Add tasks for all the new languages

Task/Runtime-evaluation-In-an-environment/EchoLisp/runtime-evaluation-in-an-environment.echolisp

@@ -0,0 +1,12 @@
+(define (eval-with-x prog x)
+    (eval prog (environment-new (list (list 'x x)))))
+
+(define prog '( + 1 (* x x)))
+
+(eval-with-x prog 10) → 101
+(eval-with-x prog 1000) → 1000001
+(- (eval-with-x prog 1000) (eval-with-x prog 10)) → 999900
+
+;; check x is unbound (no global)
+x
+😖️ error: #|user| : unbound variable : x

Task/Runtime-evaluation-In-an-environment/Ring/runtime-evaluation-in-an-environment.ring

@@ -0,0 +1,7 @@
+expression = "return pow(x,2) - 7"
+one = evalwithx(expression, 1.2)
+two = evalwithx(expression, 3.4)
+see "one = " + one + nl + "two = " + two + nl
+
+func evalwithx expr, x
+     return eval(expr)

Task/Runtime-evaluation-In-an-environment/Sidef/runtime-evaluation-in-an-environment.sidef

@@ -0,0 +1,7 @@
+func eval_with_x(code, x, y) {
+    var f = eval(code);
+    x = y;
+    eval(code) - f;
+}
+
+say eval_with_x(x: 3, y: 5, code: '2 ** x');   # => 24