Hi Tadziu, At 2024-12-03T00:22:40+0100, Tadziu Hoffmann wrote: > > .ne Advance drawing position to the next vertical position > > trap if it is nearer than one vee. > > .ne d Advance drawing position to the next vertical position > > trap if it is nearer than distance d (default scaling > > unit v). > > > > How do people feel about that wording? > > Perhaps you could additionally point out that this advancing > of the drawing position then springs the trap in question. > I think this is a core feature of .ne.
Later in the same page we have this:
--snip--
Traps
Traps are locations in the output, or conditions on the input that, when
reached or fulfilled, call a specified macro. A vertical position trap
calls a macro when the formatter’s vertical drawing position reaches or
passes, in the downward direction, a certain location on the output page
or in a diversion. Its applications include setting page headers and
footers, body text in multiple columns, and footnotes. These traps can
occur at a given location on the page (.wh, .ch); at a given location in
the current diversion (.dt)—together, these are known as vertical posi‐
tion traps, which can be disabled and reënabled (.vpt). Setting a trap
is also called planting one. It is said that a trap is sprung if its
condition is fulfilled.
A diversion is not formatted in the context of a page, so it lacks page
location traps; instead it can have a diversion trap. There can exist at
most one such vertical position trap per diversion.
Other kinds of trap can be planted at a blank line (.blm); at a line with
leading space characters (.lsm); after a certain number of productive in‐
put lines (.it, .itc); or at the end of input (.em). Macros called by
traps are passed no arguments.
Registers associated with trap management include vertical position trap
enablement status (\n[.vpt]), distance to the next trap (\n[.t]), and the
name of that trap (\n[.trap]); the count of lines remaining in the pend‐
ing input trap (\n[.it]), the name of the macro associated with it
(\n[.itm]), and whether that input trap honors the \c output line contin‐
uation escape sequence (\n[.itc]); amount of needed (.ne‐requested) space
that caused the most recent vertical position trap to be sprung
(\n[.ne]), amount of needed space truncated from the amount requested
(\n[.trunc]); page ejection status (\n[.pe]); and leading space count
(\n[lsn]) with its corresponding amount of motion (\n[lss]).
---end snip---
Does that cover the base in question? The request synopses are supposed
to be really terse, following the CSTR #54 model and serve as a
refresher for the experienced. The basic fact that moving the drawing
position to (or past) a vertical position trap springs it is, I think,
covered in the narrative above.
Regards,
Branden
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