[rca]

I tried using slimv as well some time ago but I never managed to get it working properly. I don't remember exactly what happened but I believe there were some bugs (like the lag you mention) and I couldn't figure out how to properly transfer just the piece of code I wanted to the repl. Plus I didn't want most of the plugins that slimv added (paredit for instance).

I ended up using this method http://technotales.wordpress.com/2007/10/03/like-slime-for-v... instead. I put just the basic functions into a plugin and that has been enough for me ever since. I use it for lisps though, not haskell.