.. 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. Specifications ============== We formalize some DataFusion semantics and behaviors through specification documents. These specifications are useful to be used as references to help resolve ambiguities during development or code reviews. You are also welcome to propose changes to existing specifications or create new specifications as you see fit. All specifications are stored in the `docs/source/specification` folder. Here is the list current active specifications: .. toctree:: :maxdepth: 1 invariants output-field-name-semantic