how to deduplicate packpath / runtimepath?

Question

Problem:

I noticed that my "&packpath" has some duplicates, I want to remove them.

What I have tried:

My viml knowledge is not very strong but I did manage to create a unique "List", but I am not sure how to turn that list back into the correct string without calling "!awk/!sed/!perl", I now think that perhaps there is a simpler "vim" way to do it? my example:

let newpackpath = string(uniq(split(&packpath, ',')))

Returns this string:

['/data/data/com.termux/files/home/conf/nvim', 
'/data/data/com.termux/files/home/data/nvim/site', 
'/data/data/com.termux/files/usr/share/nvim/runtime', 
'/data/data/com.termux/files/usr/lib/nvim', 
'/data/data/com.termux/files/home/data/nvim/site/after', 
'/data/data/com.termux/files/home/conf/nvim/after']

To be correct, it should look like this instead:

/data/data/com.termux/files/home/conf/nvim,/data/data/com.termux/files/home/data/nvim/site,/data/data/com.termux/files/usr/share/nvim/runtime,/data/data/com.termux/files/usr/lib/nvim,/data/data/com.termux/files/home/data/nvim/site/after,/data/data/com.termux/files/home/conf/nvim/after

I'm now I'm out of my viml-depth! my only knowledge would be to use !awk/!perl/!sed somehow?!

can vim handle this itself???

either way....

How can I dedupe my "&packpath" or "&runtimepath"?

To those who can help, thank you!

Answer 1

packpath, the option

packpath is an option, which means it can be altered using the set command. The set command already does de-duplication for appending values. For example,

set packpath=a
set packpath+=dd
set packpath+=dd
set packpath+=dd
set packpath?

gives

 a,dd

It even adds/strips commas for you. It is not always possible, but if you can, use the set command.

Unfortunately, set only looks at new values added, and offers no way to fix an existing duplicate.

&packpath, the variable

vim offers a read/write variable "view" into this option using the & syntax. When using this you syntax, you don't get the de-duplication or comma addition. Thus,

let &packpath='a'
let &packpath+='b'
let &packpath+='b'
echo &packpath

gives

abb

your example

There are two issues here, first using uniq( only applies to sorted arrays, thus is not guaranteed to give you a unique array, and second string( does not join a string with commas.

let newpackpath = string(uniq(split(&packpath, ',')))

Instead,

let &packpath = join(uniq(sort(split(&packpath, ','))), ',')

or

let &packpath = &packpath->split(',')->sort()->uniq()->join(',')

are valid solutions, except that the order of packpath will be altered, which may or may not be what you want.