Data commit

Task/FizzBuzz/Mercury/fizzbuzz.mercury

@@ -0,0 +1,31 @@
+:- module fizzbuzz.
+:- interface.
+:- import_module io.
+:- pred main(io::di, io::uo) is det.
+:- implementation.
+:- import_module int, string, bool.
+
+:- func fizz(int) = bool.
+fizz(N) = ( if N mod 3 = 0 then yes else no ).
+
+:- func buzz(int) = bool.
+buzz(N) = ( if N mod 5 = 0 then yes else no ).
+
+%                N    3?    5?
+:- func fizzbuzz(int, bool, bool) = string.
+fizzbuzz(_, yes, yes) = "FizzBuzz".
+fizzbuzz(_, yes, no)  = "Fizz".
+fizzbuzz(_, no,  yes) = "Buzz".
+fizzbuzz(N, no,  no)  = 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(fizzbuzz(N, fizz(N), buzz(N)), !IO),
+    io.nl(!IO),
+    ( if N < To then
+        main(N + 1, To, !IO)
+    else
+        true
+    ).