> `sp` has a noteworthy limitation. > > .sp dist [...] > dist is ignored inside a diversion.
This is not true. (See below.) > Check the final sentence. `ne` inherits this limitation. In > a diversion, you can ask `ne` for tons of space, but you'll > only get 1v at a time. Even if you invoke it more than once. .sp works inside a diversion exactly like it works in the top-level diversion. Take a look at the attached example. There is precisely 10v between "foo" and "bar". However, .sp will not space beyond a trap, so "trap sprung" occurs with 15v above it. You can replace the ".sp 100v" with ".ne 100v" and the result will be exactly the same. > .tm ALMOST DONE (.d=\n[.d]u) > .ne > .tm JUST A BIT MORE (.d=\n[.d]u) > .ne > .tm I KEEP MASHING THIS THING BUT NOTHING HAPPENS (.d=\n[.d]u) I'm not sure what you are trying to show here. .ne means "I need this much space". If that space is available, nothing happens. If you invoke it a second time with the same argument and without having output something in the meantime, that space is still available, so again nothing happens. The effect of .ne is not cumulative. > .sp dist Break and move the next text baseline down by dist > [...]; > in all cases, one line height (vee) is added to dist. Thinking in terms of the positions of baselines may be tempting because that's how Postscript and PDF work, but I don't think it's the best mental model for troff. Interpreting the behavior of .sp as in metal typesetting seems more appropriate. That is, ".sp dist" means "leave this much space *between* the last line and the next".
.\" .\" ---------------------------------------------------------------- .de YY .gcolor red trap sprung .br .gcolor .. .\" ---------------------------------------------------------------- .de ZZ \t\v'0.3m'\\ni\v'-0.3m' \t\D'l 80p 0' .br .if \\n+i<26 .ZZ .. .\" ---------------------------------------------------------------- .ps 12 .vs 14 .fcolor yellow .nr dy 15*\n(.v .vs 0 \D'P 100p 0 0 \n(dyu -100p 0' .br .vs .mk .ta 15pR .nr i 1 1 .gcolor grey .ps 8 .ZZ .ps .rt .di XX .dt 15v YY .gcolor blue foo .br .sp 10v bar .br .sp 100v baz .br .di .in 3n .nf .XX
diversiontrap.pdf
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