   ;(add-hook 'text-mode-hook 'turn-on-fci-mode)
   ;(add-hook 'org-mode-hook  'turn-off-fci-mode 'append)
   ;;
+  ;; ESS: Turn off the automatic replacement of `_' by `<-'
+  (add-hook 'ess-mode-hook (lambda () (ess-toggle-underscore nil)))
+  ;;
   ;; mu4e: https://github.com/djcb/mu
   (push "~/.spacemacs.d/config" load-path)
   (require 'aly-mu4e-config nil t)

   ;; For now available distributions are `spacemacs-base' or `spacemacs'.
   dotspacemacs-distribution 'spacemacs
   ;; List of additional paths where to look for configuration layers.
   ;; Paths must have a trailing slash (i.e. `~/.mycontribs/').
   dotspacemacs-configuration-layer-path '("~/.spacemacs.d/layers/")
   ;; List of configuration layers to load.
   ;; If it is the symbol `all' instead of a list then all discovered

     shell-scripts
     spell-checking
     syntax-checking
     (version-control :variables
                      version-control-diff-tool 'diff-hl
                      version-control-global-margin t)
     xkcd
     )
   ;; List of additional packages that will be installed without being
   ;; wrapped in a layer.  If you need some configuration for these
