A functional programming "library" (some headers with some magic love found in scala)

launchers/macosx/obj-cpp/include/neither/lift.hpp

@@ -0,0 +1,60 @@
+#include "either.hpp"
+
+namespace neither {
+
+  template<class L, class R>
+  constexpr bool hasValue(Either<L,R> const& e) {
+    return e;
+  }
+
+
+  template<class T>
+  constexpr bool hasValue(Maybe<T> const& m) {
+    return m;
+  }
+
+  template<class T>
+  constexpr bool hasValue(T) {
+    return true;
+  }
+
+
+
+  template<class L, class R>
+  constexpr R unpack(Either<L, R> const& e) {
+    return e.rightValue;
+  }
+
+
+  template<class T>
+  constexpr T unpack(Maybe<T> const& m) {
+    return m.value;
+  }
+
+  template<class T>
+  constexpr T unpack(T const& x) {
+    return x;
+  }
+
+  constexpr auto allTrue(bool x=true, bool y=true) {
+    return x && y;
+  }
+
+
+  template<class X, class...Xs>
+  auto allTrue(X x, Xs...xs) {
+    return allTrue(x, allTrue(xs...));
+  }
+
+  template<class F>
+  auto lift(F const& f) {
+    return [f](auto...x) -> decltype(maybe(f(unpack(x)...))) {
+      if ( allTrue(hasValue(x)...) ) {
+        return f(unpack(x)...);
+      }
+
+      return maybe();
+    };
+  }
+
+}