Again.

2025-10-10 08:44:08 -04:00
parent 72872c1fb1
commit 316e33e3eb
2 changed files with 11 additions and 10 deletions
@@ -61,9 +61,10 @@
 ; good-bt?: t BT → Bool
 ; Determine whether bt is good.
 (define (good-bt? t)
-  ()
-  #|
-  (local [; <2: U{Num, Sym}, Num, U{Num, Sym} → Bool
+  (cases t
+    [end (symbol]))
+#|  (local [; <2: U{Num, Sym}, Num, U{Num, Sym} → Bool
+          (: (U Number Symbol))
          ; Convenient form of greater than. Slightly hack.
          (define (<2 a b c)
            (cond [(and (symbol? a) (symbol? c)) #t]