I strongly disagree. I work on Dart, which has had string interpolation since before Dart 1.0. And, also, since before Dart 1.0, I've wanted to have support for

I strongly disagree. I work on Dart, which has had string interpolation since before Dart 1.0. And, also, since before Dart 1.0, I've wanted to have support for custom string interpolation processors. It's just really useful if you can have an API that can decide how interpolated stuff gets handled. You can santize, do custom formatting, lazy evaluation, all sorts of fun stuff.