> Are the LS and PS characters actually used in real plain-text documents? > At some point in the early 1990s, the thinking was that ASCII control characters were included in Unicode only for round-trip compatibility with existing character sets, but their semantics were undefined, and anyway they were not needed since they were from the bygone days of terminals and similar antique contraptions, whereas in modern times all text is "flowed" by "smart rendering engines".
Ten years hence, the terminal-to-host model is still widely used, as is text with hard line breaks, but to convince the skeptics and ultra-modernists that line breaks were still a useful concept, I mentioned line-oriented programming languages (such as Fortran), and poetry. Hence the line separator. Later everybody realized you couldn't stamp out ASCII control characters, so we're still using them; LS and PS never caught on as far as I know. Although obviously, LS would have been an improvement over the existing situation, in which different line separators (CR, LF, CRLF) are used on different platforms, which would otherwise have compatible text record formats, which to this day causes no end of confusion. At some point after Unicode 2.0, the C1 controls were adopted from ISO 6429, in which we have a Next Line control (NEL, U+0085), which might also have served the purpose, but it never caught on either. - Frank
