Re: Proposed GNU troff behavior change: require end-of-input macros to exit

[Holger Herrlich]

As far as I got, by playing around, the '\c' doesn't matter. It seems
that the additional page comes from an additional call to the
default page break. 


Using a custom trap, just disable it in your end trap:
----8<----
.\"
.\" run: groff em-test.groff > em-test.ps
.\"
.nr PAGE-trap 20c
.nr PAGE-ll   13c
.\"
.de my-trap
.tl '\\v'|\\n[PAGE-trap]u'\\h'|0'\\D'l \\n[PAGE-ll]u 0c''''
'bp                   \" matters: not .bp
..
.\"
.de your-end
\c                 \" doesn't matter
.  ne 3v
.  sp (\\n[.t]u - 3v)
.wh \n[PAGE-trap]u    \" matters: disable regular trap
.  in +4i
.  lc _
.  br
Approved:\t\a
.  sp
Date:\t\t\a
..
.\"
.wh \n[PAGE-trap]u my-trap
.em your-end
.\"
.\".SF-std
.\"
XXX first line XXX
.br
.\"
.sp |(\n[PAGE-trap]u-2.99v)  \" matters: 3.01v get you one page only
YYY last line YYY
.\"
----8<----


Without custom trap handling, one need to prevent the default one to
engage:
----8<----
.\"
.\" run: groff em-test.groff > em-test.ps
.\"  or: groff em-test.groff > em-test.ps
.\"
.nr Pt 20c    \" page trap
.nr Pl 13c    \" page length
.\"
.pl \n(Ptu
.\"
.\".de mt        \" my trap
.\".tl '\\v'|\\n(Ptu'\\h'|0'\\D'l \\n(Plu 0c''''
.\"'bp           \" matters: not .bp
.\"..
.\"
.de ye        \" your end
.\"\c         \" doesn't matter
.  ne 3v
.  sp (\\n(.tu - 3.01v) \" prevent another page break
.\".wh \n(Ptu    \" matters: disable regular trap
.  in +4i
.  lc _
.  br
Approved:\t\a
.  sp
Date:\t\t\a
..
.\"
.\".wh \n(Ptu mt
.em ye
.\"
.\".SF-std
.\"
XXX first line XXX
.br
.\"
.sp |(\n(Ptu-2.99v)  \" matters: 3.01v get you one page only
YYY last line YYY
.\"
----8<----