feat: lift runtime into language, start of zelus 2024 compatibility

exm/zelus/cradle/main.ml

@@ -0,0 +1,30 @@
+
+open Std
+
+let input2 _ = ()
+let output2 (now, (h, (p0, v0), (p1, v1))) =
+  Format.printf "%.10e\t%.10e\t%.10e\n" now p0 p1
+
+let input3 _ = ()
+let output3 (now, (p0, p1, p2, h1, h2)) =
+  Format.printf "%.10e\t%.10e\t%.10e\t%.10e\t%.10e\t%.10e\n"
+  now p0 (p1 +. 1.0) (p2 +. 2.0) (h1 +. 3.0) (h2 +. 4.0)
+
+let input_main _ = ()
+let output_main (now, ()) = ()
+
+let three = ref false
+let main  = ref false
+
+let toggle y n () =
+  y := true;
+  List.iter (fun n -> n := false) n
+
+let () =
+  Runtime.register_args [
+    "-three", Arg.Unit (toggle three [main]), "\tUse the third model";
+    "-main", Arg.Unit (toggle main [three]), "\tUse the main model";
+  ];
+  if !main then Runtime.go input_main Cradle.main output_main
+  else if !three then Runtime.go input3 Cradle.cradle3 output3
+  else Runtime.go input2 Cradle.cradle2 output2