[Rd] problem with \eqn (PR#8322)

[hin-tak.leung@cimr.cam.ac.uk]

Martin Maechler wrote:
>>>>>>"Hin-Tak" == Hin-Tak Leung <hin-tak.leung at cimr.cam.ac.uk>
>>>>>>    on Fri, 18 Nov 2005 16:38:28 +0000 writes:
> 
> 
>     Hin-Tak> Your own fault. See below. It is basic LaTeX and any LaTeX person
>     Hin-Tak> can tell you the answer...(most probably haven't bothered...)
> 
> No.  Whereas I partly agree that it's Ross ``fault'' trying to
> use too smart LaTex (and using outdated \bf instead of \mathbf), 
> ;-)
> 
> The bug is really there, since we are talking about the Rd "language",
> not LaTeX, an in Rd,  \eqn and \deqn are defined to have either
> one or two arguments -- where Ross used the 2-argument version
> correctly (in principle at least) --> See the manual "Writing R
> Extensions".

Forgive me for not reading R-ext carefully, but Ross's Rd code is
still "obviously" wrong in the lights of the two-argument \eqn:
(really doesn't differ from the 1-arg interpretaion of \eqn)

\eqn{{\bf\beta}_j}{\bf\beta}_jnormal-bracket5bracket-normal{b(j)}

In other words,
\eqn{...}{...}_...

and the "_" is still outside of any maths environment, which is most
probably not Ross's intention.

> 
> 
>     >> Full_Name: Ross Boylan
>     >> Version: 2.2.0
>     >> OS: Linux
>     >> Submission from: (NULL) (65.175.48.58)
>     >> 
>     >> 
>     >> \eqn{{\bf\beta}_j}{b(j)} in my .Rd file produces this error
> 
>     >> --------------------------------------------
>     >> ! Missing $ inserted.
>     >> <inserted text> 
>     >> $
>     >> l.7 \eqn{{\bf\beta}_j}{\bf\beta}_jnormal-bracket5bracket-normal{b(j)}
> 
>     Hin-Tak> \eqn{{\bf\beta}_j} is already syntactically complete, so latex
>     Hin-Tak> complains the next "_" is not in maths mode, and automatically
>     Hin-Tak> switch into maths mode for you (the $ inserted message) You have
>     Hin-Tak> to match all the braces - you need 3 right-braces after \eqn,
>     Hin-Tak> like this, at least:
> 
>     Hin-Tak> \eqn{  {  {\bf\beta
>     Hin-Tak> }_j
>     Hin-Tak> }
>     Hin-Tak> {\bf\beta
>     Hin-Tak> }_ ....
>     Hin-Tak> {b(j)
>     Hin-Tak> }
>     Hin-Tak> }