Spartan REPL

A Clojure REPL hooked up to vanilla Vim in two lines of code. No (Spac)Emacs, no Cider, no fireplace.

spar•tan
(noun)

a Canadian dessert apple of a variety with crisp white flesh and maroon-flushed yellow skin.

Requirements

VIM (vanilla) Clojure >= 1.8 (CLI or lein both work)

Socket REPL

Clojure 1.8 introduced the ability for any arbitrary clojure program to have a socket REPL that can be externally switched on via a JVM opt flag:

;; $HOME/.clojure/deps.edn
{:aliases
  {
    ,,,
    :socket {:jvm-opts ["-Dclojure.server.repl={:port,50505,:accept,clojure.core.server/repl}"]}
    ,,,
  }
}

Alternatively for Leiningen:

;; $HOME/.lein/profiles.clj
{
  :user {:aliases {,,,
                   :jvm-opts ["-Dclojure.server.repl={:port,50505,:accept,clojure.core.server/repl}"]
                   ,,,
  }}
}

Configuring VIM

Save this macro in your VIMRC (optionally bound to p) then highlight the expression(s) you want to send to the repl and invoke the macro.

" this is not very paste friendly...
" ^M is return
" ^] is ESC
"$HOME/.vimrc
let @p = '"1ygg0"2y3w:new^M"2pa)^M^["1p:% ! nc -N localhost 50505^M'

What this does:

yank the selected code to register 1
move to the top of the current file you are in (NOTE: this assumes your ns declaration is on line 1)
yank until the end of your namespace name to register 2
create a fresh unnamed buffer
paste the namespace declaration and close it
paste your copied code to be evaluated
pipe the entire contents of your buffer to your repl (via netcat on port 50505)

Tying it all together

Create a fresh REPL by using either:

lein repl # by default user profile will be merged in via lein
# or
clojure -A:socket # use the global socket alias which turns on the socket repl

in your repl navigate to the sparta namespace:

(ns spartan-repl.sparta)

this namespace should be empty, test it via:

madness?
  ;; Syntax error compiling at (REPL:0:0).
  ;; Unable to resolve symbol: madness? in this context

over in sparta.clj evaluate the code within the comment block using the @p macro
your REPL session should now have madness? bound

madness?
;;=> :THIS-IS-SPARTA!

Limitations

anything preceding the namespace declaration - don't do it 🙂 what did you expected from a 2 line hack?

djtango / spartan-repl