Search and replace in vimscript using a range?

Question

I was wondering how it is that I would place VIMScript variable values in my regex range and also in the replacement portion of my regex?

function! GoogleFormsStep(startnum, endnum)

    let x = startnum
    let line = 1

    while x <= endnum

      line, line s/$/x/g " What do I do here?

      let x = x + 1
      let line = line + 1
    endwhile

endfunction

Answer 1

Use :execute and concatenation:

let startline = 2
let endline = 56
let searchpattern = "foo"
let replacepattern = "bar"

execute startline . "," . endline . "s/" . searchpattern ."/" . replacepattern . "/g"

Alternative:

let cmd = startline . "," . endline . "s/" . searchpattern ."/" . replacepattern . "/g"
execute cmd