mirror of
https://github.com/duke-git/lancet.git
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e138043289
AcceptIf returns another function of the same signature as the apply function but also includes a bool value to indicate success or failure. A predicate function that takes an argument of type T and returns a bool. An apply function that also takes an argument of type T and returns a modified value of the same type.
695 lines
13 KiB
Markdown
695 lines
13 KiB
Markdown
# Function
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Package function can control the flow of function execution and support part of functional programming.
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<div STYLE="page-break-after: always;"></div>
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## Source:
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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/predicate.go](https://github.com/duke-git/lancet/blob/main/function/predicate.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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## Usage:
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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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## Index
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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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- [And](#And)
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- [Or](#Or)
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- [Negate](#Negate)
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- [Nor](#Nor)
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- [Xnor](#Xnor)
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- [Nand](#Nand)
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- [AcceptIf](#AcceptIf)
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<div STYLE="page-break-after: always;"></div>
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## Documentation
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### <span id="After">After</span>
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<p>Creates a function that invokes given func once it's called n or more times.</p>
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<b>Signature:</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>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/eRD5k2vzUVX)</span></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>creates a function that invokes func once it's called less than n times.</p>
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<b>Signature:</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>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/0HqUDIFZ3IL)</span></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.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>Make curry function.</p>
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<b>Signature:</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>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/5HopfDwANKX)</span></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>Compose the function list from right to left, then return the composed function.</p>
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<b>Signature:</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>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/KKfugD4PKYF)</span></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>Creates a debounced function that delays invoking fn until after wait duration have elapsed since the last time the debounced function was invoked.</p>
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<b>Signature:</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>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/absuEGB_GN7)</span></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>Invoke function after delayed time.</p>
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<b>Signature:</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>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/Ivtc2ZE-Tye)</span></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>Invoke function every duration time, until close the returned bool chan.</p>
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<b>Signature:</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>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/hbON-Xeyn5N)</span></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>Pipeline takes a list of functions and returns a function whose param will be passed into
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the functions one by one.</p>
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<b>Signature:</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>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/mPdUVvj6HD6)</span></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 is used for record code excution time. can start/stop/reset the watch timer. get the elapsed time of function execution.</p>
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<b>Signature:</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>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/l2yrOpCLd1I)</span></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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### <span id="And">And</span>
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<p>Returns a composed predicate that represents the logical AND of a list of predicates. It evaluates to true only if all predicates evaluate to true for the given value.</p>
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<b>Signature:</b>
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```go
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func And[T any](predicates ...func(T) bool) func(T) bool
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```
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<b>Example:</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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isNumericAndLength5 := function.And(
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func(s string) bool { return strings.ContainsAny(s, "0123456789") },
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func(s string) bool { return len(s) == 5 },
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)
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fmt.Println(isNumericAndLength5("12345"))
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fmt.Println(isNumericAndLength5("1234"))
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fmt.Println(isNumericAndLength5("abcde"))
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// Output:
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// true
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// false
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// false
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}
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```
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### <span id="Or">Or</span>
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<p>Returns a composed predicate that represents the logical OR of a list of predicates. It evaluates to true if at least one of the predicates evaluates to true for the given value.</p>
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<b>Signature:</b>
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```go
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func Or[T any](predicates ...func(T) bool) func(T) bool
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```
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<b>Example:</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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containsDigitOrSpecialChar := function.Or(
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func(s string) bool { return strings.ContainsAny(s, "0123456789") },
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func(s string) bool { return strings.ContainsAny(s, "!@#$%") },
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)
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fmt.Println(containsDigitOrSpecialChar("hello!"))
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fmt.Println(containsDigitOrSpecialChar("hello"))
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// Output:
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// true
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// false
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}
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```
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### <span id="Negate">Negate</span>
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<p>Returns a predicate that represents the logical negation of this predicate.</p>
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<b>Signature:</b>
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```go
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func Negate[T any](predicate func(T) bool) func(T) bool
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```
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<b>Example:</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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// Define some simple predicates for demonstration
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isUpperCase := func(s string) bool {
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return strings.ToUpper(s) == s
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}
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isLowerCase := func(s string) bool {
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return strings.ToLower(s) == s
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}
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isMixedCase := function.Negate(function.Or(isUpperCase, isLowerCase))
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fmt.Println(isMixedCase("ABC"))
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fmt.Println(isMixedCase("AbC"))
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// Output:
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// false
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// true
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}
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```
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### <span id="Nor">Nor</span>
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<p>Returns a composed predicate that represents the logical NOR of a list of predicates. It evaluates to true only if all predicates evaluate to false for the given value.</p>
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<b>Signature:</b>
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```go
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func Nor[T any](predicates ...func(T) bool) func(T) bool
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```
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<b>Example:</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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match := function.Nor(
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func(s string) bool { return strings.ContainsAny(s, "0123456789") },
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func(s string) bool { return len(s) == 5 },
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)
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fmt.Println(match("dbcdckkeee"))
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match = function.Nor(
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func(s string) bool { return strings.ContainsAny(s, "0123456789") },
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func(s string) bool { return len(s) == 5 },
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)
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fmt.Println(match("0123456789"))
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// Output:
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// true
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// false
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}
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```
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### <span id="Nand">Nand</span>
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<p>Returns a composed predicate that represents the logical NAND of a list of predicates. It evaluates to true only if all predicates evaluate to false for the given value.</p>
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<b>Signature:</b>
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```go
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func Nand[T any](predicates ...func(T) bool) func(T) bool
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```
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<b>Example:</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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isNumericAndLength5 := function.Nand(
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func(s string) bool { return strings.ContainsAny(s, "0123456789") },
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func(s string) bool { return len(s) == 5 },
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)
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fmt.Println(isNumericAndLength5("12345"))
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fmt.Println(isNumericAndLength5("1234"))
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fmt.Println(isNumericAndLength5("abcdef"))
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// Output:
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// false
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// false
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// true
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}
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```
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### <span id="Xnor">Xnor</span>
|
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|
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<p>Returns a composed predicate that represents the logical XNOR of a list of predicates. It evaluates to true only if all predicates evaluate to true or false for the given value.</p>
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<b>Signature:</b>
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```go
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func Xnor[T any](predicates ...func(T) bool) func(T) bool
|
|
```
|
|
|
|
<b>Example:</b>
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"github.com/duke-git/lancet/v2/function"
|
|
)
|
|
|
|
func main() {
|
|
isEven := func(i int) bool { return i%2 == 0 }
|
|
isPositive := func(i int) bool { return i > 0 }
|
|
|
|
match := function.Xnor(isEven, isPositive)
|
|
|
|
fmt.Println(match(2))
|
|
fmt.Println(match(-3))
|
|
fmt.Println(match(3))
|
|
|
|
// Output:
|
|
// true
|
|
// true
|
|
// false
|
|
}
|
|
```
|
|
|
|
### <span id="AcceptIf">AcceptIf</span>
|
|
|
|
<p>AcceptIf returns another function of the same signature as the apply function but also includes a bool value to indicate success or failure.
|
|
A predicate function that takes an argument of type T and returns a bool.
|
|
An apply function that also takes an argument of type T and returns a modified value of the same type.</p>
|
|
|
|
<b>Signature:</b>
|
|
|
|
```go
|
|
func AcceptIf[T any](predicate func(T) bool, apply func(T) T) func(T) (T, bool)
|
|
```
|
|
|
|
<b>Example:</b>
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"github.com/duke-git/lancet/v2/function"
|
|
)
|
|
|
|
func main() {
|
|
|
|
adder := AcceptIf(
|
|
And(
|
|
func(x int) bool {
|
|
return x > 10
|
|
}, func(x int) bool {
|
|
return x%2 == 0
|
|
}),
|
|
func(x int) int {
|
|
return x + 1
|
|
},
|
|
)
|
|
|
|
result, ok := adder(20)
|
|
fmt.Println(result)
|
|
fmt.Println(ok)
|
|
|
|
result, ok = adder(21)
|
|
fmt.Println(result)
|
|
fmt.Println(ok)
|
|
|
|
// Output:
|
|
// 21
|
|
// true
|
|
// 0
|
|
// false
|
|
}
|
|
|
|
``` |