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diff --git a/info/laan/paradigm/paradigm.itm b/info/laan/paradigm/paradigm.itm new file mode 100644 index 0000000000..e3e25928b9 --- /dev/null +++ b/info/laan/paradigm/paradigm.itm @@ -0,0 +1,216 @@ +%November 1994, +%Paradigm: plain's item extended +%C.G. van der laan, cgl@rc.service.rig.nl +\input blue.tex \loadtocmacros +\loadindexmacros\preindex{\head{Index}} +\tolerance500\hbadness=499\hfuzz=5pt +\parindent=1pc +\everyverbatim{\emc} + +\bluetitle Paradigms: Plain's \cs{item}-s extended + +\blueissue \maps{94}2 {\small revision March \on1996} + +\beginscript + +\bluehead A new series + +Hi folks. After having given birth to BLUe's Format\Dash yes YAF, +yet another format, to paraphrase YACC\Dash I considered it of +general interest to spread gems to the world outside +via MAPS and hopefully via TTN's `Hey \Dash{} It works' column. + +The reason for me doing so is that apparently trivial +design aspects need careful attention in this macro +expansion branch of software engineering. +We have to start allover from the basics---slowly and +carefully---and end up with paradigms of macro expansion +coding. + +I intend a series of backside of the envelope contributions. + +\bluehead BLUe's Design I + +^^|\item| +When you like plain's \cs{item}-s so much as I do then this is for you. +Hang on! +In practice we all like bulleted \cs{item}-s and +\cs{item}-s with automatic numbering and lettering. +It looks like---biased by \LaTeX---that we need some +|\begin<tag>| and |\end<tag>| to begin and end. +Not so! + +It can be done simpler, with nearly the same +minimal markup as with \cs{item}. +The extra is to end the list by \cs{smallbreak}, +which is nearly natural.\ftn{I use \cs{smallskip} after \cs{item}-s + for setting the list slightly apart from what follows. + When a header follows, or you just like to + end the list, say \cs{endlist} which \TeX nically ends + the group.} + +Remember \TB~\on102, where Knuth states +\beginquote +`It is customary to put \cs{medskip} before and after + a group of of itemized paragraphs, and to say \cs{noindent} +before any closing remarks that apply to all of the cases.' +\endquote +I decided not to include \cs{noindent} because +the list is set apart already. + +\bluesubhead Appetizer + +The coding of the bulleted item reads\ftn{\TB, exercise \on14.\on20.} + +\beginverbatim +\def\bitem{\item{$\bullet$}} +!endverbatim + +\bluesubhead Coding AN-items + +^^|\Aitem| +With automatic numbering and lettering we have +to stop the automatism of increasing the counter and +to reset the counter for subsequent use +at the end of the list. + +In \cs{item} nothing special had to be done. +Ending the paragraph via a blank line (or \cs{par}) +was enough. +We cannot modify \cs{par} locally +because \cs{par} starts the replacement text of +\cs{item} (and \cs{itemitem} as well). +So the natural markup to let a blank line (or \cs{par}) +end the list is not possible. + +I could not work along the remark made in \TB{} ex\on14.\on29{} either, +because this goes wrong with nesting, read with the use of \cs{itemitem}. + +My solution is a mixture of coding borrowed from +\cs{item} page \on355, +\cs{beginchapter} \on418, and of +\cs{d@nger} \on419{} of \TB.\ftn +{The more I come to think of it the more ways of doing boil up. + How to decide which one is the best?} + +\def\ftntxt{{\rm Do you see the extension for \cs{Aitem}?}} +\beginverbatim +\newcount\itemno +\def\nitem{\bgroup + \def\nitem{\advance\itemno1 + \item{\the\prenum + {\oldstyle\the\itemno + }\the\postnum}} + \def\smallbreak{\endgraf\egroup + \smallbreak} + \let\smallskip\smallbreak\nitem} +\def\aitem{\bgroup\itemno96!ftn!ftntxt + \def\aitem{\advance\itemno1 + \item{\char\itemno.}} + \def\smallbreak{\endgraf\egroup + \smallbreak} + \let\smallskip\smallbreak + \aitem} +\def\endlist{\endgraf\egroup} +%and the defaults +\prenum{(}\postnum{)} +!endverbatim + +We not only have to end the paragraph(s) but also to end the scope. + +\blueexample Numbered and nested items + +\prenum{}\postnum{.} +\beginverbatim +Text preceding\\next line +\prenum{}\postnum{.} +\nitem first numbered item\\next line +\itemitem- sublist\\next line +\nitem second numbered item\\next line +\itemitem- sublist\\next line +\smallbreak +Text in between\\next line +\aitem first lettered item\\next line +\aitem second lettered item\\next line +\smallbreak +Text after\\next line. +!endverbatim +with result +\medskip +Text preceding\\next line +\nitem first numbered item\\next line +\itemitem- sublist\\next line +\nitem second numbered item\\next line +\itemitem- sublist\\next line +\smallbreak +Text in between\\next line +\aitem first lettered item\\next line +\aitem second lettered item\\next line +\smallbreak +Text after\\ +next line. + +\bluesubhead Enumerated items + +Along the same line we can add an enumerated item as follows. + +\beginverbatim +\def\eitem{\bgroup + \def\eitem##1{\item{##1}}% + \def\smallbreak{\endgraf + \egroup\smallbreak}% + \let\smallskip\smallbreak + \eitem} +!endverbatim + +\bluesubhead Verbatim items + +Of late\ftn{In my tutorial flyer `Macro writing,' \on1995.} +I needed a list of items with each item only verbatim texts. + +To use \vrt{} at the end and the beginning of each line +and to add |\\| or so at the end is +in the spirit of \TB, as done with \cs{displaylines}. +Not bad but a nuisance to insert all those \vrt s. + +Another modular solution was to use \cs{bitem} and after that + +\beginverbatim +\preverbatim{}\postverbatim{}\beginverbatim +!endverbatim + +and to end each item entry by + +\thisverbatim{\catcode`\!=12 \catcode`\*=0 } +\beginverbatim +!endverbatim +*endverbatim + +The minimal markup solution is to provide a \cs{verbitem} tag which +assumes only verbatim text as entry. + +Pitfalls. +The second and so on tag must begin with !verbitem.\\ +The tag must appear on a line of its own.\\ +End with !smallbreak. + +\beginverbatim +\def\bitem{\begingroup + \def\bitem{\item{$\bullet$}}% + \def\smallbreak{\endverbatim + \endgraf\endgroup\smallbreak}% + \let\smallskip\smallbreak + \bitem + \def\item{\endverbatim%to close + \par\hang\textindent}% +} +\def\verbitem{\bitem +\preverbatim{}\postverbatim{}% +\beginverbatim} +!endverbatim + +Have fun, and all the best +\makesignature +\pasteuptoc +\sortindex\pasteupindex +\endscript |