What is this repo

A portable Emacs configuration focused on adding IDE-level features for C++ and Lisp/Clojure programming. It is only intended to work with Emacs version 27.1 and above on Linux and OS X including in -nw mode, but it should work on Windows as well. It is modular and customizable. It is not a starter kit, it is a hacker kit.

If you are looking for a good generic Emacs configuration to start with, you might want to check these links: Emacs Prelude, Steve Purcell's config, Spacemacs, Awesome Emacs.

Table Of Contents

• Features
• Installation
• Keymap
• Projectile
• Git
  • Conflict Resolution
• C++
  • Utilities
  • Snippets
  • RTags
• Lisp
• Markdown
• LSP
• Customization
• Troubleshooting

Features

• Usability: IDO (completion engine, turned on by default); Helm (an alternative to IDO); Auto Complete and Company (completion engines) Expand Region (increase selected region by semantic units); Fill Column Indicator (80-character column marker); Treemacs (directory tree); Avy (jump to visible text in 2 or 3 key-strokes); ace-window (quick jump between windows); helpful (a better Emacs help buffer); which-key (display available keybindings). Treesitter(Parser-based font lock.)
• Projects: Projectile (project-based file management tool).
• Git: Magit (git UI); Forge (work with Git forges); Git Gutter (diffs in buffer).
• C++:
  • RTags: a LLVM/Clang-based code indexer providing goto definition, find references, refactoring, compilation errors in buffer, auto-complete etc.
  • Formatting keys and snippets for the BDE code style.
  • include-what-you-use: a LLVM/Clang-based tool for use with clang to analyze #includes in C and C++ source files.
• JavaScript: JS2-mode.
• Clojure: Cider and Lein.
• Eye candy: a few themes that do not look like an "angry fruit salad", and PowerLine.

Installation

Backup any .emacs file or .emacs.d directory you may have, and then clone this repo:

$ git clone https://github.com/emacs-exordium/exordium.git ~/.emacs.d

The first time you start Emacs it will download and compile the required packages, which may take a couple of minutes. If your machine is behind a proxy server, you should create a file .emacs.d/before-init.el with the address of the proxy before you start Emacs:

(setq url-proxy-services
      '(("no_proxy" . "^\\(localhost\\|10.*\\)")
        ("http"     . "<proxy-name>:<proxy-port>")
        ("https"    . "<proxy-name>:<proxy-port>")))

You can also clone the repository elsewhere, and use the init-test.sh script to try out exordium. init-test.sh will run your default emacs with the current directory as your user-emacs-directory, loading init.el, and no other init files.

Updates

To update Exordium, do M-x update-config. This command pulls from Github and recompiles everything. Restart Emacs after that.

Melpa packages are not updated automatically: you can do it with M-x package-list-packages, then U then x.

Files

The main file is init.el: it load the modules from the modules subdirectory and the default theme from the themes subdirectory. The extensions subdirectory is used for third-party plugins that are not available in Melpa.

3 files can be added in your directory ~/.emacs.d to customize the configuration for the local machine (these files are not tracked by git):

File name	Usage
prefs.el	Loaded before any module. The module init-prefs.el defines a number of customization variables for fonts, theme etc. prefs.el is where you should override any of these variables.
before-init.el	Loaded before anything else. Use it to set up the HTTP proxy for instance.
after-init.el	Loaded after everything else. This is where you should add your own features.

You can also have local modules in a directory ~/.emacs.d/local.

See the Customization section below for more details.

Keymap

General:

Keybinding	Description
C-z	Undo! (undo).
C-`	kill-this-buffer (faster than C-x k).
C-x C-r	Open recent file (completes open file with C-x C-f).
M-g	goto-line (prompts for a line number).
C-+	Increase font size (text-scale-increase).
C--	Decrease font size (text-scale-decrease).
M-C-l	Switch back and forth between the 2 top buffers (from XEmacs).
C-c C-SPC	Toggle highlight of the symbol under the cursor (up to 4 different symbols using different colors).

Editing:

Keybinding	Description
RETURN	Return and indent by default; use S-RETURN for just return.
M-BCKSP	backward-kill-word (e.g. the opposite of M-d kill-word).
C-\	Delete spaces after cursor (delete-horizontal-space-forward).
C-BCKSP	Delete spaces before cursor (delete-horizontal-space-backward).
M-\	Delete all spaces around cursor.
M-LEFT and M-RIGHT	Move cursor by semantic units (use C-LEFT and C-RIGHT to move by words).
C-c d	Duplicate line.
C-=	Expand region by semantic units.
M-C-=	Contract region by semantic units.
M-	Move region one line up
M-	Move region one line down
C-|	Toggle the 80-column ruler (fill column indicator).

Navigation:

Keybinding	Description
C-x C-\	Goto last change in buffer. Repeat to go to the second most recent edit, etc.
C-x C-/	Goto last change in reverse direction.
C-c j or C-'	Goto visible word or subword (avy-goto-word-or-subword-1). It first asks for the first character of the word, then annotates all words starting with that character with a unique touch-type friendly code.
C-c s	Push point onto position stack (e.g. bookmarks).
C-c b	Pop point from position stack.

Window manager:

Keybinding	Description
C-c ARROW	Move cursor between windows.
C-c S-ARROW	Move the windows themselves.
M-p NUMBER	Jump to the specified window number using ace-window. If you only have 2 windows, cycle between them.

Auto-complete/Company:

Keybinding	Description
C-.	Force trigger auto-complete/company-complete.
ESC	Abort auto-complete/company-complete.

Tip: if you are looking for a particular key and you know it starts with a given prefix, type the prefix followed by C-h: Emacs will display the list of keys starting with that prefix. For example C-c C-h lists all the keys starting with C-c.

Projectile

Projectile adds the notion of "projects" to Emacs. It provides many keys to find files within a project, grep in all files etc. Projectile maintains an index of files for each project it knows about; this list is created by scanning the project root directory. The main usage is to jump to a file using a partial name without having to remember in which directory it is, but it also supports grep/ack and replace in project. Projectile works with Helm or IDO, so you can use either one with different keys. Alternatively, you can always use Helm by setting exordium-helm-everywhere to true.

Here is an example: C-c h shows the list of buffers and files in the current project using Helm; to find a file you just need to type a few letters and the list shrinks as it performs fuzzy matching:

Setting up projects

A .git repo or a .projectile file defines the root directory of a project. Even if you have a git repo, you can create a .projectile file at the root of your project: it allows for filtering out the files you don't care about, such as binaries, scripts etc. For example, suppose you have a workspace directory containing among other things the BDE library and a project "bar"; you could create .projectile file like this:

+/bde/groups
+/bar
-.*
-*.md
-*.cap
-*.mem
-*.dep
-*.opts
-*.defs

The plus sign is used to ignore everything except specific directories; alternatively the minus sign is used to indicate what directories to ignore, starting at the root of the project. The minus sign can also ignore file patterns. If both directories to keep and ignore are specified, the directories to keep first apply, restricting what files are considered. The paths and patterns to ignore are then applied to that set. Refer to the Projectile documentation for details.

Now you need to teach Projectile where your projects are. You can do that by:

1. Simply opening the project's root dir in Dired, and then pretending to search a file with Helm (C-c h), or switching project with IDO (C-c p p). The top of the Helm buffer should show the list of projects including yours.

2. Sometimes method 1 works for the current session, but then Projectile forgets your projects as soon as you restart Emacs. In this case try to restart Emacs in the project's root directory for Projectile to find it. You should only need to do this one time for each project, after that it is cached.

3. The brute force method which is guaranteed to work is to edit the file where Projectile saves the list of projects. This file is ~/.emacs.d/projectile-bookmarks.eld. Since it is constantly written by Emacs itself, you need to exit emacs and restart it with emacs -Q (so that Projectile does not run). Edit the file, save and restart Emacs normally. Here is my bookmark file:

("/bb/mbig7/mbig2387/workspaces/rsp/" "/bb/mbig7/mbig2387/workspaces/si-core/" "/home12/pgrenet/.emacs.d/" "/bb/mbig7/mbig2387/workspaces/bsl-internal/" "/bb/mbig7/mbig2387/workspaces/bde-core/")

Using Projectile

The name of the current project is displayed in the mode line, between square brackets. There are only 2 keys to remember:

• To open a file in the current project using Helm, type C-c h. This will display the Helm buffer. Start typing for a partial name to narrow the selection until you find what you were looking for. Note that it performs fuzzy matching.
• If you want to open a file from a different project, type C-c M-h instead. The Helm buffer will initially display just the list of projects. Choose your project and press enter; Helm will now display all indexed files in that project.

C-c p C-h displays the list of keys for Projectile. Below are the most important ones.

Keybinding	Description
C-c h	Find file in current project with helm
C-c M-h or C-c H	Same, but first select project
C-c p p	IDO: switch project (alternative: Helm)
C-c p f	IDO: find file in current project (alternative Helm)
C-c p .	IDO: find file at point based on context (alternative Helm)
C-c p s g	Grep in current project
C-c p s a	Same but using ack
C-c p r	Interactive query-replace on all files in project
C-c p i	Invalidate the cache

See Projectile documentation for other keys.

Helm

Helm can be set up as a primary completion and selection narrowing framework for most commonly used functions. You can achieve that by setting exordium-helm-everywhere to true. The following keys will use Helm:

Keybinding	Description
C-c p p	Select project and open file with projectile.
C-c p f	Open file with projectile.
C-x C-r	Open recent file.
M-x	Execute command.
M-y	Select yank pop.
C-x b	Switch buffer.
C-x C-f	Find file.

Other Helm tools

Helm is a pretty good when you need quickly scan search results. The commands below will start different search modes. By default, they will use symbol under the point. However if it is not there just start typing text: the Helm window shows all matching lines, and you can jump from one to another using the arrow keys.

Some of them will use Helm Swoop while the reminder will use Silver Searcher. The latter, abbreviated Ag, being substitute to grep and ack has support for regular expressions.

• C-S-a: Ag search for text in current projectile project.
• C-S-s or M-x helm-swoop: Swoop search for text in current buffer.
• C-S-d: Ag search for text, but ask for directory to start first.
• C-S-f: Ag search for text in current buffer (similar to Swoop).
• C-S-r: ripgrep search for text in current projectile project.
• M-x helm-multiple-swoop-all: Swoop search within all buffers.

Note that C-S-a and C-S-r work also directly from helm-projectile-switch-project. This means that you searching a project with ag or rg simply by selecting it in helm and hitting appropriate keybinding.

Treemacs

Treemacs is a tree layout file explorer for Emacs. It is linked with Projectile and Git, and it can display the project directory structure on the left side:

Keybinding	Description
C-c e	Toggle treemacs the current directory.
C-c E	Open a projectile project (with a selector).

Treemacs displays the git status of files (added, modified, ignored etc.) using different faces.

With the cursor in the Treemacs window, you can use TAB to open/close directories, RETURN to open a file, and q to quit. Use ? to view all the available keys. See the documentation of Treemacs for details.

Git

All git-related keys use prefix C-c g plus one more key. For example C-c g s runs Magit status:

The bottom window shows the current git status. Use the tab key on any file to fold or unfold its diff. Use the s key to stage or unstage a file, and the capital S to stage all of them. Use the k key to revert a file. Type c twice to commit; it will ask for the commit message (C-c C-c to close the window and commit). Finally the q key quits magit.

By default running Magit via global keybindings will start it in a full screen mode (whole frame). This is controlled by exordium-use-magit-fullscreen preference. You can customize it to nil to get original Magit behavior.

The screenshot above also shows git gutter in the top buffer. Git gutter displays a git diff of the file in the left-side fringe (you can customize it). Git gutter defines a few keys for navigating between hunks, diffing and reverting.

Magit keys:

Keybinding	Description
C-c g s	Open git status (magit-status).
C-c g l	Open git log (magit-log or magit-dired-log when in dired-mode).
C-c g f	Open git file log (magit-file-log).
C-c g b	Toggles git blame mode on and off (magit-blame-mode).
C-c g c	Clone a repository (magit-clone).
C-c g g	Git grep (vc-git-grep) or (helm-grep-do-git-grep).

Forge keys:

Keybinding	Description
C-c C-p	in forge-post-mode: Preview post with markdown (exordium-forge-markdown-preview)
C-c C-d	in forge-post-mode: Submit current post (a Pull Request) as a draft (exordium-forge-post-submit-draft)
C-c C-d	in magit-status-mode and in forge-topic-mode: Mark a Pull Request at point as ready for review (exordium-forge-mark-ready-for-rewiew)

Git gutter keys:

Keybinding	Description
C-c g down	Goto next hunk in buffer (git-gutter:next-hunk).
C-c g n	Goto next hunk in buffer (git-gutter:next-hunk).
C-c g up	Goto previous hunk in buffer (git-gutter:previous-hunk).
C-c g p	Goto previous hunk in buffer (git-gutter:previous-hunk).
C-c g d	Diff the current hunk (git-gutter:popup-diff).
C-c g r	Revert the current hunk after confirmation (git-gutter:revert-hunk).

Git Timemachine key	Description
C-c g t	Enter the git time machine (git-timemachine-toggle)

Conflict Resolution

If you use ediff to solve merge conflicts you may find the following keys useful (in *Ediff Control Panel*):

ediff key	Description
A	Copy buffer A's region followed by buffer B's region to C
B	Copy buffer B's region followed by buffer A's region to C

When the variable exordium-smerge-show-dispatch is set to t (the default) hitting RET on a file with unmerged changes in Magit status buffer will display a SMerge dispatch that will assist with merge using built-in smerge-mode. When all conflicts are resolved, hitting C-c C-c will bring you back to Magit status. Hitting C-c C-k will revert the buffer to last saved changes and will bring you back to Magit status.

The SMerge dispatch is a transient command (like most of magit and forge commands), so it can always be dismissed with C-g.

In addition to keys presented in the dispatch, the following keys are added to SMerge keys:

Keybinding	Description
C-c ^ d	Show SMerge dispatch (exordium-smerge-dispatch).

C++

Utilities

Keybinding	Description
C-TAB	Alternate between header file and source file.
C-u C-TAB	Alternate between source/header file and BDE test driver.
C-c ;	Rename variable under cursor (but see also RTags, which is a better solution).

Keys for formatting code according to the BDE style:

Keybinding	Description
C-c a	Align function arguments (in signature).
C-c f	Align function arguments (in function call).
C-c m	Align class members (region must be selected).
C->	Right-align end-of-line comment or text after cursor.
C-c i	Insert redundant #include guard.
C-c =	Insert class definition header.
C-c -	Insert class implementation header.

Snippets

YASnippet is a template system which replaces a keyword by a template after you hit the trigger key. YASnippet is only enabled for C++ mode currently. The trigger key is set to C-c y because the default TAB key is already way overused between intention and auto-complete/company-complete. You can easily use a function key if you prefer by adding this in your after-init.el:

(define-key yas-minor-mode-map (kbd "<f2>") 'yas-expand)

Snippets are stored in ~/.emacs.d/snippets/c++-mode. Here are the snippets.

Note that variable *bde-component-author* defines the default author for a header file template (see modules/init-yasnippet.el). You can set it to your name in after-init.el.

RTags

RTags is a LLVM-based C++ indexer which provides a daemon called "rdm" that maintains a persistent (memory mapped) file-based index. The client for "rdm" is command-line client called "rc". RTags uses a single index for all symbols, but it allows for loading and unloading projects individually.

The rdm daemon knows how to compile your project with a CLang compilation database, which is a file named compile_commands.json. The compilation database contains one entry for each file to compile, like the following (simplified for clarity):

{ "directory": "/home/phil/workspaces/foo/",
  "command":   "/usr/bin/clang++
                -D_POSIX_PTHREAD_SEMANTICS -D_REENTRANT
                -I/home/phil/workspaces/bde/groups/bsl/bsl+stdhdrs
                -I/home/phil/workspaces/bde/groups/bsl/bslma
                -I/home/phil/workspaces/bde/groups/bsl/bsls
                -c -o bar.o bar.cpp",
   "file":      "bar.cpp" }

Basically the compilation database contains the list of files to compile and the exact command to compile them. There are several ways to generate this file:

• RTags provides compiler wrapper scripts which tell rdm to parse and index each compilation unit before it gets compiled. While this is the easiest way (all you need to do is to build), the inconvenient is that you need to build before you can use the latest index, and any unused header won't be indexed.
• You can build with CMake: it generates a compilation database for you each time you build.
• Exordium provides a command to generate the compilation database by scanning source directories. It requires you to write a simple text file indicating where these source directories are.

The first thing you need to do is to build and install RTags: refer to the RTags documentation. The sections below explain how to use it.

Using RTags from the shell

First start the daemon:

$ rdm

This will start the daemon on the foreground, using a number of concurrent "rp" jobs that is function of the number of CPUs on the local machine. By default it logs to the console but you can make it log to a file instead with -L file or make it silent with -S. There are many options; use --help to see the list.

RTags stores project indices into a directory ~/.rtags by default, and reloads them as needed. It watches for file changes using inotify and refreshes the index automatically. Note that you can change the location of the .rtags directory with a ~/.rdmrc file; it is recommended to store it into a local SSD drive and avoid NFS-mounted directories.

By default rc and rdm communicate with each other using a socket file ~/.rdm, but there are other ways: refer to the RTags documentation.

The main commands are:

Command	Description
rc -w	List projects in the index.
rc -w proj	Switch to project "proj" (a regex).
rc -W proj	Unload and delete project "proj".
rc -J .	Reload the compilation DB from the current directory.
rc --find-project-root /path/to/sourcefile.cpp	Print what it determines to be the correct project root.
rc -T sourcefile.cpp	Say whether this file is indexed or not.
rc -q	Shutdown rdm.

Note that a job may crash while trying to index a file. If it does, rdm will retry a few times and then give up with the file it cannot parse.

Using RTags from Emacs

Alternatively you can run rdm as an Emacs subprocess. The logs will go into a buffer (in color!).

Command	Description
M-x rtags-start	Start rdm and RTags diagnostics.
M-x rtags-stop	Stop rdm and Rtags diagnostics.

CMake projects

If your project compiles with CMake, you're in luck: CMake generates this compilation database for you every time you build. Adding this line in your ~/.emacs.d/prefs.el will make RTags work automagically:

(setq exordium-rtags-cmake t)

In addition you may set the following variables:

• Exordium assumes that your build directory is named like cmake.bld/<arch>, relative to the project root, where <arch> is the uname of your OS. If this is not the case you can change it like so in ~/.emacs.d/prefs.el:

  (setq exordium-rtags-cmake-build-dir "build")

• Exordium runs rdm with no argument by default. You can add arguments by setting this variable in ~/.emacs.d/prefs.el:

  (setq exordium-rtags-rdm-args
        "--isystem /opt/bb/lib64/clang/3.6.2/include -DBAS_NOBBENV")

You can also specify where the build directory is using a .rtags file at the root of your project with a content like build /path/to/my/build; it takes precedence over exordium-rtags-cmake-build-dir.

Exordium will automatically detect if your project is CMake-enabled when you open a C++ file, by looking for CMakeLists.txt files along the path from the root of your project to the location of the file you open (your project must be a git repo). If this is a CMake project, Exordium will start rdm if it is not running, and ask rdm to index the project using the CMake-generated compilation database in the build directory. If the project was already indexed, it is simply reloaded and RTags commands work immediately. Otherwise rdm compiles the index, and you can see the progress with C-c r l (rerun to dismiss).

If you need to add or remove components from your project, just rebuild it (e.g. "make" in the build directory) and CMake will update the compilation database accordingly. Because rdm watches for changes to the compilation database file, it will pick up the changes automatically.

Non-CMake projects

You can generate the compilation database with the command M-x rtags-create-compilation-database. But before you do, it needs a little help: you need to tell it what clang++ command to use to compile any file, with all the -I directives that are necessary for your project.

The command uses a file compile_includes in the project root directory, which specifies how to generate compilation_database.json for your project. It is a simple text file indicating where are all the source files and all the include files. The "src" directives indicate where to find the source files to put in the index (each of them will have its own entry in the compilation database). The "include" directives indicate additional "-I" includes in the clang command line. Both are recursive: any path will be scanned for source files or subdirectories; however the "exclude" directives indicate what patterns (regex) to exclude when scanning the "src" and "include" paths. Finally the "excludesrc" directive is used to specify patterns (regex) of source files names to exclude.

Note that all directives except "src" are optional. Also note that paths are either absolute or relative to the project root. Here is an example:

  # 'compile_includes' file for project foo

  # Where are the source files (there could be multiple directories).
  # We will scan recursively any subdirectories that do not match any
  # 'exclude' regex.
  src .

  # What to put in -I directives (in addition to the source files above).
  # We will scan recursively any subdirectories that do not match any
  # 'exclude' regex.
  include /Users/phil/Code/cpp/include/bsl
  include /Users/phil/Code/cpp/include/bdl

  # Optional: patterns to exclude in -I directives and while looking for
  # sources. Here we explicitly don't want to index the tests subdir:
  exclude /test$

  # Optional: if any file name pattern must be excluded from the "src" files,
  use the "excludesrc" directive. For example this will exclude all test
  # drivers (extension .t.cpp):
  excludesrc \.t\.cpp$

  # Optional: -D macros, if any:
  macro BDE_BUILD_TARGET_SAFE

In addition, the creation of a compilation database uses these variables:

Variable	Description
rtags-compile-includes-base-dir	Set this to your workspace path if you want to use relative paths in compile_includes that are not relative to the project's root directory (the default).
rtags-clang-command-prefix	Default is "/usr/bin/clang++ -Irelative" (note that RTags ignores the clang++ command because it uses libclang).
rtags-clang-command-suffix	Default is "-c -o".

Once you have created the compile_includes file, run the command M-x rtags-create-compilation-database. It will:

• Prompt for the project root dir;
• Read the compile_includes file;
• Scan all source dirs and include dirs according to what the file says;
• Create compilation_database.json (note: it overwrites it without asking);
• Ask if you want to reload it (if rdm is running as an Emacs subprocess).

You can reload the compilation database manually with rc:

$ cd /where/your/compilation/db/is
$ rc -J

Check the output of rdm for any compilation errors and adjust your compilation database accordingly.

The rdm daemon should automatically re-compile any file you edit in Emacs as soon as you save it or otherwise touch it.

Using the index

While RTags uses C-x r as default prefix, this configuration uses C-c r instead because it it less crowded. It also adds a few keys such as M-C-g to display the list of symbols from the current buffer using Helm:

Navigation keys:

Keybinding	Description
M-. or C-c r .	Jump to symbol definition. With prefix: in other window.
M-, or C-c r ,	Find references to symbol.
C-c r >	Find symbol (prompts for symbol name).
C-c r <	Find references (prompts for symbol name).
C-c r v	Find all implementations of virtual function.
C-c r S	Show symbol summary in tooltip (rtags-display-summary).
M-C-g	Find symbol in file using Helm.
C-c r ;	rtags-find-file using partial name (non IDO).

Any navigation is recorded onto a stack, so it is easy to go back and forth:

Keybinding	Description
C-c r LEFT or C-c r [	Go back to previous location.
C-c r RIGHT or C-c r ]	Go forward to next location.

Refactoring:

Keybinding	Description
C-c r R	Rename symbol.

Control:

Keybinding	Description
C-c r p	Switch project.
C-c r e	Reparse file, e.g. recompile.

Debugging utilities:

Keybinding	Description
C-c r l	Show/hide the rdm log buffer.
C-c r U	Show what rdm knows about a symbol.
C-c r P	Show all includes for the current file.
C-c r T	Show the tag list for the current file.

Using syntax checker

"Rtags diagnostics" is a way to get compilation warnings and errors from rdm, and display them using Flymake or Flychek in buffers. Set the variable exordium-rtags-syntax-checker to :flymake (default) or to :flycheck to select the syntax-checker in use.

The compilation warnings are enabled by default if you run rdm from Emacs. Otherwise you can turn it on manually with M-x rtags-diagnostics bound to C-c r D.

By default Powerline displays the name of the buffer in green if the project compiles and in red if there are errors:

Click on the highlighted symbol in your code to view the error message. Click on the error line in the diagnostics buffer to jump to the error location.

Keybinding	Description
C-c r D	Run rtags-diagnostics if it wasn't and force reparsing of current buffer.
C-c r d	Show/hide the diagnostics buffer without force reparsing.
C-c r r	Run helm-flycheck to show errors in helm buffer (only with :flycheck syntax checker)
C-c r DOWN	Goto next problem (rtags-next-diag).
C-c r UP	Goto previous problem.
C-c r F	Fix the error using Clang's "did you mean" (try it with "inft x;")
C-c r c	Clears all errors and warnings (rtags-clear-diagnostics)
C-c r Q	rtags-stop-diagnostics stop the async process.

Autocomplete

You can use RTags as source for auto-complete suggestions. Notes:

• This feature makes RTags be the only source for auto-complete in C/C++ mode, e.g. all other classic sources such as names in open buffers are disabled. The reasoning being that surely Clang must be more accurate.
• This feature requires RTags diagnostics to be turned on.

To enable it automatically, set the variable exordium-rtags-auto-complete to true in your prefs.el. Note that auto-complete for #include header files does not work in this case, because it does not know what project you are in.

To enable it manually, type C-c r A. This will take effect for all C++ files you open from that point. This key also sets auto-complete for the #include header files in the current project.

Possible issues:

• There might be a graphical glitch in the auto-complete popup if the Emacs window is too small. Just enlarge the window a bit if this happens.
• It's a tiny bit slow and it may trigger rdm a bit often.
• Auto-complete for header files does not understand when you are switching project.

Company

As an alternative to auto-complete you can choose company-mode. You can do that by setting exordium-complete-mode to :company. It will use RTags as a completion engine when rdm is started.

include-what-you-use

include-what-you-use is a tool for use with clang to analyze #includes in C and C++ source files. The main goal of include-what-you-use is to remove superfluous #includes. It does this both by figuring out what #includes are not actually needed for this file (for both .cpp and .h files), and suggesting fixes to #includes with forward-declares when possible. Please note that since this tool is not 100% accurate, Exordium support does not include automatic file modification. Instead it provides support to spawn the process and capture the suggestions in a diagnostic buffer that can be later checked by human.

Similarly to RTags, include-what-you-use relies on the compilation database to be available in compile_commands.json file. It uses exordium-rtags-cmake-build-dir to locate the compilation database for the current project.

On top of that two variables are available to customise the behavior:

• exordium-iwyu-filter-args: a list of arguments that should be taken out of the include-what-you-use invocation. This is useful, when project's compilation database contains arguments specific to the compiler and those arguments are not supported by LLVM/Clang.
• exordium-iwyu-filter-args: a list of arguments that should be passed to the include-what-you-use executable. This becomes useful, i.e., when LLVM/Clang is not installed in the system directory and extra includes has to be passed.

Exordium defines the following keybindings:

Keybinding	Description
C-c w e	Run include-what-you-use for the current buffer.
C-c w d	Show/hide the diagnostics buffer without force reparsing.
g	Reparse recent file (in IWYU-mode buffer).

Lisp

Coming soon: Emacs Lisp, Common Lisp and Clojure.

Markdown

M-x impatient-markdown-mode starts a minor mode that provides a live preview of a markdown buffer in your favorite web browser. The web page is updated as you type (this feature is implemented with the impatient mode). Before you can use it, you need to set the variable markdown-command to the command to execute to render a markdown file into HTML. For example, to use the GitHub command, clone markup and set markdown-command to the path of bin/github-markup in your after-init.el. Other options include Pandoc or RedCarpet.

Note that markdown-mode itself provides a few keys to render into HTML, and it does not need an external renderer to be installed:

Key	Behavior
C-c C-c v	Render and open in web browser
C-c C-c m	Render and open in another buffer
C-c C-c l	Live preview in EWW (the internal browser)

Another interesting feature is M-x orgtbl-mode, a minor mode for editing tables: it works like org tables but it uses the GitHub-flavored format. Use the tab key to switch to the next cell and reformat the whole table.

LSP

Exordium includes configuration for lsp-mode a language server protocol client. The configuration currently supports C++ using clangd. It is enabled with the customization option exordium-lsp-mode-enable. The settings that are enabled by default have been in use by some Exordium in anger, but may need tweaking. The authors of lsp-mode also have a policy of enabling new features by default, so that new capabilities are visible and discoverable.

The lsp-mode keymap is bound to C-c l.

LSP mode is available via TRAMP, and in particular via tramp to docker containers.

LSP mode in the shared Exordium base is stable enough for use, but the configuration details are experimental and subject to change without notification.

Tree-sitter

Exordium can be configured to use tree-sitter for parser directed font lock. In emacs versions 29 or greater it uses the new built in treesit mode if emacs was built with treesitter support, otherwise it falls back to using the tree-sitter mode from melpa. In emacs 29, language mode support is via treesit-auto and an exordium function that automatically forwards the hook from the new lang-ts-mode modes to the hook for lang-mode, hopefully preserving your customizaations. If treesit is unavailable, tree-sitter-langs is used.

The configuration variable is exordium-treesit-modes-enable and is disabled by default.

Customization

The main file of the configuration is init.el. It looks like this:

;;; 1. Load all before-init.el files. The ~/.emacs.d/before-init.el
;;; comes first (if exists), followed by any existing before-init.el
;;; file from all ~/.emacs.d/taps/subdirs.
(dolist (tapped-file exordium-tapped-before-init-files)
  (load tapped-file))

;;; 2. Define the list of Melpa packages that we need, and load any missing
;;; one. Note that they are NOT updated automatically.

;;; 3. Local preferences: load all prefs.el. The ~/.emacs.d/prefs.el
;;; comes first (if exists), followed by any existing prefs.el
;;; file from all ~/.emacs.d/taps/subdirs.
(require 'init-prefs)       ; defines variables that prefs.el can override
(dolist (tapped-file exordium-tapped-prefs-files)
  (load tapped-file))

;;; 4. Load the "modules" in ~/.emacs.d/modules. See below.

;;; 5. Load the default theme in ~/.emacs.d/themes.

;;; 6. Load all after-init.el files.The ~/.emacs.d/after-init.el
;;; comes first (if exists), followed by any existing after-init.el
;;; file from all ~/.emacs.d/taps/subdirs.
(dolist (tapped-file exordium-tapped-after-init-files)
  (load tapped-file))

Modules can be individually commented out if needed:

;;; Uncomment the modules you'd like to use and restart Emacs afterwards,
;;; or evaluate the require expression with M-C-x.

;;; Look and feel
(require 'init-look-and-feel)   ; fonts, UI, keybindings, saving files etc.
(require 'init-linum)           ; line numbers

;;; Usability
(require 'init-window-manager)  ; navigate between windows
(require 'init-util)            ; utilities like match paren, bookmarks...
(require 'init-ido)             ; supercharged completion engine
(require 'init-highlight)       ; highlighting current line, symbol under point
(cond ((eq exordium-complete-mode :auto-complete)
       (require 'init-autocomplete)) ; auto-completion (see below for RTags AC)
      ((eq exordium-complete-mode :company)
       (require 'init-company))) ; company mode (rtags are on by default)
(when exordium-helm-projectile  ; find files anywhere in project
  (require 'init-helm-projectile))
(require 'init-helm)            ; setup helm

;;; Magit and git gutter
(require 'init-git)

;;; Themes
(if exordium-nw
    (set-face-background 'highlight nil)
  ;; Using Emacs with GUI:
  (require 'init-themes)
  (require 'init-powerline))

;;; Shell mode
(require 'init-shell)

;;; Major modes
(require 'init-markdown)
(require 'init-org)
(require 'init-xml)

;;; OS-specific things
(when *environment-osx*
  (require 'init-osx))

;;; Etc.

If you are looking for a specific feature or key binding, this page explains the code organization. Each module starts with a commentary including all key bindings.

Local files

3 files can be added in your directory ~/.emacs.d to customize the configuration for the local machine:

File name	Usage
prefs.el	Loaded before any module. Use it to override fonts, window size etc. See init-prefs.el.
before-init.el	Loaded before anything else. Use it to set up the http proxy for instance.
after-init.el	Loaded after everything else. Use it to load machine-specific extensions.

Taps

The idea is inspired by taps from Homebrew. You can clone any git repository into ~/.emacs.d/taps/ directory (as a subdirectory of the latter). It is going to be called tap. Anything below taps subdirectory is not tracked by Exordium, although each tap can be a repository itself, allowing for tracked customisation.

When Exordium is initialised, it searches for the three special Local files in each tap. Files are then added to the tapped lists: before, prefs, and after. taps are searched in alphabetical order of their respective names in ~/.emacs.d/taps directory (string-lessp to be exact). This order determines the order of files in each tapped list. This lets you influence the order of processing within each tapped list, i.e., you can rename your tapped repositories (clones). The Local files from your ~/.emacs.d are always first in each respective tapped list. Each tapped list is processed (each file from it is loaded) as a replacement for a respective Local file.

Exordium-specific emacs functions are WIP.

Preferences

modules/init-prefs.el defines the preferences that can be changed in your prefs.el. For example, your prefs.el could contain:

;; Fonts + size in order of preference. First available one will be picked.
(setq exordium-preferred-fonts '("Monospace" . 120) ("Mono" . 120))

;; Default Emacs frame size in chars
(setq exordium-preferred-frame-width  120
      exordium-preferred-frame-height 65)

;; Show line numbers (default t)
(setq exordium-display-line-numbers t)

;; Highlight current line (default t)
(setq exordium-line-mode t)

;; Don't set ESC key to C-g (quit/abort)
(setq exordium-keyboard-escape nil)

;; Disable electric-pair (automatically inserts a closing parenthese,
;; curly brace, etc.)
(setq exordium-enable-electric-pair-mode nil)

;; Don't use Powerline (may cause Emacs to crash on startup sometimes)
(setq exordium-enable-powerline nil)

There are more options, see init-prefs.el.

Themes

Exordium includes several themes that are integrated with Powerline and that should work well in -nw mode. Use M-x switch-theme to change the theme. Otherwise, setting your favorite theme in prefs.el like the following will give you this:

;; Available themes (default is tomorrow-night):
;; - tomorrow-night, tomorrow-night-bright, tomorrow-night-blue,
;;   tomorrow-night-eighties, tomorrow-day
;; - solarized-dark, solarized-light
;; - monokai
;; - zenburn
;; - material
;; - atom-one
(setq exordium-theme 'material)

;; Powerline theme:
(setq exordium-powerline-theme :wave)

Local modules

You can create a directory ~/.emacs.d/local for your own local modules (this directory is ignored in git). In that case you should use require forms in after-init.el to load them.

Here is an example. Create a file named ~/.emacs.d/local/init-test-local.el with this content:

;;;; Test local module

(message "**** This test local module is loaded! ****")

(provide 'init-test-local)

Then create a file ~/.emacs.d/after-init.el with this content:

;;;; Local stuff

(message "**** after_init ****")

(require 'init-test-local)

Restart Emacs. The message buffer should show two lines:

**** after_init ****
**** This test local module is loaded! ****

Local modules files can be named anything as long as the file name, the symbol in provide and the symbol in require are the same.

Troubleshooting

Bugs

• Powerline may cause Emacs to crash on startup because of a race condition inside Emacs. A solution is to make it display after one second of idle time in order to guarantee that Emacs has finished initializing. For this, add (setq exordium-display-powerline-after-idle-time 1) in your prefs.el. Another solution is to enable powerline manually using a function like this:

(defun powerline ()
  "Enable powerline."
  (interactive)
  (require 'powerline)
  (powerline-set-selected-window)
  (require 'init-powerline)
  (redraw-display))

• Sometimes a random bug may occur that displays this error: fringe-helper-modification-func: Invalid search bound (wrong side of point). I'm pretty sure this is a bug in git-gutter-fringe which display git diff icons in the left-side fringe.

  There are two ways to work around it: either add (setq exordium-git-gutter nil) if your prefs.el to disable this feature entirely, or add (setq exordium-git-gutter-non-fringe t) in your prefs.el to display git diffs on the left side of line numbers, e.g. not in the fringe. Note that the latter disables the highlighting of the current line number for now.

• Editing large comment blocks in C++ can be slow as hell. Unfortunately this is a problem with CC-mode and not with this config. A simple solution is to turn off font lock temporarily with M-x font-lock-mode. Do it again to re-enable font lock after you're done editing your large component-level comment.

• exordium-preferred-fonts does not work with emacs --daemon. This is annoying if you start Emacs as a server and then only use emacsclient afterwards. The problem is that functions like font-family-list return nil in Emacs server, so there is no good way to verify what fonts are available in the server process (believe me I tried). The solution is to put something like (setq default-frame-alist '((font . "Inconsolata-12"))) in your pref.el (you need to know exactly what font and size you want for your local machine). The code below works for both Emacs and emacsclient:

;; ~/.emacs.d/prefs.el

;; Font and initial frame size
(cond ((daemonp)
       (message "Setting prefs for emacsclient")
       (setq exordium-preferred-frame-width nil
             exordium-preferred-frame-height nil)
       (setq default-frame-alist
             (append '((font   . "Consolas 13")
                       (top    . 0)
                       (left   . 50)
                       (width  . 110)
                       (height . 71))
                     default-frame-alist)))
      (t
       (message "Setting prefs for emacs")
       (setq exordium-preferred-frame-width 110
             exordium-preferred-frame-height 71)
       (setq exordium-preferred-fonts '(("Consolas" . 120)
                                        ("Monaco"   . 120)))))

• Sometimes weird bugs may happen after an upgrade or during development on a module. Exordium recompiles any .el file for which the corresponding .elc files is older on startup, but does not try to force any .el file to be compiled. Two functions are useful in this case: M-x uncompile-modules removes all .elc files (if you restart Emacs it will not compile anything). M-x force-recompile-modules recompiles everything.

• RTags now uses memory mapped files instead of loading projects into memory. It may be slow if your home directory is NFS-mounted, since by default the index is stored in ~/.rtags. The solution is to store the index on a local drive, preferably an SSD. You do this by creating a file ~/.rdmrc with a content like this: --data-dir=/local/drive/.rtags.

Configuration profiling

M-x emacs-init-time shows the time Emacs took to start. You can profile the configuration using this command (this example is for OS X):

$ Applications/Emacs.app/Contents/MacOS/Emacs -Q -l ~/.emacs.d/extensions/profile-dotemacs.el -f profile-dotemacs