#+TITLE: crystal layer

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

[[file:img/crystal.png]]

* Table of Contents                     :TOC_5_gh:noexport:
- [[#description][Description]]
  - [[#features][Features:]]
- [[#install][Install]]
  - [[#repl][REPL]]
  - [[#ameba][Ameba]]
  - [[#layer][Layer]]
- [[#key-bindings][Key bindings]]
  - [[#crystal-commands][Crystal commands]]
  - [[#repl-1][REPL]]
  - [[#ameba-1][Ameba]]

* Description
This layer provides support for the Crystal language.

** Features:
- =crystal tool format= on file save
- integration [[https://play.crystal-lang.org][play.crystal-lang.org]] using [[https://github.com/veelenga/play-crystal.el][play-crystal.el]]
- Linting with flycheck
- test runner (=crystal spec=)
- =crystal tool= integration
- Interactive REPL ([[https://github.com/brantou/inf-crystal.el][inf-crystal.el]] and [[https://github.com/crystal-community/icr][icr]])
- static code analysis using [[https://github.com/veelenga/ameba.el][ameba]]

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

** REPL
To be able to connect to [[https://github.com/brantou/inf-crystal.el][inf-crystal]], you need to make sure that [[https://github.com/crystal-community/icr][icr]] is
installed.

Installation instructions can be found on the main page of [[https://github.com/crystal-community/icr#installation][icr]].

Although not in the installation instruction it seems that on macOS you can
install it with Homebrew:

#+BEGIN_SRC sh
  brew install crystal-icr
#+END_SRC

** Ameba
To be able to use [[https://github.com/veelenga/ameba.el][ameba.el]], you need to make sure that [[https://github.com/veelenga/ameba][ameba]] is installed.

Installation instructions can be found on the main page of [[https://github.com/veelenga/ameba][ameba]].

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

* Key bindings
** Crystal commands

| Key binding | Description                                               |
|-------------+-----------------------------------------------------------|
| ~SPC m e b~ | play-crystal submit buffer                                |
| ~SPC m e e~ | play-crystal show code in a browser                       |
| ~SPC m e i~ | download play-crystal snippet                             |
| ~SPC m e r~ | play-crystal submit region                                |
| ~SPC m g G~ | jump to definition in other window                        |
| ~SPC m g a~ | jump to matching spec file or back from spec to code file |
| ~SPC m g g~ | jump to definition                                        |
| ~SPC m t b~ | run =crystal spec= for the current buffer                 |
| ~SPC m t p~ | run =crystal spec= for the current project                |
| ~SPC m u c~ | show context                                              |
| ~SPC m u e~ | show macro expansion                                      |
| ~SPC m u f~ | format the current buffer                                 |
| ~SPC m u i~ | show implementations for given call                       |
| ~SPC m x x~ | run =crystal run= for the current file                    |

** REPL
Start a inferior crystal REPL process with ~SPC m '​~ or ~SPC m s i~.
Send code to inferior process commands:

| Key binding | Description                                 |
|-------------+---------------------------------------------|
| ~SPC m '​~   | start inferior REPL process                 |
| ~SPC m s B~ | send buffer and switch to REPL              |
| ~SPC m s F~ | send function definition and switch to REPL |
| ~SPC m s R~ | send region and switch to REPL              |
| ~SPC m s b~ | send buffer                                 |
| ~SPC m s f~ | send function definition                    |
| ~SPC m s i~ | start inferior REPL process                 |
| ~SPC m s r~ | send region                                 |
| ~SPC m s s~ | switch to REPL                              |

** Ameba

| Key binding | Description                                    |
|-------------+------------------------------------------------|
| ~SPC m a d~ | Prompts from a directory on which to run Ameba |
| ~SPC m a f~ | Runs Ameba on the current visited file         |
| ~SPC m a p~ | Runs Ameba on the entire project               |