CSHARP-1621: added support for $range.

Author: craiggwilson

src/MongoDB.Driver/Linq/Translators/AggregateLanguageTranslator.cs

@@ -17,6 +17,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Text;
@@ -342,6 +343,12 @@ private BsonValue TranslateMethodCall(MethodCallExpression node)
                 {
                     return result;
                 }
+
+                if (node.Method.DeclaringType == typeof(Enumerable)
+                    && TryTranslateStaticEnumerableMethodCall(node, out result))
+                {
+                    return result;
+                }
             }
             else
             {
@@ -778,6 +785,28 @@ private bool TryTranslateMinResultOperator(PipelineExpression node, out BsonValu
             return false;
         }
 
+        private bool TryTranslateStaticEnumerableMethodCall(MethodCallExpression node, out BsonValue result)
+        {
+            result = null;
+            switch (node.Method.Name)
+            {
+                case "Range":
+                    var start = TranslateValue(node.Arguments[0]);
+                    result = new BsonDocument("$range", new BsonArray
+                    {
+                        start,
+                        new BsonDocument("$add", new BsonArray
+                        {
+                            start,
+                            TranslateValue(node.Arguments[1])
+                        })
+                    });
+                    return true;
+            }
+
+            return false;
+        }
+
         private bool TryTranslateStaticMathMethodCall(MethodCallExpression node, out BsonValue result)
         {
             result = null;

tests/MongoDB.Driver.Tests/Linq/Translators/AggregateProjectTranslatorTests.cs

@@ -800,6 +800,18 @@ public void Should_translate_pow()
             result.Value.Result.Should().Be(161051);
         }
 
+        [SkippableFact]
+        public void Should_translate_range()
+        {
+            RequireServer.Where(minimumVersion: "3.3.4");
+
+            var result = Project(x => new { Result = Enumerable.Range(x.C.E.F, 3) });
+
+            result.Projection.Should().Be("{ Result: { \"$range\": [\"$C.E.F\", { \"$add\": [\"$C.E.F\", 3] } ] }, _id: 0 }");
+
+            result.Value.Result.Should().BeEquivalentTo(11, 12, 13);
+        }
+
         [SkippableFact]
         public void Should_translate_reverse()
         {