2016 Update

Task/Generator-Exponential/PHP/generator-exponential.php

@@ -0,0 +1,30 @@
+<?php
+function powers($m) {
+    for ($n = 0; ; $n++) {
+        yield pow($n, $m);
+    }
+}
+
+function filtered($s1, $s2) {
+    while (true) {
+        list($v, $f) = [$s1->current(), $s2->current()];
+        if ($v > $f) {
+            $s2->next();
+            continue;
+        } else if ($v < $f) {
+            yield $v;
+        }
+        $s1->next();
+    }
+}
+
+list($squares, $cubes) = [powers(2), powers(3)];
+$f = filtered($squares, $cubes);
+foreach (range(0, 19) as $i) {
+    $f->next();
+}
+foreach (range(20, 29) as $i) {
+    echo $i, "\t", $f->current(), "\n";
+    $f->next();
+}
+?>