scheme types need not store their indices

prim.ss

@@ -1,7 +1,7 @@
 ; (define $IORes (lambda (nm-1 nm-2) (vector 0 #f nm-1 nm-2)))
 (define $IORes (lambda (nm-1 nm-2) (cons nm-1 nm-2)))
-(define ($Left x) (vector 0 #f #f x))
-(define ($Right x) (vector 1 #f #f x))
+(define ($Left x) (vector 0 x))
+(define ($Right x) (vector 1 x))
 (define $LT 0)
 (define $EQ 1)
 (define $GT 2)
@@ -65,7 +65,9 @@
 ;; Actually should return unit..
 (define (Data.IORef.primWriteIORef _ ref a) (lambda (w) ($IORes (set-box! ref a) w)))
 (define (Node.readLine w)
-  ($IORes ($Right (get-line (current-input-port))) w))
+  (case (get-line (current-input-port))
+        (#!eof ($IORes ($Left "EOF") w))
+        (else ($IORes ($Right (get-line (current-input-port))) w))))
 (define (Prelude.subInt a b) (- a b))
 (define (Prelude.jsEq _ a b) (= a b))
 (define (Prelude.divInt a b) (fx/ a b))