Initial

examples/src/util/Comparison.jetl

@@ -0,0 +1,19 @@
+type Comparison<in T> = {T, T => Int}
+
+fun naturalOrder<in T : IComparable<T>>(a : T, b : T) : Int = a.compareTo(b)
+
+fun castingNaturalOrder(a : Object, b : Object) : Int = a.as<Comparable<Object>>.compareTo(b.as<Comparable<Object>>)
+
+enum class ComparisonResult {
+  LS,EQ, GR
+}
+
+type MatchableComparison<in T> = {T, T, => ComparisonResult}
+
+fun asMatchableComparison<T>(cmp : Comparison<T>) : MatchableComparison<T> = {a, b =>
+  val res = cmp(a, b)
+  if (res == 0) return ComparisonResult.EQ
+  if (res < 0) return ComparisonResult.LS
+  return ComparisonResult.GR
+}
+

examples/src/util/IComparable.jetl

@@ -0,0 +1,3 @@
+interface class IComparable<in T> {
+  fun compareTo(other : T) : Int
+}