;; lib/flow/remote.sx — distributed nodes via fed-sx (Phase 4).
;;
;; A node can execute on a federation peer. The transport is the fed-sx boundary;
;; it is MOCKED in tests by a peer registry mapping addr -> function table. In
;; production flow-transport would issue a fed-sx call; here it dispatches locally.
;;
;;   (flow-peer-register! addr table) — register a mock peer. table is a list of
;;     (fn-name proc) entries — the functions that peer exposes.
;;   (flow-transport addr fn input)   — invoke fn on the peer with input. Raises
;;     (flow-remote-unreachable) if the addr is unknown, (flow-remote-no-fn) if the
;;     peer does not expose fn.
;;   (remote-node addr fn)            — a node that runs fn on the peer at addr.

(define
  flow-remote-src
  "(define flow-peers (list))\n   (define (flow-assoc key alist)\n     (if (null? alist)\n         #f\n         (if (eq? (car (car alist)) key) (car (cdr (car alist))) (flow-assoc key (cdr alist)))))\n   (define (flow-peer-register! addr table) (set! flow-peers (cons (list addr table) flow-peers)))\n   (define (flow-transport addr fn input)\n     (let ((table (flow-assoc addr flow-peers)))\n       (if table\n           (let ((proc (flow-assoc fn table)))\n             (if proc (proc input) (raise (quote flow-remote-no-fn))))\n           (raise (quote flow-remote-unreachable)))))\n   (define (remote-node addr fn) (lambda (input) (flow-transport addr fn input)))")

(define
  flow-load-remote!
  (fn
    (env)
    (begin (scheme-eval-program (scheme-parse-all flow-remote-src) env) env)))