erlang: register/whereis, Phase 5 complete (+12 tests)

lib/erlang/transpile.sx

@@ -597,6 +597,10 @@
       (= name "monitor") (er-bif-monitor vs)
       (= name "demonitor") (er-bif-demonitor vs)
       (= name "process_flag") (er-bif-process-flag vs)
+      (= name "register") (er-bif-register vs)
+      (= name "unregister") (er-bif-unregister vs)
+      (= name "whereis") (er-bif-whereis vs)
+      (= name "registered") (er-bif-registered vs)
       (= name "throw") (raise (er-mk-throw-marker (er-bif-arg1 vs "throw")))
       (= name "error") (raise (er-mk-error-marker (er-bif-arg1 vs "error")))
       :else (error
@@ -966,6 +970,8 @@
         (reduce str "" out)))))
 
 ;; ── send: Pid ! Msg ──────────────────────────────────────────────
+;; Target may be a pid or a registered atom name. Atom resolution
+;; goes through the scheduler's `:registered` table.
 (define
   er-eval-send
   (fn
@@ -973,18 +979,36 @@
     (let
       ((to-val (er-eval-expr (get node :to) env))
         (msg-val (er-eval-expr (get node :msg) env)))
-      (if
-        (not (er-pid? to-val))
-        (error "Erlang: '!': target is not a pid")
-        (do
+      (let
+        ((pid (er-resolve-send-target to-val)))
+        (when
+          (er-proc-exists? pid)
+          (er-proc-mailbox-push! pid msg-val)
           (when
-            (er-proc-exists? to-val)
-            (er-proc-mailbox-push! to-val msg-val)
-            (when
-              (= (er-proc-field to-val :state) "waiting")
-              (er-proc-set! to-val :state "runnable")
-              (er-sched-enqueue! to-val)))
-          msg-val)))))
+            (= (er-proc-field pid :state) "waiting")
+            (er-proc-set! pid :state "runnable")
+            (er-sched-enqueue! pid)))
+        msg-val))))
+
+(define
+  er-resolve-send-target
+  (fn
+    (v)
+    (cond
+      (er-pid? v) v
+      (er-atom? v)
+      (let
+        ((name (get v :name)))
+        (if
+          (dict-has? (er-registered) name)
+          (get (er-registered) name)
+          (raise
+            (er-mk-error-marker
+              (er-mk-tuple
+                (list (er-mk-atom "badarg") v))))))
+      :else (raise
+        (er-mk-error-marker
+          (er-mk-tuple (list (er-mk-atom "badarg") v)))))))
 
 ;; ── receive (selective, delimited-continuation suspension) ──────
 (define