spacemacs/layers/+lang/scala/README.org

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#+TITLE: Scala layer
#+HTML_HEAD_EXTRA: <link rel="stylesheet" type="text/css" href="../../../css/readtheorg.css" />
[[file:img/scala.png]] with [[file:img/ensime.png]]
* Table of Contents :TOC_4_org:noexport:
- [[Description][Description]]
- [[Layer Installation][Layer Installation]]
- [[Ensime][Ensime]]
- [[Installation][Installation]]
- [[Usage][Usage]]
- [[Scalastyle][Scalastyle]]
- [[Automatically show the type of the symbol under the cursor][Automatically show the type of the symbol under the cursor]]
- [[Automatically insert asterisk in multiline comments][Automatically insert asterisk in multiline comments]]
- [[Key bindings][Key bindings]]
- [[Ensime key bindings][Ensime key bindings]]
- [[Search][Search]]
- [[sbt][sbt]]
- [[Typecheck][Typecheck]]
- [[Debug][Debug]]
- [[Errors][Errors]]
- [[Goto][Goto]]
- [[Documentation, Inspect][Documentation, Inspect]]
- [[Server][Server]]
- [[Refactoring][Refactoring]]
- [[Tests][Tests]]
- [[REPL][REPL]]
* Description
This layer adds support for the Scala language using the excellent [[https://github.com/ensime][ENSIME]]
client/server.
* Layer Installation
To use this configuration layer, add it to your =~/.spacemacs=. You will need to
add =scala= to the existing =dotspacemacs-configuration-layers= list in this
file.
* Ensime
[[https://github.com/ensime][ENSIME]] provides IDE-like features, such as refactoring, incremental
compilation and project-wide type-checking.
ENSIME requires a configuration file at the root of each Scala project. It
provides an SBT plugin to generate these files.
** Installation
Configure the ENSIME sbt plugin by adding the following to
=~/.sbt/0.13/plugins/plugins.sbt=:
#+BEGIN_SRC scala
addSbtPlugin("org.ensime" % "ensime-sbt" % "0.2.3")
#+END_SRC
Please go to [[https://github.com/ensime/ensime-sbt][ensime-sbt Github Page]] to check the latest version of =ensime-sbt= plugin.
Please note your projects' =project/build.properties= need to use a version newer that =0.13.5= of sbt.
#+BEGIN_SRC scala
sbt.version=0.13.9
#+END_SRC
** Usage
1. Create a =.ensime= file at the root of your Scala project using =sbt
gen-ensime= at the shell.
2. Run =M-x ensime= within Emacs to start an ENSIME session.
Each Scala project uses a dedicated ENSIME session, so you only need to run =M-x
ensime= once per project. Any Scala files you create or visit within the project
will automatically use ENSIME for the remainder of your editing session.
* Scalastyle
[[http://flycheck.readthedocs.org/en/latest/guide/languages.html#el.flycheck-checker.scala-scalastyle][Scalastyle]] provides style-checking and linting. The Emacs functionality is
provided by Flycheck.
To use scalastyle,
1. Download the [[https://oss.sonatype.org/content/repositories/releases/org/scalastyle/scalastyle_2.11/0.6.0/][scalastyle jar]] and put it somewhere sensible
2. Customise the =flycheck-scalastyle-jar= variable and set it to the path of
the jar.
See the [[http://flycheck.readthedocs.org/en/latest/guide/languages.html#el.flycheck-checker.scala-scalastyle][flycheck documentation]] for up-to-date configuration instructions.
* Automatically show the type of the symbol under the cursor
To enable the feature =ensime-print-type-at-point= when cursor moves, set the variable =scala-enable-eldoc-mode= to =t=.
#+BEGIN_SRC emacs-lisp
(setq-default dotspacemacs-configuration-layers '(
(scala :variables scala-enable-eldoc-mode t)))
#+END_SRC
Enabling this option can cause slow editor performance.
* Automatically insert asterisk in multiline comments
To insert a leading asterisk in multiline comments automatically, set the variable =scala-auto-insert-asterisk-in-comments= to =t=.
#+BEGIN_SRC emacs-lisp
(setq-default dotspacemacs-configuration-layers '(
(scala :variables scala-auto-insert-asterisk-in-comments t)))
#+END_SRC
* Key bindings
** Ensime key bindings
*** Search
| Key Binding | Description |
|-------------+-----------------------------------------------------|
| ~SPC m /~ | incremental search using =ensime-scalex= major mode |
| ~SPC m ?~ | incremental search in all live buffers |
*** sbt
| Key Binding | Description |
|-------------+---------------------|
| ~SPC m b c~ | compile command |
| ~SPC m b C~ | clean command |
| ~SPC m b i~ | switch to sbt shell |
| ~SPC m b p~ | package command |
| ~SPC m b r~ | run command |
*** Typecheck
| Key Binding | Description |
|-------------+---------------------------------|
| ~SPC m c t~ | type check the current file |
| ~SPC m c T~ | type check all the open buffers |
*** Debug
| Key Binding | Description |
|-------------+-----------------------------|
| ~SPC m d A~ | Attach to a remote debugger |
| ~SPC m d b~ | set breakpoint |
| ~SPC m d B~ | clear breakpoint |
| ~SPC m d C~ | clear all breakpoints |
| ~SPC m d c~ | continue |
| ~SPC m d d~ | start a debug session |
| ~SPC m d i~ | inspect value at point |
| ~SPC m d l~ | list local variables |
| ~SPC m d n~ | next |
| ~SPC m d o~ | step out |
| ~SPC m d q~ | quit |
| ~SPC m d r~ | run |
| ~SPC m d s~ | step |
| ~SPC m d t~ | backtrace |
*Note:* These key bindings need a transient-state, PR welcome :-)
*** Errors
| Key Binding | Description |
|-------------+----------------------------------------------------|
| ~SPC m e e~ | print error at point |
| ~SPC m e l~ | show all errors and warnings |
| ~SPC m e s~ | switch to buffer containing the stack trace parser |
*** Goto
| Key Binding | Description |
|-------------+----------------------|
| ~SPC m g g~ | go to definition |
| ~SPC m g i~ | go to implementation |
| ~SPC m g t~ | go to test |
*** Documentation, Inspect
| Key Binding | Description |
|-------------+----------------------------------------|
| ~SPC m h h~ | show documentation for symbol at point |
| ~SPC m h u~ | show uses for symbol at point |
| ~SPC m h t~ | print type at point |
| ~SPC m i i~ | inspect type at point |
| ~SPC m i I~ | inspect type in other frame |
| ~SPC m i p~ | inspect project package |
*** Server
| Key Binding | Description |
|-------------+--------------------------------------------------------|
| ~SPC m n F~ | reload open files |
| ~SPC m n s~ | start ensime server |
| ~SPC m n S~ | regenerate the =.ensime= and restart the ensime server |
*** Refactoring
| Key Binding | Description |
|-------------+----------------------------------------------------------------------|
| ~SPC m r f~ | format source |
| ~SPC m r d~ | get rid of an intermediate variable (=ensime-refactor-inline-local=) |
| ~SPC m r D~ | get rid of an intermediate variable (=ensime-undo-peek=) |
| ~SPC m r i~ | organize imports |
| ~SPC m r m~ | extract a range of code into a method |
| ~SPC m r r~ | rename a symbol project wide |
| ~SPC m r t~ | import type at point |
| ~SPC m r v~ | extract a range of code into a variable |
| ~SPC m z~ | expand/contract region |
*** Tests
| Key Binding | Description |
|-------------+--------------------------|
| ~SPC m t a~ | test command (sbt) |
| ~SPC m t r~ | test quick command (sbt) |
| ~SPC m t t~ | test only (sbt) |
*** REPL
| Key Binding | Description |
|-------------+---------------------------------------------------------------------|
| ~SPC m s a~ | ask for a file to be loaded in the REPL |
| ~SPC m s b~ | send buffer to the REPL |
| ~SPC m s B~ | send buffer to the REPL and focus the REPL buffer in =insert state= |
| ~SPC m s i~ | start or switch to the REPL inferior process |
| ~SPC m s r~ | send region to the REPL |
| ~SPC m s R~ | send region to the REPL and focus the REPL buffer in =insert state= |