June 2018 Update

Task/Generator-Exponential/Julia/generator-exponential.julia

@@ -1,16 +1,20 @@
-drop(n, gen) = (for i=1:n gen() end ; gen)
+drop(gen::Function, n::Integer) = (for _ in 1:n gen() end; gen)
+take(gen::Function, n::Integer) = collect(gen() for _ in 1:n)
 
-take(n, gen) = [gen() for i=1:n]
-
-pgen(n) = let x=0; () -> (x+=1)^n; end
-
-function genfilter(gen1, gen2)
-  let r1 = -Inf, r2 = gen2()
-    () -> begin
-           r1 = gen1()
-           while r2 < r1   r2 = gen2() end
-           while r1 == r2  r1 = gen1() end
-           r1
-          end
-  end
+function pgen(n::Number)
+    x = 0
+    return () -> (x += 1) ^ n
 end
+
+function genfilter(g1::Function, g2::Function)
+    local r1
+    local r2 = g2()
+    return () -> begin
+        r1 = g1()
+        while r2 <  r1 r2 = g2() end
+        while r1 == r2 r1 = g1() end
+        return r1
+    end
+end
+
+@show take(drop(genfilter(pgen(2), pgen(3)), 20), 10)