Underline text line with dashes in vim

Question

Is there a nice quick way to have a text line underlined with dashes (exact same length)? For purpose of rst documents (sub)*sections have to have single character underlings of the same length as previous. So section heading should look like

In this section main character dies -----------------------------------

My current approach is to look at the position of cursor (when I'm at the end of the line) and then: o{N}I- where {N} is the cursors position. I'd much rather have some nice macro to do it with custom character.

Answer 1

Copy the line with Y, paste it with p, and replace everything with - using Vr- (select the line, replace character by -).

So:

YpVr-

Note: This assumes you don't have the somewhat common Y -> y$ mapping. If you do, use yy instead of Y.

---

If you want a (crude) mapping to do this a bit faster, you could use something like:

:nnoremap <leader>u YpVr

then typing \u- (assuming you haven't changed the leader key) would underline a line with -.

Answer 2

I think you might like the extline plugin: https://github.com/drmikehenry/vim-extline

It was designed for to work with reStructuredText documents, and I've been using it for years (actually for more years than it's been available as a plugin, since I've been using Dr. Mike's configuration for quite some time now).

With it you can start the line by typing the character you want and typing Ctrl+L Ctrl+L. Or use one of the other available shortcuts:

The following mappings apply in Visual and Insert modes (but, notably, NOT in
Normal mode):

CTRL-L CTRL-L     Auto-line update
CTRL-L CTRL-H     Horizontal line update
CTRL-L CTRL-U     Change to underlined title
CTRL-L CTRL-O     Change to overlined title
CTRL-L CTRL-I     Change to underlined and overlined title

CTRL-L =          Force Section heading (level 1)
CTRL-L 1
CTRL-L -          Force Subsection heading (level 2)
CTRL-L 2
CTRL-L ^          Force Subsubsection heading (level 3)
CTRL-L 3
CTRL-L "          Force Paragraph heading (level 4)
CTRL-L 4
CTRL-L '          Force level 5 heading (level 5)
CTRL-L 5