1 ! Copyright (C) 2019-2020 KUSUMOTO Norio.
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: logic kernel lists assocs math ;
7 LOGIC-VARS: F F1 F2 N N1 L ;
9 { fibo N L{ F F1 F2 . L } } {
11 [ [ N of 1 - ] N1 is ]
12 { fibo N1 L{ F1 F2 . L } }
13 [ [ [ F1 of ] [ F2 of ] bi + ] F is ] !!
16 { fibo 0 L{ 0 } } !! rule
18 { fibo 1 L{ 1 0 } } fact