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// Copyright 2018 Grove Enterprises LLC // // Licensed 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 std::rc::Rc; use super::rel::{Field, DataType}; use super::exec::ColumnData; /// Scalar function. User-defined implementations will be dynamically loaded at runtime. pub trait ScalarFunction { fn name(&self) -> String; fn args(&self) -> Vec<Field>; fn return_type(&self) -> DataType; fn execute(&self, args: Vec<Rc<ColumnData>>) -> Result<Rc<ColumnData>,Box<String>>; }