fix: implement YIELD support in function calls

Author: alexmg

NFalkorDB.Tests/FalkorDBAPITest.cs

@@ -1264,4 +1264,89 @@ public void TestSlowlogAndReset()
         var afterReset = _api.Slowlog();
         Assert.NotNull(afterReset);
     }
+
+    [Theory]
+    [InlineData(new string[0], "CALL dbms.functions()")]
+    [InlineData(new[] { "name" }, "CALL dbms.functions() YIELD name")]
+    [InlineData(new[] { "name", "internal" }, "CALL dbms.functions() YIELD name,internal")]
+    public void BuildQueryBodyForProcedureCall(string[] fields, string expected)
+    {
+        var kwargs = new Dictionary<string, List<string>>
+        {
+            { "y", fields.ToList() }
+        };
+        var args = Enumerable.Empty<string>();
+
+        var body = Graph.BuildQueryBodyForProcedureCall("dbms.functions", ref args, kwargs);
+
+        Assert.Equal(expected, body);
+    }
+
+    [Fact]
+    public void TestCallProcedureWithYield()
+    {
+        _api.Query("CREATE (:Person {name:'roi'})");
+
+        var kwargs = new Dictionary<string, List<string>>
+        {
+            { "y", new List<string> { "name", "internal" } }
+        };
+
+        var result = _api.CallProcedure("dbms.functions", null, kwargs);
+
+        Assert.Equal(2, result.First().Values.Count);
+        Assert.IsType<string>(result.First().Values[0]);
+        Assert.IsType<bool>(result.First().Values[1]);
+    }
+
+    [Fact]
+    public void TestCallProcedureReadOnlyWithYield()
+    {
+        _api.Query("CREATE (:Person {name:'roi'})");
+
+        var kwargs = new Dictionary<string, List<string>>
+        {
+            { "y", new List<string> { "name", "internal" } }
+        };
+
+        var result = _api.CallProcedureReadOnly("dbms.functions", null, kwargs);
+
+        Assert.Equal(2, result.First().Values.Count);
+        Assert.IsType<string>(result.First().Values[0]);
+        Assert.IsType<bool>(result.First().Values[1]);
+    }
+
+    [Fact]
+    public async Task TestCallProcedureAsyncWithYield()
+    {
+        _api.Query("CREATE (:Person {name:'roi'})");
+
+        var kwargs = new Dictionary<string, List<string>>
+        {
+            { "y", new List<string> { "name", "internal" } }
+        };
+
+        var result = await _api.CallProcedureAsync("dbms.functions", null, kwargs);
+
+        Assert.Equal(2, result.First().Values.Count);
+        Assert.IsType<string>(result.First().Values[0]);
+        Assert.IsType<bool>(result.First().Values[1]);
+    }
+
+    [Fact]
+    public async Task TestCallProcedureReadOnlyAsyncWithYield()
+    {
+        _api.Query("CREATE (:Person {name:'roi'})");
+
+        var kwargs = new Dictionary<string, List<string>>
+        {
+            { "y", new List<string> { "name", "internal" } }
+        };
+
+        var result = await _api.CallProcedureReadOnlyAsync("dbms.functions", null, kwargs);
+
+        Assert.Equal(2, result.First().Values.Count);
+        Assert.IsType<string>(result.First().Values[0]);
+        Assert.IsType<bool>(result.First().Values[1]);
+    }
 }

NFalkorDB/Graph.cs

@@ -283,17 +283,17 @@ public Task<ResultSet> CallProcedureReadOnlyAsync(string procedure, IEnumerable<
         return ReadOnlyQueryAsync(queryBody, flags: flags);
     }
 
-    private static string BuildQueryBodyForProcedureCall(string procedure, ref IEnumerable<string> args, Dictionary<string, List<string>> kwargs)
+    internal static string BuildQueryBodyForProcedureCall(string procedure, ref IEnumerable<string> args, Dictionary<string, List<string>> kwargs)
     {
         args = args?.Select(QuoteString);
 
         var queryBody = new StringBuilder();
 
         queryBody.Append(args != null ? $"CALL {procedure}({string.Join(",", args)})" : $"CALL {procedure}()");
 
-        if (kwargs != null && kwargs.TryGetValue("y", out var kwargsList))
+        if (kwargs != null && kwargs.TryGetValue("y", out var kwargsList) && kwargsList.Count > 0)
         {
-            queryBody.Append(string.Join(",", kwargsList));
+            queryBody.Append($" YIELD {string.Join(",", kwargsList)}");
         }
 
         return queryBody.ToString();