The title says it all. How would I, in theory, create a binding for different GUI toolkits for a programming language that has no GUI bindings. I ask because I want to experiment with this sometime in the future.
You would use the language's foreign function interface (FFI) to call out to the C bindings. You can look at how other languages have done this, like pygobject. It's not easy though. You have to understand the C implementation very well, and your FFI very well. If your goal is to learn how to do the bindings, it might be worth it. If your goal is to create a GUI desktop application in your language, there are probably easier options.