That about wanting to change mind... it touches a string! Somehow the let-downs must have been too much for me at a certain point in time. That being said, I'm curious to find out right now. Edit... no such thing found as string interpolation in cpp, at least not in my first 4 search hits. I'll crawl back.
- template-function parameters (NTTPs with a function parameter syntax rather than a template parameter syntax, tentatively spelled as `void foo(template int constant){}` )
- Scalable reflection, in combination with expansion statements (likely in C++26, spelled `template for (auto& e : array) {}` ) which would allow you to write an arbitrary parser for the template string into real C++ code. Reflection targets C++29.
Syntax2 already supports string interpolation as a special compiler feature.
That type of interpolation is something most non-scripting languages don't have anyway, and it took Python several decades to get it, and only has had it in the 5 years or so.