Improves implementation of hash-table->alist

Author: codeZeilen

rosetta-test/interpreter-tests.json

@@ -113,5 +113,7 @@
     {"input": "(hash-table-exists? ht 'b)", "expected": true},
     {"input": "(hash-table-map ht (lambda (key value) key))", "expected": ["b"]},
     {"input": "(hash-table-walk ht (lambda (key value) key))", "expected": null},
-    {"input": "(begin (hash-table-ref! ht 'c 3) (hash-table-ref ht 'c))", "expected": 3}
+    {"input": "(begin (hash-table-ref! ht 'c 3) (hash-table-ref ht 'c))", "expected": 3},
+    {"input": "(hash-table->alist ht)", "expected": [["b", 2], ["c", 3]]},
+    {"input": "(hash-table->alist (make-hash-table))", "expected": []}
 ]

rosetta-test/stdlib.scm

@@ -223,12 +223,10 @@
         ht)
 
     (define (hash-table->alist ht)
-        (define alist '())
-        (for-each 
+        (map
             (lambda (key) 
-                (set! alist (cons (list key (hash-table-ref ht key)) alist)))
-            (hash-table-keys ht))
-        alist)
+                (list key (hash-table-ref ht key)))
+            (hash-table-keys ht)))
 
     ; Aliases
     (define hash-ref hash-table-ref)