The only requirement to use CIDER is to have an nREPL server to which it may connect. Many Clojurians favour the use of tools like Leiningen, Boot or Gradle to start an nREPL server, but the use of one of them is not a prerequisite to use CIDER.
Setting up a Clojure project (optional)
CIDER features a command called cider-jack-in
that will start an nREPL server
for a particular Clojure project and connect to it automatically. Most
popular Clojure project management tools are supported by default - namely
Leiningen, Boot, clj
(tools.deps
) and Gradle.
Note
This functionality depends on Leiningen 2.5.2+ or Boot 2.7.0+. Older versions are not supported.
Let's create a simple Clojure project using Leiningen now. Provided you've installed it already, all you need to do is:
$ lein new demo
The two main ways to obtain an nREPL connection are discussed in the following sections of the manual.
Launch an nREPL server and client from Emacs
Simply open in Emacs a file belonging to your project (like foo.clj
) and type
M-x cider-jack-in
RET. This will start an nREPL server
and CIDER will automatically connect to it.
Note
If it is a lein
, boot
or tools.deps (deps.edn)
project nREPL will be
started with all dependencies loaded. Dependency auto-injection is currently
not support for Gradle projects.
Alternatively you can use C-u M-x cider-jack-in
RET to
specify the name of a lein
, boot
or tools.deps
project, without having to
visit any file in it. This option is also useful if your project contains some
combination of project.clj
, build.boot
and deps.edn
and you want to launch
a REPL for one or the other.
Tip
In Clojure(Script) buffers the command cider-jack-in
is bound to C-c C-x (C-)j (C-)j.
For further customizing the command line used for cider-jack-in
, you can
change the following (all string options):
cider-lein-global-options
,cider-boot-global-options
,cider-clojure-cli-global-options
,cider-gradle-global-options
: these are passed to the command directly, in first position (e.g.-o
tolein
enables offline mode).cider-lein-parameters
,cider-boot-parameters
,cider-clojure-cli-parameters
,cider-gradle-parameters
: these are usually tasks names and their parameters (e.g.:dev
for launching boot's dev task instead of the standardrepl -s wait
).
Note that if you try to run cider-jack-in
outside a project
directory normally you'd get a warning to confirm you really want to
do this, as more often than not you'd probably do this
accidentally. If you decide to proceed, CIDER will invoke the command
configured in cider-jack-in-default
. This used to be lein
prior to
CIDER 0.17 and it was switched to Clojure's CLI (clj
) afterwards.
Tip
You can set cider-allow-jack-in-without-project
to t
if you'd like to
disable the warning displayed when jacking-in outside a project.
Connect to a running nREPL server
Go to your project's directory in a terminal and type there:
$ lein repl
Or for boot
:
$ boot repl -s wait (or whatever task launches a repl)
It is also possible for plain clj
, although the command is somewhat longer:
$ clj -Sdeps '{:deps {cider/cider-nrepl {:mvn/version "0.18.0-SNAPSHOT"} }}' -e '(require (quote cider-nrepl.main)) (cider-nrepl.main/init ["cider.nrepl/cider-middleware"])'
Alternatively you can start nREPL either manually or by the facilities provided by your project's build tool (Maven, etc).
After you get your nREPL server running, go back to Emacs. Type there
M-x cider-connect
RET to connect to the
running nREPL server.
Tip
In Clojure(Script) buffers the command cider-connect
is bound to C-c M-c.
You can configure known endpoints used by the cider-connect
command offered
via a completing read. This is useful if you have a list of common host/ports
you want to establish remote nREPL connections to. Using an optional label is
helpful for identifying each host.
(setq cider-known-endpoints
'(("host-a" "10.10.10.1" "7888")
("host-b" "7888")))