pretty
# r1
# r11

# r3

# r2
# r22
[R]
# a
(a #c
b
(t)
# r
$r:*
)
=>
#f
(F)

[R]
(f)
=>
# c
$a
----
----
# r1
# r11

# r3

# r2
# r22
[R]
# a
(a
    #c
    b
    (t)
    # r
    $r:*
)
=>
#f
(F)

[R]
(f)
=>
# c
$a
----
----
