Add tasks for all the new languages

Task/First-class-functions/Nim/first-class-functions.nim

@@ -0,0 +1,27 @@
+from math import nil
+
+proc cube(x: float64) : float64 {.procvar.} =
+  math.pow(x, 3)
+
+proc cuberoot(x: float64) : float64 {.procvar.} =
+  math.pow(x, 1/3)
+
+proc compose[A](f: proc(x: A): A, g: proc(x: A): A) : (proc(x: A): A) =
+  proc c(x: A): A {.closure.} =
+    f(g(x))
+  return c
+
+proc sin(x: float64) : float64 {.procvar.} =
+  math.sin(x)
+proc asin(x: float64) : float64 {.procvar.}=
+  math.arcsin(x)
+proc cos(x: float64) : float64 {.procvar.} =
+  math.cos(x)
+proc acos(x: float64) : float64 {.procvar.} =
+  math.arccos(x)
+
+var fun = @[sin, cos, cube]
+var inv = @[asin, acos, cuberoot]
+
+for i in 0..2:
+  echo $compose(inv[i], fun[i])(0.5)