Has there been any attempt to rewrite Bitcoin in Clojure? I know about BitcoinJ, so I imagine that should be easy to port. But what about a "pure" version? Without calling Java directly? Easily portable to Scheme or other Lisps-style languages? Thanks.
There are several Bitcoin Clojure projects, but none of them appear to have a full rewrite of Bitcoin as a goal.
Of particular interest is https://github.com/johnwalker/bitcoin-protocol , which is an implementation of the Bitcoin networking protocol. It can be used to communicate with peers within Bitcoin networks.
Rewriting Bitcoin core in another language is doable, as the btcd developers have done porting it to the Go language - https://github.com/btcsuite/btcd , however it took almost a year of development time between several developers to become fully functional.