I'm not sure why we actually need the box request, since the desired functionality can be achieved with the macros below (and they don't create a blank line if the box is empty!).
They circumvent the problem of the existing partially filled line by starting a new environment. The only caveat with this approach is that an environment carries with it its own font size, line length, etc., so their values might need to be set explicitly when first entering the environment. On the other hand, this is not necessarily a bad idea, for example when creating framed boxes in which the line length needs to be a bit shorter anyway. .\" .\" ------------------------------------------------------------------------ .\" wrapper .de box .ie '\\$1'' .EB .el .BB \\$1 .. .\" begin box .de BB .ev \\$1 .di \\$1 .. .\" end box .de EB .br .di .ev .. .\" print box .de PB .ev \\$1 .nf .\\$1 .fi .ev .. .\" print box (variant) .de PB1 .nf .\\$1 .fi .. .\" ------------------------------------------------------------------------ .sp 2c Before the box. .BB XX .gcolor red In the box. .EB .PB XX After the box. .sp 2c Before the box. .BB XX .gcolor red In the box. .EB .PB1 XX After the box. The "box" macro is not necessary if you prefer separate begin and end box macros; it only serves to provide an interface with a similar syntax as the box request. Also, if you do not intend to nest boxes, you can hardcode the environment name (or number) and the diversion name, and always recycle those.
