Babel, a multilingual package for use with LATEX's ... - linsrv.net

This macro expects the name of a group of shorthands in its first argument and a
shorthand character in its second argument. It will expand to either \bbl@firstcs
or \bbl@scndcs. Hence two more arguments need to follow it.
560 \def\bbl@sh@select#1#2{%
561 \expandafter\ifx\csname#1@sh@#2@sel\endcsname\relax
562 \bbl@afterelse\bbl@scndcs
563 \else
564 \bbl@afterfi\csname#1@sh@#2@sel\endcsname
565 \fi}
\active@prefix
The command \active@prefix which is used in the expansion of active characters
has a function similar to \OT1-cmd in that it \protects the active character
whenever \protect is not \@typeset@protect.
566 \def\active@prefix#1{%
567 \ifx\protect\@typeset@protect
568 \else
When \protect is set to \@unexpandable@protect we make sure that the active
character is als not expanded by inserting \noexpand in front of it. The \@gobble
is needed to remove a token such as \activechar: (when the double colon was
the active character to be dealt with).
569 \ifx\protect\@unexpandable@protect
570 \noexpand#1%
571 \else
572 \protect#1%
573 \fi
574 \expandafter\@gobble
575 \fi}
\if@safe@actives
\bbl@restore@actives
\bbl@activate
\bbl@deactivate
\bbl@firstcs
\bbl@scndcs
In some circumstances it is necessary to be able to change the expansion of an
active character on the fly. For this purpose the switch @safe@actives is available.
The setting of this switch should be checked in the first level expansion of
\active@char〈char〉.
576 \newif\if@safe@actives
577 \@safe@activesfalse
When the output routine kicks in while the active characters were made “safe” this
must be undone in the headers to prevent unexpected typeset results. For this
situation we define a command to make them “unsafe” again.
578 \def\bbl@restore@actives{\if@safe@actives\@safe@activesfalse\fi}
Both macros take one argument, like \initiate@active@char. The macro is used
to change the definition of an active character to expand to \active@char〈char〉 in
the case of \bbl@activate, or \normal@char〈char〉 in the case of
\bbl@deactivate.
579 \def\bbl@activate#1{%
580 \bbl@withactive{\expandafter\let\expandafter}#1%
581 \csname bbl@active@\string#1\endcsname}
582 \def\bbl@deactivate#1{%
583 \bbl@withactive{\expandafter\let\expandafter}#1%
584 \csname bbl@normal@\string#1\endcsname}
These macros have two arguments. They use one of their arguments to build a
control sequence from.
585 \def\bbl@firstcs#1#2{\csname#1\endcsname}
586 \def\bbl@scndcs#1#2{\csname#2\endcsname}
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