mirror of
https://github.com/python/cpython.git
synced 2025-11-04 03:44:55 +00:00
232 lines
9.9 KiB
TeX
232 lines
9.9 KiB
TeX
% 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{|}~
|