June 2018 Update

Task/Arithmetic-Rational/Factor/arithmetic-rational.factor

@@ -0,0 +1,21 @@
+USING: generalizations io kernel math math.functions
+math.primes.factors math.ranges prettyprint sequences ;
+IN: rosetta-code.arithmetic-rational
+
+2/5              ! literal syntax 2/5
+2/4              ! automatically simplifies to 1/2
+5/1              ! automatically coerced to 5
+26/5             ! mixed fraction 5+1/5
+13/178 >fraction ! get the numerator and denominator 13 178
+8 recip          ! get the reciprocal 1/8
+
+! ratios can be any size
+12417829731289312/61237812937138912735712
+8 ndrop ! clear the stack
+! arithmetic works the same as any other number.
+
+: perfect? ( n -- ? )
+    divisors rest [ recip ] map-sum 1 = ;
+
+"Perfect numbers <= 2^19: " print
+2 19 ^ [1,b] [ perfect? ] filter .