Add cast

CONTRIBUTING.md

@@ -280,7 +280,7 @@ Type structs should not handle PostgreSQL types, even which is different compare
 For example `SMALLINT` and `INTEGER` are classified as two different types in DoltgreSQL, while they both fall under a generic `Number` type in [GMS](https://github.com/dolthub/go-mysql-server).
 This difference is due to how types are treated in PostgreSQL, with one such example being function overloading, where two different functions sharing the same name are differentiated only by their parameter types.
 
-When adding types, it is usually necessary to also add any relevant casts to `server/functions/framework/cast.go::init()`.
+When adding types, it is usually necessary to also add any relevant casts to `server/cast/init.go::Init()`.
 You'll need to add casts that go from existing types to the new type, and also from the new type to existing types (casts are not bidirectional).
 
 TODO: adding operator functions

server/cast/char.go

@@ -164,6 +164,13 @@ func charExplicit() {
 			return handleCharExplicitCast(val.(string), targetType)
 		},
 	})
+	framework.MustAddExplicitTypeCast(framework.TypeCast{
+		FromType: pgtypes.BpChar,
+		ToType:   pgtypes.Name,
+		Function: func(ctx framework.Context, val any, targetType pgtypes.DoltgresType) (any, error) {
+			return handleCharExplicitCast(val.(string), targetType)
+		},
+	})
 }
 
 // charImplicit registers all implicit casts. This comprises only the "From" types.
@@ -297,4 +304,11 @@ func charImplicit() {
 			return handleCharImplicitCast(val.(string), targetType)
 		},
 	})
+	framework.MustAddImplicitTypeCast(framework.TypeCast{
+		FromType: pgtypes.BpChar,
+		ToType:   pgtypes.Name,
+		Function: func(ctx framework.Context, val any, targetType pgtypes.DoltgresType) (any, error) {
+			return handleCharImplicitCast(val.(string), targetType)
+		},
+	})
 }

server/cast/utils.go

@@ -34,6 +34,9 @@ func handleCharExplicitCast(str string, targetType pgtypes.DoltgresType) (string
 			return str + strings.Repeat(" ", int(targetType.Length-runeCount)), nil
 		}
 		return str, nil
+	case pgtypes.NameType:
+		str, _ = truncateString(str, targetType.Length)
+		return str, nil
 	case pgtypes.VarCharType:
 		if targetType.IsUnbounded() {
 			return str, nil
@@ -61,6 +64,12 @@ func handleCharImplicitCast(str string, targetType pgtypes.DoltgresType) (string
 				return str, nil
 			}
 		}
+	case pgtypes.NameType:
+		if uint32(utf8.RuneCountInString(str)) > targetType.Length {
+			return "", fmt.Errorf("value too long for type %s", targetType.String())
+		} else {
+			return str, nil
+		}
 	case pgtypes.VarCharType:
 		if !targetType.IsUnbounded() && uint32(utf8.RuneCountInString(str)) > targetType.Length {
 			return "", fmt.Errorf("value too long for type %s", targetType.String())

server/cast/varchar.go

@@ -164,6 +164,13 @@ func varcharExplicit() {
 			return handleCharExplicitCast(val.(string), targetType)
 		},
 	})
+	framework.MustAddExplicitTypeCast(framework.TypeCast{
+		FromType: pgtypes.VarChar,
+		ToType:   pgtypes.Name,
+		Function: func(ctx framework.Context, val any, targetType pgtypes.DoltgresType) (any, error) {
+			return handleCharExplicitCast(val.(string), targetType)
+		},
+	})
 }
 
 // varcharImplicit registers all implicit casts. This comprises only the "From" types.
@@ -297,4 +304,11 @@ func varcharImplicit() {
 			return handleCharImplicitCast(val.(string), targetType)
 		},
 	})
+	framework.MustAddImplicitTypeCast(framework.TypeCast{
+		FromType: pgtypes.VarChar,
+		ToType:   pgtypes.Name,
+		Function: func(ctx framework.Context, val any, targetType pgtypes.DoltgresType) (any, error) {
+			return handleCharImplicitCast(val.(string), targetType)
+		},
+	})
 }