chore: import upstream snapshot with attribution

server/functions/framework/cast.go

@@ -0,0 +1,76 @@
+// 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 framework
+
+import (
+	"github.com/dolthub/doltgresql/core/casts"
+	"github.com/dolthub/doltgresql/core/id"
+	pgtypes "github.com/dolthub/doltgresql/server/types"
+)
+
+// TODO: no need to use these functions, should instead add everything directly to built-in.
+//  For now, this just makes the transition easier since it's less to rewrite
+
+// TypeCast is used to cast from one type to another.
+type TypeCast struct {
+	FromType *pgtypes.DoltgresType
+	ToType   *pgtypes.DoltgresType
+	Function pgtypes.TypeCastFunction
+}
+
+// MustAddExplicitTypeCast registers the given explicit type cast. Panics if an error occurs.
+func MustAddExplicitTypeCast(builtInCasts map[id.Cast]casts.Cast, cast TypeCast) {
+	castID := id.NewCast(cast.FromType.ID, cast.ToType.ID)
+	if _, ok := builtInCasts[castID]; ok {
+		panic("duplicate built-in cast")
+	}
+	builtInCasts[castID] = casts.Cast{
+		ID:       castID,
+		CastType: casts.CastType_Explicit,
+		Function: id.NullFunction,
+		BuiltIn:  cast.Function,
+		UseInOut: false,
+	}
+}
+
+// MustAddAssignmentTypeCast registers the given assignment type cast. Panics if an error occurs.
+func MustAddAssignmentTypeCast(builtInCasts map[id.Cast]casts.Cast, cast TypeCast) {
+	castID := id.NewCast(cast.FromType.ID, cast.ToType.ID)
+	if _, ok := builtInCasts[castID]; ok {
+		panic("duplicate built-in cast")
+	}
+	builtInCasts[castID] = casts.Cast{
+		ID:       castID,
+		CastType: casts.CastType_Assignment,
+		Function: id.NullFunction,
+		BuiltIn:  cast.Function,
+		UseInOut: false,
+	}
+}
+
+// MustAddImplicitTypeCast registers the given implicit type cast. Panics if an error occurs.
+func MustAddImplicitTypeCast(builtInCasts map[id.Cast]casts.Cast, cast TypeCast) {
+	castID := id.NewCast(cast.FromType.ID, cast.ToType.ID)
+	if _, ok := builtInCasts[castID]; ok {
+		panic("duplicate built-in cast")
+	}
+	builtInCasts[castID] = casts.Cast{
+		ID:       castID,
+		CastType: casts.CastType_Implicit,
+		Function: id.NullFunction,
+		BuiltIn:  cast.Function,
+		UseInOut: false,
+	}
+}