I have some colorschemes that I really like. I also find changing between them adds some freshness to my work. I've been changing manually for a while, but would love to automate this.
I'd like to put a line in my .vimrc that assigns a random colorscheme from a pre-defined allowlist. I googled around and didn't find obvious answers, and even some debate about whether there's even a random function in vimscript.
I don't know much vimscript, and though I've read the basics here and there over the years, I don't have a working knowledge of it because I rarely use it. So I thought I'd reach out to the community. I tried to do this myself after some reasearch, but the following code fails:
let my_colorschemes = ['torte', 'Dark2' , 'ubloh']
colorscheme my_colorschemes[rand() % (len(my_colorschemes) - 1 ) ]
Cannot find color scheme 'my_colorschemes[rand() % (len(my_colorschemes)+ 1 ) ]'
Can anyone help me get this right? There seems to be some fundamental concepts I'm missing in vimscript...
Thanks!
-------- UPDATE ---------
For posterity, after the correct answer below, the code that works for me is:
let my_colorschemes = ['torte', 'Dark2' , 'ubloh', 'znake']
execute 'colorscheme' my_colorschemes[rand() % (len(my_colorschemes) - 1 ) ]
I guess I was close, but there's no way I would have come up with what was wrong on my own.
Vim bits are explained in User Manual (:h user-manual). The relevant chapter 41 "Write a Vim script" (:h usr_41.txt), section 41.5 (:h 41.5).
To put it short, only few commands accept expressions, while others accept only literal arguments (btw. this is the reason one writes :colo torte and not :colo "torte"). Therefore to compose a command dynamically one needs both to build a string representation of a command and to re-evaluate it.
So it becomes :execute 'colo' my_colors[rand() % len(my_colors)]