How to create a LESS variable with a Plugin

I want to create a simple LESS plugin that create variables on a function call

I want to do this because i want to have a less variable dynamic on runtime (link of unanswered question on why i want to do that)

In short

i want to do this :

without having to do :

And just declare each variable once like :

And var() is the custom LESS plugin function i wanna make

What i tried

I tried to learn how to create plugin on lesscss.org, github.com, and on diverse site, but it's either just not enough, or really obscure on how to create variables

I also saw this blog post where he creates variables, but i tried every thing, and nothing worked

Finally

I just want some advices or code, and ideally an explanation on how tf it works

Thanks :)

The issue does not name a repository file, test, or implementation entry point. Start by reproducing the desired LESS input and output from the linked examples, then read the plugin and variable documentation in lesscss.org and the less/less.js repository; done would require a defined plugin approach and an accompanying example or test.