diff options
Diffstat (limited to 'docs/examples/monads/simpleInterpreter.scala')
-rw-r--r-- | docs/examples/monads/simpleInterpreter.scala | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/docs/examples/monads/simpleInterpreter.scala b/docs/examples/monads/simpleInterpreter.scala index cde3a92dbb..64636749ff 100644 --- a/docs/examples/monads/simpleInterpreter.scala +++ b/docs/examples/monads/simpleInterpreter.scala @@ -22,7 +22,7 @@ object simpleInterpreter { trait Value; case object Wrong extends Value { override def toString() = "wrong" - } + } case class Num(n: Int) extends Value { override def toString() = n.toString(); } @@ -30,15 +30,15 @@ object simpleInterpreter { override def toString() = "<function>" } - type Environment = List[Pair[Name, Value]]; + type Environment = List[Tuple2[Name, Value]]; def lookup(x: Name, e: Environment): M[Value] = e match { case List() => unitM(Wrong) - case Pair(y, b) :: e1 => if (x == y) unitM(b) else lookup(x, e1) + case (y, b) :: e1 => if (x == y) unitM(b) else lookup(x, e1) } - def add(a: Value, b: Value): M[Value] = Pair(a, b) match { - case Pair(Num(m), Num(n)) => unitM(Num(m + n)) + def add(a: Value, b: Value): M[Value] = (a, b) match { + case (Num(m), Num(n)) => unitM(Num(m + n)) case _ => unitM(Wrong) } @@ -54,14 +54,14 @@ object simpleInterpreter { b <- interp(r, e); c <- add(a, b)) yield c - case Lam(x, t) => unitM(Fun(a => interp(t, Pair(x, a) :: e))) + case Lam(x, t) => unitM(Fun(a => interp(t, (x, a) :: e))) case App(f, t) => for (a <- interp(f, e); b <- interp(t, e); c <- apply(a, b)) yield c } - def test(t: Term): String = + def test(t: Term): String = showM(interp(t, List())); val term0 = App(Lam("x", Add(Var("x"), Var("x"))), Add(Con(10), Con(11))); |