diff -r f70d74fea67f -r 2a30c7dfe3ed core_marking3/postfix_test2.scala
--- a/core_marking3/postfix_test2.scala	Sun Sep 15 12:57:59 2024 +0100
+++ b/core_marking3/postfix_test2.scala	Mon Jul 21 16:38:07 2025 +0100
@@ -1,8 +1,11 @@
-import C3a._
+
+def urbanmain() = {
+  import C3a._
 
-assert(compute(syard(split("3 + 4 * ( 2 - 1 )"))) == 7)
-assert(compute(syard(split("10 + 12 * 33"))) == 406)
-assert(compute(syard(split("( 5 + 7 ) * 2"))) == 24)
-assert(compute(syard(split("5 + 7 / 2"))) == 8)
-assert(compute(syard(split("5 * 7 / 2"))) == 17)
-assert(compute(syard(split("9 + 24 / ( 7 - 3 )"))) == 15)
+  assert(compute(syard(split("3 + 4 * ( 2 - 1 )"))) == 7)
+  assert(compute(syard(split("10 + 12 * 33"))) == 406)
+  assert(compute(syard(split("( 5 + 7 ) * 2"))) == 24)
+  assert(compute(syard(split("5 + 7 / 2"))) == 8)
+  assert(compute(syard(split("5 * 7 / 2"))) == 17)
+  assert(compute(syard(split("9 + 24 / ( 7 - 3 )"))) == 15)
+}