Vim-Operator-Rot-N

This Vim plugin provides an operator for Rot-N encryption/decryption.

... Why?

Do your friends send you Rot-N encrypted messages because they think it's funny, leaving you agonized over a mess of jumbled letters, frantically searching for that ad-free website with a military-grade-Rot-N-decryption service?
That sadness ends today!
Dwell in serenity as you open their obfuscated message in Vim, press g?ip........ and laugh silently as soon as the brute-force decrypted message appears. Afterwards, spend 2 minutes writing an answer message, and 15+ minutes to design a macro that Rot-N encrypts every word of your reply with a different N.

Features

Vim has a built-in ROT13 operator g?, see :help rot13. In contrast, this plugin provides a more general Rot-N operator with special count handling:

10g?2aw does a ROT-10 encryption on the next 2 words.
Repeatable: 5. does a ROT-5 encryption on the same 2 word.
With g?{motion}, a customizable default value is used for N.

Guide

Mappings

No mappings are created automatically. Add your own. I use:

nmap g? <Plug>(operator-rot-n)
nmap g?? <Plug>(operator-rot-n-linewise)
nmap g?g? <Plug>(operator-rot-n-linewise)
xmap g? <Plug>(operator-rot-n-visual)

Usage

Assuming my suggested mappings, you can use this operator with [count]g?{motion}.
The [count] before the operator determines the N for the Rot-N transformation.
The {motion} can also take a count as usual, but that one does not influence the already chosen N.
If no [count] is supplied, the value from g:OperatorRotN_default_count is used (default 1).
In visual mode, the [count] is interpreted analogously.

Repeat

You can repeat the transformation on the same text with ..
Using [count]. executes a Rot-[count] transformation on the same text as before.
If . is used without a [count], the used N depends on the value of g:OperatorRotN_reuse_count_on_repeat:
If enabled, the [count] from the last invocation is reused.
If disabled, g:OperatorRotN_default_count is used.

Behaviour on linewise motions.

If g:OperatorRotN_linewise_motions_select_whole_lines is enabled (default 1), then linewise operators such as j select whole lines.
Otherwise, the '[ and '] marks determine the selection. There is usually no good reason to change this setting.

Requirements

Requires vim-repeat for clever count handling, but also works without, just less cool.
Developed and tested on Neovim 0.4.3. When I tested it on Vim 8.2, it worked, too.

Implementation

100% highly-efficient Vimscript, especially optimized for double ROT13 encryption.

Related Plugins

I didn't find any. This probably means that no one else's friends send them ROT-N encrypted messages for fun. But you can install this plugin today and tqsfbe the word!

License

The Vim licence applies. See :help license.

bagohart/vim-operator-rot-n