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Task/Permutations/Sidef/permutations-2.sidef

@@ -0,0 +1,21 @@
+func forperm(callback, n) {
+    var idx = @^n
+
+    loop {
+        callback([idx...])
+
+        var p = n-1
+        while (idx[p-1] > idx[p]) {--p}
+        p == 0 && return()
+
+        var d = p
+        idx += idx.splice(p).reverse
+
+        while (idx[p-1] > idx[d]) {++d}
+        idx.swap(p-1, d)
+    }
+
+    return()
+}
+
+forperm({|p| say p }, 3)