From 1a39377ca158fe9ae286c66d70426c563d81a5b8 Mon Sep 17 00:00:00 2001
From: Yiyun Liu <liuyiyun@seas.upenn.edu>
Date: Fri, 6 Jun 2025 00:17:27 -0400
Subject: [PATCH] Fix the add-node function

---
 printer.rkt   | 6 ++++--
 semantics.rkt | 5 +++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/printer.rkt b/printer.rkt
index 408f620..72ab6ff 100644
--- a/printer.rkt
+++ b/printer.rkt
@@ -115,7 +115,7 @@
 (define (ppr-node a)
   (cond
     [(integer? a)
-     (iseq-append "NNum" (number->string a))]
+     (iseq-append "NNum " (number->string a))]
     [(not (eq? (car a) 'define))
      (let ([fun (first a)]
            [arg (second a)])
@@ -136,7 +136,7 @@
   (let ([ppr-stack-item
          : (-> Addr ISeq)
          (λ (addr) (iseq-append (ppr-fwaddr addr) ": " (ppr-stack-node heap (lookup-node heap addr))))])
-    (iseq-append "Stk [" (list 'Hang -1 (ppr-list ppr-stack-item 'Newline stack)))))
+    (iseq-append "Stk [" (list 'Hang 0 (ppr-list ppr-stack-item 'Newline stack)) "]")))
 
 (: ppr-state (-> State ISeq))
 (define (ppr-state st)
@@ -170,3 +170,5 @@
                      [(? string?) (display i s)]))])
       (go l a)
       (get-output-string s))))
+
+(provide (all-defined-out))
diff --git a/semantics.rkt b/semantics.rkt
index e25fed8..15b4f47 100644
--- a/semantics.rkt
+++ b/semantics.rkt
@@ -48,8 +48,9 @@
 
 (: allocate-node (-> Heap Node (Values Heap Addr)))
 (define (allocate-node heap node)
-  (let ([heap (treelist-add heap node)])
-    (values heap (treelist-length heap))))
+  (let ([addr (treelist-length heap)]
+        [heap (treelist-add heap node)])
+    (values heap addr)))
 
 (: lookup-node (-> Heap Addr Node))
 (define lookup-node treelist-ref)