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From: neumann@FUNCTION.MPS.OHIO-STATE.EDU ("Walter D. Neumann")
Newsgroups: comp.text.tex
Subject: summary on \midinsert
Message-ID: <9103121529.AA20581@function.mps.ohio-state.edu>
Date: 12 Mar 91 15:29:50 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 42

Thank-you to all who responded about the problems with midinserts
getting out of order.  The most severe problems I was having turned
out to be an error in a local style file, though the same problem
existed in early versions of plain.tex.  After careful testing I am
fairly sure that this problem (a midinsert that does not fit on the
current page being converted to a topinsert that then does fit on the
current page) is truly fixed in version 3.0 of plain.tex.  Michael
Downes was the one who pointed this out:
 
"You might try checking your version of plain.tex to see if you have a
recent one (version 3.0 or later).  There was a problem with the
definition of \endinsert in older versions because \pageshrink was not
taken into account."
 
A lesser problem (obscurely documented in Exercise 15.5 of the
TeXbook) was addressed by Romesh Kumar:
 
"The problem arises if a relatively large insertion is followed almost
immediately by a short one, and there is enough space on the current
page to accommodate the second insertion but not the first one.  In
this case, the first insertion is converted (by TeX) to a \topinsert,
after which the second insertion is processed for the current page as
usual.  A possible way to way to avoid this is to type:
   \ifnum \insertpenalties > 0 \topinsert \else \midinsert \fi
instead of \midinsert to begin the insertions. \insertpenalties is the
number of insertions being held over for a succeeding page."
 
Indeed, one might use \MidInsert instead of \midinsert, defined by:
\def\MidInsert{\ifnum\insertpenalties>0\topinsert\else\midinsert\fi}
 
This appears to work fine, but I am not sure why.  My experiments
indicate that \insertpenalties is 100 if any topinsertions are
pending, no matter how many, which is not what the TeXbook led me
(or Kumar) to believe.
 
 
 
--
 Walter Neumann                     Email:       neumann@mps.ohio-state.edu
 Department of Mathematics                       neumann@ohstpy.bitnet
 Ohio State University              Fax: 614-292-3639 to Neumann, Math Dept
 Columbus, OH 43210          Tel: (614)-292-4886(office) 292-4975(messages)