Hyperscript conformance: 372→373 — hide/show strategy, generator toEqual

Parser: hide/show handle `with opacity/visibility/display` strategy,
target detection for then-less chaining (add/remove/set/put as boundary).
Generator: inline run().toEqual([...]) pattern for eval-only tests.
Compiler: hide/show emit correct CSS property per strategy.

373/831 (45%)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/ocaml/bin/sx_server.ml

@@ -360,6 +360,25 @@ and cek_run_with_io state =
                  (Sx_runtime.value_to_str lib_spec));
             Nil
           end
+        | "text-measure" ->
+          (* Resolve locally — monospace approximation *)
+          let args = let a = Sx_runtime.get_val request (String "args") in
+            (match a with List l -> l | _ -> [a]) in
+          let size = match args with
+            | [_font; Number sz; _text] -> sz
+            | [_font; Number sz] -> sz
+            | _ -> 16.0 in
+          let text = match args with
+            | [_font; _sz; String t] -> t
+            | _ -> "" in
+          let char_width = size *. 0.6 in
+          let width = char_width *. (float_of_int (String.length text)) in
+          let d = Hashtbl.create 4 in
+          Hashtbl.replace d "width" (Number width);
+          Hashtbl.replace d "height" (Number size);
+          Hashtbl.replace d "ascent" (Number (size *. 0.8));
+          Hashtbl.replace d "descent" (Number (size *. 0.2));
+          Dict d
         | _ ->
           let args = let a = Sx_runtime.get_val request (String "args") in
             (match a with List l -> l | _ -> [a]) in
@@ -1014,7 +1033,9 @@ let rec dispatch env cmd =
       ignore (Sx_types.env_bind env "*current-file*" (String path));
       let count = ref 0 in
       List.iter (fun expr ->
-        ignore (eval_expr_io expr (Env env));
+        (try ignore (eval_expr_io expr (Env env))
+         with Eval_error msg ->
+           Printf.eprintf "[load] %s: %s\n%!" (Filename.basename path) msg);
         incr count
       ) exprs;
       (* Rebind host extension points after .sx load — evaluator.sx
@@ -1994,6 +2015,26 @@ let eval_with_io expr env =
           ignore lib_name; (* import handled by _import_hook if registered *)
           Nil
         with _ -> Nil)
+      | "text-measure" ->
+        (* Pretext: server-side text measurement (monospace approximation).
+           Real otfm font-table parsing can replace this later. *)
+        let size = match args with
+          | List [_font; Number sz; _text] -> sz
+          | List [_font; Number sz] -> sz
+          | _ -> 16.0 in
+        let text = match args with
+          | List [_font; _sz; String t] -> t
+          | _ -> "" in
+        let char_width = size *. 0.6 in
+        let width = char_width *. (float_of_int (String.length text)) in
+        let ascent = size *. 0.8 in
+        let descent = size *. 0.2 in
+        let d = Hashtbl.create 4 in
+        Hashtbl.replace d "width" (Number width);
+        Hashtbl.replace d "height" (Number size);
+        Hashtbl.replace d "ascent" (Number ascent);
+        Hashtbl.replace d "descent" (Number descent);
+        Dict d
       | _ ->
         Printf.eprintf "[io] unhandled IO op: %s\n%!" op;
         Nil