I am a French student very inspired by Bourbaki's but I can no longer stand to write approximate proofs. I was wondering if there was a language between formal and natural language that was both non-binding for the reader (he or she had nothing to learn to read the demonstration) and mechanical enough to be understood by a computer.
I found two or three projects but no clear documentation.
To be precise, I don't mind that the project is abandoned as long as there is an exhaustive (and high level) description of the syntax.
I recommend reading "Book of Proof" $2009$ by Richard H. Hammack. Hardcover is only about $25$ USD and it describes the language (mostly natural) to be used in proofs. It shows how to address the reader as though in a conversation: "We can see that...". It also shows some mathematical symbols used in proofs but mostly, it's how to approach a proof by induction or whatever with examples.
I don't know how a proof would fit in a computer but it appears that PYTHON is the preferred language for doing math stuff. On the other hand, there is a movement to have machines both write and validate proofs. I don't know the language but it is described in "Mathematics without Apologies: Portrait of a Problematic Vocation (Science Essentials)" $2015$ by Michael Harris.
If you find what you are looking for, give us an update. I'm sure that many people would be interested.