Passing Lambda Variables not working in HISE?

[HISEnberg]

On both my systems I receive an error in the console when trying to pass a labmda variable (from inline function to function). This was prompted by the recent videos @David-Healey shared on the topic. The functions seem to work but I am not sure why I receive the error.

Interface:! Line 6, column 60: Accessing parameter reference outside the function call

The examples from the HISE docs are also producing the same error. I know I can script around this if necessary but I am curious to know if anyone else is experiencing the same issue?

Wonder if this is a question for @Christoph-Hart ? Does using lambdas require a certain version of C++? In Visual Studio 2026 the C++ Language Standard is set to ISO C++20 Standard (/std:c++20) , so I think I should be covered here.

Anyone else seeing these error messages?

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[Christoph Hart]

@HISEnberg have you enabled the optimizations in the Scripting Settings?

[Christoph Hart]

@HISEnberg haha don‘t mix up the extremely complex issue of C++ lambdas (where the C++ standard does in fact have an impact) with our little „lamda“ extension to HiseScript where you can just pass on some variables in a function to a sub function call.

Usually you just need to rename and introduce a variable from a function parameter because you cannot pass on an incoming parameter from the outside function. However this might be another case of „var-local“-gate where I could easily patch things up internally so you and the robot overlords will not need that information in your context window…

[David Healey]

@Christoph-Hart He's using lambda's as expected in HISE - I'm not seeing the error he reports, do you see it?

[HISEnberg]

@Christoph-Hart hehe that makes sense, they seem super simple in HISE which doesn't appear to be true for C++

@David-Healey is correct though, for some reason I am getting an error when using them. If I use his example I get that error message Accessing parameter reference outside the function call

It doesn't seem to be a breaking change as the code still functions. But I see red in the Console and get nervous....

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[Christoph Hart]

@HISEnberg have you enabled the optimizations in the Scripting Settings?

[Christoph Hart]

So here's the journey for the fix:

https://opncd.ai/share/JfA7e3J6

I completely lost it at the end :)

[dannytaurus]

@Christoph-Hart Is there a specific reason you used Haiku? It's not the best model for reasoning about code. It's quite lightweight.

I find Opus to be the best, but it's the most expensive I think, and Sonnet is a good balance between cost and performance.

[HISEnberg]

@Christoph-Hart said in Passing Lambda Variables not working in HISE?:

@HISEnberg have you enabled the optimizations in the Scripting Settings?

It was this exactly. Disabling the Scripting Optimizations removes the Error. It seems your human reasoning is superior to AI rational here.

@dannytaurus agree, I typically use Sonnet for the best cost/performance usage but Opus is the better for complex/large tasks.

[David Healey]

@dannytaurus I ran into a context limit with sonnet

[Christoph Hart]

Is there a specific reason you used Haiku?

Nothing else than pure cheapness - I didn't deemed this fix was worthy to use the bigger models :)

JK, I just regularly swap out models to compare their performance and I kind of guessed that this is more of a "lookup stuff in the codebase" job than a "be able to reason on the highest level".

I ran into a context limit with sonnet

Yeah that happened to me weirdly too. To be honest I never really used Sonnet too much - it's either Haiku for the stupid stuff or Opus for the complex things, I find it hard enough to juggle all the other variables so I try to black/white as much as possible.

Have you tried the /compact function in Opencode? You basically get around 200k tokens (also displayed as percentage in the sidebar), and at ~85% it starts autocompacting the session to keep on working. Ideally you never go above 50% - 60% of context window usage before exiting plan mode and this is where the /compact function comes in really handy - it basically tells the LLM to summarize the key points, then start fresh with a new context window. You have to be careful at which state in the conversation you do this step, but that's another skill to learn...

[Christoph Hart]

Also I would say the days of a messy develop git policy are finally over:

https://opncd.ai/share/7MSo7ue3

[David Healey]

@Christoph-Hart said in Passing Lambda Variables not working in HISE?:

Have you tried the /compact function in Opencode?

Sounds promising, looking into it now.