When a window is split, given that Vi/Vim splits are not stored in a tree structure, the "direction of the split" is basically "the window in which the cursor is placed after the command".
Update 2018-05-01: @mass clarified that splits are stored in a tree structure and that the direction actually refers to the direction of the "split bar". Thanks!
I however, think of my splits as a, in some way, spatial history of my editing session where time flows from left to right (as in a web browser) and from up to down (like when scrolling a text document)*.
When I split a window, it is usually because I want to reference something based on my current file, and would need to navigate this file before continuing with my work. I think of opening a buffer in a new window is a event that adds to the session history.
Why are Vi's and Vim's defaults left (
:vsplit) and above (
:split)? Was the decision motivated by technical, UI/workflow, or legacy reasons? Or something completely different? I noticed that the default in Emacs is to split down (
C-x 2 is
split-window-below) and right (
C-x 3 is
If you know the history behind the defaults, I would be happy if you could share the answer! If you prefer the defaults, please comment on why!
* also reading most current European written languages