3491 Kusto Execute Function support (#1055)

* 3491 Added GenerateExecuteFunctionScript to IDataSource, DataSourceBase, and KustoDataSource. Added ExecutionFunction to Scripter and IScripter.

* 3491 Refactored GenerateScriptForFunction in ScriptAsScriptingOperation to handle execute and alter

src/Microsoft.Kusto.ServiceLayer/DataSource/DataSourceBase.cs

@@ -105,6 +105,8 @@ namespace Microsoft.Kusto.ServiceLayer.DataSource
 
         public abstract string GenerateAlterFunctionScript(string functionName);
 
+        public abstract string GenerateExecuteFunctionScript(string functionName);
+
         /// <inheritdoc/>
         public DataSourceType DataSourceType { get; protected set; }
 

src/Microsoft.Kusto.ServiceLayer/DataSource/IDataSource.cs

@@ -123,10 +123,17 @@ namespace Microsoft.Kusto.ServiceLayer.DataSource
         bool Exists(DataSourceObjectMetadata objectMetadata);
 
         /// <summary>
-        /// Gets FunctionInfo object for a function
+        /// Generates an alter script for a function
         /// </summary>
         /// <param name="functionName"></param>
         /// <returns></returns>
         string GenerateAlterFunctionScript(string functionName);
+
+        /// <summary>
+        /// Generates an execute script for a function
+        /// </summary>
+        /// <param name="functionName"></param>
+        /// <returns></returns>
+        string GenerateExecuteFunctionScript(string functionName);
     }
 }

src/Microsoft.Kusto.ServiceLayer/DataSource/KustoDataSource.cs

@@ -1047,6 +1047,15 @@ namespace Microsoft.Kusto.ServiceLayer.DataSource
             return alterCommand.ToString();
         }
 
+        public override string GenerateExecuteFunctionScript(string functionName)
+        {
+            var functionInfo = GetFunctionInfo(functionName);
+            
+            return functionInfo == null 
+                ? string.Empty 
+                : $"{functionInfo.Name}{functionInfo.Parameters}";
+        }
+
         private string GenerateMetadataKey(string databaseName, string objectName)
         {
             return string.IsNullOrWhiteSpace(objectName) ? databaseName : $"{databaseName}.{objectName}";