goptional 一个轻量级库,为golang中的可选值提供容器
goptional 一个轻量级库,为golang中的可选值提供容器
Go 其它杂项
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详细介绍
goptional is a lightweight library to provide a container for optional values in golang.
Initialization
// Create an optional with an initial value
opt, _ := optional.Of(5)
// An optional created with a nil value returns an error
_, err := optional.Of(nil)
// Create an empty optional
opt := optional.OfEmpty()
Nil pointer
var nilPointer *int
_, err := Of(nilPointer) // err is not nil
Nil array
nilArray := [3]int{}
_, err := Of(nilArray) // err is not nil
Nil slice
var nilSlice []int
_, err := Of(nilSlice) // err is not nil
Nil map
var nilMap map[int]int
_, err := Of(nilMap) // err is not nil
Nil function
var nilFunction func()
_, err := Of(nilFunction) // err is not nil
Nil structure
type Point struct {
x, y int
}
var emptyPoint Point
_, err = Of(emptyPoint) // err is nil
Features
// Get its value and an eventual error if the optional is empty
v, err := opt.Get()
// Get the optional value regardless of its emptiness
v := opt.GetValue()
// Test if the optional is not empty
opt.IsPresent()
// Execute a function if the optional is not empty
opt.IfPresent(f)
// Execute a function if the optional is empty
opt.IfNotPresent(f)
// Returns an error if the optional is not empty (otherwise returns a nil value)
err := opt.IfPresentError(errors.New("present")
// Returns an error if the optional is empty (otherwise returns a nil value)
err := opt.IfNotPresentError(errors.New("not present")
// Panic if the optional is not empty
opt.IfPresentPanic("present")
// Panic if the optional is empty
opt.IfNotPresentPanic("not present")