For fun: Expressive C++ 17 Coding Challenge in D

[Ali Çehreli]

Found on Reddit:

 
https://www.reddit.com/r/programming/comments/740617/the_expressive_c17_coding_challenge/

How would you do it in D?

Ali

P.S. You can ignore the following note from the challenge text; I don't 
think it applies to D. Honestly, I don't think it matters for C++17 
either. :)

   "You can assume input files won't be super large and can fit fully 
into memory."