push ((flip ($)) (const 'b') . ((.) . (const . (flip ($)) Pure)))
name_1:
| catchFail
|   <try>
|   | push ((.) . (cons . const 'a'))
|   | read
|   | lift ($)
|   | call name_1
|   | lift ($)
|   | popFail
|   | ret
|   <handler>
|     pushInput
|     lift Pure
|     choices [id]
|       <branch>
|       | push id
|       | ret
|       <default>
|         fail
call name_1
lift ($)
read
lift ($)
ret