spacemacs/contrib/lang/scala/README.md

Scala contribution layer for Spacemacs

Table of Contents

• Scala contribution layer for Spacemacs
  • Description
  • Layer Installation
  • Ensime
    • Installation
    • Usage
  • Scalastyle
  • Key bindings
    • Ensime key bindings
      • Search
      • sbt
      • Typecheck
      • Debug
      • Errors
      • Goto
      • Documentation, Inspect
      • Server
      • Refactoring
      • Tests
      • REPL

Description

This layer adds support for the Scala language using the excellent ENSIME client/server.

Layer Installation

Add this contribution to your ~/.spacemacs.

(setq-default dotspacemacs-configuration-layers '(scala)
  "List of contribution to load."
)

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

1. Configure the ENSIME sbt plugin by adding the following to ~/.sbt/0.13/plugins/plugins.sbt:

   resolvers += Resolver.sonatypeRepo("snapshots")
   
   addSbtPlugin("org.ensime" % "ensime-sbt" % "0.1.5-SNAPSHOT")
   

2. Run sbt at the shell to download and install the plugin.

See the ENSIME quickstart guide for further information.

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

Scalastyle provides style-checking and linting. The Emacs functionality is provided by Flycheck.

To use scalastyle,

1. Download the 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 flycheck documentation for up-to-date configuration instructions.

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 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 micro-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