Say I want to copy what f does. f takes an "argument" keystroke and moves the cursor there. How do I create such a mapping?
I want to have a functionality that would require me to have a character as an argument. I'm not looking for the exact, or even close, functionality of f
You're looking for getchar(). Since that usually returns a number, convert the result back to a String:
let char = nr2char(getchar())
This is not a full equivalent of what the built-in f does; for example, it doesn't handle digraphs (i.e. <C-K>xy combinations).
If you use this in a mapping, ensure that all keys from the mapping have been consumed, or wrap the getchar() around inputsave() / inputrestore().
y/+ the desired keystroke? :) (so create a map fory/) - it has the advantage that it works on multiple lines, can search for more than one char, but you have to hit Enter.:h getchar()in a function.yf+<a char>"to copy what f does" (so - mapyf)fdoesn't take arguments, it's a motion (see:h left-right-motions) that can be used with operators (see:h operator; in fact read the entire:h motion.txt, about everything there is very useful). So, what are you trying to do?