anchor.diff:  
   statement
       :   namespace
  -    |   enumeration
       |   if_stmt
       |   foreach_stmt
       |   while_stmt
  
positive.code:     ;
  
  enumeration
      :   Identifier ASSIGN 
          (   elements
          |   INDENT elements DEDENT
          )
      ;
  
negative.code:     |   PRINT '(' expression ')'
      |   DEBUG '(' expression ')'
      |   TRACE '(' expression ')'
      |   regex
      |   match
      |   enumeration
      |   func
      |   call
      |   tuple
  