notfilippo commented on code in PR #12853: URL: https://github.com/apache/datafusion/pull/12853#discussion_r1810645738
########## datafusion/common/src/types/logical.rs: ########## @@ -0,0 +1,118 @@ +// 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; + +/// Signature that uniquely identifies a type among other types. +#[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, Review Comment: TypeSignature uses lifetimes just to make pattern matching easier when dealing with parameters (or lack thereof). ```rust pub fn important_stuff(logical_type: &dyn LogicalType) { match logical_type.signature() { TypeSignature::Native(NativeType::Utf8) => todo!(), TypeSignature::Extension { name: "JSON", // <-- changing from &'a str to String leads to: expected `String`, but found `&str`, parameters: &[] } => todo!(), _ => unimplemented!() } } ``` -- 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
