[flang-commits] [flang] [flang][Evaluate] Add `ExtractSubstring` to evaluate/tools.h (PR #81265)

[Valentin Clement バレンタイン クレメン via flang-commits]

clementval wrote:

Can you add you use case to this PR or push this when you have a need for it?

https://github.com/llvm/llvm-project/pull/81265