c2z

inspeired by this article uses zig to create zig bindgens for c++

zig cc -x c++ -std=c++11 -Xclang -ast-dump=json {input_file}

Notes

• Glue is invitable … snap … and needed to make the bindings cross platform
• Transpiled code can leak memory (implicit destructors aren’t called)
• Manual adjustments are required, specially to make bindings idiomatic and easer to read
• Meant to work with libraries that follow the C with classes coding style
• No Zig side inheritance, instead create bindings of a C++ implementation

Usage

Setup

1. make sure zig in your PATH, you will need the version 0.13 and up
2. build the project and copy the c2z executable from zig-out to your desired location
3. or just run the project using zig build run -- ARGS

Running it

1. zig build run -- lib.h or c2z lib.h
2. pass any clang argument like include and defines e.g. zig build run -- -DNDEBUG -I.\include -target x86-linux -- .\include\lib.h
3. modify the generated bindings until it works ;) you might need to import cpp.zig it is located in the src folder

Misc

• msvc has a second tier support, just pass it as target tuple like as: -no-glue -target x86_64-windows-msvc to generate a target specifc binding for it. Debug builds aren’t fully supported, use ReleaseFast or at least -O1, you might also wan’t to find a way of define _ITERATOR_DEBUG_LEVEL to something different than 2.

Todo

• transpile inline or constexpr constructors when the class isn’t polymorphic

• use function pointers to handle varidact functions

• (hard) #include -> @import

• (easy) walk a directory tree

• transpile vector of vectors

• (easy) better input file not found error

• (easy) verbose option

• (easy) handle BlockCommandComment and ParamCommandComment in FullComment

• (easy) resolve return of function with a aliased return type

• (easy) fail when clang ast-bump has failed, because missing headers or wrong code

• (hard) if (*data++ == v) { ... } should generate { const __tmp0 = data; data += 1; if (__tmp0.* == v) { ... } }

• (hard) solve UnresolvedMemberExpr, maybe when integrating clang ast directly

• (hard) solve implicit destructors calls

• (easy) handle private members, class is default private, struct default public, in code is referenced as self.public

• (hard) handle varidact functions myFunction(va_args) -> myFunction(args: [*c]u8) and myFunction__VA(...)

• (hard) apply keywordFix

• use @compileError for objects that couldn’t be transpiled

• write layout tests

Test cases

C++ libs

• fpng (99.99 %)
• xatlas (86.40 %)
• imgui (67.21 %)
• msdfgen (~80% ish)
• box2d
• basis_universal
• JoltPhysics
• astc-encoder

C libs (or with builtin C bindings)

• SDL2
• stbi
• raylib
• meshoptimizer
• tinyexr
• minimp3