This plugin is provided as-is with no guarantees of any kind.
Syntax highlighting isn't great, but setting breakpoints in the GUI should work.
Based on: https://github.com/youknowone/rust-xcode-langspec https://github.com/steventroughtonsmith/lua-xclangspec
Place the Plug-ins and Specifications folders in ~Library/Developer/Xcode
You may have to quit and reopen Xcode once or twice and click the Load Bundle button in a popup that should appear automatically.
Additionally if your Xcode UUID is not listed here, please make an issue (or a pull request!) and I'll add it.
You can check your UUID with this command:
$ defaults read /Applications/Xcode.app/Contents/Info DVTPlugInCompatibilityUUID