139 lines
5.1 KiB
Org Mode
139 lines
5.1 KiB
Org Mode
#+TITLE: Scala layer
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[[file:img/scala.png]] with [[file:img/ensime.png]]
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* Table of Contents :TOC_4_gh:noexport:
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- [[#description][Description]]
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- [[#features][Features:]]
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- [[#layer-installation][Layer Installation]]
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- [[#ensime][Ensime]]
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- [[#scalastyle][Scalastyle]]
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- [[#use-java-doc-style][Use Java doc-style]]
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- [[#automatically-show-the-type-of-the-symbol-under-the-cursor][Automatically show the type of the symbol under the cursor]]
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- [[#automatically-insert-asterisk-in-multiline-comments][Automatically insert asterisk in multiline comments]]
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- [[#automatically-replace-arrows-with-unicode-ones][Automatically replace arrows with unicode ones]]
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- [[#auto-start][Auto-start]]
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- [[#key-bindings][Key bindings]]
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* Description
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This layer adds support for the Scala language to Spacemacs.
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** Features:
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- Syntax highlighting
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- Auto-completion
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- Syntax-checking
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- Refactoring
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- Incremental compilation
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- Scala Repl
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- Style linting
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- Eldoc integration
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- Test execution directly from emacs
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- Automatic replacement of ASCII arrows with unicode ones
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- Automatic starting/stopping of [[https://ensime.github.io/][ENSIME]] IDE server
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* Layer Installation
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To use this configuration layer, add it to your =~/.spacemacs=. You will need to
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add =scala= to the existing =dotspacemacs-configuration-layers= list in this
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file.
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Then, you should modify your =~/.spacemacs= to use the recommended Ensime
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version (Stable). Please add the following lines to =dotspacemacs/user-init=:
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#+BEGIN_SRC emacs-lisp
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(add-to-list 'configuration-layer-elpa-archives '("melpa-stable" . "stable.melpa.org/packages/"))
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(add-to-list 'package-pinned-packages '(ensime . "melpa-stable"))
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#+END_SRC
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* Ensime
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[[https://ensime.github.io/][ENSIME]] provides IDE-like features, such as refactoring, incremental compilation
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and project-wide type-checking.
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ENSIME requires a configuration file at the root of each Scala project. It
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provides an SBT plugin, a gradle plugin and others (see [[https://ensime.github.io/build_tools/][ensime.org]] for a full
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list) to generate these files.
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Installation instructions and usage can be found in the =Java= layer
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[[https://github.com/syl20bnr/spacemacs/tree/develop/layers/%2Blang/java/README.org#ensime][README.org]].
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* Scalastyle
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[[http://www.scalastyle.org/][Scalastyle]] provides style-checking and linting. The Emacs functionality is
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provided by Flycheck.
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To use scalastyle, it must be present as an executable in your =PATH=.
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- OSX users: =brew install scalastyle=
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- Linux, please see [[http://www.scalastyle.org/command-line.html]]
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To test if =scalastyle= executable is in your path, run =scalastyle= in a new
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terminal, it should output something like:
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#+BEGIN_SRC bash
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$ scalastyle
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scalastyle 0.8.0
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Usage: scalastyle [options] <source directory>
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...
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#+END_SRC
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Finally, enable the =syntax-checking= layer and set the =flycheck-scalastylerc=
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variable to a valid location.
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#+BEGIN_SRC emacs-lisp
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(setq-default flycheck-scalastylerc "/usr/local/etc/scalastyle_config.xml")
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#+END_SRC
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See the [[http://www.flycheck.org/en/latest/languages.html?highlight=scala#syntax-checker-scala-scalastyle][flycheck documentation]] and [[http://www.scalastyle.org/configuration.html][scalastyle configuration]] for up-to-date
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configuration instructions.
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** Use Java doc-style
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To enable =java-doc-style=, set the variable =scala-indent:use-javadoc-style= to
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=t=
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#+BEGIN_SRC emacs-lisp
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(setq-default dotspacemacs-configuration-layers '(
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(scala :variables scala-indent:use-javadoc-style t)))
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#+END_SRC
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* Automatically show the type of the symbol under the cursor
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To enable the feature =ensime-type-at-point= when cursor moves, set the
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variable =scala-enable-eldoc= to =t=.
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#+BEGIN_SRC emacs-lisp
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(setq-default dotspacemacs-configuration-layers '(
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(scala :variables scala-enable-eldoc t)))
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#+END_SRC
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Enabling this option can cause slow editor performance.
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* Automatically insert asterisk in multiline comments
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To insert a leading asterisk in multiline comments automatically, set the
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variable =scala-auto-insert-asterisk-in-comments= to =t=.
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#+BEGIN_SRC emacs-lisp
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(setq-default dotspacemacs-configuration-layers '(
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(scala :variables scala-auto-insert-asterisk-in-comments t)))
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#+END_SRC
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* Automatically replace arrows with unicode ones
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To replace ~=>~, =->= and =<-= with unicode arrows =⇒=, =→= and =←=, set the
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variable =scala-use-unicode-arrows= to =t=.
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If in some occasions you don’t want the arrows replaced (for example when
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defining compound operators like ~=>>~), you can always undo the change and get
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the ascii arrows back.
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#+BEGIN_SRC emacs-lisp
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(setq-default dotspacemacs-configuration-layers '(
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(scala :variables scala-use-unicode-arrows t)))
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#+END_SRC
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* Auto-start
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If you prefer to have Ensime start when you load a scala file, you can enable it
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with
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#+BEGIN_SRC emacs-lisp
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(setq-default dotspacemacs-configuration-layers '(
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(scala :variables scala-auto-start-ensime t)))
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#+END_SRC
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* Key bindings
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All ensime key bindings are listed in the =java= layer [[https://github.com/syl20bnr/spacemacs/tree/develop/layers/%2Blang/java/README.org#ensime-key-bindings][README.org]].
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