Re: [Groff] .IP quoting incompatibility

[Larry Jones]

Werner LEMBERG writes:
> 
> Sigh.  It's a not a bug in GNU troff, I think.

Well, it's an incompatibility then.  It seems to involve argument
substitution inside quoted strings.  Consider the following:

        .de XX
        \\$1
        ..
        .de YY
        .XX "\\$1"
        ..
        .YY "$"""""

According to the parsing rules, YY gets called with $1 set to $"".  When
it calls XX, Unix troff seems to do literal textual substitution, so the
call is:

        .XX "$"""

(that is, the inserted quotes are just inserted literally without
reguard to being in a quoted string) and thus XX gets called with $1 set
to $".  groff, on the other hand, does seem to note that the
substitution is in a quoted string and thus, in effect, doubles the
quotes to preserve them, acting as if the call were:

        .XX "$"""""

Thus, Unix troff's final output is:

        $"

whereas groff's is:

        $""

-Larry Jones

These findings suggest a logical course of action. -- Calvin