Cannot use default TraceListener on .Net Runtime as it throws Null pointers

[Marti2203]

Code Generation Target : C# 4.8.0 Runtime
Hello, today I tried to do a simple tracing of a grammar and I constantly got NullReferenceExceptions. After poking around in the code for the TraceListener, I see that it has two constructors - one that accepts a parser and one that accepts a Text Writer as an output, but never both... This implies that I have to either make my own Trace Listener which does exactly the same thing as the default one or use reflection to set a private readonly field as both the output TextWriter and Parser are such.
Here is the code for the TraceListener

[ericvergnaud]

Hi, can you submit a PR? Eric

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Le 1 sept. 2020 à 08:34, Martin Mirchev ***@***.***> a écrit : Code Generation Target : C# Hello, today I tried to do a simple tracing of a grammar and I constantly got NullReferenceExceptions. After poking around in the code for the TraceListener, I see that it has two constructors - one that accepts a parser and one that accepts a Text Writer as an output, but never both... This implies that I have to either make my own Trace Listener which does exactly the same thing as the default one or use reflection to set a private readonly field as both the output TextWriter and Parser are such. Here is the code for the TraceListener <https://github.com/antlr/antlr4/blob/master/runtime/CSharp/runtime/CSharp/Antlr4.Runtime/Parser.cs#L24-L58> — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#2893>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAZNQJHPKQVJYDJ5AHPLFJTSDSIWDANCNFSM4QRKVJSA>.

[Marti2203]

With a fix?

[ericvergnaud]

yes

[Marti2203]

Okay. I will make one tomorrow for it

[Marti2203]

Hi @ericvergnaud , I see that a lot of the code does not use the newer C# features, is it possible to add them or just do this fix?

[KvanTTT]

At least I think it makes sense to support different language versions. For instance, ILSpy do this.

[Marti2203]

Okay, True. That I had not thought about, will push only the TraceListener change then.

[Marti2203]

#2934 Fixes this