Add tasks for all the new languages

Task/History-variables/Sidef/history-variables.sidef

@@ -0,0 +1,28 @@
+class HistoryVar(v) {
+
+    has history = []
+    has variable = v
+
+    method ≔(value) {
+        history << variable
+        variable = value
+    }
+
+    method to_s {
+        "#{variable}"
+    }
+
+    method AUTOLOAD(_, name, *args) {
+        variable.(name)(args...)
+    }
+}
+
+var foo = HistoryVar(0)
+
+foo ≔ 1
+foo ≔ 2
+foo ≔ foo+3
+foo ≔ 42
+
+say "History: #{foo.history}"
+say "Current value: #{foo}"