essentials/dotfiles/emacs.d/package.el

(require 'cl)

(defvar my-packages '(ag 
                      ;; Completion Frameworks
                      company
                      company-irony
                      company-emacs-eclim

                      ;; We don't need the `jedi` package
                      ;; since we are using company. If we
                      ;; include both we get an annoying
                      ;; *Python Completions* buffer that
                      ;; isn't useful to us.
                      company-jedi

                      eclim
                      irony
                      counsel
                      swiper
                      ;;;;;;;;;;;;;;;;;;;;;;;;

                      ;; Programming modes
                      cc-mode
                      python-mode
                      yaml-mode
                      markdown-mode
                      gitignore-mode
                      feature-mode
                      gradle-mode
                      protobuf-mode
                      meson-mode
                      paredit
                      magit
                      ;;;;;;;;;;;;;;;;;;;;

                      ;; Navigation
                      neotree
                      ;;;;;;;;;;;;;

                      ;; Cleanup
                      ws-butler
                      ;;;;;;;;;;

                      ;; Shell helpers
                      exec-path-from-shell
                      ;;;;;;;;;;;;;;;;;;;;

                      ;; Editing Utility
                      autopair
                      ;;;;;;;;;;;;;;;;;;
                      
                      ;; UI
                      fill-column-indicator
                      golden-ratio
                      linum-relative
                      powerline
                      rainbow-delimiters
                      zenburn-theme
                      wrap-region
                      expand-region
                      wrap-region
                      material-theme
                      ;;;;;

                      ;; Project Interaction/Search/Syntax
                      flycheck
                      flycheck-pos-tip
                      grizzl
                      smex
                      projectile
                      ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
                      
                    )
  "Packages to make sure are installed")

(defun my-packages-installed-p ()
  (loop for p in my-packages
        when (not (package-installed-p p)) do (return nil)
        finally (return t)))

(unless (my-packages-installed-p)
  ;; check for new packages (package versions)
  (package-refresh-contents)
  ;; install the missing packages
  (dolist (p my-packages)
    (when (not (package-installed-p p))
      (package-install p))))