fix: better constructor pattern parsing

examples/sample/validators/swap.ak

@@ -33,9 +33,10 @@ pub fn spend(
   rdmr: Redeemer,
   ctx: spend.ScriptContext,
 ) -> Bool {
-  when datum.rdmr is {
-    sample.Buy(tipo1, fin) -> fin > 0
-    sample.Sell(twice, find: fin) -> fin > 0
+  let x = datum.rdmr
+  when x is {
+    sample.Buy { fin: fin, .. } -> fin > 0
+    sample.Sell { find: fin, .. } -> fin > 0
     sample.Hold(some) -> some > 0
   }
 }