[
 (let)
 (binding)
 (simple_fun)
 (def)
 (arglist)
 (if)
 (if_condition)
 (if_then)
 (elsif_condition)
 (elsif_then)
 (if_else)
 (for)
 (for_do)
 (while)
 (while_do)
 (try)
 (try_body)
 (try_do)
 (block)
] @fold
