% F W L W . S T Y ( First Word, Last Word ) % % Donald Arseneau (1993, 1995) % % Modifications to LaTeX output mechanism to determine the first and % last words on the current page, plus the first word on the *next* % page. These can be used in head-lines or foot-lines. The `words' % you see may not be real words, but any unbreakable object. % % Such labelling does not make sense when \chapter generates a page % break, so the last page before a \chapter (or any \clearpage) gets % a blank "next word", and the first page of the chapter gets a blank % "first word". There is a problem when footnotes split: the "next word" % is blank. % % Two pagestyles are defined to print these words: \pagestyle{NextWordFoot} % which helps you read ahead to the word on the next page; and \pagestyle % {fwlwhead} which is like the headers in a lexicon. Or you can use the % words in your own page-style... % The words are available in the box registers: % \FirstWordBox - first word on this page % \NextWordBox - first word on next page % \LastWordBox - last word on this page % Use them in your header lines like: \copy\LastWordBox. % % Note that `words' may be things like: % - two~words % - [ ]Word ( [ ] represents a parindent box) % - a whole displayed equation % - the first column of an aligned equation % - anomalously blank, if there are \writes or split footnotes etc. % - partial words like par- or -tial. % % An entirely different approach is possible using \mark and \obeyspaces, % and would have different problems. The problems with catcode changes % may be more or less serious for your particular application. You are % welcome to write a package using that method. The best solution would % involve \mark and an input filter program to % `\w{tag} \w{each} \w{word}, \w{in} \w{some} \w{way}.' \mathchardef\LW@pen 12345 \newbox\FirstWordBox \global\setbox\FirstWordBox\hbox{} \newbox\NextWordBox \global\setbox\NextWordBox\hbox{} \newbox\LastWordBox \global\setbox\LastWordBox\hbox{} \newbox\LW@box \global\setbox\LW@box\hbox{} \newbox\LW@saved \def\ps@fwlwhead{\let\@mkboth\@gobbletwo \def\@oddhead{\if@fcolmade\else \copy\FirstWordBox\hfil\copy\LastWordBox\fi}% \let\@evenhead\@oddhead % no word-heads on float pages. \let\@oddfoot\@empty\let\@evenfoot\@oddfoot \let\chaptermark\@gobble\let\sectionmark\@gobble\let\subsectionmark\@gobble } \def\ps@NextWordFoot{\let\@mkboth\@gobbletwo \let\@oddhead\@empty\let\@evenhead\@oddhead \def\@oddfoot{\hfil\thepage\hfil\llap{\copy\NextWordBox}}\let\@evenfoot\@empty \let\chaptermark\@gobble\let\sectionmark\@gobble\let\subsectionmark\@gobble } % Shell around old output routine. Gets first word from next page by % letting TeX continue with \vsize=0 to get a look at the next line. % Values of \outputpenalty for \specialoutput ( -10001 to -19999 ) are % simply run through the output routine. % \supereject and \clearpage give a blank "next word" % When called after making a stub-page the stub is returned to the vertical % list, the previous page is restored and shipped out normally, but % knowing what the next word will be. \edef\FWLWnorm@L@output{\the\output} \output{\@tempswafalse \ifnum \outputpenalty>-\@MM \ifnum\outputpenalty<-\@M \@tempswatrue\fi\fi \if@tempswa % special (float) output % \message{Float handler: penalty=\the\outputpenalty}% \FWLWnorm@L@output \else \ifvoid\LW@saved % end of real page % \message{End of real page}% \global\setbox\LW@saved\copy\@cclv % save page \setbox\@tempboxa\vbox{\unvbox\@cclv \unskip\unkern\unpenalty \unskip\unkern\unpenalty \unskip\unkern\unpenalty \setbox\@tempboxa\lastbox \LW@getlast@word\@tempboxa\LastWordBox }\ifnum\outputpenalty>-\@MM % not \supereject \xdef\LW@vsize{\global\vsize\the\vsize \global\holdinginserts\the\holdinginserts}% \global\vsize\z@ \global\holdinginserts\@ne \else % \supereject, just output, don't look for word on next page % \message{caused by super-eject.} \global\setbox\@cclv\box\LW@saved \global\setbox\NextWordBox\hbox{}% \FWLWnorm@L@output \global\setbox\FirstWordBox\box\NextWordBox \fi \else % saved page => just did tiny page to get next word % \message{Just got next line:}{\tracingall\showboxdepth2 \showbox\@cclv}% \setbox\@tempboxa\vbox{\penalty\LW@pen\unvcopy\@cclv \LW@getall@boxes \ifvbox\LW@box \penalty\LW@pen\unvbox\LW@box \LW@getall@boxes\fi \ifvbox\LW@box \global\setbox\NextWordBox\hbox{}\else \LW@getfirst@word\LW@box\NextWordBox \fi}% Return tiny page to page list: \unvbox\@cclv \ifnum\outputpenalty<\@M \penalty\outputpenalty\fi \LW@vsize\relax \global\setbox\@cclv\box\LW@saved \FWLWnorm@L@output \global\setbox\FirstWordBox\box\NextWordBox \fi\fi} % globally get last "word" from a box (#1) into another box (#2) \def\LW@getlast@word#1#2{\setbox\@tempboxa\vbox{\hsize\maxdimen \@parboxrestore \hyphenpenalty\@M \exhyphenpenalty\@M \rightskip\fill \looseness\@M \linepenalty\z@ \noindent\unhbox#1\endgraf \unskip\unkern\unpenalty \global\setbox\LW@box\lastbox }\LW@repack{#2}} % globally get first "word" from a box (#1) into another box (#2) \def\LW@getfirst@word#1#2{\setbox\@tempboxa\vbox{\@parboxrestore \parshape\thr@@ \z@\z@ \z@\z@ \z@\maxdimen \parfillskip\fill \hyphenpenalty\@M \exhyphenpenalty\@M \hbadness\@MM \overfullrule\z@ \hfuzz\maxdimen \ifhbox#1\noindent \vadjust{\penalty\LW@pen}\penalty-\@M\unhbox#1% eliminate previous \leftskip \else\ifvbox#1\penalty\LW@pen\unvbox#1\fi\fi \endgraf \@tempcnta\z@ \LW@getall@boxes}\LW@repack{#2}} % Go through a vertical list that starts with special penalty \def\LW@getall@boxes{\global\setbox\LW@box\lastbox \unskip\unkern \unskip\unkern \let\@tempa\relax \ifvoid \LW@box \advance\@tempcnta\@ne \else \@tempcnta\z@ \fi \ifnum\lastpenalty=\LW@pen \else \unpenalty\fi \ifnum\lastpenalty=\LW@pen \else \unpenalty\fi \ifnum\lastpenalty=\LW@pen \else \ifnum\@tempcnta<5 \let\@tempa\LW@getall@boxes \fi \fi \unpenalty \@tempa} % Put contents of \LW@box into hbox #1 \def\LW@repack#1{\global\setbox#1\hbox{\ifhbox\LW@box \unhbox\LW@box\unskip\unskip\unpenalty\unskip \else\ifvbox\LW@box\box\LW@box\fi\fi}}