1 files changed, 84 insertions, 0 deletions
diff --git a/src/Order.gleam b/src/Order.gleam
new file mode 100644
index 0000000..76ed92b
--- /dev/null
+++ b/src/Order.gleam
@@ -0,0 +1,84 @@
+module Order
+
+export Order(..), reverse/1, to_int/1, compare/2, max/2, min/2
+
+type Order
+  = LT
+  | EQ
+  | GT
+
+fn reverse(order) =
+  case order
+  | LT => GT
+  | EQ => EQ
+  | GT => LT
+
+test reverse =
+  reverse(LT) |> Assert.equal(_, GT)
+  reverse(EQ) |> Assert.equal(_, EQ)
+  reverse(GT) |> Assert.equal(_, LT)
+
+fn to_int(order) =
+  case order
+  | LT => -1
+  | EQ => 0
+  | GT => 1
+
+test to_int =
+  to_int(LT) |> Assert.equal(_, -1)
+  to_int(EQ) |> Assert.equal(_, 0)
+  to_int(GT) |> Assert.equal(_, 1)
+
+fn compare(a, b) =
+  case (a, b)
+  | (LT, LT) => EQ
+  | (LT, _) => LT
+  | (EQ, EQ) => EQ
+  | (GT, GT) => EQ
+  | (EQ, GT) => LT
+  | _ => GT
+
+test compare =
+  compare(LT, LT) |> Assert.equal(_, EQ)
+  compare(LT, EQ) |> Assert.equal(_, LT)
+  compare(LT, GT) |> Assert.equal(_, LT)
+  compare(EQ, LT) |> Assert.equal(_, GT)
+  compare(EQ, EQ) |> Assert.equal(_, EQ)
+  compare(EQ, GT) |> Assert.equal(_, LT)
+  compare(GT, LT) |> Assert.equal(_, GT)
+  compare(GT, EQ) |> Assert.equal(_, GT)
+  compare(GT, GT) |> Assert.equal(_, EQ)
+
+fn max(a, b) =
+  case (a, b)
+  | (GT, _) => GT
+  | (EQ, LT) => EQ
+  | _ => b
+
+test max =
+  max(LT, LT) |> Assert.equal(_, LT)
+  max(LT, EQ) |> Assert.equal(_, EQ)
+  max(LT, GT) |> Assert.equal(_, GT)
+  max(EQ, LT) |> Assert.equal(_, EQ)
+  max(EQ, EQ) |> Assert.equal(_, EQ)
+  max(EQ, GT) |> Assert.equal(_, GT)
+  max(GT, LT) |> Assert.equal(_, GT)
+  max(GT, EQ) |> Assert.equal(_, GT)
+  max(GT, GT) |> Assert.equal(_, GT)
+
+fn min(a, b) =
+  case (a, b)
+  | (LT, _) => LT
+  | (EQ, GT) => EQ
+  | _ => b
+
+test min =
+  min(LT, LT) |> Assert.equal(_, LT)
+  min(LT, EQ) |> Assert.equal(_, LT)
+  min(LT, GT) |> Assert.equal(_, LT)
+  min(EQ, LT) |> Assert.equal(_, LT)
+  min(EQ, EQ) |> Assert.equal(_, EQ)
+  min(EQ, GT) |> Assert.equal(_, EQ)
+  min(GT, LT) |> Assert.equal(_, LT)
+  min(GT, EQ) |> Assert.equal(_, EQ)
+  min(GT, GT) |> Assert.equal(_, GT)