I'm not sure how to write this block header digest/hash generation in another language then C(++). Is this even possible without a lot of hacking?
If so: Could a language-neutral format for the digest message be documented?
If not: This would be a very undesireable lock-in: EOS blocks will not be able to be validated on other blockchains like ethereum. Perhaps this hash function should be refined in a more language-neutral way.
Edit 1 (May 10) I found this serialiser that was written for steem data types, but obviously there's a lot of interoperability!