all tasks

Task/Y-combinator/Go/y-combinator.go

@@ -0,0 +1,41 @@
+package main
+
+import "fmt"
+
+type Func func(int) int
+type FuncFunc func(Func) Func
+type RecursiveFunc func (RecursiveFunc) Func
+
+func main() {
+	fac := fix(almost_fac)
+	fib := fix(almost_fib)
+	fmt.Println("fac(10) = ", fac(10))
+	fmt.Println("fib(10) = ", fib(10))
+}
+
+func fix(f FuncFunc) Func {
+	g := func(r RecursiveFunc) Func {
+		return f(func(x int) int {
+			return r(r)(x)
+		})
+	}
+	return g(g)
+}
+
+func almost_fac(f Func) Func {
+	return func(x int) int {
+		if x <= 1 {
+			return 1
+		}
+		return x * f(x-1)
+	}
+}
+
+func almost_fib(f Func) Func {
+	return func(x int) int {
+		if x <= 2 {
+			return 1
+		}
+		return f(x-1)+f(x-2)
+	}
+}