Loading grammar from swift

[FreakTheMighty]

I'm using the example swiftui application as a starting place and would like to add grammar constraints. I'm a bit stuck on how to actually load a grammar file. In the c++ examples, the grammar_parser::parse, but in swift this API doesn't appear to be exposed.

Any suggested on how to load a grammar would be much appreciated.

[spprichard]

I'm running into the same issue.

From what I can tell, it is due to the fact that grammar-parser.h is not added in the spm-headers folder.

I'm not sure what the reason for that is, maybe someone with more knowledge could answer

[FreakTheMighty]

I'm leaning towards an approach similar to https://github.com/mybigday/llama.rn/tree/main/scripts. Seems like using a bridging header will provide more complete access to the core library.

Interestingly, tt seems that llama-cpp-python performs much of the grammar parsing within python rather than leveraging the C utils in llama.cpp.

[spprichard]

I went ahead and opened #7186 to get the llama maintainers perspective on this. There's got to be a reason why more of the library wasn't made available via the swift package

I'd have to dig more into the python implementation, but I wonder if there are performance impact of that decision.

For my use case, being able to set the model in "JSON Mode" by using a specifc JSON grammar would simplify the model output post processing & hopefully lead to more consistent, better output overall.

[spprichard]

Based on the reply in the issue mentioned above, replicating the parser logic & any other C++ functionality found in common should be left to your Swift project.

From what I can tell, the scripts mentioned above do that to an extent. So seems like the best way forward