A-M baby

Task/FizzBuzz/Mercury/fizzbuzz.mercury

@@ -0,0 +1,26 @@
+:- module fizzbuzz.
+:- interface.
+:- import_module io.
+:- pred main(io::di, io::uo) is det.
+:- implementation.
+:- import_module int, string, bool.
+
+:- func fizz(int) = bool.
+:- func buzz(int) = bool.
+fizz(N) = ( if N mod 3 = 0 then yes else no ).
+buzz(N) = ( if N mod 5 = 0 then yes else no ).
+
+:- pred fizzbuzz(int::in, bool::in, bool::in, string::out) is det.
+%           3?   5?
+fizzbuzz(_, yes, yes, "FizzBuzz").
+fizzbuzz(_, yes, no,  "Fizz").
+fizzbuzz(_, no,  yes, "Buzz").
+fizzbuzz(N, no,  no,  S) :- S = from_int(N).
+
+main(!IO) :- main(1, 100, !IO).
+
+:- pred main(int::in, int::in, io::di, io::uo) is det.
+main(N, To, !IO) :-
+	io.write_string(S, !IO), io.nl(!IO),
+	fizzbuzz(N, fizz(N), buzz(N), S),
+	( if N < To then main(N + 1, To, !IO) else !:IO = !.IO ).