Troubleshooting issues with custom layer key bindings

[dathinaios]

I am trying to incorporate a package for the SuperCollider programming language as a layer into spacemacs. It is all working well but I dont seem to be able to define custom key bindings under , or SPC m.

Click here to see the code of the underlying sclang package (at local/sclang). It defines quite a few bindings starting with C-c in sclang-mode.el. These are working fine.

In the commented out code bellow you can see all the things I tried.

(setq supercollider-packages '((sclang :location local)))

(defun supercollider/init-sclang ()
  (use-package sclang
    :config
    (setenv "PATH" (concat (getenv "PATH") ":/Applications/SuperCollider.app/Contents/Resources"))
    (setq exec-path (append exec-path '("/Applications/SuperCollider.app/Contents/Resources" )))
    ;; (define-key key-translation-map (kbd ",s") (kbd "\C-c\C-c"))
    ;; (define-key sclang-mode-map (kbd ",s")   'sclang-eval-line) 
    ;; (evil-leader/set-key-for-mode 'sclang-mode "s" 'sclang-eval-line)
    ;; (spacemacs/set-leader-keys-for-major-mode 'sclang-mode "l" 'sclang-eval-line)
    ))

[dathinaios]

I finally solved this with help from the Spacemacs Gitter channel.

There was a deeper issue with the definition of the major mode itself. More specifically (quoting NJBS's answer on Gitter):

Your issue is that sclang-mode doesn't define itself properly by
deriving from fundamental-mode, but rather it defines itself using
defun. You can change sclang-mode.el's mode definition to the
following and your bindings should stick:

(define-derived-mode sclang-mode fundamental-mode "sclang-mode"
  "Major mode for editing SuperCollider language code.
\\{sclang-mode-map}
"
  (sclang-mode-set-local-variables)
  (sclang-set-font-lock-keywords)
  (sclang-init-document)
  (sclang-make-document))

Link to the commit where I fixed the issue.