A-M baby

Task/Generator-Exponential/Go/generator-exponential-1.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+    "fmt"
+    "math"
+)
+
+// note: exponent not limited to ints
+func newPowGen(e float64) func() float64 {
+    var i float64
+    return func() (r float64) {
+        r = math.Pow(i, e)
+        i++
+        return
+    }
+}
+
+// given two functions af, bf, both monotonically increasing, return a
+// new function that returns values of af not returned by bf.
+func newMonoIncA_NotMonoIncB_Gen(af, bf func() float64) func() float64 {
+    a, b := af(), bf()
+    return func() (r float64) {
+        for {
+            if a < b {
+                r = a
+                a = af()
+                break
+            }
+            if b == a {
+                a = af()
+            }
+            b = bf()
+        }
+        return
+    }
+}
+
+func main() {
+    fGen := newMonoIncA_NotMonoIncB_Gen(newPowGen(2), newPowGen(3))
+    for i := 0; i < 20; i++ {
+        fGen()
+    }
+    for i := 0; i < 10; i++ {
+        fmt.Print(fGen(), " ")
+    }
+    fmt.Println()
+}