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// Copyright 2016 Google Inc. All Rights Reserved.
//
// 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 optional provides versions of primitive types that can
// be nil. These are useful in methods that update some of an API object's
// fields.
package optional
import (
"fmt"
"strings"
)
type (
// Bool is either a bool or nil.
Bool interface{}
// String is either a string or nil.
String interface{}
// Int is either an int or nil.
Int interface{}
// Uint is either a uint or nil.
Uint interface{}
// Float64 is either a float64 or nil.
Float64 interface{}
)
// ToBool returns its argument as a bool.
// It panics if its argument is nil or not a bool.
func ToBool(v Bool) bool {
x, ok := v.(bool)
if !ok {
doPanic("Bool", v)
}
return x
}
// ToString returns its argument as a string.
// It panics if its argument is nil or not a string.
func ToString(v String) string {
x, ok := v.(string)
if !ok {
doPanic("String", v)
}
return x
}
// ToInt returns its argument as an int.
// It panics if its argument is nil or not an int.
func ToInt(v Int) int {
x, ok := v.(int)
if !ok {
doPanic("Int", v)
}
return x
}
// ToUint returns its argument as a uint.
// It panics if its argument is nil or not a uint.
func ToUint(v Uint) uint {
x, ok := v.(uint)
if !ok {
doPanic("Uint", v)
}
return x
}
// ToFloat64 returns its argument as a float64.
// It panics if its argument is nil or not a float64.
func ToFloat64(v Float64) float64 {
x, ok := v.(float64)
if !ok {
doPanic("Float64", v)
}
return x
}
func doPanic(capType string, v interface{}) {
panic(fmt.Sprintf("optional.%s value should be %s, got %T", capType, strings.ToLower(capType), v))
}
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