native(NativeType::Binary) => todo!(), + _ => unimplemented!(), + }; + } Review Comment: I've added a more structured `TypeSignature`. I've encountered some problems while iterating for a design of this structure since I wanted to balance ease of handling and information contained. I think I've ended up with a good baseline that can be easily pattern matched and limits the copying of information. ptal @findepi @jayzhan211 -- 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: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
