Add tasks for all the new languages

Task/Power-set/EchoLisp/power-set.echolisp

@@ -0,0 +1,29 @@
+(define (set-cons a A)
+    (make-set (cons a A)))
+
+(define (power-set e)
+    (cond ((null? e)
+       (make-set (list ∅)))
+    (else (let [(ps (power-set (cdr e)))]
+       (make-set
+       (append ps (map set-cons (circular-list (car e)) ps)))))))
+
+(define B (make-set ' ( 🍎 🍇 🎂 🎄 )))
+(power-set B)
+    → { ∅ { 🍇 } { 🍇 🍎 } { 🍇 🍎 🎂 } { 🍇 🍎 🎂 🎄 } { 🍇 🍎 🎄 } { 🍇 🎂 } { 🍇 🎂 🎄 }
+      { 🍇 🎄 } { 🍎 } { 🍎 🎂 } { 🍎 🎂 🎄 } { 🍎 🎄 } { 🎂 } { 🎂 🎄 } { 🎄 } }
+
+;; The Von Neumann universe
+
+(define V0 (power-set null)) ;; null and ∅ are the same
+       → { ∅ }
+(define V1 (power-set V0))
+       → { ∅ { ∅ } }
+(define V2 (power-set V1))
+       → { ∅ { ∅ } { ∅ { ∅ } } { { ∅ } } }
+(define V3 (power-set V2))
+       → { ∅ { ∅ } { ∅ { ∅ } } …🔃 )
+(length V3) → 16
+(define V4 (power-set V3))
+(length V4)  → 65536
+;; length V5 = 2^65536 : out of bounds

Task/Power-set/FunL/power-set-1.funl

@@ -0,0 +1 @@
+def powerset( s ) = s.subsets().toSet()

Task/Power-set/FunL/power-set-2.funl

@@ -0,0 +1,5 @@
+def
+  powerset( {} ) = {{}}
+  powerset( s ) =
+    acc = powerset( s.tail() )
+    acc + map( x -> {s.head()} + x, acc )

Task/Power-set/FunL/power-set-3.funl

@@ -0,0 +1,5 @@
+import lists.foldr
+
+def powerset( s ) = foldr( \x, acc -> acc + map( a -> {x} + a, acc), {{}}, s )
+
+println( powerset({1, 2, 3, 4}) )

Task/Power-set/Nim/power-set.nim

@@ -0,0 +1,19 @@
+import sets, hashes
+
+proc hash(x): THash =
+  var h = 0
+  for i in x: h = h !& hash(i)
+  result = !$h
+
+proc powerset[T](inset: HashSet[T]): auto =
+  result = toSet([initSet[T]()])
+
+  for i in inset:
+    var tmp = result
+    for j in result:
+      var k = j
+      k.incl(i)
+      tmp.incl(k)
+    result = tmp
+
+echo powerset(toSet([1,2,3,4]))

Task/Power-set/Sidef/power-set.sidef

@@ -0,0 +1,4 @@
+var arr = %w(a b c)
+for i in (0 .. arr.len) {
+    say arr.combinations(i)
+}

Task/Power-set/jq/power-set-1.jq

@@ -0,0 +1,3 @@
+def powerset:
+  reduce .[] as $i ([[]];
+     reduce .[] as $r (.; . + [$r + [$i]]));

Task/Power-set/jq/power-set-2.jq

@@ -0,0 +1,7 @@
+# The power set of the empty set:
+  [] | powerset
+  # => [[]]
+
+# The power set of the set which contains only the empty set:
+  [ [] ] | powerset
+  # => [[],[[]]]

Task/Power-set/jq/power-set-3.jq

@@ -0,0 +1,6 @@
+def powerset:
+  if length == 0 then [[]]
+  else .[0] as $first
+    | (.[1:] | powerset)
+    | map([$first] + . ) + .
+  end;