Eric M. wrote
The cursor should be thought to lie between two characters rather
than on a character. Because of this, inserting before and after is the
same. The cursor is >>represented by the node containing the line that
the
cursor is on, and the index of the character to the right of the
cursor.Actually, they are different. Both insert the character at the same
point in the text. The difference is the final position of the
cursor/caret. insert_after is not a normal editor operation though.
It is equivalent to typing right-to-left instead of left-to-right
(what insert_before does). Since insert_after isn’t a common
operation, and it can be done using insert_before followed by left, it
isn’t needed. The main reason I threw it in was symmetry.
Actually, I wouldn’t call it different. I prefer just to call “inserting
a character” adding a character at the position of the cursor. If you
want the cursor to end up at the right, I’d call that a second
operation.
(One could probably have an argument all day over whether the One True
Name for this is “insert_before” or “insert followed by cursor_right”
with no movement toward consensus.)