// 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::data::{ColumnData, DataType, Field};

/// 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>>;
}

