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% $Id: mdwlist.dtx,v 1.1 2000/07/13 09:10:21 michael Exp $
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% Various list-related things
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% (c) 1996 Mark Wooding
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%----- Revision history -----------------------------------------------------
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% $Log: mdwlist.dtx,v $
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% Revision 1.1 2000/07/13 09:10:21 michael
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% Revision 1.1 1998/09/21 10:19:01 michael
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% Initial implementation
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% Revision 1.1 1996/11/19 20:52:26 mdw
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% \begin{meta-comment} <general public licence>
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%% mdwlist package -- various list-related things
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%% Copyright (c) 1996 Mark Wooding
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%% This program is free software; you can redistribute it and/or modify
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%% it under the terms of the GNU General Public License as published by
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%% the Free Software Foundation; either version 2 of the License, or
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%% (at your option) any later version.
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%% This program is distributed in the hope that it will be useful,
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%% but WITHOUT ANY WARRANTY; without even the implied warranty of
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%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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%% GNU General Public License for more details.
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%% You should have received a copy of the GNU General Public License
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%% along with this program; if not, write to the Free Software
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%% Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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% \begin{meta-comment} <Package preambles>
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%<+package>\NeedsTeXFormat{LaTeX2e}
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%<+package>\ProvidesPackage{mdwlist}
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%<+package> [1996/05/02 1.1 Various list-related things]
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%% {Upper-case \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
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%% Lower-case \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
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%% Digits \0\1\2\3\4\5\6\7\8\9
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%% Exclamation \! Double quote \" Hash (number) \#
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%% Dollar \$ Percent \% Ampersand \&
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%% Acute accent \' Left paren \( Right paren \)
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%% Asterisk \* Plus \+ Comma \,
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%% Minus \- Point \. Solidus \/
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%% Colon \: Semicolon \; Less than \<
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%% Equals \= Greater than \> Question mark \?
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%% Commercial at \@ Left bracket \[ Backslash \\
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%% Right bracket \] Circumflex \^ Underscore \_
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%% Grave accent \` Left brace \{ Vertical bar \|
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%% Right brace \} Tilde \~}
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% \begin{meta-comment}
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\describespackage{mdwlist}
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\desclabelwidth{80pt}%
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\desclabelstyle\nextlinelabel%
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\def\makelabel{\bfseries}%
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\newenvironment{cmdlist}
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{\basedescript{\let\makelabel\cmd}}
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% \section{User guide}
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% This package provides some vaguely useful list-related commands and
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% \item A way of building \env{description}-like environments.
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% \item Commands for making `compacted' versions of list environments
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% \item A method for suspending and resuming enumerated lists.
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% \subsection{Description list handling}
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% Different sorts of description-type lists require different sorts of
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% formatting: I think that's fairly obvious. There are essentially three
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% different attributes which should be changable:
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% \item the indentation of the items being described,
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% \item the handling of labels which don't fit properly, and
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% \item the style used to typeset the label text.
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% The first two items should usually be decided for all description-like
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% lists in the document, to ensure consistency of appearance. The last
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% depends much more on the content of the labels.
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% \DescribeEnv{basedescript}
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% The \env{basedescript} environment acts as a `skeleton' for description
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% environments. It takes one argument, which contains declarations to
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% be performed while constructing the list. I'd consider it unusual for
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% the \env{basedescript} environment to be used in the main text: it's
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% intended to be used to build other environments.
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% The declarations which can be used to define description-type environments
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% include all of those which are allowed when setting up a list (see the
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% \LaTeX\ book for information here). Some others, which apply specifically
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% to description lists, are also provided:
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% \item \DescribeMacro{\desclabelwidth}
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% The \syntax{"\\desclabelwidth{"<length>"}"} declaration sets labels
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% to be left-aligned, with a standard width of \<length>; the item
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% text is indented by \<length> plus the value of |\labelsep|.
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% \item \DescribeMacro{\desclabelstyle}
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% The label style determines how overlong labels are typeset. A style
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% may be set using the \syntax{"\\desclabelstyle{"<style>"}"}
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% declaration. The following \<style>s are provided:
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% \item [\nextlinelabel] If the label is too wide to fit next to the
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% first line of text, then it is placed on a line by itself;
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% the main text is started on the next line with the usual
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% \item [\multilinelabel] The label is typeset in a parbox with the
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% appropriate width; if it won't fit on one line, then the
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% text will be split onto subsequent lines.
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% \item [\pushlabel] If the label is too wide to fit in the space
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% allocated to it, the start of the item's text will be `pushed'
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% over to the right to provide space for the label. This is
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% the standard \LaTeX\ \env{description} behaviour.
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% \item \DescribeMacro{\makelabel}
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% The |\makelabel| command is responsible for typesetting a label.
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% It is given one argument, which is the text given as an argument
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% to the |\item| command; it should typeset it appropriately. The
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% text will then be arranged appropriately according to the chosen
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% label style. This command should be redefined using |\renewcommand|.
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% \begin{demo}[w]{Various labelling styles}
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%\begin{basedescript}{\desclabelstyle{\nextlinelabel}}
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%\item [Short label] This is a short item, although it has quite a
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% lot of text attached to it.
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%\item [Slightly longer label text] This is a rather longer piece
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% of text, with a correspondingly slightly longer label.
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%\begin{basedescript}{\desclabelstyle{\multilinelabel}}
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%\item [Short label] This is a short item, although it has quite a
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% lot of text attached to it.
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%\item [Slightly longer label text] This is a rather longer piece
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% of text, with a correspondingly slightly longer label.
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%\begin{basedescript}{\desclabelstyle{\pushlabel}}
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%\item [Short label] This is a short item, although it has quite a
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% lot of text attached to it.
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%\item [Slightly longer label text] This is a rather longer piece
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% of text, with a correspondingly slightly longer label.
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% \DescribeMacro{\defaultdesc}
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% To allow document designers to control the global appearance of description
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% lists, the |\defaultdesc| command may be redefined; it is called while
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% setting up a new \env{basedescript} list, before performing the user's
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% declarations. By default, it attempts to emulate the standard \LaTeX\
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% \env{description} environment:\footnote{^^A
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% This is a slightly sanitised version of the real definition, which is
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% given in the implementation section of this document.}
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%\providecommand{\defaultdesc}{%
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% \desclabelstyle{\pushlabel}%
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% \renewcommand{\makelabel}[1]{\bfseries##1}%
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% \setlength{\labelwidth}{0pt}%
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% Unfortunately, \LaTeX\ doesn't provide a means for overriding a command
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% which may or may not have been defined yet; in this case, I'd probably
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% recommend using the \TeX\ primitive |\def| to redefine |\defaultdesc|.
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% If you want to redefine the \env{description} environment in terms of
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% the commands in this package, the following method is recommended:
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%\renewenvironment{description}{%
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% \begin{basedescript}{%
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% \renewcommand{\makelabel}[1]{\bfseries##1}%
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% \end{basedescript}%
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% This ensures that labels are typeset in bold, as is usual, but other
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% properties of the list are determined by the overall document style.
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% \subsection{Compacted lists}
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% \LaTeX\ tends to leave a certain amount of vertical space between list
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% items. While this is normally correct for lists in which the items are
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% several lines long, it tends to look odd if all or almost all the items
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% are only one line long.
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% \DescribeMacro{\makecompactlist}
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% \syntax{"\\makecompactlist{"<new-env-name>"}{"<old-env-name>"}"}
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% defines a new environment \<new-env-name> to be a `compacted' version of
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% the existing environment \<old-env-name>; i.e., the two environments are
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% the same except that the compacted version leaves no space between items
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% or paragraphs within the list.
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% \DescribeEnv{itemize*}
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% \DescribeEnv{enumerate*}
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% \DescribeEnv{description*}
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% So that the most common cases are already handled, the package creates
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% compacted $*$-variants of the \env{itemize}, \env{enumerate} and
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% \env{description} environments. These were created using the commands
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%\makecompactlist{itemize*}{itemize}
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%\makecompactlist{enumerate*}{enumerate}
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%\makecompactlist{description*}{description}
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% Some list environments accept arguments. You can pass an argument to a
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% list environment using an optional argument to its compact variant. For
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%\begin{foolist*}[{someargument}]
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% \subsection{Suspending and resuming list environments}
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% \DescribeMacro{\suspend}
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% \DescribeMacro{\resume}
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% The |\suspend| and |\resume| commands allow you to temporarily end a list
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% environment and then pick it up where you left off. The syntax is fairly
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% <suspend-cmd> ::= \[[
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% \begin{stack} \\ "[" <name> "]" \end{stack} "{" <env-name> "}"
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% <resume-cmd> ::= \[[
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% \begin{stack} \\ "[" <name> "]" \end{stack} "{" <env-name> "}"
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% \begin{stack} \\ "[" <text> "]" \end{stack}
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% The \<env-name> is the name of the environment; this will more often than
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% not be the \env{enumerate} environment. The \<name> is a magic name you
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% can use to identify the suspended environment; if you don't specify this,
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% the environment name is used instead.
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% \begin{demo}{Suspended environments}
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%Here's some initial text. It's
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%not very interesting.
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%\item This is an item.
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%\item This is another.
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%\suspend{enumerate*}
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%Some more commentry text.
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% You can pass arguments to a resumed list environment through the second
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% optional argument of the |\resume| command. If, for example, you're using
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% David Carlisle's \package{enumerate} package, you could say something like
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%\begin{enumerate}[\bfseries{Item} i]
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%Some intervening text.
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%\resume{enumerate}[{[\bfseries{Item} i]}]
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%\item Yet another item
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% \section{Implementation}
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% \subsection{Description lists}
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% \subsubsection{Label styles}
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% \begin{macro}{\nextlinelabel}
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% The idea here is that if the label is too long to fit in its box, we put
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% it on its own line and start the text of the item on the next. I've
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% used |\sbox| here to capture colour changes properly, even though I have
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% deep moral objections to the use of \LaTeX\ boxing commands. Anyway,
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% I capture the text in box~0 and compare its width to the amount of space
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% I have in the label box. If there's enough, I can just unbox the box;
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% otherwise I build a vbox containing the label text and an empty hbox --
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% |\baselineskip| glue inserted between the two boxes makes sure we get
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% the correct spacing between the two lines, and the vboxness of the vbox
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% ensures that the baseline of my strange thing is the baseline of the
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% \emph{bottom} box. I then bash the vbox on the nose, so as to make its
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% width zero, and leave that as the result. Either way, I then add glue
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% to left align whatever it is I've created.
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\def\nextlinelabel#1{%
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\ifdim\wd\z@>\labelwidth%
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\setbox\z@\vbox{\box\z@\hbox{}}%
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% \begin{macro}{\multilinelabel}
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% A different idea -- make the label text wrap around onto the next line if
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% it's too long. This is really easy, actually. I use a parbox to contain
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% the label text, set to be ragged right, because there won't be enough
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% space to do proper justification. There's also a funny hskip there --
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% this is because \TeX\ only hyphenates things it finds sitting \emph{after}
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% glue items. The parbox is top-aligned, so the label text and the item
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% run downwards together. I put the result in box~0, and remove the depth,
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% so as not to make the top line of the item text look really strange.
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% All this leaves a little problem, though: if the item text isn't very long,
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% the label might go further down the page than the main item, and possibly
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% collide with the label below. I must confess that I'm not actually sure
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% how to deal with this possibility, so I just hope it doesn't happen.
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% By the way, I don't have moral objections to |\parbox|.
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\def\multilinelabel#1{%
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\parbox[t]\labelwidth{\raggedright\hskip\z@skip#1}%
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% \begin{macro}{\pushlabel}
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% Now we implement the old style behaviour -- if the label is too wide, we
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% just push the first line of the item further over to the right. This
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% is really very easy indeed -- we just stick some |\hfil| space on the
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% right hand side (to left align if the label comes up too short). The
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% `push' behaviour is handled automatically by \LaTeX's item handling.
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\def\pushlabel#1{{#1}\hfil}
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% \subsubsection{The main environment}
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% \begin{macro}{\desclabelstyle}
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% This is a declaration intended to be used only in the argument to the
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% \env{basedescript} environment. It sets the label style for the list.
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% All we do is take the argument and assign it to a magic control sequence
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% which \env{basedescript} will understand later.
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\def\desclabelstyle#1{\def\desc@labelstyle{#1}}
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% \begin{macro}{\desclabelwidth}
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% We set the label width and various other bits of information which will
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% make all the bits of the description line up beautifully. We set
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% |\labelwidth| to the value we're given (using |\setlength|, so that
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% people can use the \package{calc} package if they so wish), and make
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% the |\leftmargin| equal $|\labelwidth|+|\labelsep|$.
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\def\desclabelwidth#1{%
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\setlength\labelwidth{#1}%
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\leftmargin\labelwidth%
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\advance\leftmargin\labelsep%
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% \begin{environment}{basedescript}
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% This is the new description environment. It does almost everything you
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% could want from a description environment, I think. The argument is a
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% collection of declarations to be performed while setting up the list.
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% This environment isn't really intended to be used by users -- it's here
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% so that you can define other description environments in terms of it,
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% The environment is defined in two bits -- the `start' bit here simply
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% starts the list and inserts the user declarations in an appropriate
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% point, although sensible details will be inerted if the argument was
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\def\basedescript#1{%
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% We must start the list. If the |\item| command's optional argument is
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% missing, we should just leave a blank space, I think.
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% So far, so good. Now put in some default declarations. I'll use a
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% separate macro for this, so that the global appearance of lists can be
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% Now we do the user's declarations.
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% Now set up the other parts of the list. We set |\itemindent| so that the
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% label is up against the current left margin. (The standard version
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% actually leaves the label hanging to the left of the margin by a
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% distance of |\labelsep| for a reason I can't quite comprehend -- there's
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% an |\hspace{\labelsep}| in the standard |\makelabel| to compensate for
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% this. Strange\dots)
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% To make the label start in the right place, the text of the item must
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% start a distance of $|\labelwidth|+|\labelsep|$ from the (pre-list) left
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% hand margin; this means that we must set |\itemindent| to be
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% $|\labelwidth|+|\labelsep|-|\leftmargin|$. Time for some \TeX\ arithmetic.
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\itemindent\labelwidth%
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\advance\itemindent\labelsep%
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\advance\itemindent-\leftmargin%
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% Now we must set up the label typesetting. We'll take the |\makelabel|
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% provided by the user, remember it, and then redefine |\makelabel| in
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% terms of the |\desclabelstyle| and the saved |\makelabel|.
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\let\desc@makelabel\makelabel%
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\def\makelabel##1{\desc@labelstyle{\desc@makelabel{##1}}}%
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% I can't think of anything else which needs doing, so I'll call it a day
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% Now we define the `end-bit' of the environment. Since all we need to do
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% is to close the list, we can be ever-so slightly clever and use |\let|.
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\let\endbasedescript\endlist
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% Note that with these definitions, the standard \env{description}
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% environment can be emulated by saying simply:
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%\renewenvironment{description}{%
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% \begin{basedescript}{}%
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% \begin{macro}{\defaultdesc}
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% Now to set up the standard description appearance. In the absence
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% of any other declarations, the label will `push' the text out the way if
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% the text is too long. The standard |\labelsep| and |\leftmargin| are not
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% our problem. We typeset the label text in bold by default. Also,
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% |\labelwidth| is cleared to 0\,pt, because this is what \LaTeX's usual
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% \env{description} does.
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\providecommand\defaultdesc{%
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\desclabelstyle\pushlabel%
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\def\makelabel##1{\bfseries##1}%
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% \subsubsection{An example}
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% \begin{environment}{note}
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% The \env{note} environment is a simple application of the general
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% description list shown above. It typesets the label (by default, the
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% text `\textbf{note}') at the left margin, and the note text indented by
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% the width of the label.
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% The code is simple -- we take the environment's argument (which may have
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% been omitted), store it in a box (using |\sbox| again, to handle colour
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% changes correctly), set the label width from the width of the box, and
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% then create a single item containing the label text. The text of the
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% environment then appears in exactly the desired place.
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% I've not used |\newcommand| here, for the following reasons:
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% \item I don't like it much, to be honest.
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% \item Until very recently, |\newcommand| only allowed you to define
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% `long' commands, where new paragraphs were allowed to be started
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% in command arguments; this removes a useful check which traps
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% common errors like missing out `|}|' characters. I'd prefer to
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% be compatible with older \LaTeX s than to use the new |\newcommand|
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% which provides a $*$-form to work around this restriction.
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\def\note{\@ifnextchar[\note@i{\note@i[Note:]}}
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\sbox\z@{\makelabel{#1}}%
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\desclabelwidth{\wd\z@}%
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\let\endnote\endbasedescript
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% \subsection{Compacted environments}
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% Normal lists tend to have rather too much space between items if all or
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% most of the item texts are one line or less each. We therefore define
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% a macro |\makecompactlist| whuch creates `compacted' versions of existing
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% \begin{macro}{\makecompactlist}
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% We're given two arguments: the name of the new environment to create, and
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% the name of the existing list environment to create.
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% The first thing to do is to ensure that the environment we're creating is
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% actually valid (i.e., it doesn't exist already, and it has a sensible
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% name). We can do this with the internal \LaTeX\ macro |\@ifdefinable|.
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\def\makecompactlist#1#2{%
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\expandafter\@ifdefinable\csname#1\endcsname%
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{\makecompactlist@i{#1}{#2}}%
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% We also ought to ensure that the other environment already exists. This
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% isn't too tricky. We'll steal \LaTeX's error and message for this.
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\def\makecompactlist@i#1#2{%
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\@ifundefined{#2}{\me@err{Environment `#2' not defined}\@ehc}{}%
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% The main work for starting a compact list is done elsewhere.
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\@namedef{#1}{\@compact@list{#2}}%
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% Now to define the end of the environment; this isn't terribly difficult.
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\expandafter\let\csname end#1\expandafter\endcsname%
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\csname end#2\endcsname%
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% That's a compacted environment created. Easy, no?
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% The general case macro has to try slurping some arguments, calling the
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% underlying environment, and removing vertical space.
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\def\@compact@list#1{\@testopt{\@compact@list@i{#1}}{}}
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\def\@compact@list@i#1[#2]{%
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% \begin{environment}{itemize*}
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% \begin{environment}{enumerate*}
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% \begin{environment}{description*}
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% Let's build some compacted environments now. These are easy now that
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% we've done all the work above.
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\makecompactlist{itemize*}{itemize}
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\makecompactlist{enumerate*}{enumerate}
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\makecompactlist{description*}{description}
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% \subsection{Suspending and resuming lists}
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% This is nowhere near perfect; it relies a lot on the goodwill of the user,
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% although it seems to work fairly well.
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% \begin{macro}{\suspend}
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% The only thing that needs saving here is the list counter, whose name
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% is stored in |\@listctr|. When I get a request to save the counter, I'll
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% build a macro which will restore it when the environment is restored later.
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% The first thing to do is to handle the optional argument. |\@dblarg| will
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% sort this out, giving me a copy of the mandatory argument if there's no
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% optional one provided.
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\def\suspend{\@dblarg\suspend@i}
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% That's all we need to do here.
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\def\suspend@i[#1]#2{%
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% Now I have a little problem; when I |\end| the environment, it will close
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% off the grouping level, and the counter value will be forgotten. This is
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% bad. I'll store all my definitions into a macro, and build the |\end|
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% command into it; that way, everything will be expanded correctly. This
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% requires the use of |\edef|, which means I must be a little careful.
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% The first thing to do is to end the environment. I don't want |\end|
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% expanded yet, so I'll use |\noexpand|.
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% Now I must define the `resume' macro. I'll use |\csname| to build the
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% named identifier into the name, so it won't go wrong (maybe). There's
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% a little fun here to make the control sequence name but not expand it
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\def\expandafter\noexpand\csname resume.#1\endcsname{%
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% The counter name is hidden inside |\@listctr|, so the actual counter is
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% called `|\csname c@\@listctr\endcsname|'. I'll use |\the| to read its
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% current value, and assign it to the counter when the macro is used later.
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\csname c@\@listctr\endcsname\the\csname c@\@listctr\endcsname%
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% That's all we need to do there. Now close the macros and run them.
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% \begin{macro}{\resume}
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% Resuming environments is much easier. Since I use |\csname| to build the
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% name, nothing happens if you try to resume environments which weren't
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% suspended. I'll trap this and raise an error. Provide an optional
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% argument for collecting arguments to the target list.
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\def\resume{\@dblarg\resume@i}
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\def\resume@i[#1]#2{\@testopt{\resume@ii{#1}{#2}}{}}
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\def\resume@ii#1#2[#3]{%
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\@ifundefined{resume.#1}{\ml@err@resume}{\@nameuse{resume.#1}}%
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% That's all there is.
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% \hfill Mark Wooding, \today
added
removed
docs/packages/mdwtools/mdwlist.dtx
