Substitute variable into match

Question

This highlights the parts of the lines that are over 80 columns long:

augroup over_length
    autocmd!
    autocmd BufEnter * highlight OverLength ctermbg=darkgrey
    autocmd BufEnter * match OverLength /\%80v.*/
augroup END

However, I would like to modify it to use &textwidth. Using /\%.&textwidth.v.*/ doesn't seem to work. Is there a way to substitute the value into the regular expression?

Answer 1

Yes, you have to use execute and put it in a string:

execute 'match OverLength /\%'. &textwidth .'v.*/'