chore: import upstream snapshot with attribution

server/functions/split_part.go

@@ -0,0 +1,58 @@
+// Copyright 2024 Dolthub, Inc.
+//
+// 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.
+
+package functions
+
+import (
+	"strings"
+
+	"github.com/cockroachdb/errors"
+	"github.com/dolthub/go-mysql-server/sql"
+
+	"github.com/dolthub/doltgresql/server/functions/framework"
+	pgtypes "github.com/dolthub/doltgresql/server/types"
+	"github.com/dolthub/doltgresql/utils"
+)
+
+// initSplitPart registers the functions to the catalog.
+func initSplitPart() {
+	framework.RegisterFunction(split_part_text_text_int32)
+}
+
+// split_part_text_text_int32 represents the PostgreSQL function of the same name, taking the same parameters.
+var split_part_text_text_int32 = framework.Function3{
+	Name:       "split_part",
+	Return:     pgtypes.Text,
+	Parameters: [3]*pgtypes.DoltgresType{pgtypes.Text, pgtypes.Text, pgtypes.Int32},
+	Strict:     true,
+	Callable: func(ctx *sql.Context, _ [4]*pgtypes.DoltgresType, str any, delimiter any, n any) (any, error) {
+		if n.(int32) == 0 {
+			return nil, errors.Errorf("field position must not be zero")
+		}
+		var parts []string
+		if len(delimiter.(string)) > 0 {
+			parts = strings.Split(str.(string), delimiter.(string))
+		} else {
+			parts = []string{str.(string)}
+		}
+		if int(utils.Abs(n.(int32))) > len(parts) {
+			return "", nil
+		}
+		if n.(int32) > 0 {
+			return parts[n.(int32)-1], nil
+		} else {
+			return parts[int32(len(parts))+n.(int32)], nil
+		}
+	},
+}