chore: import upstream snapshot with attribution

server/functions/left.go

@@ -0,0 +1,50 @@
+// 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 (
+	"github.com/dolthub/go-mysql-server/sql"
+
+	"github.com/dolthub/doltgresql/server/functions/framework"
+	pgtypes "github.com/dolthub/doltgresql/server/types"
+)
+
+// initLeft registers the functions to the catalog.
+func initLeft() {
+	framework.RegisterFunction(left_text_int32)
+}
+
+// left_text_int32 represents the PostgreSQL function of the same name, taking the same parameters.
+var left_text_int32 = framework.Function2{
+	Name:       "left",
+	Return:     pgtypes.Text,
+	Parameters: [2]*pgtypes.DoltgresType{pgtypes.Text, pgtypes.Int32},
+	Strict:     true,
+	Callable: func(ctx *sql.Context, _ [3]*pgtypes.DoltgresType, strInt any, nInt any) (any, error) {
+		str := strInt.(string)
+		n := nInt.(int32)
+		if n >= 0 {
+			if int(n) > len(str) {
+				return str, nil
+			}
+			return str[:n], nil
+		} else {
+			if len(str)+int(n) <= 0 {
+				return "", nil
+			}
+			return str[:len(str)+int(n)], nil
+		}
+	},
+}