Error when executing simple script when executing code in IronPython from C#

[Legends]

Nuget packages:

• DynamiclanguageRuntime 1.3.3
• IronPython 3.4

The following code executes correctly but also throws a Syntax error

C#:

ScriptEngine engine = Python.CreateEngine();
ScriptScope scope = engine.CreateScope();
var sb = new StringBuilder("Hello");
scope.SetVariable("sb", sb);

string code = "sb.Append(\"World\")";
ScriptSource source = engine.CreateScriptSourceFromString(code, SourceCodeKind.SingleStatement);

source.Execute(scope);  

Console.WriteLine(sb.ToString()); // HelloWorld

Error:

Question: Is something wrong with the user code or with the IronPython parser?

[slozier]

Hmm, I'm not seeing the syntax error? If you mean <System.Text.StringBuilder object at 0x000000000000002B [HelloWorld]> then that's the repr of the StringBuilder and not a syntax error...

[Legends]

Don't know what's a repr is?

The SyntaxErrorException is thrown in Microsoft.Scripting.SourceUnit (probably unrelated to my issue).

<System.Text.StringBuilder object at 0x000000000000002B [HelloWorld]> is printed to the console, when source.Execute(scope); has executed.

How can I prevent this?

[slozier]

I am still not seeing a SyntaxError with the code you provided... Anyway, if you don't want to see the repr of the StringBuilder, either redirect the return value of sb.Append to something (e.g. _ = sb.Append("World")) or don't use SourceCodeKind.SingleStatement (not sure why SingleStatement outputs the value but looks like it's been this way for a long time).

[Legends]

_ = sb.Append("World") The discard did the trick, now I only get HelloWorld.

I don't see a SyntaxError too, but when debugging the SyntaxError is thrown in Microsoft.Scripting.dll, because compileCode is apparently null.

After adding the discard, the code does not jump into the throw statement anymore.