implement map expr function

datafusion/functions-array/src/map.rs

@@ -0,0 +1,30 @@
+// 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 datafusion_expr::Expr;
+use datafusion_expr::expr::ScalarFunction;
+use datafusion_functions::core::map::map_udf;
+use crate::make_array::make_array;
+
+pub fn map(keys: Vec<Expr>, values: Vec<Expr>) -> Expr {
+    let keys = make_array(keys);
+    let values = make_array(values);
+    Expr::ScalarFunction(ScalarFunction::new_udf(
+        map_udf(),
+        vec![keys, values],
+    ))
+}