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

lib/erlang/runtime.sx

@@ -149,6 +149,7 @@
         :next-ref 0
         :current nil
         :processes {}
+        :registered {}
         :runnable (er-q-new)})))
 
 (define er-sched (fn () (nth er-scheduler 0)))
@@ -324,6 +325,104 @@
   er-bif-is-reference
   (fn (vs) (er-bool (er-ref? (er-bif-arg1 vs "is_reference")))))
 
+;; ── name registry ─────────────────────────────────────────────
+(define er-registered (fn () (get (er-sched) :registered)))
+
+(define
+  er-bif-register
+  (fn
+    (vs)
+    (if
+      (not (= (len vs) 2))
+      (error "Erlang: register/2: arity")
+      (let
+        ((name (nth vs 0)) (pid (nth vs 1)))
+        (cond
+          (not (er-atom? name))
+          (raise (er-mk-error-marker (er-mk-atom "badarg")))
+          (not (er-pid? pid))
+          (raise (er-mk-error-marker (er-mk-atom "badarg")))
+          (not (er-proc-exists? pid))
+          (raise (er-mk-error-marker (er-mk-atom "badarg")))
+          (dict-has? (er-registered) (get name :name))
+          (raise (er-mk-error-marker (er-mk-atom "badarg")))
+          :else (do
+            (dict-set! (er-registered) (get name :name) pid)
+            (er-mk-atom "true")))))))
+
+(define
+  er-bif-unregister
+  (fn
+    (vs)
+    (let
+      ((name (er-bif-arg1 vs "unregister")))
+      (cond
+        (not (er-atom? name))
+        (raise (er-mk-error-marker (er-mk-atom "badarg")))
+        (not (dict-has? (er-registered) (get name :name)))
+        (raise (er-mk-error-marker (er-mk-atom "badarg")))
+        :else (do
+          (dict-delete! (er-registered) (get name :name))
+          (er-mk-atom "true"))))))
+
+(define
+  er-bif-whereis
+  (fn
+    (vs)
+    (let
+      ((name (er-bif-arg1 vs "whereis")))
+      (cond
+        (not (er-atom? name))
+        (raise (er-mk-error-marker (er-mk-atom "badarg")))
+        (dict-has? (er-registered) (get name :name))
+        (get (er-registered) (get name :name))
+        :else (er-mk-atom "undefined")))))
+
+(define
+  er-bif-registered
+  (fn
+    (vs)
+    (if
+      (not (= (len vs) 0))
+      (error "Erlang: registered/0: arity")
+      (let
+        ((ks (keys (er-registered))) (out (er-mk-nil)))
+        (for-each
+          (fn
+            (i)
+            (let
+              ((k (nth ks (- (- (len ks) 1) i))))
+              (set! out (er-mk-cons (er-mk-atom k) out))))
+          (range 0 (len ks)))
+        out))))
+
+;; Find the registered name for a pid, if any. Returns string or nil.
+(define
+  er-find-registration
+  (fn
+    (pid)
+    (let
+      ((reg (er-registered)) (ks (keys reg)) (found (list nil)))
+      (for-each
+        (fn
+          (i)
+          (when
+            (= (nth found 0) nil)
+            (let
+              ((k (nth ks i)))
+              (when (er-pid-equal? (get reg k) pid) (set-nth! found 0 k)))))
+        (range 0 (len ks)))
+      (nth found 0))))
+
+;; Drop pid from the registry (called on process death).
+(define
+  er-unregister-pid!
+  (fn
+    (pid)
+    (let
+      ((name (er-find-registration pid)))
+      (when (not (= name nil)) (dict-delete! (er-registered) name)))))
+
 (define
   er-bif-process-flag
   (fn
@@ -643,12 +742,14 @@
             (er-proc-set! pid :exit-reason (get r :reason))
             (er-proc-set! pid :exit-result nil)
             (er-proc-set! pid :continuation nil)
+            (er-unregister-pid! pid)
             (er-propagate-exit! pid (get r :reason)))
           :else (do
             (er-proc-set! pid :state "dead")
             (er-proc-set! pid :exit-reason (er-mk-atom "normal"))
             (er-proc-set! pid :exit-result r)
             (er-proc-set! pid :continuation nil)
+            (er-unregister-pid! pid)
             (er-propagate-exit! pid (er-mk-atom "normal"))))))
     (er-sched-set-current! nil)))