Re: [Groff] broken interaction between line numbering and diversions

[Tadziu Hoffmann]

> The question I'm posing is whether a user who uses a
> diversion in this "wrong" (or, let's say, less than optimal)
> manner should see output that is so clearly not what was
> intended, or whether the software should do something
> intelligent with the user's suboptimal input, producing
> output that is probably what the user wanted.

My opinion is that software should not try to second-guess
what a user wants.  It's very bad for predictability[*],
and causes unnecessary complexity in the programs.
It's much better to have consistent behavior (and in this
case, groff *is* behaving consistently; it is how diversions
are implemented), and instead educate the user as to how the
program is intended to be used.  And regarding troff,
I think there's no excuse in not reading the documentation:
you'll seldom find a more concise yet comprehensive
description of a program's behavior as the Troff User's Guide.

[*] It's like single namespaces and global variables.
We might not like them because they make cooperation between
program code written by different people more complicated,
but in a way they *are* predictable.