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dudaodong a6eaaef563 doc: add go playground demo

2024-03-06 15:28:55 +08:00

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Function

Package function can control the flow of function execution and support part of functional programming.

Source:

Usage:

import (
    "github.com/duke-git/lancet/v2/function"
)

Index

After
Before
CurryFn
Compose
Debounced
Delay
Schedule
Pipeline
Watcher
And
Or
Negate
Nor
Xnor
Nand
AcceptIf

Documentation

After

Creates a function that invokes given func once it's called n or more times.

Signature:

func After(n int, fn any) func(args ...any) []reflect.Value

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    fn := function.After(2, func() {
        fmt.Println("hello")
    })

    fn()
    fn()

    // Output:
    // hello
}

Before

creates a function that invokes func once it's called less than n times.

Signature:

func Before(n int, fn any) func(args ...any) []reflect.Value

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    fn := function.Before(2, func() {
        fmt.Println("hello")
    })

    fn()
    fn()
    fn()
    fn()

    // Output:
    // hello
    // hello
}

CurryFn

Make curry function.

Signature:

type CurryFn[T any] func(...T) T
func (cf CurryFn[T]) New(val T) func(...T) T

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    add := func(a, b int) int {
        return a + b
    }

    var addCurry function.CurryFn[int] = func(values ...int) int {
        return add(values[0], values[1])
    }
    add1 := addCurry.New(1)

    result := add1(2)

    fmt.Println(result)

    // Output:
    // 3
}

Compose

Compose the function list from right to left, then return the composed function.

Signature:

func Compose[T any](fnList ...func(...T) T) func(...T) T

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    toUpper := func(strs ...string) string {
        return strings.ToUpper(strs[0])
    }
    toLower := func(strs ...string) string {
        return strings.ToLower(strs[0])
    }
    transform := function.Compose(toUpper, toLower)

    result := transform("aBCde")

    fmt.Println(result)

    // Output:
    // ABCDE
}

Debounced

Creates a debounced function that delays invoking fn until after wait duration have elapsed since the last time the debounced function was invoked.

Signature:

func Debounced(fn func(), duration time.Duration) func()

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    count := 0

    add := func() {
        count++
    }

    debouncedAdd := function.Debounced(add, 50*time.Microsecond)

    debouncedAdd()
    debouncedAdd()
    debouncedAdd()
    debouncedAdd()

    time.Sleep(100 * time.Millisecond)

    fmt.Println(count)

    debouncedAdd()

    time.Sleep(100 * time.Millisecond)

    fmt.Println(count)

    // Output:
    // 1
    // 2
}

Delay

Invoke function after delayed time.

Signature:

func Delay(delay time.Duration, fn any, args ...any)

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    var print = func(s string) {
        fmt.Println(s)
    }

    function.Delay(2*time.Second, print, "hello")

    // Output:
    // hello
}

Schedule

Invoke function every duration time, until close the returned bool chan.

Signature:

func Schedule(d time.Duration, fn any, args ...any) chan bool

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    count := 0

    increase := func() {
        count++
    }

    stop := function.Schedule(2*time.Second, increase)

    time.Sleep(2 * time.Second)
    close(stop)

    fmt.Println(count)

    // Output:
    // 2
}

Pipeline

Pipeline takes a list of functions and returns a function whose param will be passed into the functions one by one.

Signature:

func Pipeline[T any](funcs ...func(T) T) func(T) T

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    addOne := func(x int) int {
        return x + 1
    }
    double := func(x int) int {
        return 2 * x
    }
    square := func(x int) int {
        return x * x
    }

    fn := function.Pipeline(addOne, double, square)

    result := fn(2)

    fmt.Println(result)

    // Output:
    // 36
}

Watcher

Watcher is used for record code excution time. can start/stop/reset the watch timer. get the elapsed time of function execution.

Signature:

type Watcher struct {
    startTime int64
    stopTime  int64
    excuting  bool
}
func NewWatcher() *Watcher
func (w *Watcher) Start() //start the watcher
func (w *Watcher) Stop() //stop the watcher
func (w *Watcher) Reset() //reset the watcher
func (w *Watcher) GetElapsedTime() time.Duration //get the elapsed time of function execution

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    w := function.NewWatcher()

    w.Start()

    longRunningTask()

    fmt.Println(w.excuting) //true

    w.Stop()

    eapsedTime := w.GetElapsedTime().Milliseconds()

    fmt.Println(eapsedTime)

    w.Reset()
}

func longRunningTask() {
    var slice []int64
    for i := 0; i < 10000000; i++ {
        slice = append(slice, int64(i))
    }
}

And

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.

Signature:

func And[T any](predicates ...func(T) bool) func(T) bool

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    isNumericAndLength5 := function.And(
        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
        func(s string) bool { return len(s) == 5 },
    )

    fmt.Println(isNumericAndLength5("12345"))
    fmt.Println(isNumericAndLength5("1234"))
    fmt.Println(isNumericAndLength5("abcde"))

    // Output:
    // true
    // false
    // false
}

Or

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.

Signature:

func Or[T any](predicates ...func(T) bool) func(T) bool

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    containsDigitOrSpecialChar := function.Or(
        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
        func(s string) bool { return strings.ContainsAny(s, "!@#$%") },
    )

    fmt.Println(containsDigitOrSpecialChar("hello!"))
    fmt.Println(containsDigitOrSpecialChar("hello"))

    // Output:
    // true
    // false
}

Negate

Returns a predicate that represents the logical negation of this predicate.

Signature:

func Negate[T any](predicate func(T) bool) func(T) bool

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    // Define some simple predicates for demonstration
    isUpperCase := func(s string) bool {
        return strings.ToUpper(s) == s
    }
    isLowerCase := func(s string) bool {
        return strings.ToLower(s) == s
    }
    isMixedCase := function.Negate(function.Or(isUpperCase, isLowerCase))

    fmt.Println(isMixedCase("ABC"))
    fmt.Println(isMixedCase("AbC"))

    // Output:
    // false
    // true
}

Nor

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.

Signature:

func Nor[T any](predicates ...func(T) bool) func(T) bool

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    match := function.Nor(
        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
        func(s string) bool { return len(s) == 5 },
    )

    fmt.Println(match("dbcdckkeee"))


    match = function.Nor(
        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
        func(s string) bool { return len(s) == 5 },
    )

    fmt.Println(match("0123456789"))

    // Output:
    // true
    // false
}

Nand

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.

Signature:

func Nand[T any](predicates ...func(T) bool) func(T) bool

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {
    isNumericAndLength5 := function.Nand(
        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
        func(s string) bool { return len(s) == 5 },
    )

    fmt.Println(isNumericAndLength5("12345"))
    fmt.Println(isNumericAndLength5("1234"))
    fmt.Println(isNumericAndLength5("abcdef"))

    // Output:
    // false
    // false
    // true
}

Xnor

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.

Signature:

func Xnor[T any](predicates ...func(T) bool) func(T) bool

Example:Run

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
}

AcceptIf

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.

Signature:

func AcceptIf[T any](predicate func(T) bool, apply func(T) T) func(T) (T, bool)

Example:Run

package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/function"
)

func main() {

    adder := function.AcceptIf(
        function.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
}

14 KiB Raw Blame History

Function

Source:

Usage:

Index

Documentation

After

Before

CurryFn

Compose

Debounced

Delay

Schedule

Pipeline

Watcher

And

Or

Negate

Nor

Nand

Xnor

AcceptIf

14 KiB

Raw Blame History