you could then write &tmp to a file and use /play and /loadbuf to, respectively, message the target and add the line to a window's buffer (since both commands preserve spaces).

to reproduce mIRC's behaviour entirely is undoubtedly complicated and ultimately impractical when compared to solutions offered by, for example, Saturn's spaces.dll. however, it is interesting to know that there exist methods such as Thels's (which, by the way, is brilliant) to overcome these problems with pure mIRC script :P

"The only excuse for making a useless script is that one admires it intensely" - Oscar Wilde