#+TITLE: Ruby layer

#+TAGS: general|layer|multi-paradigm|programming

[[file:img/ruby.png]]

* Table of Contents                     :TOC_5_gh:noexport:
- [[#description][Description]]
  - [[#features][Features:]]
- [[#install][Install]]
  - [[#choosing-a-backend][Choosing a backend]]
    - [[#robe][Robe]]
    - [[#language-server-protocol][Language Server Protocol]]
  - [[#prerequisites][Prerequisites]]
  - [[#ruby-version-management][Ruby version management]]
  - [[#test-runner][Test runner]]
  - [[#formatting][Formatting]]
- [[#key-bindings][Key bindings]]
  - [[#ruby-enh-ruby-mode-robe-inf-ruby-ruby-tools][Ruby (enh-ruby-mode, robe, inf-ruby, ruby-tools)]]
  - [[#debugger][Debugger]]
  - [[#bundler][Bundler]]
  - [[#rubocop][RuboCop]]
  - [[#tests][Tests]]
    - [[#rspec-mode][RSpec-mode]]
    - [[#ruby-test-mode][Ruby-test-mode]]
    - [[#minitest-mode][minitest-mode]]
  - [[#toggles][Toggles]]
  - [[#rake][Rake]]
  - [[#refactor][Refactor]]
  - [[#seeing-is-believing][Seeing is believing]]
- [[#configuration][Configuration]]
  - [[#layer-options][Layer options]]
  - [[#disabling-the-automatic-insertion-of-encoding-comment][Disabling the automatic insertion of encoding comment]]

* Description
This layer provides support for the Ruby programming language.

** Features:
- Version manager (rbenv, rvm or chruby)
- Integration with bundler
- Test runner (ruby-test and rspec)
- Rake runner
- Linter (rubocop)
- Formatter (prettier)
- Interactive REPL and code navigation (robe)
- Interactive debugger using [[https://github.com/emacs-lsp/dap-mode][dap-mode]]

* Install
To use this configuration layer, add it to your =~/.spacemacs=. You will need to
add =ruby= to the existing =dotspacemacs-configuration-layers= list in this
file.

This layer supports two different Ruby modes: Emacs's built-in Ruby Mode and
[[https://github.com/zenspider/enhanced-ruby-mode][enh-ruby-mode]]. By default the built-in Ruby mode is enabled. To switch to the
=enh-ruby-mode= set =ruby-enable-enh-ruby-mode= to t:

#+BEGIN_SRC emacs-lisp
  (defun dotspacemacs-configuration-layers ()
     '((ruby :variables ruby-enable-enh-ruby-mode t)))
#+END_SRC

** Choosing a backend
To choose a default backend set the layer variable =ruby-backend=:

#+BEGIN_SRC elisp
  (ruby :variables ruby-backend 'robe)
#+END_SRC

Alternatively the =lsp= backend will be automatically chosen if the layer =lsp=
is used and you did not specify any value for =ruby-backend=.

Backend can be chosen on a per project basis using directory local variables
(files named =.dir-locals.el= at the root of a project), an example to use the
=lsp= backend:

#+BEGIN_SRC elisp
  ;;; Directory Local Variables
  ;;; For more information see (info "(emacs) Directory Variables")

  ((ruby-mode (ruby-backend . lsp)))
#+END_SRC

*Note:* you can easily add a directory local variable with ~SPC f v d~.

*** Robe
The default Ruby-mode backend. See Prerequisites for the necessary Gems to support Robe.

*** Language Server Protocol
IDE-like backend for Ruby. The only prerequisite gem is =solargraph= which can be
installed globally with:

#+BEGIN_SRC sh
  gem install solargraph
#+END_SRC

LSP also supports the DAP debugger which will be automatically configured upon
using the LSP backend. Dap-mode can be setup here:
[[https://github.com/emacs-lsp/dap-mode#ruby]]

** Prerequisites
Some of the advanced features supported by this layer depend on external gems
that need to be installed in the context of your project (see below for guidance
based on your version manager):
- =pry= and =pry-doc= are required for *jump to definition* and *code documentation* (=robe-mode=)
- =ruby_parser= is required for *goto-step_definition* in =feature-mode=
- =rubocop= is required for rubocop integration
- =prettier= is required for formatter
- =seeing_is_believing= helps you evaluate code inline
- =solargraph= is required for using the language server protocol in =ruby-mode=

You can install the gems in the context of your current project by
adding them to the =Gemfile=, e.g.:

#+BEGIN_SRC ruby
  gem 'pry'
#+END_SRC

or on the command line (please refer to your ruby version manager
specific documentation for details and caveats):

#+BEGIN_SRC sh
  gem install pry
#+END_SRC

** Ruby version management
This layer supports [[https://rvm.io/][RVM]], [[https://github.com/rbenv/rbenv][Rbenv]], and [[https://github.com/postmodern/chruby][Chruby]]. You can choose the default version
manager by setting the variable =ruby-version-manager= in your dotfile, for
example:

#+BEGIN_SRC emacs-lisp
  (defun dotspacemacs-configuration-layers ()
     '((ruby :variables ruby-version-manager 'rvm)))
#+END_SRC

When a version manager is enabled it will use the currently activated ruby
except if a =.ruby-version= file exists in which case the ruby version of
this file is used.
=rvm= will also try to look for a =.rvmrc= and =gemfile=, the priority order is
=.rvmrc= then =.ruby-version= then =gemfile=.

Note: Only one version manager at a time can be enabled.

** Test runner
This layer supports =RSpec=, =ruby-test= and =minitest= test runners
(frameworks). By default =ruby-test= is used, to change to another frameworks
set the layer variable =ruby-test-runner=.

Example to set the test runner to =RSpec=:

#+BEGIN_SRC emacs-lisp
  (defun dotspacemacs-configuration-layers ()
     '((ruby :variables ruby-test-runner 'rspec)))
#+END_SRC

=Tip:= You can enable different test runners for different projects by using
directory local variables.

** Formatting
If you'd like to use [[https://github.com/prettier/plugin-ruby][prettier/plugin-ruby]] to format on save:

#+BEGIN_SRC emacs-lisp
  (defun dotspacemacs-configuration-layers ()
     '((ruby :variables ruby-prettier-on-save t)))
#+END_SRC

Note that the =prettier= binary must be available in the project's
=node_modules/.bin/= or on =exec-path=.

* Key bindings
** Ruby (enh-ruby-mode, robe, inf-ruby, ruby-tools)

| Key binding | Description                                       |
|-------------+---------------------------------------------------|
| ~SPC m g g~ | go to definition (robe-jump)                      |
| ~SPC m h h~ | show documentation for method at point (robe-doc) |
| ~SPC m s b~ | send buffer                                       |
| ~SPC m s B~ | send buffer and switch to REPL                    |
| ~SPC m s f~ | send function definition                          |
| ~SPC m s F~ | send function definition and switch to REPL       |
| ~SPC m s i~ | start REPL                                        |
| ~SPC m s l~ | send line                                         |
| ~SPC m s L~ | send line and switch to REPL                      |
| ~SPC m s r~ | send region                                       |
| ~SPC m s R~ | send region and switch to REPL                    |
| ~SPC m s s~ | switch to REPL                                    |
| ~SPC m x '​~ | Change symbol or ="= string to ='=                |
| ~SPC m x "​~ | Change symbol or ='= string to ="=                |
| ~SPC m x :~ | Change string to symbol                           |
| ~SPC m x h~ | toggle hash syntax in active region               |
| ~SPC m = =~ | format buffer using prettier                      |
| ~%~         | [[https://github.com/redguardtoo/evil-matchit][evil-matchit]] jumps between blocks                 |

** Debugger
Using the =dap= layer you'll get access to all the DAP key bindings, see the
complete list of key bindings on the [[https://github.com/syl20bnr/spacemacs/tree/develop/layers/%2Btools/dap#key-bindings][dap layer description]].

** Bundler

| Key binding | Description        |
|-------------+--------------------|
| ~SPC m b c~ | run bundle check   |
| ~SPC m b i~ | run bundle install |
| ~SPC m b s~ | run bundle console |
| ~SPC m b u~ | run bundle update  |
| ~SPC m b x~ | run bundle exec    |
| ~SPC m b o~ | run bundle open    |

** RuboCop

| Key binding   | Description                                          |
|---------------+------------------------------------------------------|
| ~SPC m = r~   | Format the current buffer using RuboCop              |
| ~SPC m R r f~ | Runs RuboCop on the currently visited file           |
| ~SPC m R r F~ | Runs auto-correct on the currently visited file      |
| ~SPC m R r d~ | Prompts from a directory on which to run RuboCop     |
| ~SPC m R r D~ | Prompts for a directory on which to run auto-correct |
| ~SPC m R r p~ | Runs RuboCop on the entire project                   |
| ~SPC m R r P~ | Runs auto-correct on the project                     |

** Tests
*** RSpec-mode
When =ruby-test-runner= equals =rspec=.

| Key binding   | Description                                            |
|---------------+--------------------------------------------------------|
| ~SPC m t a~   | run all specs                                          |
| ~SPC m t b~   | run current spec file                                  |
| ~SPC m t c~   | run the current spec file and subsequent ones          |
| ~SPC m t d~   | run tests in a directory                               |
| ~SPC m t e~   | mark example as pending                                |
| ~SPC m t f~   | run method                                             |
| ~SPC m t l~   | run last failed spec                                   |
| ~SPC m t m~   | run specs related to the current buffer                |
| ~SPC m t r~   | re-run last spec                                       |
| ~SPC m t t~   | run spec at pointer                                    |
| ~SPC m t TAB~ | toggle between spec's and target's buffer              |
| ~SPC m t ~~   | toggle between spec's and target's buffer find example |

*** Ruby-test-mode
When =ruby-test-runner= equals =ruby-test=.

| Key binding | Description         |
|-------------+---------------------|
| ~SPC m t b~ | run test file       |
| ~SPC m t t~ | run test at pointer |

*** minitest-mode
When =ruby-test-runner= equals =minitest=.

| Key binding | Description               |
|-------------+---------------------------|
| ~SPC m t a~ | run all tests             |
| ~SPC m t b~ | run current file          |
| ~SPC m t r~ | repeat last test command  |
| ~SPC m t s~ | run test for current file |

** Toggles

| Key binding | Description                                          |
|-------------+------------------------------------------------------|
| ~SPC m T '~ | Toggle quotes of current string (only built-in mode) |
| ~SPC m T {~ | Toggle style of current block (only built-in mode)   |

** Rake

| Key binding | Description                     |
|-------------+---------------------------------|
| ~SPC m k k~ | Runs rake                       |
| ~SPC m k r~ | Re-runs the last rake task      |
| ~SPC m k R~ | Regenerates the rake cache      |
| ~SPC m k f~ | Finds definition of a rake task |

** Refactor

| Key binding   | Description            |
|---------------+------------------------|
| ~SPC m r e m~ | Extract to method      |
| ~SPC m r e v~ | Extract local variable |
| ~SPC m r e c~ | Extract constant       |
| ~SPC m r e l~ | Extract to let (rspec) |

** Seeing is believing

| Key binding   | Description                      |
|---------------+----------------------------------|
| ~<SPC> m @ @~ | Run seeing is believing          |
| ~<SPC> m @ c~ | Clear seeing is believing output |

* Configuration
** Layer options

| Variable                           | Default value | Description                                                                                  |
|------------------------------------+---------------+----------------------------------------------------------------------------------------------|
| =ruby-enable-enh-ruby-mode=        | =nil=         | If non-nil, use =enh-ruby-mode= package instead of the built-in Ruby Mode.                   |
| =ruby-version-manager=             | =nil=         | If non nil, defines the Ruby version manager.Possible values are =rbenv=, =rvm= or =chruby=. |
| =ruby-test-runner=                 | =ruby-test=   | Test runner to use. Possible values are =ruby-test=, =minitest= or =rspec=.                  |
| =ruby-highlight-debugger-keywords= | =t=           | If non-nil, enable highlight for debugger keywords.                                          |
| =ruby-backend=                     | =robe=        | Defines the backend for IDE feature. Possible values are =robe= or =lsp=.                    |

** Disabling the automatic insertion of encoding comment
Note that =ruby-mode= and =enh-ruby-mode= will automatically insert the encoding comment ~# coding: utf-8~ at the top of a =`.rb= file, if it contains UTF-8 characters. This might not be desired in Ruby 2.0+, since UTF-8 has become the default encoding. In fact, this will trigger [[https://www.rubydoc.info/github/bbatsov/RuboCop/RuboCop/Cop/Style/Encoding][an error]] with Robocop.

[[https://stackoverflow.com/questions/6453955/how-do-i-prevent-emacs-from-adding-coding-information-in-the-first-line][The fix]] is to set the variable =ruby-insert-encoding-magic-comment= (=ruby-mode=) or =enh-ruby-add-encoding-comment-on-save= (=enh-ruby-mode=) to =nil=, e.g.

#+BEGIN_SRC emacs-lisp
  (defun dotspacemacs-configuration-layers ()
     '((ruby :variables ruby-insert-encoding-magic-comment nil)))
#+END_SRC
