Support ADDing numbers

src/FSharp.AWS.DynamoDB/Expression/UpdateExpr.fs

@@ -220,6 +220,11 @@ let extractOpExprUpdaters (recordInfo : RecordTableInfo) (expr : Expr) : Interme
                 attrs.Add attr
                 updateOps.Add (Add (attr.Id, op))
 
+            | SpecificCall2 <@ ADD_INT64 @> (None, _, _, [AttributeGet attr; value]) ->
+                let op = getOperand attr.Pickler value
+                attrs.Add attr
+                updateOps.Add (Add (attr.Id, op))
+
             | SpecificCall2 <@ DELETE @> (None, _, _, [AttributeGet attr; value]) ->
                 let op = getOperand attr.Pickler value
                 attrs.Add attr

src/FSharp.AWS.DynamoDB/Types.fs

@@ -280,6 +280,10 @@ module UpdateOperators =
     let ADD (path : Set<'T>) (values : seq<'T>) : UpdateOp =
         invalidOp "ADD operation reserved for quoted update expressions."
 
+    /// Adds given value to attribute path
+    let ADD_INT64 (path : int64) (value : int64) : UpdateOp =
+        invalidOp "ADD_INT64 operation reserved for quoted update expressions."
+
     /// Deletes given set of values to set attribute path
     let DELETE (path : Set<'T>) (values : seq<'T>) : UpdateOp =
         invalidOp "DELETE operation reserved for quoted update expressions."

tests/FSharp.AWS.DynamoDB.Tests/UpdateExpressionTests.fs

@@ -371,6 +371,27 @@ type ``Update Expression Tests``(fixture : TableFixture) =
 
         test <@ item'.IntSet.Contains 42L @>
 
+    let [<Fact>] ``ADD to int`` () =
+        let item = mkItem()
+        let key = table.PutItem item
+        let item' = table.UpdateItem(key, <@ fun r -> ADD_INT64 r.Value 1L @>)
+
+        test <@ item.Value + 1L = item'.Value @>
+
+
+    let [<Fact>] ``ADD to int without creating item first`` () =
+        let item = mkItem()
+        let item' = table.UpdateItem(TableKey.Combined(item.HashKey, item.RangeKey), <@ fun (r : R) ->
+            ADD_INT64 r.Value 42L &&&
+            // Set attributes to satisfy default values
+            //  System.NotSupportedException : Default value...
+            //    at FSharp.AWS.DynamoDB.Pickler.Pickler`1.get_DefaultValueUntyped()
+            SET r.Union (UA 0L) &&&
+            SET r.Serialized item.Serialized &&&
+            SET r.Serialized2 item.Serialized2 @>)
+
+        test <@ 0L + 42L = item'.Value @>
+
     let [<Fact>]``DELETE from set`` () =
         let item = { mkItem() with IntSet = set [1L ; 42L] }
         let key = table.PutItem item