united-front (GitHub: ardagnir / united-front, License: AGPL v3) by James Kolb is a plugin for syncing registers between instances of Vim. First a server is run with
vim --servername name, and then you can connect other clients to it.
I had a look at the source to see how it works. Whenever one of the events
VimEnter is triggered, a function called
SendVimInfo is run. This function calls
remote_expr which causes
UnitedFront_ReadFrontFile to run on the other instances.
UnitedFront_ReadFrontFile function reads
.unitedfront for registers. That file is written by
WriteFrontFile which packs the desired registers based on an array called
It's a simple implementation but an interesting use of
remote_expr and file system functions.