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Diffstat (limited to 'Doc/texinputs/underscore.sty')
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diff --git a/Doc/texinputs/underscore.sty b/Doc/texinputs/underscore.sty new file mode 100644 index 0000000..a274b39 --- /dev/null +++ b/Doc/texinputs/underscore.sty @@ -0,0 +1,232 @@ +% underscore.sty 12-Oct-2001 Donald Arseneau asnd@triumf.ca +% Make the "_" character print as "\textunderscore" in text. +% Copyright 1998,2001 Donald Arseneau; Distribute freely if unchanged. +% Instructions follow after the definitions. + +\ProvidesPackage{underscore}[2001/10/12] + +\begingroup + \catcode`\_=\active + \gdef_{% \relax % No relax gives a small vulnerability in alignments + \ifx\if@safe@actives\iftrue % must be outermost test! + \string_% + \else + \ifx\protect\@typeset@protect + \ifmmode \sb \else \BreakableUnderscore \fi + \else + \ifx\protect\@unexpandable@protect \noexpand_% + \else \protect_% + \fi\fi + \fi} +\endgroup + +% At begin: set catcode; fix \long \ttdefault so I can use it in comparisons; +\AtBeginDocument{% + {\immediate\write\@auxout{\catcode\number\string`\_ \string\active}}% + \catcode\string`\_\string=\active + \edef\ttdefault{\ttdefault}% +} + +\newcommand{\BreakableUnderscore}{\leavevmode\nobreak\hskip\z@skip + \ifx\f@family\ttdefault \string_\else \textunderscore\fi + \usc@dischyph\nobreak\hskip\z@skip} + +\DeclareRobustCommand{\_}{% + \ifmmode \nfss@text{\textunderscore}\else \BreakableUnderscore \fi} + +\let\usc@dischyph\@dischyph +\DeclareOption{nohyphen}{\def\usc@dischyph{\discretionary{}{}{}}} +\DeclareOption{strings}{\catcode`\_=\active} + +\ProcessOptions +\ifnum\catcode`\_=\active\else \endinput \fi + +%%%%%%%% Redefine commands that use character strings %%%%%%%% + +\@ifundefined{UnderscoreCommands}{\let\UnderscoreCommands\@empty}{} +\expandafter\def\expandafter\UnderscoreCommands\expandafter{% + \UnderscoreCommands + \do\include \do\includeonly + \do\@input \do\@iinput \do\InputIfFileExists + \do\ref \do\pageref \do\newlabel + \do\bibitem \do\@bibitem \do\cite \do\nocite \do\bibcite +} + +% Macro to redefine a macro to pre-process its string argument +% with \protect -> \string. +\def\do#1{% Avoid double processing if user includes command twice! + \@ifundefined{US\string_\expandafter\@gobble\string#1}{% + \edef\@tempb{\meaning#1}% Check if macro is just a protection shell... + \def\@tempc{\protect}% + \edef\@tempc{\meaning\@tempc\string#1\space\space}% + \ifx\@tempb\@tempc % just a shell: hook into the protected inner command + \expandafter\do + \csname \expandafter\@gobble\string#1 \expandafter\endcsname + \else % Check if macro takes an optional argument + \def\@tempc{\@ifnextchar[}% + \edef\@tempa{\def\noexpand\@tempa####1\meaning\@tempc}% + \@tempa##2##3\@tempa{##2\relax}% + \edef\@tempb{\meaning#1\meaning\@tempc}% + \edef\@tempc{\noexpand\@tempd \csname + US\string_\expandafter\@gobble\string#1\endcsname}% + \if \expandafter\@tempa\@tempb \relax 12\@tempa % then no optional arg + \@tempc #1\US@prot + \else % There is optional arg + \@tempc #1\US@protopt + \fi + \fi + }{}} + +\def\@tempd#1#2#3{\let#1#2\def#2{#3#1}} + +\def\US@prot#1#2{\let\@@protect\protect \let\protect\string + \edef\US@temp##1{##1{#2}}\restore@protect\US@temp#1} +\def\US@protopt#1{\@ifnextchar[{\US@protarg#1}{\US@prot#1}} +\def\US@protarg #1[#2]{\US@prot{{#1[#2]}}} + +\UnderscoreCommands +\let\do\relax \let\@tempd\relax % un-do + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +\endinput + +underscore.sty 12-Oct-2001 Donald Arseneau + +Features: +~~~~~~~~~ +\_ prints an underscore so that the hyphenation of constituent words +is not affected and hyphenation is permitted after the underscore. +For example, "compound\_fracture" hyphenates as com- pound_- frac- ture. +If you prefer the underscore to break without a hyphen (but still with +the same rules for explicit hyphen-breaks) then use the [nohyphen] +package option. + +A simple _ acts just like \_ in text mode, but makes a subscript in +math mode: activation_energy $E_a$ + +Both forms use an underscore character if the font encoding contains +one (e.g., "\usepackage[T1]{fontenc}" or typewriter fonts in any encoding), +but they use a rule if the there is no proper character. + +Deficiencies: +~~~~~~~~~~~~~ +The skips and penalties ruin any kerning with the underscore character +(when a character is used). However, there doesn't seem to be much, if +any, such kerning in the ec fonts, and there is never any kerning with +a rule. + +You must avoid "_" in file names and in cite or ref tags, or you must use +the babel package, with its active-character controls, or you must give +the [strings] option, which attempts to redefine several commands (and +may not work perfectly). Even without the [strings] option or babel, you +can use occasional underscores like: "\include{file\string_name}". + +Option: [strings] +~~~~~~~~~~~~~~~~~ +The default operation is quite simple and needs no customization; but +you must avoid using "_" in any place where LaTeX uses an argument as +a string of characters for some control function or as a name. These +include the tags for \cite and \ref, file names for \input, \include, +and \includegraphics, environment names, counter names, and placement +parameters (like "[t]"). The problem with these contexts is that they +are `moving arguments' but LaTeX does not `switch on' the \protect +mechanism for them. + +If you need to use the underscore character in these places, the package +option [strings] is provided to redefine commands taking a string argument +so that the argument is protected (with \protect -> \string). The list +of commands is given in "\UnderscoreCommands", with "\do" before each, +covering \cite, \ref, \input, and their variants. Not included are many +commands regarding font names, everything with counter names, environment +names, page styles, and versions of \ref and \cite defined by external +packages (e.g. \vref and \citeyear). + +You can add to the list of supported commands by defining \UnderscoreCommands +before loading this package; e.g. + + \usepackage{chicago} + \newcommand{\UnderscoreCommands}{% (\cite already done) + \do\citeNP \do\citeA \do\citeANP \do\citeN \do\shortcite + \do\shortciteNP \do\shortciteA \do\shortciteANP \do\shortciteN + \do\citeyear \do\citeyearNP + } + \usepackage[strings]{underscore} + +Not all commands can be supported this way! Only commands that take a +string argument *first* can be protected. One optional argument before +the string argument is also permitted, as exemplified by \cite: both +\cite{tags} and \cite[text]{tags} are allowed. A command like +\@addtoreset which takes two counter names as arguments could not +be protected by adding it to \UnderscoreCommands. + +!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! +!! When you use the [strings] option, you must load this package !! +!! last (or nearly last). !! +!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! + +There are two reasons: 1) The redefinitions done for protection must come +after other packages define their customized versions of those commands. +2) The [strings] option requires the _ character to be activated immediately +in order for the cite and ref tags to be read properly from the .aux file +as plain strings, and this catcode setting might disrupt other packages. + +The babel package implements a protection mechanism for many commands, +and will be a complete fix for most documents without the [strings] option. +Many add-on packages are compatible with babel, so they will get the +strings protection also. However, there are several commands that are +not covered by babel, but can easily be supported by the [strings] and +\UnderscoreCommands mechanism. Beware that using both [strings] and babel +may lead to conflicts, but does appear to work (load babel last). + +Implementation Notes: +~~~~~~~~~~~~~~~~~~~~~ +The first setting of "_" to be an active character is performed in a local +group so as to not interfere with other packages. The catcode setting +is repeated with \AtBeginDocument so the definition is in effect for the +text. However, the catcode setting is repeated immediately when the +[strings] option is detected. + +The definition of the active "_" is essentially: + \ifmmode \sb \else \BreakableUnderscore \fi +where "\sb" retains the normal subscript meaning of "_" and where +"\BreakableUnderscore" is essentially "\_". The rest of the definition +handles the "\protect"ion without causing \relax to be inserted before +the character. + +\BreakableUnderscore uses "\nobreak\hskip\z@skip" to separate the +underscore from surrounding words, thus allowing TeX to hyphenate them, +but preventing free breaks around the underscore. Next, it checks the +current font family, and uses the underscore character from tt fonts or +otherwise \textunderscore (which is a character or rule depending on +the font encoding). After the underscore, it inserts a discretionary +hyphenation point as "\usc@dischyph", which is usually just "\-" +except that it still works in the tabbing environment, although it +will give "\discretionary{}{}{}" under the [nohyphen] option. After +that, another piece of non-breaking interword glue is inserted. +Ordinarily, the comparison "\ifx\f@family\ttdefault" will always fail +because \ttdefault is `long' where \f@family is not (boooo hisss), but +\ttdefault is redefined to be non-long by "\AtBeginDocument". + +The "\_" command is then defined to use "\BreakableUnderscore". + +If the [strings] option is not given, then that is all! + +Under the [strings] option, the list of special commands is processed to: +- retain the original command as \US_command (\US_ref) +- redefine the command as \US@prot\US_command for ordinary commands + (\ref -> \US@prot\US_ref) or as \US@protopt\US_command when an optional + argument is possible (\bibitem -> \US@protopt\US_bibitem). +- self-protecting commands (\cite) retain their self-protection. +Diagnosing the state of the pre-existing command is done by painful +contortions involving \meaning. + +\US@prot and \US@protopt read the argument, process it with \protect +enabled, then invoke the saved \US_command. + +Modifications: +~~~~~~~~~~~~~~ +12-Oct-2001 Babel (safe@actives) compatibility and [nohyphen] option. + +Test file integrity: ASCII 32-57, 58-126: !"#$%&'()*+,-./0123456789 +:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ |