// Copyright 2017 PingCAP, 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package types

// EvalType indicates the specified types that arguments and result of a built-in function should be.
type EvalType byte

const (
	// ETInt represents type INT in evaluation.
	ETInt EvalType = iota
	// ETReal represents type REAL in evaluation.
	ETReal
	// ETDecimal represents type DECIMAL in evaluation.
	ETDecimal
	// ETString represents type STRING in evaluation.
	ETString
	// ETDatetime represents type DATETIME in evaluation.
	ETDatetime
	// ETTimestamp represents type TIMESTAMP in evaluation.
	ETTimestamp
	// ETDuration represents type DURATION in evaluation.
	ETDuration
	// ETJson represents type JSON in evaluation.
	ETJson
)

// IsStringKind returns true for ETString, ETDatetime, ETTimestamp, ETDuration, ETJson EvalTypes.
func (et EvalType) IsStringKind() bool {
	return et == ETString || et == ETDatetime ||
		et == ETTimestamp || et == ETDuration || et == ETJson
}