#+TITLE:   lang/scala
#+DATE:    October 14, 2020
#+SINCE:   v1.3
#+STARTUP: inlineimages

* Table of Contents :TOC_3:noexport:
- [[#description][Description]]
  - [[#module-flags][Module Flags]]
- [[#lsp-integration][=+lsp= Integration]]
  - [[#prerequisites][Prerequisites]]
    - [[#coursier][Coursier]]
    - [[#metals][Metals]]
  - [[#features][Features]]
  - [[#notes][Notes]]

* Description
This module adds [[https://www.scala-lang.org][scala]] and [[https://www.scala-sbt.org/][sbt]] support to Doom Emacs.

** Module Flags
+ =+lsp= Enables integration for the metals LSP server.


* =+lsp= Integration

** Prerequisites

*** Coursier
Note: Coursier is only required to install Metals. If system is running arch
linux this step can be safely skipped.

**** Ubuntu / Debian / Fedora
#+BEGIN_SRC sh
curl -fLo cs https://git.io/coursier-cli-linux &&
    chmod +x cs &&
    ./cs
#+END_SRC

**** MacOS
#+BEGIN_SRC sh
curl -fLo cs https://git.io/coursier-cli-macos &&
    chmod +x cs &&
    (xattr -d com.apple.quarantine cs || true) &&
    ./cs
#+END_SRC

**** Arch
#+BEGIN_SRC sh
yay -S coursier
#+END_SRC

*** Metals

**** Ubuntu / Debian / Fedora / MacOS
Note: Update following command to latest version of metals [[https://scalameta.org/metals/docs/editors/emacs.html][found here]].

#+begin_src sh
coursier bootstrap \
  --java-opt -Xss4m \
  --java-opt -Xms100m \
  --java-opt -Dmetals.client=emacs \
  org.scalameta:metals_2.12:0.9.4 \
  -r bintray:scalacenter/releases \
  -r sonatype:snapshots \
  -o /usr/local/bin/metals-emacs -f
#+end_src

**** Arch
#+BEGIN_SRC sh
yay -S metals
#+END_SRC

** Features
According to [[https://scalameta.org/metals/docs/editors/overview.html]] it adds

+ Goto Definition
+ Completions
+ Hover
+ Paremeter Hints
+ Find References
+ Run/Debug
+ Find Implementations
+ Rename Symbol
+ Code Actions
+ Document Symbols
+ Formatting
+ Folding
+ Organize Imports

** Notes

+ Projects are required to have scala version =2.11.12=, =2.12.8=, =2.13.0= or greater.
+ Latest version of sbt is recommended.
+ Running =M-x lsp-metals-doctor-run= helps diagnose problems.
+ Full reference here: https://scalameta.org/metals/docs/editors/emacs.html