diff -r 195ad66315d9 -r 31b81f20fd9a core_testing3/postfix_test3.scala
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core_testing3/postfix_test3.scala	Thu Nov 02 13:53:37 2023 +0000
@@ -0,0 +1,23 @@
+
+
+def urbanmain() = {
+  import C3b._
+
+
+  assert(syard(split("3 + 4 * ( 2 - 1 )")) == List("3", "4", "2", "1", "-", "*", "+"))
+  assert(syard(split("( ( ( 3 ) ) + ( ( 4 + ( 5 ) ) ) )")) == List("3", "4", "5", "+", "+"))
+  assert(syard(split("5 + 7 / 2")) == List("5", "7", "2", "/", "+"))
+  assert(syard(split("5 * 7 / 2")) == List("5", "7", "*", "2", "/"))
+  assert(syard(split("3 + 4 * 8 / ( 5 - 1 ) ^ 2 ^ 3")) == List("3", "4", "8", "*", "5", "1", "-", "2", "3", "^", "^", "/", "+"))
+
+  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("4 ^ 3 ^ 2"))) == 262144)
+  assert(compute(syard(split("4 ^ ( 3 ^ 2 )"))) == 262144)
+  assert(compute(syard(split("( 4 ^ 3 ) ^ 2"))) == 4096)
+  assert(compute(syard(split("( 3 + 1 ) ^ 2 ^ 3"))) == 65536)
+}