diff --git a/Jellyfin.Plugin.SmartPlaylist/Lisp/Compiler/TokenStream.cs b/Jellyfin.Plugin.SmartPlaylist/Lisp/Compiler/TokenStream.cs
index d334f0d..0d0425f 100644
--- a/Jellyfin.Plugin.SmartPlaylist/Lisp/Compiler/TokenStream.cs
+++ b/Jellyfin.Plugin.SmartPlaylist/Lisp/Compiler/TokenStream.cs
@@ -78,7 +78,10 @@ namespace Jellyfin.Plugin.SmartPlaylist.Lisp.Compiler {
                 }
                 value += t;
             }
-            return null;
+            if (value.Equals("")) {
+                return null;
+            }
+            return new AtomToken(value);
         }
     }
 
@@ -101,7 +104,7 @@ namespace Jellyfin.Plugin.SmartPlaylist.Lisp.Compiler {
                 if (prev_avail == program.Available() && prev_avail == 0) {
                     break;
                 } else if (prev_avail == program.Available()) {
-                    throw new ApplicationException("Program is invalid");
+                    throw new ApplicationException($"Program is invalid, still available: {program.Available()}");
                 }
                 prev_avail = program.Available();
                 foreach (Type c in _classes) {
diff --git a/Tests/Tests.cs b/Tests/Tests.cs
index cd85678..3f358d1 100644
--- a/Tests/Tests.cs
+++ b/Tests/Tests.cs
@@ -148,6 +148,7 @@ namespace Tests
                     (if (> 0 1) (car (quote (1 2 3))) (cdr (quote (2 3 4)))))
             """).ToString());
 
+            Assert.Equal("a", e.eval("'a").ToString());
         }
 
         [Fact]