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

exm/zelus/ball/ball.zls

@@ -0,0 +1,21 @@
+let g = 9.81
+let y0 = 0.0
+let y'0 = 10.0
+
+let hybrid ball () = (y, y', z) where
+  rec der y  = y'   init y0
+  and der y' = -. g init y'0 reset z -> -0.8 *. (last y')
+  and z = up(-. y)
+
+let hybrid main () =
+  let der t = 1.0 init 0.0 in
+  let s = period(0.01) in
+  let (y, y', z) = ball () in
+  present z | s -> (
+    print_float t;
+    print_string "\t";
+    print_float y;
+(*    print_string "\t";
+    print_float y'; *)
+    print_newline ()
+  ); ()

exm/zelus/ball/dune

@@ -0,0 +1,16 @@
+(env
+ (dev
+  (flags
+   (:standard -w -a))))
+
+(rule
+ (targets ball.ml ball.zci)
+ (deps
+  (:zl ball.zls))
+ (action
+  (run zeluc %{zl})))
+
+(executable
+ (public_name ball.exe)
+ (name main)
+ (libraries std))

exm/zelus/ball/main.ml

@@ -0,0 +1,6 @@
+
+open Std
+
+let input _ = ()
+let output (now, (y, _, _)) = Format.printf "%.10e\t%.10e\n" now y
+let () = Runtime.go input Ball.ball output

exm/zelus/ball/ztypes.ml

@@ -0,0 +1,12 @@
+include Std
+include Ztypes
+include Solvers
+
+module type IGNORE = sig end
+module Defaultsolver : IGNORE = struct end
+
+module Zlsrun = struct
+  module Make (S : IGNORE) = struct
+    let go _ = ()
+  end
+end