Or you can use parseutils:
import parseutils
const line = " ; abc "
const commentChars = {'#', ';'}
var res = ""
let pos = skipUntil(line, commentChars)
if pos != line.len:
let start = pos + 1
discard parseUntil(line, res, '\0', start)
echo("found a comment: ", res, " starting at: ", start)
I tried to use scanp before but it offers no convenience, and so you need to use custom logic and has weird syntax.
