Add tasks for all the new languages

Task/Permutations/Sidef/permutations-1.sidef

@@ -0,0 +1,3 @@
+[0,1,2].permutations { |p|
+    say p
+}

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)

Task/Permutations/Sidef/permutations-3.sidef

@@ -0,0 +1,11 @@
+func permutations(callback, set, perm=[]) {
+    set.is_empty && callback(perm)
+    for i in ^set {
+        __FUNC__(callback, [
+            set[(0 ..^ i)..., (i+1 ..^ set.len)...]
+        ], [perm..., set[i]])
+    }
+    return()
+}
+
+permutations({|p| say p }, [0,1,2])