Limiting the output of `reg` to only those matching a string

Question

Imagine a situation, where you remember, that you want to re-use something you have deleted a while ago. Most likely the thing that has been deleted is stored in one of the numeric registers. Usually it's not a big deal to just type :reg and start looking through the list. However, I often find myself in a situation, where many of the registers are similar, and finding the register I want to use is difficult. Or it might be the case that I have yanked something to a permanent register but just can't remember which one it was. In these kind of situations I would find it quite useful to be able to search the registers: if I remember that the line I want to re-use contains the word function I would like be able get a list of just the registers containing that word.

Is this possible? Perhaps with a plugin I'm not aware of?

Answer 1

First, we need the list of all registers. It can be generated with:

let regs=split('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789/-"', '\zs')

Then, it can be filtered to keep only the register names that contain a given pattern

let pattern = 'function'
echo filter(copy(regs), 'match(getreg(v:val), pattern) >= 0')

This can be transformed to produce a result similar to :register

echo join(map(filter(copy(regs), 'match(getreg(v:val), pattern) >= 0'), '"~".v:val."   ".strtrans(getreg(v:val))[:&co-1]'), "\n")

(Unfortunately , it requires more work than just [:&co] to limit the number of characters printed on each line)

as a command, it becomes:

command! -nargs=1 Registers  
    \ echo join(map(
    \   filter(
    \      split('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789/-"', '\zs'), 
    \      'match(getreg(v:val), <q-args>) >= 0'), 
    \   '"~".v:val."   ".strtrans(getreg(v:val))[:&co-1]'), "\n")

Answer 2

The denite plugin can give you a list off all registers and you can type keys to narrow it down.

The relevant command is Denite register.

It has many more lists/sources where you can select one and expect a reasonable action to be taken (buffers, files, commands, colorschemes, help topics, ...)