This does not look like SLIME. It seems to be just copying the text from one text buffer and pasting it to another Vim buffer which is running a REPL. That is not what SLIME is really! I can't even call this a poor imitation of SLIME because it is not SLIME in any sense of what SLIME is. There is no Swank server this connects to. There is no understanding of Lisp's s-expressions. It would happily copy any random text into any random REPL and call it job done! It is weird that they have chosen the name "SLIME" for vim-slime project when it is not SLIME in any way.