constructors on heap, consuming match, move modifier in reference expression, .bring. keyword to return from block, some fixes

tests/default_constructors.lang

@@ -1,8 +1,9 @@
 namespace Employee {
   decl gen_employee : Unit -> Employee
   def gen_employee = {
+    var x = $@Complex & 11.3 & 15.87 // construct on heap
     return
-      $Employee
+      $Employee // construct on stack
         & name = "John"
         & role =
           ($Manager

tests/match.lang

@@ -1,6 +1,7 @@
 decl fruit_cost : Fruit -> Int
 def fruit_cost : fruit = {
-  return (match fruit with
+  var fruit_copy = fruit
+  return (match <- fruit_copy with // consuming match
       | $Banana -> 11
       | $Apple | $Orange -> 7)
 }

tests/test_code.lang

@@ -142,5 +142,5 @@ def func : s = {
 
 exec main {
   for i in (,0 ,1 ,2 ,3) do func: "abacaba"
-  ; print: ({ return read: })
+  ; print: ({ bring read: })
 }