Code should be self-documented. And editor should have a good mechanism to help you understand the source code. Emacs does better in this angle than Vim by far.

Code should be self-documented. And editor should have a good mechanism to help you understand the source code. Emacs does better in this angle than Vim by far. You can find the documentation for every variable (describe-variable) and functions (describe-function) easily and jump to their source codes.