#+TITLE: Go
#+AUTHOR: Christopher James Hayward
#+EMAIL: chris@chrishayward.xyz

#+PROPERTY: header-args:emacs-lisp :tangle go.el :comments org
#+PROPERTY: header-args:shell      :tangle no
#+PROPERTY: header-args            :results silent :eval no-export :comments org

#+OPTIONS: num:nil toc:nil todo:nil tasks:nil tags:nil
#+OPTIONS: skip:nil author:nil email:nil creator:nil timestamp:nil

Go is an open source programming language that makes it easy to build simple, reliable, and efficient software[fn:1]

* Setup

Install ~golang~[fn:1] on your system, and configure your environment prior to loading this module.

#+begin_src shell
RUN apt install -y golang
#+end_src

** Language server

Get started by installing the ~gopls~[fn:2] language server.

#+begin_src shell
GO111MODULE=on go get golang.org/x/tools/gopls@latest
#+end_src

** Setup the environment

Make some modifications to the environment. Set the =$GOPATH= variable prior to loading, allowing modification of the default value. Include the =bin= subdirectory of the =$GOPATH= in the =$PATH= variable, adding compiled golang applications to the system path.

#+begin_src emacs-lisp
(setenv "GOPATH" (concat (getenv "HOME") "/.go/"))
(setenv "PATH" (concat (getenv "GOPATH") "bin:" (getenv "PATH")))
#+end_src

* Config

Use the ~go-mode~[fn:3] package for integration with ~lsp-mode~, manually setting the path to ~gopls~[fn:2] before loading.

#+begin_src emacs-lisp
(use-package go-mode
  :hook (go-mode . lsp)
  :custom (lsp-go-gopls-server-path "~/.go/bin/gopls"))
#+end_src

** Before save hooks

Apply some custom behaviour when saving ~golang~[fn:1] buffers. Format and organize the imports before saving.

#+begin_src emacs-lisp
(defun dotfiles/go-hook ()
  (add-hook 'before-save-hook #'lsp-format-buffer t t)
  (add-hook 'before-save-hook #'lsp-organize-imports t t))

(add-hook 'go-mode-hook #'dotfiles/go-hook)
#+end_src

** Babel structure templates

Configure the ~babel~ engine to support ~golang~[fn:1] source blocks.

#+begin_src emacs-lisp
(add-to-list 'org-structure-template-alist '("go" . "src go"))
#+end_src

* Footnotes

[fn:1] https://golang.org

[fn:2] https://pkg.go.dev/golang.org/x/tools/gopls

[fn:3] https://emacswiki.org/emacs/GoMode