Inject arbitrary FunctionSymbol when using ServerSymbolLoader/SymbolResolver

[theta3]

Hi, I'm using https://github.com/mattwar/Kusto.Toolkit/blob/master/src/Toolkit/docs/SymbolResolver.md to analyze syntax of multiple commands. Sometimes a command relies on previous ones, e.g.

.create-or-alter function A() ...

then later

.create-or-alter function B()
{
A()
| take 1
}

How do I inject A into the GlobalState so I won't get false positive error that A doesn't refer to a known function?

[mattwar]

It's not typically how the GlobalState is used, but you can add members to the current database like this.

globals = globals.AddOrReplaceCluster(globals.Cluster.AddOrUpdateDatabase(globals.Database.AddMembers(function)));

Creating the function symbol to add from the previous command is a bit more difficult.

You can create a new function symbol given the name of the function, the parameters and the body. You can specify all three of these as strings. This is how the database functions are stored and retrieved from the database to be loaded as schema into the GlobalState.

All you need to do is pick out the correct parts of the create function command and use them to create the FunctionSymbol, and then add that function symbol to the current database symbol, etc.

However, since the individual commands don't have their own syntax node types currently, you'll have to search for the individual parts separately using syntax node types that are known. Fortunately, the create function command shares some of the nodes of the query language, for just the parts you will need.

For the name you can search for the first NameDeclaration node. It don't think there are any other name declarations. The parameter list is stored in an instance of a FunctionParameters node and the function body is stored in an instance of a FunctionBody node.

Here's some code that should work for you.

var globals = GlobalState.Default;  // or your starting globals state

var code1 = KustoCode.ParseAndAnalyze(".create-or-alter function A() { print x=10, y='ten' }", globals);

var functionName = code1.Syntax.GetFirstDescendant<NameDeclaration>().SimpleName;
var functionParameters = code1.Syntax.GetFirstDescendant<FunctionParameters>().ToString();
var functionBody = code1.Syntax.GetFirstDescendant<FunctionBody>().ToString();

var function = new FunctionSymbol(functionName, functionParameters, functionBody);

var globals2 = globals.AddOrReplaceCluster(globals.Cluster.AddOrUpdateDatabase(globals.Database.AddMembers(function)));
var code2 = KustoCode.ParseAndAnalyze(".create-or-alter function B() { A() | take 1 }", globals2);

[mattwar]

I've added a new feature and published a new version to help you and others with similar scenarios.

Version 1.4.0 now has the GlobalState.ApplyCommand extension method that you can use to apply a command and get back a new GlobalState modified by the command.

var newGlobals = globals.ApplyCommand(".create table T (x: long, y: string)");

[theta3]

Thank you. In your previous comment, instead of

var functionName = code1.Syntax.GetFirstDescendant<NameDeclaration>().SimpleName;
var functionParameters = code1.Syntax.GetFirstDescendant<FunctionParameters>().ToString();
var functionBody = code1.Syntax.GetFirstDescendant<FunctionBody>().ToString();

var function = new FunctionSymbol(functionName, functionParameters, functionBody);

can I try

var function = (FunctionSymbol)(code1.Syntax
                .GetDescendantsOrSelf<NameReference>(n => n.ReferencedSymbol is FunctionSymbol)
                .Select(n => n.ReferencedSymbol).First());

?

I also want to keep track of the functions I'm evaluating and from your sample, it looks like the parsed FunctionSymbol can do this nicely

[mattwar]

The previous example was how you can create a function symbol from the create function command so you can add it to the global state to make it available for the analysis of another command/query.

Otherwise, yes, you can simply search for all the function symbol references in a query to discover which functions are used.

[theta3]

Thanks. Is DocString and Folder also exposed in FunctionSymbol?

[mattwar]

DocString is found in FunctionSymbol.Description.