106 lines
2.7 KiB
Go
106 lines
2.7 KiB
Go
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package main
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import (
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"fmt"
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"math"
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"reflect"
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)
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func compute(fn func(float64, float64) float64) float64 {
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return fn(2, 7)
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}
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func incrementer() func() int { // returns a function -that requires and returns an int value-
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curVal := 0
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return func() int {
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curVal += 1
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return curVal
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}
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}
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func incrementWithNum() func(int) int { // returns a function -that requires and returns an int value-
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curVal := 0
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return func(i int) int {
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curVal += i
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return curVal
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}
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}
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func adder(a int) func(int) int { // gets first value with adder(int), returns a function -that requires and returns an int value-
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return func(b int) int {
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return a + b
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}
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}
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func main() {
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fmt.Println("Includes function values, closures and other function related subject, if you want to see functions basics, go to 0basics/basics.go > Section \"Functions\"")
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fmt.Println("Functions are values too, They can be passed around just like other values")
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sum := func(x, y float64) float64 {
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return float64(x + y)
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}
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fmt.Println(sum(2, 3))
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fmt.Println(sum)
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fmt.Println(&sum)
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fmt.Println(reflect.TypeOf(sum))
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fmt.Println(reflect.TypeOf(sum).Kind())
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fmt.Printf("\n\n")
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fmt.Println("Function values may be used as function arguments and return values")
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fmt.Println(compute(sum))
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fmt.Println(compute(math.Pow))
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fmt.Printf("%p\n", compute)
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fmt.Println(reflect.TypeOf(compute))
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fmt.Println(reflect.TypeOf(compute).Kind())
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fmt.Printf("\ncompute a function that gets a function as an argument (that gets two float64 values and returns float64) and returns float64\n\n\n")
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fmt.Println("Go functions may be closures")
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fmt.Println("With this feature inner functions can read outer functions values, use them. Also with assigning it to a variable we can use same function from scratch")
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fmt.Println("A bit confusing but just see the examples:")
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// SECTION incrementer()
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newInc1 := incrementer()
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fmt.Println(newInc1())
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fmt.Println(newInc1())
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fmt.Println(newInc1())
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fmt.Printf("\n")
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newInc1 = incrementer() // you can initialize again
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fmt.Println(newInc1())
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newInc2 := incrementer()
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newInc2()
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newInc2()
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newInc2()
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newInc2()
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newInc2()
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fmt.Println(newInc2())
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fmt.Println(newInc1())
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fmt.Printf("\n\n")
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// !SECTION
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// SECTION incrementWithNum()
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numInc1 := incrementWithNum()
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// fmt.Println(numInc1()) // ERROR, not enough arguments in call to numInc1
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fmt.Println(numInc1(4)) // Increments curVal by 4 and print out
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fmt.Println(numInc1(3)) // Increments curVal by 3 and print out
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fmt.Println(numInc1(2)) // "" 2 ""
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fmt.Println(numInc1(1)) // "" 1 ""
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fmt.Printf("\n\n")
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// !SECTION
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// SECTION adder()
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myAdder1 := adder(5)
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fmt.Println(myAdder1(1)) // 5+1=6
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fmt.Println(myAdder1(8)) // 5+8=13
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myAdder2 := adder(8)
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fmt.Println(myAdder2(myAdder1(3))) // 8 + (5+3)
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}
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