[cpp] make tmp/list.cpp

cpp/tmp/list.cpp

@@ -0,0 +1,31 @@
+#include<iostream>
+
+// https://www.lambdadays.org/static/upload/media/161672564665589vitsefltranslatinglambdacalculusintoctemplates.pdf
+
+template<int>
+struct Int {};
+
+template<bool>
+struct Bool {};
+
+// Can't have floating point numbers as non-type parameters to templates.
+// https://stackoverflow.com/questions/2183087/why-cant-i-use-float-value-as-a-template-parameter
+//template<double>
+//struct Float {};
+
+struct Nil {};
+
+template<typename, typename>
+struct Cons {};
+
+int main() {
+  // [2]
+  Cons<Int<2>, Nil> x;
+
+  // [2, 3, 5]
+  Cons<Int<2>, Cons<Int<3>, Cons<Int<5>, Nil>>> y;
+
+  // It's untyped...
+  // [2, true] possible
+  Cons<Int<2>, Cons<Bool<true>, Nil>> z;
+}