Testcase for explicit exports

Also extended conslist testcase with multi-token list items

examples/rule_demo/main.orc

@@ -1,12 +1,18 @@
-export main := [foo, bar, baz, quz]
+export ::(main, foo)
+
+main := [foo, bar, baz, quz]
+
+foo := steamed hams
 
 [...$data] := (cons_start ...$data cons_carriage(none))
 
 [] := none
 
-, $item cons_carriage($tail) := cons_carriage(
-  (some (cons $item $tail))
+...$prefix:1 , ...$item cons_carriage(
+  $tail
+) := ...$prefix cons_carriage(
+  (some (cons (...$item) $tail))
 )
 
-cons_start $item cons_carriage($tail) := some (cons $item $tail)
+cons_start ...$item cons_carriage($tail) := some (cons (...$item) $tail)