That's not useful though when the regular expression libraries written to be portable across different schemes all suffer because almost none of the actual implementations optimise string handling.
It's like tail recursion elimination. It's a major gotcha unless written into the standard.
Unfortunately guile's performance in so many other areas is so bad that it's not really an alternative for some projects. It does have a lot of nice features not available in many of the major scheme implementations. But if you code to them, your code is no longer portable.
Seems like the kind of thing that'll be nice for the big language. The nice thing about Scheme is you can implement it in a weekend. You want as little as possible in it. But having standard recommended ways is a good idea. I.e. "IF you include mutable strings, this is how you do it." Maybe the big language might have that.
It's like tail recursion elimination. It's a major gotcha unless written into the standard.
Unfortunately guile's performance in so many other areas is so bad that it's not really an alternative for some projects. It does have a lot of nice features not available in many of the major scheme implementations. But if you code to them, your code is no longer portable.