define factorial(n)
if {n <= 1}
1
{n * factorial{n - 1}}
begin define begin factorial n end
begin if begin <= n 1 end
1
begin * n begin factorial begin - n 1 end end end end end
define
|-- factorial
| \-- n
\-- if
|-- <=
| |-- n
| \-- 1
|-- 1
\-- *
|-- n
\-- factorial
\-- -
|-- n
\-- 1