Question

I remember seeing this functionnality while editing elisp code, using a config cloned from someone on github.
However, I can’t find it anymore, and would especially like to know if this feature is possible using other major modes (especially javascript, ruby, and maybe nXhtml).

Answer 1

Block scope? Do you mean highlight the current function? If so, your function is mark-defun usually bound to C-M-h.

Specific language modes (like the python-mode) have extra functions to mark the current class/block etc.