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diff --git a/macros/latex/contrib/url/url.tex b/macros/latex/contrib/url/url.tex new file mode 100644 index 0000000000..a53a3a8fa5 --- /dev/null +++ b/macros/latex/contrib/url/url.tex @@ -0,0 +1,325 @@ +\documentclass[a4paper,11pt]{article} +\usepackage[T1]{fontenc} +\usepackage{lmodern} +\usepackage{miscdoc,url,booktabs,microtype} +\addtolength\textwidth{1cm} +\addtolength\oddsidemargin{-.5cm} +\addtolength\evensidemargin{-.5cm} +\raggedbottom +\setlength\parskip{4pt plus 2pt} + +\begin{document} +\title{\texttt{url.sty} version 3.4} +\date{2013-09-16} +\author{Donald Arseneau% + \thanks{Thanks to Robin Fairbairns for documentation conversion!}} +\maketitle + +% url.sty ver 3.4 16-Sep-2013 Donald Arseneau asnd@triumf.ca +% Copyright 1996-2013 Donald Arseneau, Vancouver, Canada. +% This program can be used, distributed, and modified under the terms +% of the LaTeX Project Public License, version 2 or later. + +The package defines a form of \cs{verb} command that allows linebreaks +at certain characters or combinations of characters, accepts +reconfiguration, and can usually be used in the argument to another +command. It is intended for formatting email addresses, hypertext links, +directories/paths, etc., which normally have no spaces. The font used +may be selected using the \cs{urlstyle} command, and new url-like +commands may be defined using \cs{urldef}. +This package does not make hyper-links! For that purpose, see the hyperref +package (or some other deprecated ones). + +\begin{center} + \begin{tabular}{lp{3.5in}} + \toprule + Usage & Conditions \\ + \midrule + \verb+\url{ }+ & The argument must not contain unbalanced braces. + If used in the argument to another command, the + \cs{url} argument cannot contain any ``\verb+%+'', + ``\verb+#+'', or ``\verb+^^+'', or end with + ``\verb+\+''.\\ + \verb+\url| |+ & where ``\texttt{|}'' is any character not used + in the argument and not ``\verb+{+'' or a space. + The same restrictions apply as above except that + the argument may contain unbalanced braces.\\ + \cs{xyz} & for the defined-url ``\cs{xyz}''; such a command can be + used anywhere, no matter what characters it contains. \\ + \bottomrule + \end{tabular} + \end{center} + +\noindent The ``\cs{url}'' command is fragile, and its argument is likely to be +very fragile, but a defined-url is robust. + +\section{Package options} + +\newitem Package Option: \texttt{obeyspaces} + +Ordinarily, all spaces are ignored in the url-text. The +``\texttt{[obeyspaces]}'' option allows spaces, but may introduce +spurious spaces when a url containing ``\cs{}'' characters is given in +the argument to another command. +So if you need to obey spaces you can say +``\cs{usepackage}\texttt{[obeyspaces]\char`\{url\char`\}}'', and if +you need both spaces and backslashes, use a defined-url. + +\newitem Package Option: \texttt{hyphens} + +Ordinarily, breaks are not allowed after ``\texttt{-}'' characters +because this leads to confusion. (Is the ``\texttt{-}'' part of the +address or just a hyphen?) +The package option ``\texttt{[hyphens]}'' allows breaks after explicit +hyphen characters. The \cs{url} command will \textbf{never ever} +hyphenate words. + +\newitem Package Option: \texttt{spaces} + +Likewise, given the ``\texttt{[obeyspaces]}'' option, breaks are not +usually allowed after the spaces, but if you give the options +``\texttt{[obeyspaces,spaces]}'', \cs{url} will allow breaks at those +spaces. +\begin{quote} + Note that it seems logical to allow the sole option + ``\texttt{[spaces]}'' to let input spaces indicate break points, but + not to display them in the output. This would be easy to implement, + but is left out to avoid(?)\ confusion. +\end{quote} + +\newitem Package Option: \texttt{lowtilde} + +Normal treatment of the \verb+~+ character is to use the font's +``\cs{textasciitilde}'' character, if it has one (or claims to). +Otherwise, the character is faked using a mathematical ``\cs{sim}''. +The ``\texttt{[lowtilde]}'' option causes a faked character to be used +always (and a bit lower than usual). + +\newitem Package Option: \texttt{allowmove} + +This option suppresses the test for \cs{url} being used in a so-called +moving argument (check ``fragile command''). Using it will enable \cs{url} +to function in more contexts, but when it does fail, the error message +may be incomprehensible. + + +\section{Defining a defined-url} + +Take for example the email address ``\url{myself%node@gateway.net}" +which could not be given (using ``\cs{url}'' or ``\cs{verb}'') in a +caption or parbox due to the percent sign. This address can be +predefined with +\begin{quote} + \verb|\urldef{\myself}\url{myself%node@gateway.net}| or\\ + \verb+\urldef{\myself}\url|myself%node@gateway.net|+ +\end{quote} +and then you may use ``\cs{myself}'' instead of +``\verb+\url{myself%node@gateway.net}+'' +in an argument, and even in a moving argument like a caption because a +defined-url is robust. + +\section{Style} + +You can switch the style of printing using ``\verb+\urlstyle{+$xx$\verb+}+'', +where ``$xx$'' can be any defined style. The pre-defined styles are +``\texttt{tt}'', ``\texttt{rm}'', ``\texttt{sf}'' and ``\texttt{same}'' +which all allow the same linebreaks but use different fonts~--- the +first three select a specific font and the ``\texttt{same}'' style +uses the current text font. You can define your own styles with +different fonts and/or line-breaking by following the explanations +below. The ``\cs{url}'' command follows whatever the currently-set +style dictates. + +\section{Alternate commands} + +It may be desireable to have different things treated differently, each +in a predefined style; e.g., if you want directory paths to always be +in typewriter and email addresses to be roman, then you would define new +url-like commands as follows: +\begin{quote} + \verb+\DeclareUrlCommand+\meta{command}\verb+{+\meta{settings}\verb+}+\\ + \verb+\DeclareUrlCommand\email{\urlstyle{rm}}+\\ + \verb+\DeclareUrlCommand\directory{\urlstyle{tt}}+. +\end{quote} +In fact, this \cs{directory} example is exactly the \cs{path} +definition which might be pre-defined by the package. Furthermore, +basic \cs{url} is defined with +\begin{quote} + \verb+\DeclareUrlCommand\url{}+, +\end{quote} +without any \emph{settings}, so it uses whatever \cs{urlstyle} +and other settings are already in effect. + +You can make a defined-url for these other styles, using the usual +\cs{urldef} command as in this example: +\begin{quote} +\verb+\urldef{\myself}{\email}{myself%node.domain@gateway.net}+ +\end{quote} +which makes \cs{myself} act like +\verb+\email{myself%node.domain@gateway.net}+, +if the \cs{email} command is defined as above. The \cs{myself} +command would then be robust. + +\section{Defining styles} + +Before describing how to customize the printing style, it is best to +mention something about the unusual implementation of \cs{url}. Although +the material is textual in nature, and the font specification required +is a text-font command, the text is actually typeset in \emph{math} mode. +This allows the context-sensitive linebreaking, but also accounts for +the default behavior of ignoring spaces. (Maybe that underlying design +will eventually change.) Now on to defining styles. + +To change the font or the list of characters that allow linebreaks, you +could redefine the commands \cs{UrlFont}, \cs{UrlBreaks}, +\cs{UrlSpecials}, etc., directly in the document, but it is better to +define a new `url-style' (following the example of \cs{url@ttstyle} +and \cs{url@rmstyle}) which defines all of \cs{UrlBigbreaks}, +\cs{UrlNoBreaks}, \cs{UrlBreaks}, \cs{UrlSpecials}, and \cs{UrlFont}. + +\subsection{Changing font} +The \cs{UrlFont} command selects the font. The definition of +\cs{UrlFont} done by the pre-defined styles varies to cope with a +variety of \LaTeX{} font selection schemes, but it could be as simple +as \verb+\def\UrlFont{\tt}+. Depending on the font selected, some +characters may need to be defined in the \cs{UrlSpecials} list because +many fonts don't contain all the standard input characters. + +\subsection{Changing linebreaks} +The list of characters after which line-breaks are permitted is +given by the two commands (list macros) +\cs{UrlBreaks} and \cs{UrlBigBreaks}. They consist of repeating +\cs{do}\cs{c} for each relevant character \texttt{c}. + +The differences are that `BigBreaks' typically have a lower penalty (more +easily chosen) and do not break within a repeating sequence (e.g., +``\verb+DEC::NODE+''). +(For gurus: `BigBreaks' are treated as mathrels while `Breaks' are mathbins; +see \textit{The TeXbook}, p.\,170.) The result is that a series of +consecutive `BigBreak' +characters will break at the end and only at the end; a series of +`Break' characters will break after the first and after every following +\emph{pair}; there will be no break between a `Break' character and a +following `BigBreak' char; breaks are permitted when a `BigBreak' +character is followed by `Break' or any other char. In the case +of \texttt{http://} it doesn't matter whether \texttt{:} is a +`Break' or `BigBreak'~--- the breaks are the same in either case; but +for (now ancient) \emph{DECnet} addresses using \texttt{::} it was +important to prevent breaks \emph{between} the colons, and that is why +colons are `BigBreaks'. (The only other `BigBreak' character is, +optionally, the hyphen; slashes are regular `Break's.) + +It is possible for characters to prevent breaks after the next +following character (this is used for parentheses). Specify these in +\cs{UrlNoBreaks}. + +You can allow some spacing around the breakable characters by assigning +\begin{quote} +\verb+\Urlmuskip = 0mu plus 1mu+ +\end{quote} +(with \texttt{mu} units because of math mode). +You can change the penalties used for BigBreaks and Breaks by assigning +\begin{quote} +\verb+\mathchardef\UrlBreakPenalty=100+\\ +\verb+\mathchardef\UrlBigBreakPenalty=100+ +\end{quote} +The default penalties are \cs{binoppenalty} and \cs{relpenalty}. +These have such odd non-\LaTeX{} syntax because I don't expect people +to need to change them often. (The \verb+\mathchardef+ does not relate to +math mode; it is only a way to store a number without consuming registers.) + +\subsubsection{Arbitrary character actions} + +You can do arbitrarily complex things with characters by specifying +their definition(s) in \cs{UrlSpecials}. This makes them `active' in +math mode (mathcode \texttt{"8000}). The format for setting +each special character \texttt{c} is: +\verb+\do\c{+\meta{definition}\verb+}+, but other definitions not +following this style can also be included. + +Here is an example to make ``\texttt{!}''\ inside \cs{url} force a line break +instead of being treated verbatim (it uses \LaTeX's \cs{g@addto@macro}): + +\begin{quote} +\verb+\makeatletter \g@addto@macro\UrlSpecials{\do\!{\newline}}+ +\end{quote} + +Here is another overly-complicated example to put extra flexible +muglue around each ``\texttt{/}'' character, except when followed +by another ``\texttt{/}'', as in ``\texttt{http://}'', where extra +spacing looks poor. + +\begin{quote} +\begin{verbatim} +% what we'll insert before and after each (lone) slash: +\newmuskip\Urlslashmuskip +\Urlslashmuskip=2mu plus2mu minus2mu + +% change what / does: +\g@addto@macro\UrlSpecials{\do\/{\Urlspaceyslash}} + +% need to look ahead: +\def\Urlspaceyslash{\futurelet\Urlssnext\finishUrlspaceyslash} + +\def\finishUrlspaceyslash{% + \mskip\Urlslashmuskip % extra space before + \mathchar8239 % "202f, i.e., binary op, \fam, / char + % if we see //, eliminate the extra space to taste: + \ifx\Urlssnext/\mskip-\Urlslashmuskip + \else\mskip\Urlslashmuskip \fi + } +\end{verbatim} +\end{quote} + +If this sounds confusing~\dots{} well, it is! But I hope you +won't need to redefine breakpoints~--- the default assignments seem to +work well for a wide variety of applications. If you do need to make +changes, you can test for breakpoints using regular math mode and the +characters ``\texttt{+=(a}''. + + +\section{Yet more flexibility} +You can also customize the presentation of verbatim text by defining +\cs{UrlRight} and/or \cs{UrlLeft}. An example for ISO formatting of +urls surrounded by \verb+< >+ is +\begin{quote} +\begin{verbatim} +\DeclareUrlCommand\url{\def\UrlLeft{<url:\ }\def\UrlRight{>}% + \urlstyle{tt}} +\end{verbatim} +\end{quote} +The meanings of \cs{UrlLeft} and \cs{UrlRight} are \emph{not} +reproduced verbatim. This lets you use formatting commands there, but +you must be careful not to use \TeX's special characters +(\verb+\^_%~#$&{}+ etc.)\ improperly. You can also define \cs{UrlLeft} +to reprocess the verbatim text, but the format of the definition is special: +\begin{quote} +\verb+\def\UrlLeft#1\UrlRight{+\,\dots\ do things with \verb+#1+ \dots\,\verb+}+ +\end{quote} +Yes, that is \verb+#1+ followed by \cs{UrlRight} then the definition (a \TeX\ +macro with delimited arguments). For example, to produce a hyper\TeX\ hypertext +link: +\begin{quote} +\verb+\def\UrlLeft#1\UrlRight{%+\\ +\verb+ \special{html:<a href="#1">}#1\special{html:</a>}}+ +\end{quote} +Using this technique, \path{url.sty} can provide a convenient +interface for performing various operations on verbatim text. You +don't even need to print out the argument! For greatest efficiency in +such obscure applications, you can define a null url-style where all +the lists like \cs{UrlBreaks} are empty. + +Please note that this method is \emph{not} how the hyperref package +manages urls for its \cs{url} command, even though it makes use of +\path{url.sty}. Instead, hyperref's \cs{url} reads its argument in +a less-verbatim manner than described above, produces its hyperlink, +and invokes \cs{nolinkurl} to format the text. \cs{nolinkurl} is +the \cs{url} command descibed herein. + +\end{document} + + +%%% Local Variables: +%%% mode: latex +%%% TeX-master: t +%%% End: |