Fibonacci numbers in Factor

Example for versions Factor 0.94

This example shows recursive calculation of Fibonacci numbers.

Word fib calculates the n-th number: if the argument is not greater than 1, it stays on the stack as the return value, otherwise it is replaced with a sum of previous numbers. Word bi is a short-hand version of cleave combinator and allows to apply two quotations (in this case calls of fib for smaller arguments) to the same element of the stack (n). 

USING: formatting kernel math sequences ;
IN: fibonacci-example

: fib ( n -- fib(n) )
    dup
    1 >
    [ [ 1 - fib ] [ 2 - fib ] bi + ]
    when ;

16 iota [ 1 + fib "%d, " printf ] each 
"...\n" printf