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Ⅰ. 插件描述

nREPL support for ClojureScript REPLs

Ⅱ. 基本信息

创建日期：  2012-08-09 使用用户：  1 Github星：  431 插件作者：  nREPL

Ⅲ. 安装方法

使用Vundle管理器安装

在你的.vimrc下添加:

Plugin 'cemerick/piggieback'

… 然后在Vim中运行以下命令:

:source %
:PluginInstall

对于Vundle版本 < 0.10.2，请用上面的Bundle替换Plugin。

使用NeoBundle管理器安装

在你的.vimrc下添加:

NeoBundle 'cemerick/piggieback'

… 然后在Vim中运行以下命令:

:source %
:NeoBundleInstall

使用VimPlug管理器安装

在你的.vimrc下添加:

Plug 'cemerick/piggieback'

… 然后在Vim中运行以下命令:

:source %
:PlugInstall

使用Pathogen管理器安装

在终端中运行以下命令:

cd ~/.vim/bundle
git clone https://github.com/cemerick/piggieback

Ⅳ. 文档说明

Piggieback

nREPL middleware that enables the
use of a ClojureScript REPL on top of an nREPL session.

Why?

Two reasons:

• The default ClojureScript REPL (as described in the
  "quick start"

tutorial) assumes that it is running in a teletype environment. This works fine
with nREPL tools in that environment (e.g. lein repl in Terminal.app or
gnome-terminal, etc), but isn't suitable for development environments that
have richer interaction models (including editors like vim ([vim-fireplace][]) and Emacs
([CIDER][]), and IDEs like Intellij ([Cursive][]) and Eclipse (Counterclockwise)).

• Most of the more advanced tool support for Clojure and ClojureScript (code
  completion, introspection and inspector utilities, refactoring tools, etc) is

packaged and delivered as nREPL extensions (e.g. [cider-nrepl][] and [refactor-nrepl][]).

Piggieback provides an alternative ClojureScript REPL entry point
(cider.piggieback/cljs-repl) that changes an nREPL session into a
ClojureScript REPL for eval and load-file operations, while accepting all
the same options as cljs.repl/repl. When the ClojureScript REPL is terminated
(by sending :cljs/quit for evaluation), the nREPL session is restored to it
original state.

Installation

Piggieback is compatible with Clojure 1.8.0+, and requires ClojureScript
1.9 or later and nREPL 0.4.0 or later.

Note Piggieback 0.3.7 is the first version compatible with nREPL 0.4+. You need
Piggieback 0.4+ for nREPL 0.6+.

Leiningen

These instructions are for Leiningen. Translating them for use in Boot should be
straightforward.

Modify your project.clj to include the following :dependencies and
:repl-options:

:profiles {:dev {:dependencies [[cider/piggieback "0.4.2"]]
                 :repl-options {:nrepl-middleware [cider.piggieback/wrap-cljs-repl]}}}

The :repl-options bit causes lein repl to automagically mix the Piggieback
nREPL middleware into its default stack.

_If you're using Leiningen directly, or as the basis for the REPLs in your local
development environment (e.g. CIDER, fireplace, counterclockwise, etc), you're
done._ Skip to starting a ClojureScript REPL.

Boot

Contributions welcome!

Clojure CLI (aka tools.deps)

The instructions below require nREPL 0.4.4 or newer

Add this alias to ~/.clojure/deps.edn:

{
;; ...
:aliases {:nrepl
          {:extra-deps
            {nrepl/nrepl {:mvn/version "0.6.0"}
             cider/piggieback {:mvn/version "0.4.2"}}}}
}

Then you can simply run a ClojureScript capable nREPL like this:

clj -R:nrepl -m nrepl.cmdline --middleware "[cider.piggieback/wrap-cljs-repl]"

Afterwards simply connect to the running server with your favourite
nREPL client (e.g. CIDER).

Embedded

If you're not starting nREPL through a build tool (e.g. maybe you're starting up
an nREPL server from within an application), you can achieve the same thing by
specifying that the wrap-cljs-repl middleware be mixed into nREPL's default
handler:

(require '[nrepl.server :as server]
         '[cider.piggieback :as pback])

(server/start-server
  :handler (server/default-handler #'pback/wrap-cljs-repl)
  ; ...additional `start-server` options as desired
  )

Alternatively, you can add wrap-cljs-repl to your application's hand-tweaked
nREPL handler. Keep two things in mind when doing so:

• Piggieback needs to be "above" nREPL's
  nrepl.middleware.interruptible-eval/interruptible-eval; it

doesn't use interruptible-eval's evaluation machinery, but it does reuse its
execution queue and thus inherits its interrupt capability.

• Piggieback depends upon persistent REPL sessions, like those provided by
  nrepl.middleware.session/session.)

Usage

$ lein repl
....
user=> (require 'cljs.repl.nashorn)
nil
user=> (cider.piggieback/cljs-repl (cljs.repl.nashorn/repl-env))
To quit, type: :cljs/quit
nil
cljs.user=> (defn <3 [a b] (str a " <3 " b "!"))
#<
function cljs$user$_LT_3(a, b) {
    return [cljs.core.str(a), cljs.core.str(" <3 "), cljs.core.str(b), cljs.core.str("!")].join("");
}
>
cljs.user=> (<3 "nREPL" "ClojureScript")
"nREPL <3 ClojureScript!"

See how the REPL prompt changed after invoking
cider.piggieback/cljs-repl? After that point, all expressions sent to the
REPL are evaluated within the ClojureScript environment.
cider.piggieback/cljs-repl's passes along all of its options to
cljs.repl/repl, so all of the tutorials and documentation related to it hold.

Important Notes

1. When using Piggieback to enable a browser REPL: the ClojureScript compiler
   defaults to putting compilation output in out, which is probably not where

your ring app is serving resources from (resources,
target/classes/public, etc). Either configure your ring app to serve
resources from out, or pass a cljs-repl :output-dir option so that a
reasonable correspondence is established.

1. The load-file nREPL operation will only load the state of files from disk.
   This is in contrast to "regular" Clojure nREPL operation, where the current

state of a file's buffer is loaded without regard to its saved state on disk.

Of course, you can concurrently take advantage of all of nREPL's other
facilities, including connecting to the same nREPL server with other clients (so
as to easily modify Clojure and ClojureScript code via the same JVM), and
interrupting hung ClojureScript invocations:

cljs.user=> (iterate inc 0)
^C
cljs.user=> "Error evaluating:" (iterate inc 0) :as "cljs.core.iterate.call(null,cljs.core.inc,0);\n"
java.lang.ThreadDeath
        java.lang.Thread.stop(Thread.java:776)
        ....
cljs.user=> (<3 "nREPL still" "ClojureScript")
"nREPL still <3 ClojureScript!"

(The ugly ThreadDeath exception will be eliminated eventually.)

Piggieback works well with all known ClojureScript REPL environments, including
Nashorn, Node, and browser REPLs.

*Support for Rhino was dropped in version 0.3. All users of Rhino are
advised to switch to using Nashorn instead.*

Acknowledgements

Nelson Morris was instrumental in the initial
development of piggieback.

Need Help?

Send a message to the
clojure-tools mailing list, or
ping @bhauman or @bbatsov on the Clojurians Slack or Twitter if you
have questions or would like to contribute patches.

License

Copyright © 2012-2019 Chas Emerick, Bruce Hauman, Bozhidar Batsov and other contributors.

Distributed under the Eclipse Public License, the same as Clojure.