Made position comparable (#378)

Author: david-driscoll

src/Protocol/Models/Position.cs

@@ -5,7 +5,7 @@
 namespace OmniSharp.Extensions.LanguageServer.Protocol.Models
 {
     [DebuggerDisplay("{" + nameof(DebuggerDisplay) + ",nq}")]
-    public class Position : IEquatable<Position>
+    public class Position : IEquatable<Position>, IComparable<Position>, IComparable
     {
         public Position()
         {
@@ -34,6 +34,21 @@ public bool Equals(Position other) =>
             Line == other.Line &&
             Character == other.Character;
 
+        public int CompareTo(Position other)
+        {
+            if (ReferenceEquals(this, other)) return 0;
+            if (ReferenceEquals(null, other)) return 1;
+            var lineComparison = Line.CompareTo(other.Line);
+            return lineComparison != 0 ? lineComparison : Character.CompareTo(other.Character);
+        }
+
+        public int CompareTo(object obj)
+        {
+            if (ReferenceEquals(null, obj)) return 1;
+            if (ReferenceEquals(this, obj)) return 0;
+            return obj is Position other ? CompareTo(other) : throw new ArgumentException($"Object must be of type {nameof(Position)}");
+        }
+
         public override int GetHashCode()
         {
             var hashCode = 1927683087;
@@ -48,6 +63,14 @@ public override int GetHashCode()
 
         public static implicit operator Position((int line, int character) value) => new Position(value.line, value.character);
 
+        public static bool operator <(Position left, Position right) => Comparer<Position>.Default.Compare(left, right) < 0;
+
+        public static bool operator >(Position left, Position right) => Comparer<Position>.Default.Compare(left, right) > 0;
+
+        public static bool operator <=(Position left, Position right) => Comparer<Position>.Default.Compare(left, right) <= 0;
+
+        public static bool operator >=(Position left, Position right) => Comparer<Position>.Default.Compare(left, right) >= 0;
+
         private string DebuggerDisplay => $"(line: {Line}, char: {Character})";
 
         /// <inheritdoc />

test/Lsp.Tests/Models/PositionTests.cs

@@ -20,5 +20,37 @@ public void SimpleTest(string expected)
             var deresult = new Serializer(ClientVersion.Lsp3).DeserializeObject<Position>(expected);
             deresult.Should().BeEquivalentTo(model);
         }
+
+        [Fact]
+        public void Is_Sortable_By_Character()
+        {
+            var a = new Position(1, 1);
+            var b = new Position(1, 2);
+            var c = new Position(1, 1);
+
+            a.Should().BeLessThan(b);
+            b.Should().BeGreaterThan(a);
+
+            a.CompareTo(c).Should().Be(0);
+
+            a.Should().BeLessOrEqualTo(c);
+            a.Should().BeGreaterOrEqualTo(c);
+        }
+
+        [Fact]
+        public void Is_Sortable_By_Line()
+        {
+            var a = new Position(1, 1);
+            var b = new Position(2, 1);
+            var c = new Position(1, 1);
+
+            a.Should().BeLessThan(b);
+            b.Should().BeGreaterThan(a);
+
+            a.CompareTo(c).Should().Be(0);
+
+            a.Should().BeLessOrEqualTo(c);
+            a.Should().BeGreaterOrEqualTo(c);
+        }
     }
 }