340 lines
13 KiB
Org Mode
340 lines
13 KiB
Org Mode
#+TITLE: Scala layer
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#+TAGS: general|layer|multi-paradigm|programming
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[[file:img/scala.png]] with [[file:img/ensime.png]]
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* Table of Contents :TOC_5_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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- [[#backends][Backends]]
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- [[#ensime][Ensime]]
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- [[#installation-when-using-sbt][Installation when using SBT]]
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- [[#installation-when-using-gradle][Installation when using Gradle]]
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- [[#configuration][Configuration]]
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- [[#usage][Usage]]
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- [[#metals][Metals]]
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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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- [[#ensime-1][Ensime]]
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- [[#search][Search]]
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- [[#ensime-search-mode][Ensime Search Mode]]
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- [[#sbt][sbt]]
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- [[#typecheck][Typecheck]]
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- [[#debug][Debug]]
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- [[#errors][Errors]]
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- [[#goto][Goto]]
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- [[#print-and-yank-types][Print and yank types]]
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- [[#documentation-inspect][Documentation, Inspect]]
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- [[#server][Server]]
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- [[#refactoring][Refactoring]]
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- [[#tests][Tests]]
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- [[#repl][REPL]]
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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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- Support for language backend. Either using [[https://ensime.github.io/][ENSIME]] or [[https://scalameta.org/metals/][Metals]]
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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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* 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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* Backends
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The currently supported language backends are:
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- scala-ensime (default)
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- scala-metals
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To set your choice of backend, configure the layer variable =scala-backend=.
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#+BEGIN_SRC emacs-lisp
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(setq-default dotspacemacs-configuration-layers
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'((scala :variables scala-backend 'scala-ensime))) ;or 'scala-metals
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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://web.archive.org/web/20190427005241/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 when using SBT
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Find it with your favourite package manager, eg:
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#+BEGIN_SRC shell
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nix-env --install sbt
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#+END_SRC
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or refer to [[http://www.scala-sbt.org/download.html][the sbt installation instructions]].
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*** Installation when using Gradle
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Refer to the [[https://web.archive.org/web/20190324005432/http://ensime.github.io/build_tools/gradle/][Ensime installation instructions]] to install the =ensime-gradle=
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plugin.
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*** Configuration
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Follow [[https://web.archive.org/web/20190417132406/http://ensime.github.io/build_tools/sbt/][the ENSIME configuration instructions]]. Spacemacs uses
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the development version of Ensime so follow the appropriate steps.
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To use the build functions under ~SPC m b~ you need to use version =0.13.5= or
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newer of =sbt=, and specify that in your project's =project/build.properties=.
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For example,
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#+BEGIN_SRC scala
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sbt.version=0.13.11
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#+END_SRC
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*** Usage
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~SPC SPC spacemacs/ensime-gen-and-restart~ or ~SPC m D r~ generates a new config
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for a project and starts the server. Afterwards ~SPC SPC ensime~ or ~SPC m D s~
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will suffice do the trick.
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** Metals
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Currently, you must manually install the metals server. It is possible to do so
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via coursier; the latest version can be built using the following commands,
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where =0.7.6= can be replaced with the current version of [[https://github.com/scalameta/metals/][Metals]]:
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#+BEGIN_SRC bash
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./coursier bootstrap \
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--java-opt -Xss4m \
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--java-opt -Xms100m \
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--java-opt -Dmetals.client=emacs \
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org.scalameta:metals_2.12:0.7.6 \
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-r bintray:scalacenter/releases \
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-r sonatype:snapshots \
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-o /usr/local/bin/metals-emacs -f
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#+END_SRC
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You will then have the common LSP key bindings; see
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[[https://github.com/syl20bnr/spacemacs/tree/develop/layers/%2Btools/lsp#key-bindings][LSP#key-bindings]] for more details.
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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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- macOS 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 the backend 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-backend t)))
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#+END_SRC
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* Key bindings
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** Ensime
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*** Search
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| Key binding | Description |
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|-------------+-----------------------------------------------------|
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| ~SPC m /~ | incremental search using =ensime-scalex= major mode |
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| ~SPC m ?~ | incremental search in all live buffers |
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*** Ensime Search Mode
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| Key binding | Description |
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|-------------+-------------------------------------------------------------------|
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| ~C-j~ | Move to next match |
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| ~C-k~ | Move to previous match |
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| ~C-i~ | Insert at point import of current result |
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| ~RET~ | Jump to the target of the currently selected ensime-search-result |
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| ~C-q~ | Quit ensime search |
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*** sbt
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| Key binding | Description |
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|-------------+---------------------|
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| ~SPC m b .~ | sbt transient state |
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| ~SPC m b b~ | sbt command |
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| ~SPC m b c~ | compile |
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| ~SPC m b C~ | clean command |
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| ~SPC m b i~ | switch to sbt shell |
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| ~SPC m b p~ | package command |
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| ~SPC m b r~ | run command |
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*** Typecheck
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| Key binding | Description |
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|-------------+-----------------------------|
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| ~SPC m c t~ | type check the current file |
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*** Debug
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| Key binding | Description |
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|-------------+-----------------------------|
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| ~SPC m d A~ | Attach to a remote debugger |
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| ~SPC m d b~ | set breakpoint |
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| ~SPC m d B~ | clear breakpoint |
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| ~SPC m d C~ | clear all breakpoints |
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| ~SPC m d c~ | continue |
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| ~SPC m d i~ | inspect value at point |
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| ~SPC m d n~ | next |
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| ~SPC m d o~ | step out |
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| ~SPC m d q~ | quit |
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| ~SPC m d r~ | run |
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| ~SPC m d s~ | step |
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| ~SPC m d t~ | backtrace |
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*Note:* These key bindings need a transient-state, PR welcome :-)
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*** Errors
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| Key binding | Description |
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|-------------+----------------------------------------------------|
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| ~SPC m e e~ | print error at point |
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| ~SPC m e s~ | switch to buffer containing the stack trace parser |
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*** Goto
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| Key binding | Description |
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|-------------+------------------|
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| ~SPC m g g~ | go to definition |
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*** Print and yank types
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|-------------+--------------------------------|
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| ~SPC m h T~ | print full type name at point |
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| ~SPC m h t~ | print short type name at point |
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| ~SPC m y T~ | yank full type name at point |
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| ~SPC m y t~ | yank short type name at point |
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*** Documentation, Inspect
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| Key binding | Description |
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|-------------+----------------------------------------|
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| ~SPC m h h~ | show documentation for symbol at point |
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| ~SPC m h u~ | show uses for symbol at point |
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*** Server
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| Key binding | Description |
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|-------------+--------------------------------------------------------|
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| ~SPC m D f~ | reload open files |
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| ~SPC m D r~ | regenerate the =.ensime= and restart the ensime server |
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| ~SPC m D s~ | start ensime server |
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*** Refactoring
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| Key binding | Description |
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|-------------+----------------------------------------------------------------------|
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| ~SPC m r a~ | add type annotation |
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| ~SPC m r d~ | get rid of an intermediate variable (=ensime-refactor-inline-local=) |
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| ~SPC m r D~ | get rid of an intermediate variable (=ensime-undo-peek=) |
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| ~SPC m r i~ | organize imports |
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| ~SPC m r m~ | extract a range of code into a method |
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| ~SPC m r r~ | rename a symbol project wide |
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| ~SPC m r t~ | import type at point |
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| ~SPC m r v~ | extract a range of code into a variable |
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| ~SPC m z~ | expand/contract region |
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*** Tests
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| Key binding | Description |
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|-------------+--------------------------|
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| ~SPC m t a~ | test command (sbt) |
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| ~SPC m t r~ | test quick command (sbt) |
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| ~SPC m t t~ | test only (sbt) |
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*** REPL
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| Key binding | Description |
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|-------------+---------------------------------------------------------------------|
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| ~SPC m s a~ | ask for a file to be loaded in the REPL |
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| ~SPC m s b~ | send buffer to the REPL |
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| ~SPC m s B~ | send buffer to the REPL and focus the REPL buffer in =insert state= |
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| ~SPC m s i~ | start or switch to the REPL inferior process |
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| ~SPC m s r~ | send region to the REPL |
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| ~SPC m s R~ | send region to the REPL and focus the REPL buffer in =insert state= |
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