>>105884630
>as to not load useless shit (all the C and C++ crap) if I don't need it.
you can just use with-eval-after-load to eval the entire configuration of a specific mode only once that mode is loaded by emacs. like this:
(with-eval-after-load 'sly
(setq inferior-lisp-program "/usr/bin/sbcl"
sly-mrepl-history-file-name "~/.emacs.d/.sly-mrepl-history")
;; etc.
)