programdemos/factorial.xtl

Factorial: recursion with guards, one statement per line. Run it with "xetal run demos/factorial.xtl" (or "./demos/factorial.xtl"); it prints 3628800, the factorial of 10. Read u:f_act for how a guard (c ? r) ends a function early and how a function calls itself.

source

ᵘf̲act : Num a => a -> a

function · line 9

n u:f_act: the factorial of n, 1 when n is at most 1, otherwise n times the factorial of n - 1.

ᵘf̲act ← { n →
  n ≤ 1 ? 1
  n × ᵘf̲act n − 1
}

Used in: ᵘf̲act, demos/factorial.xtl:13