(WIP) Generate C FFI bindings by parsing the clang AST dump.

As it stands, this is just my small effort in automating some of the work for https://github.com/bradrn/wlhs. The point for the time being is just to handle the trivial stuff automatically, and keep this tool as simple as possible.

I figure that, at some point in the future, this could emit proper hsc files, but for now I’m emitting the bespoke templating language used in WLHS.

 clang -I/path/to/includes \
	-DANY_NECESSARY_DEFINES \
	-x c -Xclang -ast-dump=json -fsyntax-only \
	header_file_to_bind_to.h > header_file_to_bind_to.json
 ast2hsc header_file_to_bind_to.json

I’m not sure if there are any substantial differences in the AST between recent versions of clang, but I’ve been using clang-18.

If you’d like to help, there’s still so much that can be done. In terms of functionality:

• Supporting nested structs is the biggest priority
• More conversions in convertType
• Remove dependency on aeson-lens
• Start adding options for rendered output (genuine hsc instead of just the templating language)
• Tests! I’m not sure how I want to do these. Ideally, they call compiled C code.
• Longer term: import all that’s needed. Instead of just generating bindings to what’s in a single header, bind recursively to all of the bindings that those bindings depend on.

For formatting I’ve been using ormolu.

I’m still a noob when it comes to Haskell. Any help cleaning up my code would be much appreciated.