X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["2980" "Mon" "29" "March" "93" "08:31:46" "BST" "Mike Piff" "M.Piff@SHEFFIELD.AC.UK" nil "93" "Re: Bug in LaTeX." "^Date:" nil nil "3"]) Return-Path: Received: from sc.ZIB-Berlin.DE (mailserv) by dagobert.ZIB-Berlin.DE (4.1/SMI-4.0/1.9.92 ) id AA11828; Mon, 29 Mar 93 10:44:30 +0200 Received: from vm.urz.Uni-Heidelberg.de (vm.hd-net.uni-heidelberg.de) by sc.ZIB-Berlin.DE (4.1/SMI-4.0-sc/19.6.92) id AA13246; Mon, 29 Mar 93 10:44:25 +0200 Message-Id: <9303290844.AA13246@sc.zib-berlin.dbp.de> Received: from DHDURZ1 by vm.urz.Uni-Heidelberg.de (IBM VM SMTP V2R2) with BSMTP id 0110; Mon, 29 Mar 93 10:44:22 CET Received: from DHDURZ1 by DHDURZ1 (Mailer R2.08 R208004) with BSMTP id 0705; Mon, 29 Mar 93 10:44:19 CET Received: from DHDURZ1 by DHDURZ1 (Mailer R2.08 R208004) with BSMTP id 0703; Mon, 29 Mar 93 10:44:15 CET Reply-To: Mailing list for the LaTeX3 project Date: Mon, 29 Mar 93 08:31:46 BST From: Mike Piff Sender: Mailing list for the LaTeX3 project To: Multiple Recipients of Subject: Re: Bug in LaTeX. Status: R X-Status: X-Keywords: X-UID: 1019 > Date: Thu, 25 Mar 93 14:40:47 GMT > Reply-To: Mailing list for the LaTeX3 project > Sender: Mailing list for the LaTeX3 project > From: CHAA006@vax.rhbnc.ac.uk > Subject: Bug in LaTeX. > To: Multiple Recipients of > > > The following short LaTeX-2.09 file appears to demonstrate a bug in LaTeX, > which goes into an infinite loop; the significant part of the log file is > appended. The problem was reported by Adrian Johnstone of the Department of > Computer Science at RHBNC. > > Philip Taylor, RHBNC > -------- > \tracingall > \documentstyle {article} > \begin {document} > \tracingall > \begin {enumerate} > \section {foo} > \end {enumerate} > \end {document} > -------- > This is TeX, Version 3.141 [PD VMS 3.4] (preloaded format=lplain 92.7.10) 25 MA > R 1993 14:01 > [...] > \@xsect #1->\@tempskipa #1\relax \ifdim \@tempskipa >\z@ \par \nobreak \vskip \ > @tempskipa \@afterheading \else \global \@nobreakfalse \global \@noskipsectrue > \everypar {\if@noskipsec \global \@noskipsecfalse \clubpenalty \@M \hskip -\pa r > indent \begingroup \@svsechd \endgroup \unskip \hskip -#1\relax \else \clubpen a > lty \@clubpenalty \everypar {}\fi }\fi \ignorespaces > #1<-2.3ex plus .2ex > {\skip19} > {\relax} > {\ifdim} > {true} > > \par ->\if@newlist \else {\@@par }\fi > {\iftrue} > {true} > {\else} > > \nobreak ->\penalty \@M > {\penalty} > {\vskip} > > \par ->\if@newlist \else {\@@par }\fi > {\iftrue} > {true} > {\else} > {\vskip} > > \par ->\if@newlist \else {\@@par }\fi > {\iftrue} > {true} > {\else} > {\vskip} > > [etc...] Sorry, your message has taken this long to arrive. This is a well-known one, which I believe manifests itself whenever a \begin{enumerate} is followed bt text rather than an \item. Chris Rowley put me on to the solution some time ago. Somewhere in the TeXbook---p286 in my copy, explanation of commands incompatible with horizontal mode---it says that \vskip in horizontal mode causes TeX to output a \par token. But in this case \par is clobbered. I cured the problem locally by a bodge which caused \@donoparitem (??) or wherever this bug originated from to output a real \par---ie, \@@par--- under certain circumstances, after I discovered that not putting in \item was one of the commonest mistakes novices made. As with all such bugs in LaTeX, they will all be solved in LaTeX-3... Mike %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% Dr M J Piff %% e-mail: %% Department of Pure Mathematics %% %% University of Sheffield %% M.Piff@sheffield.ac.uk %% Hicks Building %% PM1MJP@derwent.shef.ac.uk %% Hounsfield Road %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% SHEFFIELD S3 7RH %% Telephone: (0742) 824431 %% England %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%