56 lines
1.3 KiB
Go
56 lines
1.3 KiB
Go
package main
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import "fmt"
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// Using a method bound to a function type:
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// fn is a simple function taking an integer and returning another.
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type fn func(int) int
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// fs applies fn to each argument returning all results.
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func (f fn) fs(s ...int) (r []int) {
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for _, i := range s {
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r = append(r, f(i))
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}
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return r
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}
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// Two simple functions for demonstration.
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func f1(i int) int { return i * 2 }
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func f2(i int) int { return i * i }
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// Another way:
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// addn returns a function that adds n to a sequence of numbers
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func addn(n int) func(...int) []int {
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return func(s ...int) []int {
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var r []int
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for _, i := range s {
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r = append(r, n+i)
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}
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return r
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}
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}
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func main() {
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// Turning a method into a function bound to it's reciever:
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fsf1 := fn(f1).fs
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fsf2 := fn(f2).fs
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// Or using a function that returns a function:
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fsf3 := addn(100)
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s := []int{0, 1, 2, 3}
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fmt.Println("For s =", s)
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fmt.Println(" fsf1:", fsf1(s...)) // Called with a slice
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fmt.Println(" fsf2:", fsf2(0, 1, 2, 3)) // ... or with individual arguments
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fmt.Println(" fsf3:", fsf3(0, 1, 2, 3))
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fmt.Println(" fsf2(fsf1):", fsf2(fsf1(s...)...))
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s = []int{2, 4, 6, 8}
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fmt.Println("For s =", s)
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fmt.Println(" fsf1:", fsf1(2, 4, 6, 8))
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fmt.Println(" fsf2:", fsf2(s...))
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fmt.Println(" fsf3:", fsf3(s...))
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fmt.Println(" fsf3(fsf1):", fsf3(fsf1(s...)...))
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}
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