I was wondering - is it possible to programmatically expand a TokenStream during proc macro execution?
I have a token stream that gets copied into N branches of a match, and if that token stream itself contains a macro, this will result in that inner macro being executed N times. (Or really, N^depth times).
Unfortunately, I cannot store the results of that token stream into a variable at run time, as that would create borrowck issues, and ruin the whole point of the exercise
So I'm thinking - I either cache the results of that macro (which we all know is a hard problem, especially since there is no thread-local storage), or expand it in advance, and insert the expanded tokenstream into the N branches of the match. Is this possible?