is it possible to take a function that creates a string and use it in/as a generator? converting the function to a generator would be impractical, if not outright impossible

there is such a thing in test.chuck - generates string that match a regex

https://github.com/gfredericks/test.chuck#string-from-regex

Regal also has generators from regexes: https://github.com/lambdaisland/regal#use-with-specalpha