mirror of
https://github.com/duke-git/lancet.git
synced 2026-02-04 12:52:28 +08:00
407 lines
6.3 KiB
Markdown
407 lines
6.3 KiB
Markdown
# Function
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function 函数包控制函数执行流程，包含部分函数式编程。
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<div STYLE="page-break-after: always;"></div>
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## 源码:
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- [https://github.com/duke-git/lancet/blob/main/function/function.go](https://github.com/duke-git/lancet/blob/main/function/function.go)
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- [https://github.com/duke-git/lancet/blob/main/function/watcher.go](https://github.com/duke-git/lancet/blob/main/function/watcher.go)
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<div STYLE="page-break-after: always;"></div>
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## 用法:
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```go
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import (
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"github.com/duke-git/lancet/v2/function"
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)
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```
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<div STYLE="page-break-after: always;"></div>
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## 目录
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- [After](#After)
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- [Before](#Before)
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- [CurryFn](#CurryFn)
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- [Compose](#Compose)
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- [Debounced](#Debounced)
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- [Delay](#Delay)
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- [Schedule](#Schedule)
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- [Pipeline](#Pipeline)
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- [Watcher](#Watcher)
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<div STYLE="page-break-after: always;"></div>
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## 文档
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### <span id="After">After</span>
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<p>创建一个函数，当他被调用n或更多次之后将马上触发fn</p>
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<b>函数签名:</b>
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```go
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func After(n int, fn any) func(args ...any) []reflect.Value
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```
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<b>示例:</b>
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```go
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package main
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import (
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"fmt"
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"github.com/duke-git/lancet/v2/function"
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)
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func main() {
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fn := function.After(2, func() {
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fmt.Println("hello")
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})
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fn()
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fn()
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// Output:
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// hello
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}
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```
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### <span id="Before">Before</span>
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<p>创建一个函数，调用次数不超过n次，之后再调用这个函数，将返回一次最后调用fn的结果</p>
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<b>函数签名:</b>
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```go
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func Before(n int, fn any) func(args ...any) []reflect.Value
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```
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<b>示例:</b>
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```go
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package main
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import (
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"fmt"
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"github.com/duke-git/lancet/v2/function"
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"github.com/duke-git/lancet/v2/internal"
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)
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func main() {
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fn := function.Before(2, func() {
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fmt.Println("hello")
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})
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fn()
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fn()
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fn()
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fn()
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// Output:
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// hello
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// hello
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}
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```
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### <span id="CurryFn">CurryFn</span>
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<p>创建柯里化函数</p>
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<b>函数签名:</b>
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```go
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type CurryFn[T any] func(...T) T
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func (cf CurryFn[T]) New(val T) func(...T) T
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```
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<b>示例:</b>
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```go
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package main
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import (
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"fmt"
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"github.com/duke-git/lancet/v2/function"
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)
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func main() {
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add := func(a, b int) int {
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return a + b
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}
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var addCurry function.CurryFn[int] = func(values ...int) int {
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return add(values[0], values[1])
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}
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add1 := addCurry.New(1)
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result := add1(2)
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fmt.Println(result)
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// Output:
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// 3
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}
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```
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### <span id="Compose">Compose</span>
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<p>从右至左组合函数列表fnList，返回组合后的函数</p>
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<b>函数签名:</b>
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```go
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func Compose[T any](fnList ...func(...T) T) func(...T) T
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```
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<b>示例:</b>
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```go
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package main
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import (
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"fmt"
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"github.com/duke-git/lancet/v2/function"
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)
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func main() {
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toUpper := func(strs ...string) string {
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return strings.ToUpper(strs[0])
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}
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toLower := func(strs ...string) string {
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return strings.ToLower(strs[0])
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}
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transform := function.Compose(toUpper, toLower)
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result := transform("aBCde")
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fmt.Println(result)
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// Output:
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// ABCDE
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}
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```
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### <span id="Debounced">Debounced</span>
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<p>创建一个debounced函数，该函数延迟调用fn直到自上次调用debounced函数后等待持续时间过去。</p>
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<b>函数签名:</b>
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```go
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func Debounced(fn func(), duration time.Duration) func()
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```
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<b>示例:</b>
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```go
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package main
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import (
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"fmt"
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"github.com/duke-git/lancet/v2/function"
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)
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func main() {
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count := 0
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add := func() {
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count++
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}
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debouncedAdd := function.Debounced(add, 50*time.Microsecond)
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debouncedAdd()
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debouncedAdd()
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debouncedAdd()
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debouncedAdd()
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time.Sleep(100 * time.Millisecond)
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fmt.Println(count)
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debouncedAdd()
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time.Sleep(100 * time.Millisecond)
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fmt.Println(count)
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// Output:
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// 1
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// 2
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}
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```
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### <span id="Delay">Delay</span>
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<p>延迟delay时间后调用函数</p>
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<b>函数签名:</b>
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```go
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func Delay(delay time.Duration, fn any, args ...any)
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```
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<b>示例:</b>
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```go
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package main
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import (
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"fmt"
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"github.com/duke-git/lancet/v2/function"
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)
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func main() {
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var print = func(s string) {
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fmt.Println(s)
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}
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function.Delay(2*time.Second, print, "hello")
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// Output:
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// hello
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}
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```
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### <span id="Schedule">Schedule</span>
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<p>每次持续时间调用函数，直到关闭返回的 bool chan</p>
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<b>函数签名:</b>
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```go
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func Schedule(d time.Duration, fn any, args ...any) chan bool
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```
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<b>示例:</b>
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```go
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package main
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import (
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"fmt"
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"github.com/duke-git/lancet/v2/function"
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)
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func main() {
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count := 0
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increase := func() {
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count++
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}
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stop := function.Schedule(2*time.Second, increase)
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time.Sleep(2 * time.Second)
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close(stop)
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fmt.Println(count)
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// Output:
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// 2
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}
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```
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### <span id="Pipeline">Pipeline</span>
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<p>执行函数pipeline.</p>
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<b>函数签名:</b>
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```go
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func Pipeline[T any](funcs ...func(T) T) func(T) T
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```
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<b>示例:</b>
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```go
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package main
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import (
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"fmt"
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"github.com/duke-git/lancet/v2/function"
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)
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func main() {
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addOne := func(x int) int {
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return x + 1
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}
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double := func(x int) int {
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return 2 * x
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}
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square := func(x int) int {
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return x * x
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}
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fn := function.Pipeline(addOne, double, square)
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result := fn(2)
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fmt.Println(result)
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// Output:
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// 36
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}
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```
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### <span id="Watcher">Watcher</span>
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<p>Watcher用于记录代码执行时间。可以启动/停止/重置手表定时器。获取函数执行的时间。</p>
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<b>函数签名:</b>
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```go
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type Watcher struct {
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startTime int64
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stopTime int64
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excuting bool
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}
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func NewWatcher() *Watcher
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func (w *Watcher) Start() //start the watcher
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func (w *Watcher) Stop() //stop the watcher
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func (w *Watcher) Reset() //reset the watcher
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func (w *Watcher) GetElapsedTime() time.Duration //get the elapsed time of function execution
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```
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<b>示例:</b>
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```go
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package main
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import (
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"fmt"
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"github.com/duke-git/lancet/v2/function"
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)
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func main() {
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w := function.NewWatcher()
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w.Start()
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longRunningTask()
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fmt.Println(w.excuting) //true
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w.Stop()
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eapsedTime := w.GetElapsedTime().Milliseconds()
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fmt.Println(eapsedTime)
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w.Reset()
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}
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func longRunningTask() {
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var slice []int64
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for i := 0; i < 10000000; i++ {
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slice = append(slice, int64(i))
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}
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}
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```
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