[comp.text.tex] eqnarray bug in LaTeX?

bjornl@sics.se (Bj|rn Lisper) (09/25/90)

In our LaTeX, version 2.09, the following is processed correctly:

\begin{eqnarray}
x&=&y\\
z&=&u
\end{eqnarray}

Also the following works fine:

\begin{eqnarray}
 x&=&y\\
z&=&u
\end{eqnarray}

But if empty lines are added, like the following:

\begin{eqnarray}

x&=&y\\
z&=&u

\end{eqnarray}

then LaTeX gets messed up and starts complaining about missing $ etc. Why
is this? It seems to me like a newline and a space should be equal in math
mode. Is this a bug?

Bjorn Lisper	bjornl@tds.kth.se

piet@cs.ruu.nl (Piet van Oostrum) (10/01/90)

>>>>> In article <1990Sep25.075127.5715@sics.se>, bjornl@sics.se (Bj|rn
>>>>> Lisper) (BL) writes:

BL> But if empty lines are added, like the following:

BL> \begin{eqnarray}

BL> x&=&y\\
BL> z&=&u

BL> \end{eqnarray}

BL> then LaTeX gets messed up and starts complaining about missing $ etc. Why
BL> is this? It seems to me like a newline and a space should be equal in math
BL> mode. Is this a bug?

An empty line is equal to \par in TeX and \par is forbidden in math mode
(see the TeX book, ch 26, page 293).

Of course \par could have been redefined in eqnarray environments, but it
isn't.
-- 
Piet* van Oostrum, Dept of Computer Science, Utrecht University,
Padualaan 14, P.O. Box 80.089, 3508 TB Utrecht, The Netherlands.
Telephone: +31 30 531806   Uucp:   uunet!mcsun!ruuinf!piet
Telefax:   +31 30 513791   Internet:  piet@cs.ruu.nl   (*`Pete')