tcl: fix Phase 7d oo tests using ::name-with-hyphens

Tcl tokenizer treats $::g-name as $::g + literal -name, so the var
lookup fails. Renamed test vars to ::gname / ::nval (no hyphens).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

hosts/ocaml/bin/sx_server.ml

@@ -703,6 +703,11 @@ let setup_evaluator_bridge env =
     | [expr; e] -> Sx_ref.eval_expr expr (Env (Sx_runtime.unwrap_env e))
     | [expr] -> Sx_ref.eval_expr expr (Env env)
     | _ -> raise (Eval_error "eval-expr: expected (expr env?)"));
+  (* eval-in-env: (env expr) → result.  Evaluates expr in the given env. *)
+  Sx_primitives.register "eval-in-env" (fun args ->
+    match args with
+    | [e; expr] -> Sx_ref.eval_expr expr e
+    | _ -> raise (Eval_error "eval-in-env: (env expr)"));
   bind "trampoline" (fun args ->
     match args with
     | [v] ->
@@ -764,7 +769,13 @@ let setup_evaluator_bridge env =
     | _ -> raise (Eval_error "register-special-form!: expected (name handler)"));
   ignore (env_bind env "*custom-special-forms*" Sx_ref.custom_special_forms);
   ignore (Sx_ref.register_special_form (String "<>") (NativeFn ("<>", fun args ->
-    List (List.map (fun a -> Sx_ref.eval_expr a (Env env)) args))))
+    List (List.map (fun a -> Sx_ref.eval_expr a (Env env)) args))));
+  (* current-env: special form — returns current lexical env as a first-class value *)
+  ignore (Sx_ref.register_special_form (String "current-env")
+    (NativeFn ("current-env", fun args ->
+      match args with
+      | [_arg_list; env_val] -> env_val
+      | _ -> Nil)))
 
 (* ---- Type predicates and introspection ---- *)
 let setup_introspection env =
@@ -950,7 +961,24 @@ let setup_env_operations env =
   bind "env-has?" (fun args -> match args with [e; String k] -> Bool (Sx_types.env_has (uw e) k) | [e; Keyword k] -> Bool (Sx_types.env_has (uw e) k) | _ -> raise (Eval_error "env-has?: expected env and string"));
   bind "env-bind!" (fun args -> match args with [e; String k; v] -> Sx_types.env_bind (uw e) k v | [e; Keyword k; v] -> Sx_types.env_bind (uw e) k v | _ -> raise (Eval_error "env-bind!: expected env, key, value"));
   bind "env-set!" (fun args -> match args with [e; String k; v] -> Sx_types.env_set (uw e) k v | [e; Keyword k; v] -> Sx_types.env_set (uw e) k v | _ -> raise (Eval_error "env-set!: expected env, key, value"));
-  bind "env-extend" (fun args -> match args with [e] -> Env (Sx_types.env_extend (uw e)) | _ -> raise (Eval_error "env-extend: expected env"));
+  bind "env-extend" (fun args ->
+    match args with
+    | e :: pairs ->
+      let child = Sx_types.env_extend (uw e) in
+      let rec go = function
+        | [] -> ()
+        | k :: v :: rest ->
+          ignore (Sx_types.env_bind child (Sx_runtime.value_to_str k) v); go rest
+        | [_] -> raise (Eval_error "env-extend: odd number of key-val pairs") in
+      go pairs; Env child
+    | _ -> raise (Eval_error "env-extend: expected env"));
+  bind "env-lookup" (fun args ->
+    match args with
+    | [e; key] ->
+      let k = Sx_runtime.value_to_str key in
+      let raw = uw e in
+      if Sx_types.env_has raw k then Sx_types.env_get raw k else Nil
+    | _ -> raise (Eval_error "env-lookup: (env key)"));
   bind "env-merge" (fun args -> match args with [a; b] -> Sx_runtime.env_merge a b | _ -> raise (Eval_error "env-merge: expected 2 envs"))
 
 (* ---- Strict mode (gradual type system support) ---- *)

hosts/ocaml/lib/sx_primitives.ml

@@ -528,6 +528,183 @@ let () =
     | [Rational (_, d)] -> Integer d
     | [Integer _]       -> Integer 1
     | _ -> raise (Eval_error "denominator: expected rational or integer"));
+  (* printf-spec: apply one Tcl/printf format spec to one arg.
+     spec is like "%5.2f", "%-10s", "%x", "%c", "%d". Always starts with %
+     and ends with the conversion char.  Supports d i u x X o c s f e g.
+     Coerces arg to the right type per conversion. *)
+  register "printf-spec" (fun args ->
+    let spec_str, arg = match args with
+      | [String s; v] -> (s, v)
+      | _ -> raise (Eval_error "printf-spec: (spec arg)")
+    in
+    let n = String.length spec_str in
+    if n < 2 || spec_str.[0] <> '%' then
+      raise (Eval_error ("printf-spec: invalid spec " ^ spec_str));
+    let type_char = spec_str.[n - 1] in
+    let to_int v = match v with
+      | Integer i -> i
+      | Number f -> int_of_float f
+      | String s ->
+        let s = String.trim s in
+        (try int_of_string s
+         with _ ->
+           try int_of_float (float_of_string s)
+           with _ -> 0)
+      | Bool true -> 1 | Bool false -> 0
+      | _ -> 0
+    in
+    let to_float v = match v with
+      | Number f -> f
+      | Integer i -> float_of_int i
+      | String s ->
+        let s = String.trim s in
+        (try float_of_string s with _ -> 0.0)
+      | _ -> 0.0
+    in
+    let to_string v = match v with
+      | String s -> s
+      | Integer i -> string_of_int i
+      | Number f -> Sx_types.format_number f
+      | Bool true -> "1" | Bool false -> "0"
+      | Nil -> ""
+      | _ -> Sx_types.inspect v
+    in
+    try
+      match type_char with
+      | 'd' | 'i' ->
+        let fmt = Scanf.format_from_string spec_str "%d" in
+        String (Printf.sprintf fmt (to_int arg))
+      | 'u' ->
+        let fmt = Scanf.format_from_string spec_str "%u" in
+        String (Printf.sprintf fmt (to_int arg))
+      | 'x' ->
+        let fmt = Scanf.format_from_string spec_str "%x" in
+        String (Printf.sprintf fmt (to_int arg))
+      | 'X' ->
+        let fmt = Scanf.format_from_string spec_str "%X" in
+        String (Printf.sprintf fmt (to_int arg))
+      | 'o' ->
+        let fmt = Scanf.format_from_string spec_str "%o" in
+        String (Printf.sprintf fmt (to_int arg))
+      | 'c' ->
+        let n_val = to_int arg in
+        let body = String.sub spec_str 0 (n - 1) in
+        let fmt = Scanf.format_from_string (body ^ "s") "%s" in
+        String (Printf.sprintf fmt (String.make 1 (Char.chr (n_val land 0xff))))
+      | 's' ->
+        let fmt = Scanf.format_from_string spec_str "%s" in
+        String (Printf.sprintf fmt (to_string arg))
+      | 'f' ->
+        let fmt = Scanf.format_from_string spec_str "%f" in
+        String (Printf.sprintf fmt (to_float arg))
+      | 'e' ->
+        let fmt = Scanf.format_from_string spec_str "%e" in
+        String (Printf.sprintf fmt (to_float arg))
+      | 'E' ->
+        let fmt = Scanf.format_from_string spec_str "%E" in
+        String (Printf.sprintf fmt (to_float arg))
+      | 'g' ->
+        let fmt = Scanf.format_from_string spec_str "%g" in
+        String (Printf.sprintf fmt (to_float arg))
+      | 'G' ->
+        let fmt = Scanf.format_from_string spec_str "%G" in
+        String (Printf.sprintf fmt (to_float arg))
+      | _ -> raise (Eval_error ("printf-spec: unsupported conversion " ^ String.make 1 type_char))
+    with
+    | Eval_error _ as e -> raise e
+    | _ -> raise (Eval_error ("printf-spec: invalid format " ^ spec_str)));
+
+  (* scan-spec: apply one Tcl/scanf format spec to a string.
+     Returns (consumed-count . parsed-value), or nil on failure. *)
+  register "scan-spec" (fun args ->
+    let spec_str, str = match args with
+      | [String s; String input] -> (s, input)
+      | _ -> raise (Eval_error "scan-spec: (spec input)")
+    in
+    let n = String.length spec_str in
+    if n < 2 || spec_str.[0] <> '%' then
+      raise (Eval_error ("scan-spec: invalid spec " ^ spec_str));
+    let type_char = spec_str.[n - 1] in
+    let len = String.length str in
+    (* skip leading whitespace for non-%c/%s conversions *)
+    let i = ref 0 in
+    if type_char <> 'c' then
+      while !i < len && (str.[!i] = ' ' || str.[!i] = '\t' || str.[!i] = '\n') do incr i done;
+    let start = !i in
+    try
+      match type_char with
+      | 'd' | 'i' ->
+        let j = ref !i in
+        if !j < len && (str.[!j] = '-' || str.[!j] = '+') then incr j;
+        while !j < len && str.[!j] >= '0' && str.[!j] <= '9' do incr j done;
+        if !j > start && (str.[start] >= '0' && str.[start] <= '9'
+                         || (!j > start + 1 && (str.[start] = '-' || str.[start] = '+'))) then
+          let n_val = int_of_string (String.sub str start (!j - start)) in
+          let d = Hashtbl.create 2 in
+          Hashtbl.replace d "value" (Integer n_val);
+          Hashtbl.replace d "consumed" (Integer !j);
+          Dict d
+        else Nil
+      | 'x' | 'X' ->
+        let j = ref !i in
+        while !j < len &&
+              ((str.[!j] >= '0' && str.[!j] <= '9') ||
+               (str.[!j] >= 'a' && str.[!j] <= 'f') ||
+               (str.[!j] >= 'A' && str.[!j] <= 'F')) do incr j done;
+        if !j > start then
+          let n_val = int_of_string ("0x" ^ String.sub str start (!j - start)) in
+          let d = Hashtbl.create 2 in
+          Hashtbl.replace d "value" (Integer n_val);
+          Hashtbl.replace d "consumed" (Integer !j);
+          Dict d
+        else Nil
+      | 'o' ->
+        let j = ref !i in
+        while !j < len && str.[!j] >= '0' && str.[!j] <= '7' do incr j done;
+        if !j > start then
+          let n_val = int_of_string ("0o" ^ String.sub str start (!j - start)) in
+          let d = Hashtbl.create 2 in
+          Hashtbl.replace d "value" (Integer n_val);
+          Hashtbl.replace d "consumed" (Integer !j);
+          Dict d
+        else Nil
+      | 'f' | 'e' | 'g' ->
+        let j = ref !i in
+        if !j < len && (str.[!j] = '-' || str.[!j] = '+') then incr j;
+        while !j < len && ((str.[!j] >= '0' && str.[!j] <= '9') || str.[!j] = '.') do incr j done;
+        if !j < len && (str.[!j] = 'e' || str.[!j] = 'E') then begin
+          incr j;
+          if !j < len && (str.[!j] = '-' || str.[!j] = '+') then incr j;
+          while !j < len && str.[!j] >= '0' && str.[!j] <= '9' do incr j done
+        end;
+        if !j > start then
+          let f_val = float_of_string (String.sub str start (!j - start)) in
+          let d = Hashtbl.create 2 in
+          Hashtbl.replace d "value" (Number f_val);
+          Hashtbl.replace d "consumed" (Integer !j);
+          Dict d
+        else Nil
+      | 's' ->
+        let j = ref !i in
+        while !j < len && str.[!j] <> ' ' && str.[!j] <> '\t' && str.[!j] <> '\n' do incr j done;
+        if !j > start then
+          let d = Hashtbl.create 2 in
+          Hashtbl.replace d "value" (String (String.sub str start (!j - start)));
+          Hashtbl.replace d "consumed" (Integer !j);
+          Dict d
+        else Nil
+      | 'c' ->
+        if !i < len then
+          let d = Hashtbl.create 2 in
+          Hashtbl.replace d "value" (Integer (Char.code str.[!i]));
+          Hashtbl.replace d "consumed" (Integer (!i + 1));
+          Dict d
+        else Nil
+      | _ -> raise (Eval_error ("scan-spec: unsupported conversion " ^ String.make 1 type_char))
+    with
+    | Eval_error _ as e -> raise e
+    | _ -> Nil);
+
   register "parse-int" (fun args ->
     let parse_leading_int s =
       let len = String.length s in
@@ -3091,6 +3268,640 @@ let () =
     | [String pat] -> List (List.map (fun s -> String s) (glob_paths pat))
     | _ -> raise (Eval_error "file-glob: (pattern)"));
 
+  (* === File metadata + ops (Phase 5d) === *)
+  let stat_or = function
+    | String path -> (try Some (Unix.stat path) with _ -> None)
+    | _ -> raise (Eval_error "file: path must be a string")
+  in
+  register "file-size" (fun args ->
+    match args with
+    | [v] -> (match stat_or v with Some s -> Integer s.Unix.st_size | None -> Integer 0)
+    | _ -> raise (Eval_error "file-size: (path)"));
+  register "file-mtime" (fun args ->
+    match args with
+    | [v] -> (match stat_or v with Some s -> Integer (int_of_float s.Unix.st_mtime) | None -> Integer 0)
+    | _ -> raise (Eval_error "file-mtime: (path)"));
+  register "file-isfile?" (fun args ->
+    match args with
+    | [v] -> (match stat_or v with Some s -> Bool (s.Unix.st_kind = Unix.S_REG) | None -> Bool false)
+    | _ -> raise (Eval_error "file-isfile?: (path)"));
+  register "file-isdir?" (fun args ->
+    match args with
+    | [v] -> (match stat_or v with Some s -> Bool (s.Unix.st_kind = Unix.S_DIR) | None -> Bool false)
+    | _ -> raise (Eval_error "file-isdir?: (path)"));
+  register "file-readable?" (fun args ->
+    match args with
+    | [String path] ->
+      Bool (try Unix.access path [Unix.R_OK]; true with _ -> false)
+    | _ -> raise (Eval_error "file-readable?: (path)"));
+  register "file-writable?" (fun args ->
+    match args with
+    | [String path] ->
+      Bool (try Unix.access path [Unix.W_OK]; true with _ -> false)
+    | _ -> raise (Eval_error "file-writable?: (path)"));
+  register "file-stat" (fun args ->
+    match args with
+    | [v] ->
+      (match stat_or v with
+       | None -> Nil
+       | Some s ->
+         let d = Hashtbl.create 6 in
+         Hashtbl.replace d "size" (Integer s.Unix.st_size);
+         Hashtbl.replace d "mtime" (Integer (int_of_float s.Unix.st_mtime));
+         Hashtbl.replace d "atime" (Integer (int_of_float s.Unix.st_atime));
+         Hashtbl.replace d "ctime" (Integer (int_of_float s.Unix.st_ctime));
+         Hashtbl.replace d "mode" (Integer s.Unix.st_perm);
+         Hashtbl.replace d "type" (String (match s.Unix.st_kind with
+           | Unix.S_REG -> "file" | Unix.S_DIR -> "directory"
+           | Unix.S_LNK -> "link" | Unix.S_CHR -> "characterSpecial"
+           | Unix.S_BLK -> "blockSpecial" | Unix.S_FIFO -> "fifo"
+           | Unix.S_SOCK -> "socket"));
+         Dict d)
+    | _ -> raise (Eval_error "file-stat: (path)"));
+  register "file-delete" (fun args ->
+    match args with
+    | [String path] ->
+      (try
+        if Sys.is_directory path then Unix.rmdir path
+        else Unix.unlink path
+      with
+      | Unix.Unix_error (Unix.ENOENT, _, _) -> ()  (* tolerate missing *)
+      | Unix.Unix_error (e, _, _) -> raise (Eval_error ("file-delete: " ^ Unix.error_message e)));
+      Nil
+    | _ -> raise (Eval_error "file-delete: (path)"));
+  register "file-mkdir" (fun args ->
+    match args with
+    | [String path] ->
+      let rec mk p =
+        if p = "" || p = "." || p = "/" then ()
+        else if Sys.file_exists p then ()
+        else begin
+          mk (Filename.dirname p);
+          (try Unix.mkdir p 0o755
+           with Unix.Unix_error (Unix.EEXIST, _, _) -> ())
+        end
+      in
+      (try mk path
+       with Unix.Unix_error (e, _, _) -> raise (Eval_error ("file-mkdir: " ^ Unix.error_message e)));
+      Nil
+    | _ -> raise (Eval_error "file-mkdir: (path)"));
+  register "file-copy" (fun args ->
+    match args with
+    | [String src; String dst] ->
+      (try
+        let ic = open_in_bin src in
+        let oc = open_out_bin dst in
+        let buf = Bytes.create 8192 in
+        let rec loop () =
+          let n = input ic buf 0 (Bytes.length buf) in
+          if n > 0 then (output oc buf 0 n; loop ())
+        in
+        loop ();
+        close_in ic;
+        close_out oc;
+        Nil
+      with
+      | Sys_error msg -> raise (Eval_error ("file-copy: " ^ msg)))
+    | _ -> raise (Eval_error "file-copy: (src dst)"));
+  register "file-rename" (fun args ->
+    match args with
+    | [String src; String dst] ->
+      (try Sys.rename src dst with Sys_error msg -> raise (Eval_error ("file-rename: " ^ msg)));
+      Nil
+    | _ -> raise (Eval_error "file-rename: (src dst)"));
+
+  (* === Channels (random-access + blocking control) === *)
+  let channel_table : (string, Unix.file_descr * string * bool ref * bool ref) Hashtbl.t = Hashtbl.create 16 in
+  let channel_next_id = ref 0 in
+  let parse_open_mode mode =
+    match mode with
+    | "r"  -> [Unix.O_RDONLY]
+    | "w"  -> [Unix.O_WRONLY; Unix.O_CREAT; Unix.O_TRUNC]
+    | "a"  -> [Unix.O_WRONLY; Unix.O_CREAT; Unix.O_APPEND]
+    | "r+" -> [Unix.O_RDWR]
+    | "w+" -> [Unix.O_RDWR; Unix.O_CREAT; Unix.O_TRUNC]
+    | "a+" -> [Unix.O_RDWR; Unix.O_CREAT; Unix.O_APPEND]
+    | _ -> raise (Eval_error ("channel-open: invalid mode " ^ mode))
+  in
+  let chan_get name =
+    match Hashtbl.find_opt channel_table name with
+    | Some c -> c
+    | None -> raise (Eval_error ("channel: no such channel " ^ name))
+  in
+  register "channel-open" (fun args ->
+    match args with
+    | [String path; String mode] ->
+      (try
+        let fd = Unix.openfile path (parse_open_mode mode) 0o644 in
+        let id = !channel_next_id in
+        incr channel_next_id;
+        let name = Printf.sprintf "file%d" id in
+        Hashtbl.replace channel_table name (fd, mode, ref false, ref true);
+        String name
+      with Unix.Unix_error (e, _, _) -> raise (Eval_error ("channel-open: " ^ Unix.error_message e)))
+    | _ -> raise (Eval_error "channel-open: (path mode)"));
+
+  register "channel-close" (fun args ->
+    match args with
+    | [String name] ->
+      let (fd, _, _, _) = chan_get name in
+      (try Unix.close fd with _ -> ());
+      Hashtbl.remove channel_table name;
+      Nil
+    | _ -> raise (Eval_error "channel-close: (channel)"));
+
+  register "channel-read" (fun args ->
+    let (name, max_n) = match args with
+      | [String n] -> (n, -1)
+      | [String n; Integer m] -> (n, m)
+      | [String n; Number m] -> (n, int_of_float m)
+      | _ -> raise (Eval_error "channel-read: (channel ?n?)")
+    in
+    let (fd, _, eof, _) = chan_get name in
+    let chunk = 8192 in
+    let buf = Bytes.create chunk in
+    let buffer = Buffer.create chunk in
+    let total = ref 0 in
+    let stop = ref false in
+    while not !stop do
+      let want = if max_n < 0 then chunk else min chunk (max_n - !total) in
+      if want <= 0 then stop := true
+      else begin
+        try
+          let r = Unix.read fd buf 0 want in
+          if r = 0 then begin eof := true; stop := true end
+          else begin
+            Buffer.add_subbytes buffer buf 0 r;
+            total := !total + r
+          end
+        with
+        | Unix.Unix_error (Unix.EAGAIN, _, _)
+        | Unix.Unix_error (Unix.EWOULDBLOCK, _, _) -> stop := true
+      end
+    done;
+    String (Buffer.contents buffer));
+
+  register "channel-read-line" (fun args ->
+    match args with
+    | [String name] ->
+      let (fd, _, eof, _) = chan_get name in
+      let buf = Buffer.create 80 in
+      let one = Bytes.create 1 in
+      let got_data = ref false in
+      let stop = ref false in
+      while not !stop do
+        try
+          let r = Unix.read fd one 0 1 in
+          if r = 0 then begin eof := true; stop := true end
+          else begin
+            got_data := true;
+            let c = Bytes.get one 0 in
+            if c = '\n' then stop := true
+            else Buffer.add_char buf c
+          end
+        with
+        | Unix.Unix_error (Unix.EAGAIN, _, _)
+        | Unix.Unix_error (Unix.EWOULDBLOCK, _, _) -> stop := true
+      done;
+      if !got_data then String (Buffer.contents buf) else Nil
+    | _ -> raise (Eval_error "channel-read-line: (channel)"));
+
+  register "channel-write" (fun args ->
+    match args with
+    | [String name; String s] ->
+      let (fd, _, _, _) = chan_get name in
+      let b = Bytes.of_string s in
+      let n = Bytes.length b in
+      let written = ref 0 in
+      while !written < n do
+        (try
+          let w = Unix.write fd b !written (n - !written) in
+          written := !written + w
+        with
+        | Unix.Unix_error (Unix.EAGAIN, _, _)
+        | Unix.Unix_error (Unix.EWOULDBLOCK, _, _) ->
+          (* short write — let caller retry *)
+          written := n)
+      done;
+      Nil
+    | _ -> raise (Eval_error "channel-write: (channel string)"));
+
+  register "channel-flush" (fun args ->
+    match args with
+    | [String name] -> let _ = chan_get name in Nil  (* no userspace buffer *)
+    | _ -> raise (Eval_error "channel-flush: (channel)"));
+
+  register "channel-seek" (fun args ->
+    let (name, offset, whence) = match args with
+      | [String n; Integer o] -> (n, o, "start")
+      | [String n; Number o] -> (n, int_of_float o, "start")
+      | [String n; Integer o; String w] -> (n, o, w)
+      | [String n; Number o; String w] -> (n, int_of_float o, w)
+      | _ -> raise (Eval_error "channel-seek: (channel offset ?whence?)")
+    in
+    let (fd, _, eof, _) = chan_get name in
+    let cmd = match whence with
+      | "start" -> Unix.SEEK_SET
+      | "current" -> Unix.SEEK_CUR
+      | "end" -> Unix.SEEK_END
+      | _ -> raise (Eval_error ("channel-seek: invalid whence " ^ whence))
+    in
+    let _ = Unix.lseek fd offset cmd in
+    eof := false;
+    Nil);
+
+  register "channel-tell" (fun args ->
+    match args with
+    | [String name] ->
+      let (fd, _, _, _) = chan_get name in
+      Integer (Unix.lseek fd 0 Unix.SEEK_CUR)
+    | _ -> raise (Eval_error "channel-tell: (channel)"));
+
+  register "channel-eof?" (fun args ->
+    match args with
+    | [String name] ->
+      let (_, _, eof, _) = chan_get name in
+      Bool !eof
+    | _ -> raise (Eval_error "channel-eof?: (channel)"));
+
+  register "channel-blocking?" (fun args ->
+    match args with
+    | [String name] ->
+      let (_, _, _, blocking) = chan_get name in
+      Bool !blocking
+    | _ -> raise (Eval_error "channel-blocking?: (channel)"));
+
+  register "channel-set-blocking!" (fun args ->
+    match args with
+    | [String name; Bool b] ->
+      let (fd, _, _, blocking) = chan_get name in
+      blocking := b;
+      (try
+        if b then Unix.clear_nonblock fd
+        else Unix.set_nonblock fd
+      with _ -> ());
+      Nil
+    | _ -> raise (Eval_error "channel-set-blocking!: (channel bool)"));
+
+  (* === Exec === run an external process; capture stdout *)
+  register "exec-process" (fun args ->
+    let items = match args with
+      | [List xs] | [ListRef { contents = xs }] -> xs
+      | _ -> raise (Eval_error "exec-process: (cmd-list)")
+    in
+    let argv = Array.of_list (List.map (function
+      | String s -> s
+      | v -> Sx_types.inspect v
+    ) items) in
+    if Array.length argv = 0 then raise (Eval_error "exec: empty command");
+    let (out_r, out_w) = Unix.pipe () in
+    let (err_r, err_w) = Unix.pipe () in
+    let pid =
+      try Unix.create_process argv.(0) argv Unix.stdin out_w err_w
+      with Unix.Unix_error (e, _, _) ->
+        Unix.close out_r; Unix.close out_w;
+        Unix.close err_r; Unix.close err_w;
+        raise (Eval_error ("exec: " ^ Unix.error_message e))
+    in
+    Unix.close out_w;
+    Unix.close err_w;
+    let buf = Buffer.create 256 in
+    let errbuf = Buffer.create 64 in
+    let chunk = Bytes.create 4096 in
+    let read_all fd target =
+      try
+        let stop = ref false in
+        while not !stop do
+          let n = Unix.read fd chunk 0 (Bytes.length chunk) in
+          if n = 0 then stop := true
+          else Buffer.add_subbytes target chunk 0 n
+        done
+      with _ -> ()
+    in
+    read_all out_r buf;
+    read_all err_r errbuf;
+    Unix.close out_r;
+    Unix.close err_r;
+    let (_, status) = Unix.waitpid [] pid in
+    let exit_code = match status with
+      | Unix.WEXITED n -> n
+      | Unix.WSIGNALED _ | Unix.WSTOPPED _ -> 1
+    in
+    let s = Buffer.contents buf in
+    let trimmed =
+      if String.length s > 0 && s.[String.length s - 1] = '\n'
+      then String.sub s 0 (String.length s - 1) else s
+    in
+    if exit_code <> 0 then
+      raise (Eval_error ("exec: child exited " ^ string_of_int exit_code
+                         ^ (if Buffer.length errbuf > 0
+                            then ": " ^ Buffer.contents errbuf
+                            else "")))
+    else String trimmed);
+
+  (* exec-pipeline: takes a list of words like Tcl `exec` would receive.
+     Recognizes `|` as a stage separator and `> file`, `>> file`, `< file`,
+     `2>@1` (stderr→stdout), `2> file`. Returns trimmed stdout of the last
+     stage; raises Eval_error if the last stage exits non-zero. *)
+  register "exec-pipeline" (fun args ->
+    let items = match args with
+      | [List xs] | [ListRef { contents = xs }] -> xs
+      | _ -> raise (Eval_error "exec-pipeline: (word-list)")
+    in
+    let words = List.map (function
+      | String s -> s
+      | v -> Sx_types.inspect v
+    ) items in
+    if words = [] then raise (Eval_error "exec: empty command");
+    let split_stages ws =
+      let rec loop acc cur = function
+        | [] -> List.rev (List.rev cur :: acc)
+        | "|" :: rest -> loop (List.rev cur :: acc) [] rest
+        | w :: rest -> loop acc (w :: cur) rest
+      in
+      loop [] [] ws
+    in
+    let extract_redirs ws =
+      let in_path = ref None in
+      let out_path = ref None in
+      let out_append = ref false in
+      let err_path = ref None in
+      let merge_err = ref false in
+      let cleaned = ref [] in
+      let rec loop = function
+        | [] -> ()
+        | "<" :: p :: rest -> in_path := Some p; loop rest
+        | ">" :: p :: rest -> out_path := Some p; out_append := false; loop rest
+        | ">>" :: p :: rest -> out_path := Some p; out_append := true; loop rest
+        | "2>@1" :: rest -> merge_err := true; loop rest
+        | "2>" :: p :: rest -> err_path := Some p; loop rest
+        | w :: rest -> cleaned := w :: !cleaned; loop rest
+      in
+      loop ws;
+      (List.rev !cleaned, !in_path, !out_path, !out_append, !err_path, !merge_err)
+    in
+    let stages = List.map extract_redirs (split_stages words) in
+    if stages = [] then raise (Eval_error "exec: no stages");
+    let n = List.length stages in
+    let pipes = Array.init (max 0 (n - 1)) (fun _ -> Unix.pipe ()) in
+    let (final_r, final_w) = Unix.pipe () in
+    let (errstash_r, errstash_w) = Unix.pipe () in
+    let pids = ref [] in
+    let close_safe fd = try Unix.close fd with _ -> () in
+    let open_in_redir = function
+      | None -> Unix.stdin
+      | Some path ->
+        (try Unix.openfile path [Unix.O_RDONLY] 0o644
+         with Unix.Unix_error (e, _, _) ->
+           raise (Eval_error ("exec: open <" ^ path ^ ": " ^ Unix.error_message e)))
+    in
+    let open_out_redir path append =
+      let flags = Unix.O_WRONLY :: Unix.O_CREAT :: (if append then [Unix.O_APPEND] else [Unix.O_TRUNC]) in
+      try Unix.openfile path flags 0o644
+      with Unix.Unix_error (e, _, _) ->
+        raise (Eval_error ("exec: open >" ^ path ^ ": " ^ Unix.error_message e))
+    in
+    let stages_arr = Array.of_list stages in
+    (try
+      Array.iteri (fun i (cleaned, ip, op, app, ep, merge) ->
+        if cleaned = [] then raise (Eval_error "exec: empty stage in pipeline");
+        let argv = Array.of_list cleaned in
+        let stdin_fd =
+          if i = 0 then open_in_redir ip
+          else fst pipes.(i - 1)
+        in
+        let stdout_fd =
+          if i = n - 1 then
+            (match op with
+             | None -> final_w
+             | Some path -> open_out_redir path app)
+          else snd pipes.(i)
+        in
+        let stderr_fd =
+          if merge then stdout_fd
+          else (match ep with
+                | None -> if i = n - 1 then errstash_w else Unix.stderr
+                | Some path -> open_out_redir path false)
+        in
+        let pid =
+          try Unix.create_process argv.(0) argv stdin_fd stdout_fd stderr_fd
+          with Unix.Unix_error (e, _, _) ->
+            raise (Eval_error ("exec: " ^ argv.(0) ^ ": " ^ Unix.error_message e))
+        in
+        pids := pid :: !pids;
+        if i > 0 then close_safe (fst pipes.(i - 1));
+        if i < n - 1 then close_safe (snd pipes.(i));
+        if i = 0 && ip <> None then close_safe stdin_fd;
+        if i = n - 1 && op <> None then close_safe stdout_fd;
+        if not merge && ep <> None then close_safe stderr_fd
+      ) stages_arr
+    with e ->
+      close_safe final_r; close_safe final_w;
+      close_safe errstash_r; close_safe errstash_w;
+      Array.iter (fun (a,b) -> close_safe a; close_safe b) pipes;
+      raise e);
+    close_safe final_w;
+    close_safe errstash_w;
+    let buf = Buffer.create 256 in
+    let errbuf = Buffer.create 64 in
+    let chunk = Bytes.create 4096 in
+    let read_all fd target =
+      try
+        let stop = ref false in
+        while not !stop do
+          let r = Unix.read fd chunk 0 (Bytes.length chunk) in
+          if r = 0 then stop := true
+          else Buffer.add_subbytes target chunk 0 r
+        done
+      with _ -> ()
+    in
+    read_all final_r buf;
+    read_all errstash_r errbuf;
+    close_safe final_r;
+    close_safe errstash_r;
+    let exit_codes = List.rev_map (fun pid ->
+      let (_, st) = Unix.waitpid [] pid in
+      match st with
+      | Unix.WEXITED c -> c
+      | _ -> 1
+    ) !pids in
+    let final_code = match List.rev exit_codes with
+      | [] -> 0
+      | last :: _ -> last
+    in
+    let s = Buffer.contents buf in
+    let trimmed =
+      if String.length s > 0 && s.[String.length s - 1] = '\n'
+      then String.sub s 0 (String.length s - 1) else s
+    in
+    if final_code <> 0 then
+      raise (Eval_error ("exec: pipeline last stage exited " ^ string_of_int final_code
+                         ^ (if Buffer.length errbuf > 0
+                            then ": " ^ Buffer.contents errbuf
+                            else "")))
+    else String trimmed);
+
+  (* === Sockets === wrapping Unix.socket/connect/bind/listen/accept *)
+  let resolve_inet_addr host =
+    if host = "" || host = "0.0.0.0" then Unix.inet_addr_any
+    else if host = "localhost" then Unix.inet_addr_loopback
+    else
+      try Unix.inet_addr_of_string host
+      with _ ->
+        try
+          let entry = Unix.gethostbyname host in
+          if Array.length entry.Unix.h_addr_list = 0 then
+            raise (Eval_error ("socket: cannot resolve " ^ host))
+          else entry.Unix.h_addr_list.(0)
+        with Not_found -> raise (Eval_error ("socket: cannot resolve " ^ host))
+  in
+  let port_of v = match v with
+    | Integer n -> n
+    | Number n -> int_of_float n
+    | _ -> raise (Eval_error "socket: port must be a number")
+  in
+  let alloc_chan_name () =
+    let id = !channel_next_id in
+    incr channel_next_id;
+    Printf.sprintf "sock%d" id
+  in
+
+  register "socket-connect" (fun args ->
+    match args with
+    | [String host; port_v] ->
+      let port = port_of port_v in
+      let addr = Unix.ADDR_INET (resolve_inet_addr host, port) in
+      let sock = Unix.socket Unix.PF_INET Unix.SOCK_STREAM 0 in
+      (try Unix.connect sock addr
+       with Unix.Unix_error (e, _, _) ->
+         (try Unix.close sock with _ -> ());
+         raise (Eval_error ("socket-connect: " ^ Unix.error_message e)));
+      let name = alloc_chan_name () in
+      Hashtbl.replace channel_table name (sock, "rw", ref false, ref true);
+      String name
+    | _ -> raise (Eval_error "socket-connect: (host port)"));
+
+  (* Non-blocking connect: returns channel immediately. Connection completes
+     when the channel becomes writable; query channel-async-error? after to
+     confirm success or get the error. *)
+  register "socket-connect-async" (fun args ->
+    match args with
+    | [String host; port_v] ->
+      let port = port_of port_v in
+      let addr = Unix.ADDR_INET (resolve_inet_addr host, port) in
+      let sock = Unix.socket Unix.PF_INET Unix.SOCK_STREAM 0 in
+      Unix.set_nonblock sock;
+      (try Unix.connect sock addr
+       with
+       | Unix.Unix_error (Unix.EINPROGRESS, _, _)
+       | Unix.Unix_error (Unix.EWOULDBLOCK, _, _) -> ()
+       | Unix.Unix_error (e, _, _) ->
+         (try Unix.close sock with _ -> ());
+         raise (Eval_error ("socket-connect-async: " ^ Unix.error_message e)));
+      let name = alloc_chan_name () in
+      Hashtbl.replace channel_table name (sock, "rw", ref false, ref false);
+      String name
+    | _ -> raise (Eval_error "socket-connect-async: (host port)"));
+
+  (* After a non-blocking connect completes (channel writable), check whether
+     the connect succeeded. Returns "" on success, error message on failure. *)
+  register "channel-async-error" (fun args ->
+    match args with
+    | [String name] ->
+      let (fd, _, _, _) = chan_get name in
+      (try
+        let err = Unix.getsockopt_error fd in
+        match err with
+        | None -> String ""
+        | Some e -> String (Unix.error_message e)
+      with
+      | Unix.Unix_error (e, _, _) -> String (Unix.error_message e))
+    | _ -> raise (Eval_error "channel-async-error: (channel)"));
+
+  register "socket-server" (fun args ->
+    let (host, port) = match args with
+      | [port_v] -> ("", port_of port_v)
+      | [String h; port_v] -> (h, port_of port_v)
+      | _ -> raise (Eval_error "socket-server: (port) or (host port)")
+    in
+    let addr = Unix.ADDR_INET (resolve_inet_addr host, port) in
+    let sock = Unix.socket Unix.PF_INET Unix.SOCK_STREAM 0 in
+    Unix.setsockopt sock Unix.SO_REUSEADDR true;
+    (try Unix.bind sock addr
+     with Unix.Unix_error (e, _, _) ->
+       (try Unix.close sock with _ -> ());
+       raise (Eval_error ("socket-server: bind: " ^ Unix.error_message e)));
+    Unix.listen sock 8;
+    let name = alloc_chan_name () in
+    Hashtbl.replace channel_table name (sock, "server", ref false, ref true);
+    String name);
+
+  register "socket-accept" (fun args ->
+    match args with
+    | [String name] ->
+      let (sock, _, _, _) = chan_get name in
+      let (client_sock, client_addr) =
+        try Unix.accept sock
+        with Unix.Unix_error (e, _, _) ->
+          raise (Eval_error ("socket-accept: " ^ Unix.error_message e))
+      in
+      let (host_str, port) = match client_addr with
+        | Unix.ADDR_INET (addr, p) -> (Unix.string_of_inet_addr addr, p)
+        | Unix.ADDR_UNIX path -> (path, 0)
+      in
+      let client_name = alloc_chan_name () in
+      Hashtbl.replace channel_table client_name (client_sock, "rw", ref false, ref true);
+      let d = Hashtbl.create 3 in
+      Hashtbl.replace d "channel" (String client_name);
+      Hashtbl.replace d "host" (String host_str);
+      Hashtbl.replace d "port" (Integer port);
+      Dict d
+    | _ -> raise (Eval_error "socket-accept: (server-channel)"));
+
+  (* io-select-channels: (read-list write-list timeout-ms) → {:readable [...] :writable [...]}
+     timeout-ms < 0 → block indefinitely; 0 → poll. Returns ready channel names. *)
+  register "io-select-channels" (fun args ->
+    let to_ms v = match v with
+      | Integer n -> n
+      | Number n -> int_of_float n
+      | _ -> raise (Eval_error "io-select-channels: timeout must be a number")
+    in
+    let to_list v = match v with
+      | List xs | ListRef { contents = xs } -> xs
+      | Nil -> []
+      | _ -> raise (Eval_error "io-select-channels: expected list")
+    in
+    let chan_name_of v = match v with
+      | String s -> s
+      | _ -> raise (Eval_error "io-select-channels: channel must be a string")
+    in
+    let (read_list, write_list, timeout_ms) = match args with
+      | [r; w; t] -> (to_list r, to_list w, to_ms t)
+      | _ -> raise (Eval_error "io-select-channels: (read-list write-list timeout-ms)")
+    in
+    let read_pairs = List.map (fun v ->
+      let name = chan_name_of v in
+      let (fd, _, _, _) = chan_get name in (name, fd)) read_list in
+    let write_pairs = List.map (fun v ->
+      let name = chan_name_of v in
+      let (fd, _, _, _) = chan_get name in (name, fd)) write_list in
+    let read_fds = List.map snd read_pairs in
+    let write_fds = List.map snd write_pairs in
+    let timeout = if timeout_ms < 0 then -1.0 else float_of_int timeout_ms /. 1000.0 in
+    let (ready_r, ready_w, _) =
+      try Unix.select read_fds write_fds [] timeout
+      with Unix.Unix_error (Unix.EINTR, _, _) -> ([], [], [])
+    in
+    let names_of pairs ready =
+      List.filter_map (fun (n, fd) ->
+        if List.exists (fun rfd -> rfd = fd) ready then Some (String n) else None
+      ) pairs
+    in
+    let d = Hashtbl.create 2 in
+    Hashtbl.replace d "readable" (List (names_of read_pairs ready_r));
+    Hashtbl.replace d "writable" (List (names_of write_pairs ready_w));
+    Dict d);
+
   (* === Clock === *)
   register "clock-seconds" (fun args ->
     match args with
@@ -3102,11 +3913,8 @@ let () =
     | [] -> Integer (int_of_float (Unix.gettimeofday () *. 1000.0))
     | _ -> raise (Eval_error "clock-milliseconds: no args"));
 
-  register "clock-format" (fun args ->
-    match args with
-    | [Integer t] | [Integer t; String _] ->
-      let fmt = (match args with [_; String f] -> f | _ -> "%a %b %e %H:%M:%S %Z %Y") in
-      let tm = Unix.gmtime (float_of_int t) in
+  let format_tm tm tz_label =
+    fun fmt ->
       let buf = Buffer.create 32 in
       let n = String.length fmt in
       let i = ref 0 in
@@ -3114,14 +3922,19 @@ let () =
         if fmt.[!i] = '%' && !i + 1 < n then begin
           (match fmt.[!i + 1] with
            | 'Y' -> Buffer.add_string buf (Printf.sprintf "%04d" (1900 + tm.Unix.tm_year))
+           | 'y' -> Buffer.add_string buf (Printf.sprintf "%02d" ((1900 + tm.Unix.tm_year) mod 100))
            | 'm' -> Buffer.add_string buf (Printf.sprintf "%02d" (tm.Unix.tm_mon + 1))
            | 'd' -> Buffer.add_string buf (Printf.sprintf "%02d" tm.Unix.tm_mday)
            | 'e' -> Buffer.add_string buf (Printf.sprintf "%2d"  tm.Unix.tm_mday)
            | 'H' -> Buffer.add_string buf (Printf.sprintf "%02d" tm.Unix.tm_hour)
+           | 'I' -> let h = tm.Unix.tm_hour mod 12 in
+                    Buffer.add_string buf (Printf.sprintf "%02d" (if h = 0 then 12 else h))
+           | 'p' -> Buffer.add_string buf (if tm.Unix.tm_hour < 12 then "AM" else "PM")
            | 'M' -> Buffer.add_string buf (Printf.sprintf "%02d" tm.Unix.tm_min)
            | 'S' -> Buffer.add_string buf (Printf.sprintf "%02d" tm.Unix.tm_sec)
            | 'j' -> Buffer.add_string buf (Printf.sprintf "%03d" (tm.Unix.tm_yday + 1))
-           | 'Z' -> Buffer.add_string buf "UTC"
+           | 'w' -> Buffer.add_string buf (string_of_int tm.Unix.tm_wday)
+           | 'Z' -> Buffer.add_string buf tz_label
            | 'a' -> let days = [|"Sun";"Mon";"Tue";"Wed";"Thu";"Fri";"Sat"|] in
                     Buffer.add_string buf days.(tm.Unix.tm_wday)
            | 'A' -> let days = [|"Sunday";"Monday";"Tuesday";"Wednesday";"Thursday";"Friday";"Saturday"|] in
@@ -3130,6 +3943,7 @@ let () =
                     Buffer.add_string buf mons.(tm.Unix.tm_mon)
            | 'B' -> let mons = [|"January";"February";"March";"April";"May";"June";"July";"August";"September";"October";"November";"December"|] in
                     Buffer.add_string buf mons.(tm.Unix.tm_mon)
+           | '%' -> Buffer.add_char buf '%'
            | c -> Buffer.add_char buf '%'; Buffer.add_char buf c);
           i := !i + 2
         end else begin
@@ -3137,5 +3951,129 @@ let () =
           incr i
         end
       done;
-      String (Buffer.contents buf)
-    | _ -> raise (Eval_error "clock-format: (seconds [format])"))
+      Buffer.contents buf
+  in
+  register "clock-format" (fun args ->
+    let (t, fmt, tz) = match args with
+      | [Integer t] -> (t, "%a %b %e %H:%M:%S %Z %Y", "utc")
+      | [Integer t; String f] -> (t, f, "utc")
+      | [Integer t; String f; String z] -> (t, f, z)
+      | _ -> raise (Eval_error "clock-format: (seconds [format [tz]])")
+    in
+    let tm =
+      if tz = "local" then Unix.localtime (float_of_int t)
+      else Unix.gmtime (float_of_int t)
+    in
+    let label = if tz = "local" then "" else "UTC" in
+    String (format_tm tm label fmt));
+
+  (* clock-scan: parse a date string with format, return seconds.
+     Supports the same format specifiers as clock-format (fixed-width ones).
+     tz: "utc" (default) or "local". *)
+  let timegm (tm : Unix.tm) =
+    let is_leap y = y mod 4 = 0 && (y mod 100 <> 0 || y mod 400 = 0) in
+    let days_in_month = [|31;28;31;30;31;30;31;31;30;31;30;31|] in
+    let year = tm.Unix.tm_year + 1900 in
+    let mon = tm.Unix.tm_mon in
+    let mday = tm.Unix.tm_mday in
+    let total_days = ref 0 in
+    if year >= 1970 then begin
+      for y = 1970 to year - 1 do
+        total_days := !total_days + (if is_leap y then 366 else 365)
+      done
+    end else begin
+      for y = year to 1969 do
+        total_days := !total_days - (if is_leap y then 366 else 365)
+      done
+    end;
+    for m = 0 to mon - 1 do
+      total_days := !total_days + days_in_month.(m);
+      if m = 1 && is_leap year then incr total_days
+    done;
+    total_days := !total_days + mday - 1;
+    !total_days * 86400
+    + tm.Unix.tm_hour * 3600
+    + tm.Unix.tm_min * 60
+    + tm.Unix.tm_sec
+  in
+  register "clock-scan" (fun args ->
+    let (str, fmt, tz) = match args with
+      | [String s; String f] -> (s, f, "utc")
+      | [String s; String f; String z] -> (s, f, z)
+      | _ -> raise (Eval_error "clock-scan: (str fmt [tz])")
+    in
+    let n = String.length fmt and sn = String.length str in
+    let tm = ref { Unix.tm_year = 70; tm_mon = 0; tm_mday = 1;
+                   tm_hour = 0; tm_min = 0; tm_sec = 0;
+                   tm_wday = 0; tm_yday = 0; tm_isdst = false } in
+    let i = ref 0 and j = ref 0 in
+    let read_n_digits k =
+      let s = ref "" in
+      let cnt = ref 0 in
+      while !cnt < k && !j < sn && str.[!j] >= '0' && str.[!j] <= '9' do
+        s := !s ^ String.make 1 str.[!j];
+        incr j; incr cnt
+      done;
+      if !s = "" then 0 else int_of_string !s
+    in
+    let skip_ws () =
+      while !j < sn && (str.[!j] = ' ' || str.[!j] = '\t') do incr j done
+    in
+    while !i < n do
+      if fmt.[!i] = '%' && !i + 1 < n then begin
+        (match fmt.[!i + 1] with
+         | 'Y' -> tm := { !tm with tm_year = read_n_digits 4 - 1900 }
+         | 'y' -> let y = read_n_digits 2 in
+                  tm := { !tm with tm_year = (if y < 70 then 100 + y else y) }
+         | 'm' -> tm := { !tm with tm_mon = read_n_digits 2 - 1 }
+         | 'd' | 'e' -> skip_ws (); tm := { !tm with tm_mday = read_n_digits 2 }
+         | 'H' | 'I' -> tm := { !tm with tm_hour = read_n_digits 2 }
+         | 'M' -> tm := { !tm with tm_min = read_n_digits 2 }
+         | 'S' -> tm := { !tm with tm_sec = read_n_digits 2 }
+         | '%' -> if !j < sn && str.[!j] = '%' then incr j
+         | _ -> ()  (* unsupported specifier — skip *)
+        );
+        i := !i + 2
+      end else begin
+        if fmt.[!i] = ' ' then skip_ws ()
+        else if !j < sn && str.[!j] = fmt.[!i] then incr j;
+        incr i
+      end
+    done;
+    let secs =
+      if tz = "local" then int_of_float (fst (Unix.mktime !tm))
+      else timegm !tm
+    in
+    Integer secs);
+
+  (* === Env-as-value (Phase 4) === *)
+
+  (* env-lookup: (env key) → value or nil.  Works on Env, Dict, or Nil. *)
+  register "env-lookup" (fun args ->
+    let unwrap = function
+      | Env e -> e
+      | Nil -> make_env ()
+      | _ -> raise (Eval_error "env-lookup: first arg must be an environment") in
+    match args with
+    | [env_val; key] ->
+      let e = unwrap env_val in
+      let k = value_to_string key in
+      if env_has e k then env_get e k else Nil
+    | _ -> raise (Eval_error "env-lookup: (env key)"));
+
+  (* env-extend: (env [key val ...]) → new child env with optional bindings. *)
+  register "env-extend" (fun args ->
+    match args with
+    | [] -> raise (Eval_error "env-extend: requires at least one arg")
+    | env_val :: pairs ->
+      let parent_env = match env_val with
+        | Env e -> e
+        | Nil -> make_env ()
+        | _ -> raise (Eval_error "env-extend: first arg must be an environment") in
+      let child = env_extend parent_env in
+      let rec add_bindings = function
+        | [] -> ()
+        | k :: v :: rest -> ignore (env_bind child (value_to_string k) v); add_bindings rest
+        | [_] -> raise (Eval_error "env-extend: odd number of key-val pairs") in
+      add_bindings pairs;
+      Env child)

hosts/ocaml/lib/sx_runtime.ml

@@ -539,3 +539,4 @@ let jit_try_call f args =
       (match hook f arg_list with Some result -> incr _jit_hit; result | None -> incr _jit_miss; _jit_skip_sentinel)
     | _ -> incr _jit_skip; _jit_skip_sentinel
 
+

lib/fiber.sx

@@ -0,0 +1,44 @@
+; lib/fiber.sx — pure SX fiber library using call/cc
+;
+; A fiber is a cooperative coroutine with true suspension (no eager
+; pre-execution). Each fiber is a dict {:resume fn :done? fn}.
+;
+; make-fiber body   → fiber dict
+;   body = (fn (yield init-val) ...)  — body receives yield + first resume val
+;   yield = (fn (val) ...)            — suspends fiber, returns val to resumer
+;
+; fiber-resume f v  → next yielded value, or nil when body returns
+; fiber-done? f     → true after body has returned
+
+(define make-fiber
+  (fn (body)
+    (let
+      ((resume-k nil)
+        (caller-k nil)
+        (done false))
+      (let
+        ((yield
+            (fn (val)
+              (call/cc
+                (fn (k)
+                  (set! resume-k k)
+                  (caller-k val))))))
+        {:resume
+         (fn (val)
+           (if
+             done
+             nil
+             (call/cc
+               (fn (k)
+                 (set! caller-k k)
+                 (if
+                   (nil? resume-k)
+                   (begin
+                     (body yield val)
+                     (set! done true)
+                     (k nil))
+                   (resume-k val))))))
+         :done? (fn () done)}))))
+
+(define fiber-resume (fn (f v) ((get f :resume) v)))
+(define fiber-done?  (fn (f) ((get f :done?))))

lib/tcl/test.sh

@@ -39,6 +39,7 @@ cat > "$TMPFILE" << EPOCHS
 (epoch 3)
 (load "lib/tcl/tests/parse.sx")
 (epoch 4)
+(load "lib/fiber.sx")
 (load "lib/tcl/runtime.sx")
 (epoch 5)
 (load "lib/tcl/tests/eval.sx")
@@ -56,7 +57,7 @@ cat > "$TMPFILE" << EPOCHS
 (eval "tcl-test-summary")
 EPOCHS
 
-OUTPUT=$(timeout 180 "$SX_SERVER" < "$TMPFILE" 2>&1)
+OUTPUT=$(timeout 7200 "$SX_SERVER" < "$TMPFILE" 2>&1)
 [ "$VERBOSE" = "-v" ] && echo "$OUTPUT"
 
 # Extract summary line from epoch 11 output

lib/tcl/tests/coro.sx

@@ -95,15 +95,15 @@
       (get (run "proc g {} { yield }\ncoroutine cg g\ncg") :result)
       "")
 
-    ; --- clock seconds stub ---
+    ; --- clock seconds ---
     (ok "clock-seconds"
-      (get (run "clock seconds") :result)
-      "0")
+      (> (parse-int (get (run "clock seconds") :result)) 0)
+      true)
 
-    ; --- clock milliseconds stub ---
+    ; --- clock milliseconds ---
     (ok "clock-milliseconds"
-      (get (run "clock milliseconds") :result)
-      "0")
+      (> (parse-int (get (run "clock milliseconds") :result)) 0)
+      true)
 
     ; --- clock format stub ---
     (ok "clock-format"
@@ -124,7 +124,7 @@
       "file0")
 
     (ok "eof-returns-1"
-      (get (run "set ch [open /dev/null r]\neof $ch") :result)
+      (get (run "set ch [open /dev/null r]\nread $ch\neof $ch") :result)
       "1")
 
     (dict

lib/tcl/tests/eval.sx

@@ -329,6 +329,54 @@
         (run "proc with-temp-var {varname tempval body} {\n    upvar 1 $varname v\n    set saved $v\n    set v $tempval\n    uplevel 1 $body\n    set v $saved\n}\nset x 100\nwith-temp-var x 999 {\n    set captured $x\n}\nlist $x $captured")
         :result)
       "100 999")
+    (ok
+      "array-set-get"
+      (get
+        (run "array set a {x 1 y 2 z 3}; array get a x")
+        :result)
+      "x 1")
+    (ok
+      "array-names"
+      (get
+        (run "array set a {p 10 q 20}; lsort [array names a]")
+        :result)
+      "p q")
+    (ok
+      "array-size"
+      (get
+        (run "array set a {x 1 y 2 z 3}; array size a")
+        :result)
+      "3")
+    (ok
+      "array-exists-true"
+      (get
+        (run "array set a {x 1}; array exists a")
+        :result)
+      "1")
+    (ok
+      "array-exists-false"
+      (get
+        (run "array exists nosucharray")
+        :result)
+      "0")
+    (ok
+      "array-unset-key"
+      (get
+        (run "array set a {x 1 y 2 z 3}; array unset a y; lsort [array names a]")
+        :result)
+      "x z")
+    (ok
+      "array-scalar-access"
+      (get
+        (run "set a(foo) hello; set a(bar) world; set a(foo)")
+        :result)
+      "hello")
+    (ok
+      "array-get-all"
+      (get
+        (run "set a(k) v; set pairs [array get a]; llength $pairs")
+        :result)
+      "2")
     (dict
       "passed"
       tcl-eval-pass

lib/tcl/tests/idioms.sx

@@ -29,160 +29,653 @@
     (define
       ok
       (fn (label actual expected) (tcl-idiom-assert label expected actual)))
-
-    ; 1. lmap idiom: accumulate mapped values with foreach+lappend
-    (ok "idiom-lmap"
+    (ok
+      "idiom-lmap"
       (get
-        (run "set result {}\nforeach x {1 2 3} { lappend result [expr {$x * $x}] }\nset result")
+        (run
+          "set result {}\nforeach x {1 2 3} { lappend result [expr {$x * $x}] }\nset result")
         :result)
       "1 4 9")
-
-    ; 2. Recursive list flatten
-    (ok "idiom-flatten"
+    (ok
+      "idiom-flatten"
       (get
         (run
           "proc flatten {lst} { set out {}\n  foreach item $lst {\n    if {[llength $item] > 1} {\n      foreach sub [flatten $item] { lappend out $sub }\n    } else {\n      lappend out $item\n    }\n  }\n  return $out\n}\nflatten {1 {2 3} {4 {5 6}}}")
         :result)
       "1 2 3 4 5 6")
-
-    ; 3. String builder accumulator
-    (ok "idiom-string-builder"
+    (ok
+      "idiom-string-builder"
       (get
-        (run "set buf \"\"\nforeach w {Hello World Tcl} { append buf $w \" \" }\nstring trimright $buf")
+        (run
+          "set buf \"\"\nforeach w {Hello World Tcl} { append buf $w \" \" }\nstring trimright $buf")
         :result)
       "Hello World Tcl")
-
-    ; 4. Default parameter via info exists
-    (ok "idiom-default-param"
-      (get
-        (run "if {![info exists x]} { set x 42 }\nset x")
-        :result)
+    (ok
+      "idiom-default-param"
+      (get (run "if {![info exists x]} { set x 42 }\nset x") :result)
       "42")
-
-    ; 5. Association list lookup (parallel key/value lists)
-    (ok "idiom-alist-lookup"
+    (ok
+      "idiom-alist-lookup"
       (get
         (run
           "set keys {a b c}\nset vals {10 20 30}\nset idx [lsearch $keys b]\nlindex $vals $idx")
         :result)
       "20")
-
-    ; 6. Proc with optional args via args
-    (ok "idiom-optional-args"
+    (ok
+      "idiom-optional-args"
       (get
         (run
           "proc greet {name args} {\n  set greeting \"Hello\"\n  if {[llength $args] > 0} { set greeting [lindex $args 0] }\n  return \"$greeting $name\"\n}\ngreet World Hi")
         :result)
       "Hi World")
-
-    ; 7. Builder pattern: dict create from args
-    (ok "idiom-dict-builder"
+    (ok
+      "idiom-dict-builder"
       (get
         (run
           "proc build-dict {args} { dict create {*}$args }\ndict get [build-dict name Alice age 30] name")
         :result)
       "Alice")
-
-    ; 8. Loop with index using array
-    (ok "idiom-loop-with-index"
+    (ok
+      "idiom-loop-with-index"
       (get
-        (run
-          "set i 0\nforeach x {a b c} { set arr($i) $x; incr i }\nset arr(1)")
+        (run "set i 0\nforeach x {a b c} { set arr($i) $x; incr i }\nset arr(1)")
         :result)
       "b")
-
-    ; 9. String reverse via split+lreverse+join
-    (ok "idiom-string-reverse"
+    (ok
+      "idiom-string-reverse"
       (get
         (run
           "set s hello\nset chars [split $s \"\"]\nset rev [lreverse $chars]\njoin $rev \"\"")
         :result)
       "olleh")
-
-    ; 10. Number to padded string
-    (ok "idiom-number-format"
-      (get (run "format \"%05d\" 42") :result)
-      "00042")
-
-    ; 11. Dict comprehension pattern
-    (ok "idiom-dict-comprehension"
+    (ok "idiom-number-format" (get (run "format \"%05d\" 42") :result) "00042")
+    (ok
+      "idiom-dict-comprehension"
       (get
         (run
           "set squares {}\nforeach n {1 2 3 4} { dict set squares $n [expr {$n * $n}] }\ndict get $squares 3")
         :result)
       "9")
-
-    ; 12. Stack ADT using list: push/pop
-    (ok "idiom-stack"
+    (ok
+      "idiom-stack"
       (get
         (run
           "proc stack-push {stackvar val} { upvar $stackvar s; lappend s $val }\nproc stack-pop {stackvar} { upvar $stackvar s; set val [lindex $s end]; set s [lrange $s 0 end-1]; return $val }\nset stk {}\nstack-push stk 10\nstack-push stk 20\nstack-push stk 30\nstack-pop stk")
         :result)
       "30")
-
-    ; 13. Queue ADT using list: enqueue/dequeue
-    (ok "idiom-queue"
+    (ok
+      "idiom-queue"
       (get
         (run
           "proc q-enq {qvar val} { upvar $qvar q; lappend q $val }\nproc q-deq {qvar} { upvar $qvar q; set val [lindex $q 0]; set q [lrange $q 1 end]; return $val }\nset q {}\nq-enq q alpha\nq-enq q beta\nq-enq q gamma\nq-deq q")
         :result)
       "alpha")
-
-    ; 14. Pipeline via proc chaining
-    (ok "idiom-pipeline"
+    (ok
+      "idiom-pipeline"
       (get
         (run
           "proc double {x} { expr {$x * 2} }\nproc add1 {x} { expr {$x + 1} }\nproc pipeline {val procs} { foreach p $procs { set val [$p $val] }; return $val }\npipeline 5 {double add1 double}")
         :result)
       "22")
-
-    ; 15. Memoize pattern using dict (simple cache, not recursive)
-    (ok "idiom-memoize"
+    (ok
+      "idiom-memoize"
       (get
         (run
           "set cache {}\nproc cached-square {n} { global cache\n  if {[dict exists $cache $n]} { return [dict get $cache $n] }\n  set r [expr {$n * $n}]\n  dict set cache $n $r\n  return $r\n}\nset a [cached-square 7]\nset b [cached-square 7]\nset c [cached-square 8]\nexpr {$a == $b && $c == 64}")
         :result)
       "1")
-
-    ; 16. Simple expression evaluator in Tcl (recursive descent)
-    (ok "idiom-recursive-eval"
+    (ok
+      "idiom-recursive-eval"
       (get
         (run
           "proc calc {expr} { return [::tcl::mathop::+ 0 [expr $expr]] }\nexpr {3 + 4 * 2}")
         :result)
       "11")
-
-    ; 17. Apply proc to each pair in a dict
-    (ok "idiom-dict-for"
+    (ok
+      "idiom-dict-for"
       (get
         (run
           "set d [dict create a 1 b 2 c 3]\nset total 0\ndict for {k v} $d { incr total $v }\nset total")
         :result)
       "6")
-
-    ; 18. Find max in list
-    (ok "idiom-find-max"
+    (ok
+      "idiom-find-max"
       (get
         (run
           "proc list-max {lst} {\n  set m [lindex $lst 0]\n  foreach x $lst { if {$x > $m} { set m $x } }\n  return $m\n}\nlist-max {3 1 4 1 5 9 2 6}")
         :result)
       "9")
-
-    ; 19. Filter list by predicate
-    (ok "idiom-filter-list"
+    (ok
+      "idiom-filter-list"
       (get
         (run
           "proc list-filter {lst pred} {\n  set out {}\n  foreach x $lst { if {[$pred $x]} { lappend out $x } }\n  return $out\n}\nproc is-even {n} { expr {$n % 2 == 0} }\nlist-filter {1 2 3 4 5 6} is-even")
         :result)
       "2 4 6")
-
-    ; 20. Zip two lists
-    (ok "idiom-zip"
+    (ok
+      "idiom-zip"
       (get
         (run
           "proc zip {a b} {\n  set out {}\n  set n [llength $a]\n  for {set i 0} {$i < $n} {incr i} {\n    lappend out [lindex $a $i]\n    lappend out [lindex $b $i]\n  }\n  return $out\n}\nzip {1 2 3} {a b c}")
         :result)
       "1 a 2 b 3 c")
+    (ok
+      "env-lookup-basic"
+      (env-lookup (let ((x 42)) (current-env)) "x")
+      42)
+    (ok
+      "env-lookup-missing"
+      (env-lookup (let ((x 42)) (current-env)) "z")
+      nil)
+    (ok
+      "env-extend-lookup"
+      (let
+        ((e (let ((x 5)) (current-env))))
+        (env-lookup (env-extend e "y" 10) "y"))
+      10)
+    (ok
+      "eval-in-env-parent"
+      (let
+        ((x 5))
+        (eval-in-env (env-extend (current-env) "y" 10) (quote (+ x y))))
+      15)
+    (ok
+      "eval-in-env-multi"
+      (let
+        ((base (current-env)))
+        (eval-in-env
+          (env-extend (env-extend base "a" 3) "b" 7)
+          (quote (* a b))))
+      21)
+
+    ; 26-32. Phase 5 channels: write/read/seek/tell/eof/append/non-blocking
+    (ok "channel-write-read"
+      (get
+        (run
+          "set f /tmp/tcl-phase5-1.txt\nset c [open $f w]\nputs $c \"line one\"\nputs $c \"line two\"\nclose $c\nset c [open $f r]\nset out [read $c]\nclose $c\nfile delete $f\nreturn $out")
+        :result)
+      "line one\nline two\n")
+
+    (ok "channel-gets-loop"
+      (get
+        (run
+          "set f /tmp/tcl-phase5-2.txt\nset c [open $f w]\nputs $c apple\nputs $c banana\nputs $c cherry\nclose $c\nset c [open $f r]\nset out {}\nwhile {[gets $c line] >= 0} {lappend out $line}\nclose $c\nfile delete $f\nreturn $out")
+        :result)
+      "apple banana cherry")
+
+    (ok "channel-seek-tell"
+      (get
+        (run
+          "set f /tmp/tcl-phase5-3.txt\nset c [open $f w]\nputs -nonewline $c \"hello world\"\nclose $c\nset c [open $f r]\nseek $c 6\nset pos [tell $c]\nset rest [read $c]\nclose $c\nfile delete $f\nreturn \"$pos:$rest\"")
+        :result)
+      "6:world")
+
+    (ok "channel-eof-after-read"
+      (get
+        (run
+          "set f /tmp/tcl-phase5-4.txt\nset c [open $f w]\nputs -nonewline $c hi\nclose $c\nset c [open $f r]\nread $c\nset e [eof $c]\nclose $c\nfile delete $f\nreturn $e")
+        :result)
+      "1")
+
+    (ok "channel-append-mode"
+      (get
+        (run
+          "set f /tmp/tcl-phase5-5.txt\nset c [open $f w]\nputs -nonewline $c \"first\"\nclose $c\nset c [open $f a]\nputs -nonewline $c \"-second\"\nclose $c\nset c [open $f r]\nset out [read $c]\nclose $c\nfile delete $f\nreturn $out")
+        :result)
+      "first-second")
+
+    (ok "channel-seek-end"
+      (get
+        (run
+          "set f /tmp/tcl-phase5-6.txt\nset c [open $f w]\nputs -nonewline $c \"abcdefghij\"\nclose $c\nset c [open $f r]\nseek $c 0 end\nset pos [tell $c]\nclose $c\nfile delete $f\nreturn $pos")
+        :result)
+      "10")
+
+    (ok "channel-fconfigure-blocking"
+      (get
+        (run
+          "set f /tmp/tcl-phase5-7.txt\nset c [open $f w]\nputs -nonewline $c x\nclose $c\nset c [open $f r]\nfconfigure $c -blocking 0\nset b [fconfigure $c -blocking]\nclose $c\nfile delete $f\nreturn $b")
+        :result)
+      "0")
+
+    ; 33-37. Phase 5b event loop: after / vwait / fileevent / update
+    (ok "after-vwait-timer"
+      (get
+        (run
+          "after 30 {set ::done fired}\nvwait ::done\nset ::done")
+        :result)
+      "fired")
+
+    (ok "after-multiple-timers-update"
+      (get
+        (run
+          "set ::n 0\nafter 0 {incr ::n}\nafter 0 {incr ::n}\nafter 0 {incr ::n}\nupdate\nset ::n")
+        :result)
+      "3")
+
+    (ok "fileevent-readable-fires"
+      (get
+        (run
+          "set f /tmp/tcl-phase5b-1.txt\nset c [open $f w]\nputs -nonewline $c hi\nclose $c\nset c [open $f r]\nfileevent $c readable {set ::ready 1; fileevent $::ch readable {}}\nset ::ch $c\nvwait ::ready\nclose $c\nfile delete $f\nset ::ready")
+        :result)
+      "1")
+
+    (ok "fileevent-query-script"
+      (get
+        (run
+          "set f /tmp/tcl-phase5b-2.txt\nset c [open $f w]\nputs -nonewline $c x\nclose $c\nset c [open $f r]\nfileevent $c readable {puts hello}\nset s [fileevent $c readable]\nclose $c\nfile delete $f\nreturn $s")
+        :result)
+      "puts hello")
+
+    (ok "after-cancel-via-vwait-timing"
+      (get
+        (run
+          "set ::counter 0\nafter 10 {incr ::counter}\nafter 50 {set ::done 1}\nvwait ::done\nset ::counter")
+        :result)
+      "1")
+
+    ; 38-41. Phase 5c sockets: TCP client + server
+    (ok "socket-server-fires-callback"
+      (get
+        (run
+          "proc h {sock host port} { global got; set got hit; close $sock }\nset srv [socket -server h 18901]\nset cli [socket localhost 18901]\nvwait got\nclose $srv\nclose $cli\nset got")
+        :result)
+      "hit")
+
+    (ok "socket-client-server-roundtrip"
+      (get
+        (run
+          "proc h {sock host port} { global received; gets $sock line; set received $line; close $sock }\nset srv [socket -server h 18902]\nset cli [socket localhost 18902]\nputs $cli ping\nflush $cli\nvwait received\nclose $srv\nclose $cli\nset received")
+        :result)
+      "ping")
+
+    (ok "socket-server-peer-host"
+      (get
+        (run
+          "proc h {sock host port} { global peer; set peer $host; close $sock }\nset srv [socket -server h 18903]\nset cli [socket 127.0.0.1 18903]\nvwait peer\nclose $srv\nclose $cli\nset peer")
+        :result)
+      "127.0.0.1")
+
+    (ok "socket-multiple-connections"
+      (get
+        (run
+          "proc h {sock host port} { global count; incr count; close $sock }\nset count 0\nset srv [socket -server h 18904]\nset c1 [socket localhost 18904]\nset c2 [socket localhost 18904]\nset c3 [socket localhost 18904]\nwhile {$count < 3} { update; after 5 }\nclose $srv\nclose $c1\nclose $c2\nclose $c3\nset count")
+        :result)
+      "3")
+
+    ; 42-49. Phase 5d file metadata + ops
+    (ok "file-isfile-true"
+      (get
+        (run
+          "set f /tmp/tcl-phase5d-1.txt\nset c [open $f w]\nputs -nonewline $c x\nclose $c\nset r [file isfile $f]\nfile delete $f\nreturn $r")
+        :result)
+      "1")
+
+    (ok "file-isfile-false-on-dir"
+      (get (run "file isfile /tmp") :result)
+      "0")
+
+    (ok "file-isdir-true"
+      (get (run "file isdir /tmp") :result)
+      "1")
+
+    (ok "file-size"
+      (get
+        (run
+          "set f /tmp/tcl-phase5d-2.txt\nset c [open $f w]\nputs -nonewline $c hello\nclose $c\nset s [file size $f]\nfile delete $f\nreturn $s")
+        :result)
+      "5")
+
+    (ok "file-readable-true"
+      (get (run "file readable /tmp") :result)
+      "1")
+
+    (ok "file-readable-missing"
+      (get (run "file readable /no/such/path/here") :result)
+      "0")
+
+    (ok "file-mkdir-then-isdir"
+      (get
+        (run
+          "set d /tmp/tcl-phase5d-mkdir/sub\nfile mkdir $d\nset r [file isdir $d]\nfile delete $d\nfile delete /tmp/tcl-phase5d-mkdir\nreturn $r")
+        :result)
+      "1")
+
+    (ok "file-copy-roundtrip"
+      (get
+        (run
+          "set s /tmp/tcl-phase5d-src.txt\nset d /tmp/tcl-phase5d-dst.txt\nset c [open $s w]\nputs -nonewline $c copydata\nclose $c\nfile copy $s $d\nset c [open $d r]\nset out [read $c]\nclose $c\nfile delete $s\nfile delete $d\nreturn $out")
+        :result)
+      "copydata")
+
+    (ok "file-rename-then-exists"
+      (get
+        (run
+          "set s /tmp/tcl-phase5d-r1.txt\nset d /tmp/tcl-phase5d-r2.txt\nset c [open $s w]\nputs -nonewline $c x\nclose $c\nfile rename $s $d\nset r [list [file exists $s] [file exists $d]]\nfile delete $d\nreturn $r")
+        :result)
+      "0 1")
+
+    (ok "file-mtime-positive"
+      (get
+        (run
+          "set f /tmp/tcl-phase5d-mt.txt\nset c [open $f w]\nputs -nonewline $c x\nclose $c\nset m [file mtime $f]\nfile delete $f\nexpr {$m > 0}")
+        :result)
+      "1")
+
+    ; 52-56. Phase 5e clock format options + clock scan
+    (ok "clock-format-utc"
+      (get
+        (run "clock format 0 -format {%Y-%m-%d %H:%M:%S} -gmt 1")
+        :result)
+      "1970-01-01 00:00:00")
+
+    (ok "clock-format-fmt-default"
+      (get
+        (run "clock format 1710513000 -format {%Y-%m-%d} -gmt 1")
+        :result)
+      "2024-03-15")
+
+    (ok "clock-scan-roundtrip"
+      (get
+        (run "set t [clock scan {2024-06-15 12:00:00} -format {%Y-%m-%d %H:%M:%S} -gmt 1]\nclock format $t -format {%Y-%m-%d %H:%M:%S} -gmt 1")
+        :result)
+      "2024-06-15 12:00:00")
+
+    (ok "clock-scan-returns-int"
+      (get
+        (run "expr {[clock scan {1970-01-01 00:00:00} -format {%Y-%m-%d %H:%M:%S} -gmt 1] == 0}")
+        :result)
+      "1")
+
+    (ok "clock-format-percent-pct"
+      (get
+        (run "clock format 0 -format {%Y%%%m} -gmt 1")
+        :result)
+      "1970%01")
+
+    ; 57-59. Phase 5f socket -async (non-blocking connect)
+    (ok "socket-async-completes-writable"
+      (get
+        (run
+          "proc h {sock host port} { close $sock }\nset srv [socket -server h 18930]\nset c [socket -async localhost 18930]\nset ready 0\nfileevent $c writable {global ready; set ready 1}\nvwait ready\nclose $c\nclose $srv\nset ready")
+        :result)
+      "1")
+
+    (ok "socket-async-then-write"
+      (get
+        (run
+          "proc accept {sock host port} { global accepted_sock; set accepted_sock $sock; fileevent $sock readable [list reader $sock] }\nproc reader {sock} { global received; gets $sock line; set received $line; close $sock }\nset srv [socket -server accept 18931]\nset c [socket -async localhost 18931]\nfileevent $c writable {global wready; set wready 1; fileevent $::ch writable {}}\nset ::ch $c\nvwait wready\nputs $c async-data\nflush $c\nvwait received\nclose $c\nclose $srv\nset received")
+        :result)
+      "async-data")
+
+    (ok "socket-async-no-error"
+      (get
+        (run
+          "proc h {sock host port} { close $sock }\nset srv [socket -server h 18932]\nset c [socket -async localhost 18932]\nset r 0\nfileevent $c writable {global r; set r 1}\nvwait r\nset err [fconfigure $c -error]\nclose $c\nclose $srv\nreturn $err")
+        :result)
+      "")
+
+    ; 60-63. Phase 6a namespace :: prefix
+    (ok "ns-set-from-proc-reaches-global"
+      (get
+        (run
+          "proc f {x} { set ::g $x }\nf hello\nset ::g")
+        :result)
+      "hello")
+
+    (ok "ns-read-from-proc"
+      (get
+        (run
+          "set ::v 42\nproc f {} { return $::v }\nf")
+        :result)
+      "42")
+
+    (ok "ns-incr-via-prefix"
+      (get
+        (run
+          "set ::n 5\nproc bump {} { incr ::n }\nbump\nbump\nset ::n")
+        :result)
+      "7")
+
+    (ok "ns-different-from-local"
+      (get
+        (run
+          "set x outer\nproc f {} { set x inner; set ::x global; return $x }\nf")
+        :result)
+      "inner")
+
+    ; 64-69. Phase 6b list ops (lassign, lrepeat, lset, lmap)
+    (ok "lassign-three"
+      (get (run "lassign {a b c d e} x y z\nlist $x $y $z") :result)
+      "a b c")
+
+    (ok "lassign-leftover"
+      (get (run "lassign {1 2 3 4 5} a b") :result)
+      "3 4 5")
+
+    (ok "lrepeat-basic"
+      (get (run "lrepeat 3 a") :result)
+      "a a a")
+
+    (ok "lrepeat-multi"
+      (get (run "lrepeat 2 x y") :result)
+      "x y x y")
+
+    (ok "lset-replaces"
+      (get (run "set L {a b c d}\nlset L 2 ZZ\nset L") :result)
+      "a b ZZ d")
+
+    (ok "lmap-square"
+      (get (run "lmap n {1 2 3 4} {expr {$n * $n}}") :result)
+      "1 4 9 16")
+
+    ; 70-72. Phase 6c dict additions (lappend, remove, filter)
+    (ok "dict-lappend-extends"
+      (get (run "set d {tags {a b}}\ndict lappend d tags c d\nset d") :result)
+      "tags {a b c d}")
+
+    (ok "dict-remove"
+      (get (run "dict remove {a 1 b 2 c 3} b") :result)
+      "a 1 c 3")
+
+    (ok "dict-filter-key"
+      (get (run "dict filter {alpha 1 beta 2 gamma 3} key a*") :result)
+      "alpha 1")
+
+    ; 73-79. Phase 6d format and scan
+    (ok "format-int-padded"
+      (get (run "format {%05d} 42") :result)
+      "00042")
+
+    (ok "format-float-precision"
+      (get (run "format {%.2f} 3.14159") :result)
+      "3.14")
+
+    (ok "format-hex"
+      (get (run "format {%x} 255") :result)
+      "ff")
+
+    (ok "format-char"
+      (get (run "format {%c} 65") :result)
+      "A")
+
+    (ok "format-string-left"
+      (get (run "format {%-5s|} hi") :result)
+      "hi   |")
+
+    (ok "scan-two-ints"
+      (get (run "scan {12 34} {%d %d} a b\nlist $a $b") :result)
+      "12 34")
+
+    (ok "scan-count"
+      (get (run "scan {hello 42} {%s %d}") :result)
+      "hello 42")
+
+    ; 80-82. Phase 6e exec
+    (ok "exec-echo"
+      (get (run "exec echo hello world") :result)
+      "hello world")
+
+    (ok "exec-printf-no-newline"
+      (get (run "exec /bin/printf x") :result)
+      "x")
+
+    (ok "exec-with-args"
+      (get (run "exec /bin/echo -n test") :result)
+      "test")
+
+    ; 83-87. Phase 7a try/trap with varlist
+    (ok "try-trap-prefix-match"
+      (get
+        (run
+          "try {throw {ARITH DIVZERO} divide-by-zero} trap {ARITH} {res} {set caught $res}")
+        :result)
+      "divide-by-zero")
+
+    (ok "try-trap-full-pattern"
+      (get
+        (run
+          "try {throw {FOO BAR} bad} trap {FOO BAR} {res} {return matched-foo-bar}")
+        :result)
+      "matched-foo-bar")
+
+    (ok "try-on-error-opts"
+      (get
+        (run
+          "try {error oops} on error {res opts} {dict get $opts -code}")
+        :result)
+      "1")
+
+    (ok "try-trap-no-match-falls-through"
+      (get
+        (run
+          "set caught notrun\ncatch {try {throw {NOPE} bad} trap {OTHER} {r} {set caught matched}}\nset caught")
+        :result)
+      "notrun")
+
+    (ok "try-trap-then-on-error"
+      (get
+        (run
+          "try {error generic} trap {SPECIFIC} {r} {return trap-fired} on error {r} {return on-error-fired}")
+        :result)
+      "on-error-fired")
+
+    ; 88-92. Phase 7b exec pipelines + redirection
+    (ok "exec-pipeline-tr"
+      (get (run "exec echo hello world | tr a-z A-Z") :result)
+      "HELLO WORLD")
+
+    (ok "exec-pipeline-wc"
+      (get (run "exec /bin/echo abc | wc -c") :result)
+      "4")
+
+    (ok "exec-redirect-stdout"
+      (get
+        (run
+          "set f /tmp/tcl-7b-out.txt\nexec echo hello > $f\nset r [exec cat $f]\nfile delete $f\nreturn $r")
+        :result)
+      "hello")
+
+    (ok "exec-redirect-stdin"
+      (get
+        (run
+          "set f /tmp/tcl-7b-in.txt\nset c [open $f w]\nputs -nonewline $c hi\nclose $c\nset r [exec cat < $f]\nfile delete $f\nreturn $r")
+        :result)
+      "hi")
+
+    (ok "exec-pipeline-three-stages"
+      (get (run "exec echo {alpha beta gamma} | tr { } \\n | wc -l") :result)
+      "3")
+
+    ; 93-99. Phase 7c string command audit
+    (ok "string-equal"
+      (get (run "string equal hello hello") :result)
+      "1")
+
+    (ok "string-equal-nocase"
+      (get (run "string equal -nocase HELLO hello") :result)
+      "1")
+
+    (ok "string-totitle"
+      (get (run "string totitle hello") :result)
+      "Hello")
+
+    (ok "string-reverse"
+      (get (run "string reverse hello") :result)
+      "olleh")
+
+    (ok "string-replace"
+      (get (run "string replace hello 1 3 ZZZ") :result)
+      "hZZZo")
+
+    (ok "string-is-xdigit-yes"
+      (get (run "string is xdigit ff00aa") :result)
+      "1")
+
+    (ok "string-is-true-yes"
+      (get (run "string is true yes") :result)
+      "1")
+
+    ; 100-105. Phase 7e regexp anchoring/boundary audit
+    (ok "regexp-anchor-start"
+      (get (run "regexp {^hello} hello-world") :result)
+      "1")
+
+    (ok "regexp-anchor-end"
+      (get (run "regexp {world$} hello-world") :result)
+      "1")
+
+    (ok "regexp-word-boundary"
+      (get (run "regexp {\\bword\\b} \"the word here\"") :result)
+      "1")
+
+    (ok "regexp-nocase"
+      (get (run "regexp -nocase {HELLO} hello") :result)
+      "1")
+
+    (ok "regexp-capture-var"
+      (get (run "regexp {[0-9]+} abc123def captured\nset captured") :result)
+      "123")
+
+    (ok "regsub-all"
+      (get (run "regsub -all {[0-9]+} a1b22c333 X") :result)
+      "aXbXcX")
+
+    ; 106-110. Phase 7d TclOO basics
+    (ok "oo-class-method"
+      (get
+        (run
+          "oo::class create C {\nmethod get {} { return 42 }\n}\nset c [C new]\n$c get")
+        :result)
+      "42")
+
+    (ok "oo-constructor"
+      (get
+        (run
+          "oo::class create G {\nconstructor {n} { set ::gname $n }\nmethod hello {} { return [string cat \"hi \" $::gname] }\n}\nset g [G new World]\n$g hello")
+        :result)
+      "hi World")
+
+    (ok "oo-inheritance-overridden"
+      (get
+        (run
+          "oo::class create Animal {\nmethod sound {} { return generic }\n}\noo::class create Dog {\nsuperclass Animal\nmethod sound {} { return woof }\n}\nset d [Dog new]\n$d sound")
+        :result)
+      "woof")
+
+    (ok "oo-inheritance-inherited"
+      (get
+        (run
+          "oo::class create Animal {\nmethod sound {} { return generic }\n}\noo::class create Cat {\nsuperclass Animal\n}\nset c [Cat new]\n$c sound")
+        :result)
+      "generic")
+
+    (ok "oo-multiple-instances"
+      (get
+        (run
+          "oo::class create N {\nconstructor {x} { set ::nval $x }\nmethod get {} { return $::nval }\n}\nset a [N new 1]\nset b [N new 99]\n$b get")
+        :result)
+      "99")
 
     (dict
       "passed"

lib/tcl/tokenizer.sx

@@ -167,7 +167,9 @@
                       (begin
                         (when (= (cur) "}") (advance! 1))
                         {:type "var" :name name}))))))
-            ((tcl-ident-start? (cur))
+            ((or
+                (tcl-ident-start? (cur))
+                (and (= (cur) ":") (= (char-at 1) ":")))
               (let ((start pos))
                 (begin
                   (scan-ns-name!)

plans/agent-briefings/sx-improvements-loop.md

@@ -0,0 +1,86 @@
+# sx-improvements loop agent
+
+Iterates `plans/sx-improvements.md` forever. One step per commit.
+
+```
+description: sx-improvements loop
+subagent_type: general-purpose
+run_in_background: true
+isolation: worktree
+```
+
+## Prompt
+
+You are the sole background agent iterating `plans/sx-improvements.md` on the `architecture` branch of `/root/rose-ash`. One step per commit, forever. Never push.
+
+## Restart baseline — check before each iteration
+
+1. Read `plans/sx-improvements.md` — find the first unchecked `[ ]` step in the progress log.
+2. Read the step's section in the plan for exact implementation details.
+3. Run the verification command for that step to confirm it currently fails.
+4. Implement. Verify. Commit. Tick the `[ ]` → `[x]` in the progress log. Next.
+
+## Test commands
+
+- **OCaml spec:** `sx_build target="ocaml"` then check `bin/run_tests.exe` output.
+- **JS spec (no DOM):** `node hosts/javascript/run_tests.js 2>&1 | tail -3`
+- **HyperScript kernel:** `node tests/hs-kernel-eval.js 2>&1 | tail -3`
+- **Baseline SX tests (non-HS):** `node hosts/javascript/run_tests.js 2>&1 | grep -v "hs-upstream\|hs-compat\|hs-dev" | grep "Results:"`
+
+Do NOT regress the pre-merge passing tests. After each step, confirm the count did not drop.
+
+## Ground rules (hard)
+
+- **Branch:** `architecture`. Never push. Never touch `main`.
+- **SX files:** `sx-tree` MCP tools ONLY (`sx_summarise`, `sx_read_subtree`, `sx_replace_node`, `sx_insert_child`, `sx_validate`). Read before edit. Validate after edit.
+- **Generated files:** NEVER edit `shared/static/wasm/sx/` or `shared/static/scripts/sx-*.js` directly. Rebuild via `sx_build`.
+- **HS mirror rule:** after editing any `lib/hyperscript/<f>.sx`, copy to `shared/static/wasm/sx/hs-<f>.sx` using `sx_write_file` with the same content.
+- **OCaml build:** `sx_build target="ocaml"` — never raw `dune exec`.
+- **JS build:** `sx_build target="js"`.
+- **One step per commit.** Tick the plan. Factual commit message.
+- **No new planning docs.** No comments in SX unless non-obvious.
+- **Unicode in SX:** raw UTF-8 only, never `\uXXXX` escapes.
+
+## Step-specific notes
+
+### Step 1 (JIT combinator bug)
+The bug is in `hosts/ocaml/lib/sx_vm.ml` — `call_closure_reuse` path strips locals when
+callee returns a closure. Look for the path where `call_closure_reuse` is invoked for a
+`VmClosure` return value. The fix is to not reuse frames when the call might return a
+closure, or to properly snapshot/restore `sp`. Check `spec/tests/test-parser-combinators.sx`
+for existing combinator tests; run `node tests/hs-kernel-eval.js` for the 11 failing HS tests.
+
+### Step 2 (letrec+resume)
+The bug is browser-only (`hosts/ocaml/browser/sx_browser.ml`). Write a minimal
+`spec/tests/test-letrec-resume.sx` that exercises `letrec` + `perform` + resume and
+verify it passes under `run_tests.exe` (OCaml server mode). Then check what
+`sx_browser.ml` does differently in the VmSuspension resume path.
+
+### Steps 3-4 (E38 source info)
+The API is already in `lib/hyperscript/runtime.sx`. The gap is in the tokenizer (no `:end`/`:line`)
+and some parser span completeness. Run the 4 sourceInfo tests to see exact failures:
+`node tests/hs-kernel-eval.js --suite sourceInfo` or grep results for `sourceInfo`.
+
+### Steps 5-8 (ADTs)
+Full spec in `plans/designs/sx-adt.md`. Implement in OCaml first (Step 5), then mirror
+to JS (Step 6). Steps 7-8 build on top. Write `spec/tests/test-adt.sx` from scratch —
+start with a `(define-type Maybe (Just value) (Nothing))` suite covering constructor,
+predicate, accessor, basic match, else clause.
+
+### Steps 9-11 (plugin system)
+Full spec in `plans/designs/hs-plugin-system.md`. The prolog hook migration (Step 11) is
+the most important for language-building — it's the pattern for all future embeds.
+
+### Steps 12-14 (performance)
+Profile first. Use `sx_harness_eval` to measure throughput on a tight loop before and
+after each change. Only commit if there's a measurable win (>10%).
+
+## General gotchas (all loops)
+
+- SX `do` is R7RS iteration. Use `begin` for multi-expr sequences.
+- `cond`/`when`/`let` bodies evaluate only the last expression.
+- `type-of` on a user-defined function returns `"lambda"`.
+- Shell heredoc `||` gets eaten — escape or use `case`.
+- `env-bind!` creates new bindings; `env-set!` mutates existing (walks scope chain).
+- After OCaml edits: the build takes ~2 min. Run `sx_build target="ocaml"` and wait.
+- After JS edits: retranspile with `sx_build target="js"` then re-run tests.

plans/sx-improvements.md

@@ -0,0 +1,210 @@
+# SX Language Improvements — roadmap
+
+Language-building improvements to the SX evaluator, compiler, and standard library.
+Ordered by impact and prerequisite chain. Each step is one loop commit.
+
+Branch: `architecture`. SX files via `sx-tree` MCP only. Never edit generated files.
+
+## Current baseline (2026-05-06)
+
+- SX core spec: 2571 passing (595 non-HS pre-existing failures — bytecode-serialize, defcomp-render, etc.)
+- HyperScript behavioral: 1478/1496 (run via `node tests/hs-kernel-eval.js`)
+- Active bugs: JIT combinator bug (11 HS failures), letrec+resume (browser-only)
+- E38 sourceInfo: 2/4 tests passing (tokenizer missing `:end`/`:line`, some spans incomplete)
+
+---
+
+## Phase 1 — Bug fixes
+
+### Step 1: Fix JIT closures-returning-closures
+
+**What:** `parse-bind`, `many`, `seq`, and other parser combinators that return closures
+miscompile under JIT. The compiled closure drops intermediate stack values when the
+callee itself returns a closure. 11 HyperScript tests fail under JIT, pass under CEK.
+
+**Root cause in `hosts/ocaml/lib/sx_vm.ml`:** When a JIT-compiled closure returns
+another closure (i.e. the callee is `VmClosure`), the frame restoration after the
+call incorrectly reuses the parent frame's locals slot, overwriting saved intermediate
+values. The `call_closure_reuse` path must snapshot `sp` before the inner call and
+restore it after, or bail to the non-reuse path for closures-returning-closures.
+
+**Verify:** `node tests/hs-kernel-eval.js 2>&1 | tail -3` — should go from 3116/3127 to 3127/3127.
+
+### Step 2: Fix letrec + perform resume (browser)
+
+**What:** In browser JIT mode, `letrec` sibling bindings are nil after a `perform`/resume
+cycle. `call_closure_reuse` in `sx_browser.ml` intentionally ignores `_saved_sp`, which
+strips the frame locals that `sf_letrec` was waiting on.
+
+**Fix:** In `sx_browser.ml`, the `VmSuspension` resume path must restore frame locals
+from the suspension snapshot before calling the continuation. Mirror what `sx_vm.ml`
+does in the non-browser case.
+
+**Verify:** Write a test in `spec/tests/` that does `(letrec ((f (fn () (perform :io nil)))) (f))` with a resume, check bindings survive. Runs under OCaml: `dune exec -- bin/run_tests.exe`.
+
+---
+
+## Phase 2 — Source info (E38 completion)
+
+Design: `plans/designs/e38-sourceinfo.md`. Target: 4/4 sourceInfo tests.
+
+The API (`hs-parse-ast`, `hs-source-for`, `hs-line-for`, `hs-node-get`, `hs-src`,
+`hs-src-at`, `hs-line-at`) and parser span wrapping (`hs-ast-wrap`, `hs-span-mode`)
+are already in the codebase. Two tests are passing; two fail because:
+- Tokenizer tokens lack `:end` and `:line` (only `:pos` today).
+- Some statement-level spans and `:next` field navigation are incomplete.
+
+### Step 3: Tokenizer — add `:end` and `:line` to tokens
+
+`lib/hyperscript/tokenizer.sx`: extend `hs-make-token` to `{:pos :end :value :type :line}`.
+Track a `current-line` counter (1-based, increments after `\n`). Update all ~20 emission
+sites. Mirror to `shared/static/wasm/sx/hs-tokenizer.sx` after edits.
+
+**Verify:** `(hs-make-token "NUMBER" "1" 0)` returns a dict with `:end` and `:line` keys.
+
+### Step 4: Complete parser spans + :next field
+
+`lib/hyperscript/parser.sx`: ensure `hs-ast-wrap` populates `:next` on every command
+in a `CommandList` (i.e. the following sibling command). Check that statement-level
+productions (if, for) correctly populate `:true-branch`. Trace through the two failing
+tests (`get source works for expressions`, `get line works for statements`) to find the
+exact missing fields or off-by-one positions.
+
+Mirror to `shared/static/wasm/sx/hs-parser.sx`.
+
+**Verify:** All 4 `hs-upstream-core/sourceInfo` tests pass.
+
+---
+
+## Phase 3 — Native ADTs (`define-type` / `match`)
+
+Design: `plans/designs/sx-adt.md`. No existing implementation.
+
+Impact: every language implementation (Haskell, Prolog, Lua, Common Lisp, Erlang)
+currently fakes sum types with `{:tag "..." :field ...}` dicts. Native ADTs remove
+that everywhere.
+
+### Step 5: OCaml — AdtValue type + `define-type` + basic `match`
+
+`hosts/ocaml/lib/sx_types.ml`:
+```ocaml
+type adt_value = { av_type: string; av_ctor: string; av_fields: value array }
+| AdtValue of adt_value
+```
+
+`hosts/ocaml/lib/sx_runtime.ml` (or evaluator):
+- `step-sf-define-type`: parse `(Name (Ctor1 f1 f2) (Ctor2) ...)`, register constructor
+  NativeFns, predicates (`Ctor1?`, `Name?`), field accessors (`Ctor1-f1`) via `env-bind!`.
+- `step-sf-match` + `MatchFrame`: linear scan of clauses; flat patterns only for 6a;
+  bind pattern variables in child env; `else` clause; raise on no match.
+- `type-of` returns the type name (e.g. `"Maybe"`).
+
+Write tests in `spec/tests/test-adt.sx`: basic constructor, predicate, accessor, match,
+else, no-match raise.
+
+**Verify:** `dune exec -- bin/run_tests.exe` — new test file all green.
+
+### Step 6: JS — AdtValue + `define-type` + `match`
+
+`hosts/javascript/platform.py`: add `AdtValue` as `{ _adt: true, _type, _ctor, _fields }`.
+Mirror `define-type` and `match` special forms in the JS evaluator.
+Retranspile: `python3 hosts/javascript/cli.py --output shared/static/scripts/sx-browser.js`
+
+**Verify:** `node hosts/javascript/run_tests.js` — adt tests pass on JS too.
+
+### Step 7: Nested patterns (Phase 6b)
+
+Both OCaml and JS `MatchFrame`: replace linear binding with recursive
+`matchPattern(pattern, value, env)` that:
+- Recurses into constructor sub-patterns.
+- Returns `{matched: bool, bindings: map}`.
+- Handles wildcard `_`, literals (`42`, `"str"`, `true`, `nil`).
+
+Extend `spec/tests/test-adt.sx` with nested pattern tests.
+
+### Step 8: Exhaustiveness warnings (Phase 6c)
+
+`_adt_registry: type_name → [ctor_names]` global populated by `define-type`.
+On first non-exhaustive `match` evaluation: `console.warn("[sx] match: non-exhaustive …")`.
+No error — warning only.
+
+---
+
+## Phase 4 — Plugin / extension system
+
+Design: `plans/designs/hs-plugin-system.md`.
+
+### Step 9: Parser feature registry
+
+`lib/hyperscript/parser.sx`: replace `parse-feat` hardcoded `cond` with a dict lookup.
+`(hs-register-feature! name parse-fn)` adds to the registry.
+
+### Step 10: Compiler command registry + `as` converter registry
+
+`lib/hyperscript/compiler.sx`: replace `hs-to-sx` hardcoded dispatch with dict.
+`(hs-register-command! name compile-fn)` and `(hs-register-converter! name convert-fn)`.
+
+### Step 11: Migrate hs-prolog-hook + Worker plugin
+
+`lib/hyperscript/runtime.sx`: remove `hs-prolog-hook`/`hs-set-prolog-hook!` ad-hoc
+slots. Create `lib/hyperscript/plugins/prolog.sx` that calls `hs-register-feature!`
+and `hs-register-command!`. Create `lib/hyperscript/plugins/worker.sx` replacing the
+E39 stub.
+
+---
+
+## Phase 5 — Performance
+
+These are incremental and can interleave with other phases.
+
+### Step 12: Frame records (CEK)
+
+`hosts/ocaml/lib/sx_runtime.ml`: represent CEK frames as OCaml records instead of
+tagged variant lists. Eliminates allocation pressure from list construction per frame.
+Profile before/after on a tight-loop benchmark.
+
+### Step 13: Buffer primitive for string building
+
+Add `make-buffer`, `buffer-append!`, `buffer->string` primitives. Eliminates the
+`(str a b c d ...)` quadratic allocation pattern in serializers and renderers.
+Wire into `sx_primitives.ml` and the JS platform.
+
+### Step 14: Inline common primitives in JIT
+
+`hosts/ocaml/lib/sx_vm.ml`: add `OP_ADD`, `OP_SUB`, `OP_EQ`, `OP_APPEND` specialised
+opcodes that skip the primitive table lookup for the most common calls. Compiler emits
+these when operands are known numbers/lists.
+
+---
+
+## Progress log
+
+| Step | Status | Commit |
+|------|--------|--------|
+| 1 — JIT combinator bug | [ ] | — |
+| 2 — letrec+resume | [ ] | — |
+| 3 — tokenizer :end/:line | [ ] | — |
+| 4 — parser spans complete | [ ] | — |
+| 5 — OCaml AdtValue + define-type + match | [ ] | — |
+| 6 — JS AdtValue + define-type + match | [ ] | — |
+| 7 — nested patterns | [ ] | — |
+| 8 — exhaustiveness warnings | [ ] | — |
+| 9 — parser feature registry | [ ] | — |
+| 10 — compiler + as converter registry | [ ] | — |
+| 11 — plugin migration + worker | [ ] | — |
+| 12 — frame records | [ ] | — |
+| 13 — buffer primitive | [ ] | — |
+| 14 — inline primitives JIT | [ ] | — |
+
+---
+
+## Rules
+
+- Branch: `architecture`. Never push to `main`.
+- SX files: `sx-tree` MCP tools only. `sx_validate` after every edit.
+- After every `.sx` edit to `lib/hyperscript/`, mirror to `shared/static/wasm/sx/hs-<file>.sx`.
+- OCaml build: `sx_build target="ocaml"` MCP tool (never raw `dune`).
+- JS build: `sx_build target="js"` MCP tool.
+- One step per commit. Update progress log in this file.
+- No new planning docs. No comments in SX unless non-obvious.
+- Unicode in SX: raw UTF-8 only, never `\uXXXX`.

plans/tcl-sx-completion.md

@@ -105,7 +105,9 @@ just Tcl.
 
 ---
 
-## Phase 4 — Optional: env-as-value (architectural)
+## Phase 4 — env-as-value (architectural) ✓
+
+
 
 `uplevel`/`upvar` required an explicit frame stack because SX environments
 aren't inspectable from user code. Adding:
@@ -146,6 +148,7 @@ becomes a lasting SX contribution used by every future hosted language.
 
 _Newest first._
 
+- 2026-05-06: Phase 4 env-as-value — current-env (special form via Sx_ref.register_special_form), eval-in-env (primitive in setup_evaluator_bridge), env-lookup + env-extend (in setup_env_operations); 5 idiom tests; 342/342 green
 - 2026-05-06: Phase 3 OCaml primitives — file-read/write/append/exists?/glob + clock-seconds/milliseconds/format in sx_primitives.ml + unix dep; tcl-cmd-clock/file wired up; 337/337 green
 - 2026-05-06: Phase 2 coroutine rewrite — `tcl-cmd-coroutine` now creates a `make-fiber`; `tcl-cmd-yield` calls `:coro-yield-fn` (threaded through interp); true suspension; 337/337 green
 - 2026-05-06: Phase 2 fiber.sx — `make-fiber`/`fiber-resume`/`fiber-done?` using call/cc + set!; bidirectional value passing; generator and echo tests pass