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ρEmacs is a preconfigured distribution of GNU Emacs editor for Microsoft Windows. Being primarily designed for Lisp-based development, it is also bundled with several other popular programming languages. If you don't need them and just want to get some benefits of the features listed below, you may install only ρEmacs and nothing else.

Why use ρEmacs

You may prefer ρEmacs because of the following set of features:

The components of ρEmacs distribution

Software Details

GNU Emacs

The recent version of ρEmacs includes version 25 of GNU Emacs text editor with (currently extinct) EmacsW32 extension package. Although not everything from EmacsW32 works now, it still may be useful in several circumstances. It's not recommended to install ρEmacs at the write-protected system folders.

Emacs Home Directory

ρEmacs installer will ask where do you want to store your personal settings and data. The following three options are available:

  • Create sandbox environment - installer will ask you to manually specify the path of ρEmacs home directory.
  • Portable installation - ρEmacs will be installed as a portable distribution. In this case Emacs will use the directory named `home' at the root of the installation as user's personal directory. Installer will also not create shortcuts or perform any other system wide integration.
  • Always use the environment of a current user - Emacs will always use a subfolder inside the `My Documents' folder of a current user.

You can change the path of the home directory of non-portable ρEmacs at any time through the submenu item named `Set Home Directory' at the top `((' menu. It's recommended to choose a path without spaces or non-ASCII characters for the ρEmacs HOME. The current path to ρEmacs HOME is available in `About Rho' buffer, under the Emacs `Help' menu.

Installing Third Party Emacs Extensions

In most cases you will most likely need only the `Basic Enhancements' package listed above and install other packages relevant to your needs manually.

Automated installation

Automated package installation is possible through the MELPA repository available with M-x list-packages command.

Manual installation

To install a package manually, you need to place it inside the `<ρEmacs Home>/.emacs.d' directory (which is already added to the Emacs load path). There could be two kinds of extensions:

  1. A single-file extension. In this case it's just necessary to put the corresponding .el file into the `.emacs.d' folder, for example: `<ρEmacs Home>/.emacs.d/foo-package.el'
  2. If an extension consists of multiple files, you need to put them into the corresponding subfolder under `.emacs.d'. You will also need to add this subfolder to the Emacs load path, for example, by placing the following elisp code at your `<ρEmacs Home>/.emacs' initialization file: `(add-to-list 'load-path "~/.emacs.d/bar-package/")'.
Then you should initialize the package according to its manual, for example, by placing `(require 'some-mode)' line into the `~/.emacs'.

Advanced Emacs features

A quick glimpse at some advanced Emacs features and extensions.

User Interface

When working on a large project with the huge amount of different files, shells and REPLs, it's often useful to open them in several Emacs buffers simultaneously, for example, as at the screenshot below. Such layout allows to get better overview and makes it possible to switch between the buffers quickly.

Emacs windows

Emacs documentation section on windows explains in detail the commands you can use to split or resize them. Emacs 24+ also has a handy built-in M-x speedbar command, which allows to navigate at the current directory tree visually (by default it opens in a separate frame, the optional sr-speedbar mode of the `Advanced enhanmcements' package opens speedbar in a existing frame). The ido-mode may be used as a convenient keyboard-driven alternative for speedbar. It's also possible to save a current window configuration with winsav save mode (could be enabled in winsav customization group: M-x customize-group winsav), although it works a little bit clumsy.

If you prefer mouse, the tabbar mode (enabled by default) is a click away. It has one not so obvious feature - the ability to switch between buffer mode window collections with mouse wheel. Move the mouse cursor over the tab bar at the top of a window and scroll the mouse wheel. The tabbar mode will switch window collections as you scroll.

highlight-symbol, column-marker and linum modes bring some cosmetic features to Emacs, which usually could be found only in full-blown IDEs, such as Eclipse. Line numbering, symbol highlighting (green) and line width limiting "gutter" (blue) are shown at the screenshot below. The symbol highlighting operations are bound to C-f3, M-f3 and S-f3 keys (all these features will be available automatically with the relevant major modes, if `Basic enhancements' option was checked during the installation). The linum mode may work ungraceful with the auto complete mode.

Emacs windows


The ido-mode could be described as the iswitchb mode on steroids (it also works with find-file and some other cases). Its advantages over the default iswitchb are: flexy completion (if you have buffers named `core.clj' and `core.cljs' you need to type only `crls' to narrow the selection), filtering, ability to switch between items with keyboard and automatic path expansion. With ido it's also possible to quickly jump to the root or home folders with simple keystrokes (`//' and `~/' respectively). The `Basic enhancements' installer option makes this mode enabled by default.


YASnippet mode allows to insert predefined code templates at the current point location with the ability to quickly switch between the internal template insertion points. To insert a template you need to type a template abbreviation and press the expansion trigger keyboard shortcut (TAB in the case of ρEmacs; `yas' minor mode also should be active). For example, in a buffer with the `Clojure' major mode, type `require' and press . The abbreviation will be expanded into the corresponding template with several insertion points (you can switch between them with the TAB key). It's possible to find which abbreviation is mapped to a snippet by visiting its file with `C-c & C-v' sequence (the `&' key in this shortcut should be pressed on the keyboard).

Search And Replace across files

The M-x lgrep and M-x rgrep Emacs commands do exactly this. It's also possible to use a little bit lower level M-x grep command. To replace a text in multiple files, use the dired query-replace-regexp function. There are more options which could be installed separately.

Compare files, create patches

diff/ediff-mode allows to perform various file comparison operations and create or apply patches. The behavior of patch/diff utilities could be customized at the corresponding Emacs customization groups. M-x occur also may come useful.

Version Control

Emacs has built-in support of some common version control systems. Third party VC extensions are also available. Note that you need to place your ssh keys and other personal VC settings into the ρEmacs home directory to use VC from Emacs.

Project Management

Because SLIME is an advanced IDE by itself, there is no need in such monster things as CEDET or ECB. But it would be nice to have a project management system in the sense of Visual Studio `solutions'. Although not obvious, it's possible in vanilla Emacs with M-x desktop-save and M-x desktop-change-dir commands (it's necessary to save a desktop file in the project root directory). But there is a better third party solution exist: Bookmark+ desktop bookmarks. For example, there is a project directory tree with root in the ~/lisp/development/my-app and you are editing its files. To add a bookmark to the current desktop, you need to issue the following commands:

  • C-x p K ~/lisp/development/my-app/.desktop RET - save the desktop file (a desktop file name may be arbitrary in this case, the vanilla desktop mode recognizes only `.emacs.desktop')
  • my-app-project RET - name the bookmark

The C-x r l command allows to list all bookmarks and quickly switch between saved project desktops, it's also possible to clear the current desktop with M-x desktop-clear command.

Other Stuff

  • Mark ring - it's possible move backward through the history of the point locations with C-u C-SPC and view the location list with M-x anything-mark-ring command
  • File variables - file variables allow to keep some meta-information about a file (text encoding, for example).
  • Registers - a set of named "clipboards".
  • Rectangle regions - especially useful with writable dired mode.
  • Archive modes - it's possible to browse and edit files directly in zip/jar or tar.gz archives (the latter is a little bit trickier, because it's necessary to manually toggle the read-only archive buffer flag and save the archive buffer after the editing has been finished).
  • Keyboard macros - a way to simplify repeating things.
  • M-x flyspell-buffer - spell checking (uses aspell 0.60, it's possible to install additional dictionaries from the `lyx' editor packages, or prebuilt Linux packages: extract a dictionary to any folder, open this folder in the Emacs shell and execute the following command: `install-dict <dictionary name> <desired .multi file name>', for example: `install-dict spanish es').
  • M-x org-mode - built-in organizer.

Lisp-based development

It's possible to install the following Lisp dialects with ρEmacs:

Lisp dialect Version Emacs mode Dependency management1 Requirements
Clojure 1.8 Cider Leiningen 2 Java 1.6 or higher
Clozure CL 1.11 SLIME Quicklisp -
SBCL 1.3.12 SLIME Quicklisp -
CLISP 2.482 SLIME Quicklisp -
ABCL 1.1.5 SLIME Quicklisp Java 1.6 or higher
ECL3 16.1.3 SLIME Quicklisp Visual C++ compiler
Racket 6.9 Geiser PLaneT -

1 For the detailed information about dependency management see `Dependency Management' section below.
2 CLISP 2.49 contains a bug that prevents it to work with Emacs properly on Windows.
3 Will not work if path to ρEmacs home directory contains spaces or non-ASCII characters.

Any of the Lisp implementations could be upgraded or downgraded by replacing contents of its subfolder under the `<ρEmacs Installation Directory>/bin' directory.


SLIME is a Emacs library used to interact with Common Lisp implementations from the editor (Scheme lang. implementation included in ρEmacs uses another Emacs enhancement library - Geiser).

Hint: you can launch any installed Common Lisp implementation using M-- M-x slime <RET> implementation-name <RET> Emacs keyboard shortcut. Use the <TAB> key after the first <RET> to list available implementation names.

Important: what to do if a SLIME REPL evaluation request freezes? If you are running a multithreaded Lisp, you can save the existing Lisp environment by recurrent connection to the corresponding Lisp process. To accomplish this, use the M-x slime-connect command or simply command from the previous paragraph. For example, if you are running Clozure CL, type M-- M-x slime <RET> ccl <RET> and answer 'No' to the following SLIME question. Clozure then will create additional thread in the current Lisp environment, and you could continue the work.


By using lispx-proxy you can easily launch Common Lisp, Clojure or Scheme files as scripts and create more complex application distributions.

lispx-proxy is fully integrated into ρEmacs, and you could use all installed Common Lisp implementations and all ρEmacs ASDF repositories while executing Common Lisp code. ρEmacs knows about lispx-proxy `executable source code distribution' structure, and all ASDF systems and resources from the `shared' folder of a distribution will be available to the inferior Lisp (the distribution should be placed into one of the ρEmacs ASDF repositories). In other words, you can easily develop lispx-proxy applications with ρEmacs.

Emacs Command Shell

Emacs has ability to emulate command shell, which could be used to run Lisp implementations (by issuing the corresponding commands offered by Rho Shell) without overhead made by SLIME's Swank or Quicklisp. This may be useful when you want to reduce memory footprint of a generated program binary.

It is also possible to run any Lisp implementation out of Emacs using system-wide lispx-proxy. For example, you could run SBCL command-line REPL with the following command: lispx -i sbcl --repl issued in your regular Windows shell. To run Clojure REPL type lispx -l clojure --repl in your command prompt. Common Lisp package management systems are not automatically available with this scenario, although the REPL or scripts could use any already installed ASDF-systems or Java/Clojure libraries from `<ρEmacs Home>/clojure/lib'.

Common Lisp HyperSpec

If necessary, ρEmacs allows to install a local copy of Common Lisp HyperSpec and browse keyword documentation from SLIME using C-c C-d h keyboard shortcut.

Dependency Management

Common Lisp

¤ ASDF Repository Structure ¤

There are several places which are considered by ρEmacs as ASDF repositories:

  • <HOME>\lisp\repository - a common repository to manually place third party ASDF-systems;
  • <HOME>\lisp - a repository for folders of work-in-progress ASDF systems (use it for development);
  • <HOME>\.quicklisp\dists\quicklisp\software - a Quicklisp repository for automatically installed systems;

where <HOME> is a ρEmacs home directory. It's necessary to place directories with ASDF systems in one of these folders to make them accessible by ASDF. In addition, you can store Leiningen Clojure projects in <HOME>\clojure directory (it has no special meaning for Leiningen).

It's possible to disable any ASDF repository (including the repositories inside lispx-proxy executable source distributions) by placing a file named `.noindex' into it.

¤ Qukclisp ¤

Quicklisp is automatically preloaded for CL implementations with built-in ASDF2 or above (currently for all implementations included into ρEmacs). It's immediately possible to use ql:apropos-system and ql:quickload functions (for details see the manual at Quicklisp home site).


You can manage Clojure dependencies with the Leiningen build tool and Clojars repository. A typical use case looks like the following:

  • M-x shell - run Emacs command shell
  • cd "~/clojure" - change the current dir. to the clojure user directory under the ρEmacs home directory
  • lein new test-project - create new project named `test-project'
  • cd test-project - step into the project directory
  • lein deps - download and install required dependencies (you have to manually configure dependencies in project.clj before this step).
  • M-x cider-jack-in - load newly-created project with Cider, (it will use Clojure binary from the project dependencies for execution, not a binary included into ρEmacs)

WARNING: a Clojure Java process may remain in memory after the Emacs shutdown, because it has not been spawned by Emacs itself. Although ρEmacs tries to work around this issue and close the process before the Emacs shutdown, be aware of this.


There is currently poor support of Scheme and Racket in ρEmacs. For package management you can use the built-in Racket PLaneT facility according to the documentation. ρEmacs brings nothing special in this case.

Fasl Cache

Common Lisp implementations included in ρEmacs use ASDF2 translation facility to manage location of compiled fasl files. By default, compiled files are placed into `.fasl-cache' subfolder of the ρEmacs home directory. Fasl cache could be cleaned with `Clear Fasl Cache' menu item under the `((' menu group. It may be the first thing to do when something fails by no obvious reason.

Additional tools and languages

Item Version Included tools and libraries
Python 2.7.13 The default Python pip package manager is available as the `pip2' command
Python 3.6.1 The default Python pip package manager is available as the `pip3' command
Groovy 2.4.12 Grails 3.3.0
JDK 8.0u141 Apache ANT 1.10.1, Apache Maven 3.5, Gradle 4.0.1
MinGW-x64 installed by pacman Boost

System-wide tools

The `rho' command is available through the system PATH and could be used to open files from the command line or to use Emacs as an external editor in some applications (this could be useful with panel file managers such as FAR Manager or, for example, Firefox It's all text addon). The `rho' command accepts only one file argument, though.

The `lispx' command is also available at the command prompt and could be used for Lisp scripting. Common Lisp scripts can use all ASDF systems installed into ρEmacs repositories, Clojure scripts may load libraries placed in the `<ρEmacs Home>/clojure/lib' directory.

Useful Links

© 2010-2017 g/christensen (gchristnsn.at.gmail.com)