As with the font definition file commands, it is also possible (although normally not necessary) to use these declarations directly within a class or package file.
Warning: Some aspects of the contents of font definition files
are still under development. Therefore, the current versions of the
files ot1enc.def and t1enc.def are temporary versions and should
not be used as models for producing further such files. For further
information you should read the documentation in ltoutenc.dtx.
\ProvidesFile{<file-name>}[<release-info>]
The file should announce itself with a \ProvidesFile
command, described in LaTeX2e for Class and Package Writers. For example:
\ProvidesFile{ot2enc.def}
[1994/06/01 Washington University Cyrillic encoding]
\DeclareFontEncoding {<encoding>} {<text-settings>}
{<math-settings>}
Declares a new encoding scheme <encoding>.
The <text-settings> are
declarations which are executed every time \selectfont changes the
encoding to be <encoding>.
The <math-settings> are similar but are for math alphabets. They
are executed whenever a math alphabet with this encoding is
called.
It also saves the value of <encoding> in the macro
\LastDeclaredEncoding.
Spaces within the arguments are ignored to avoid surplus
spaces in the document. If a real space is necessary
use \space.
Example:
\DeclareFontEncoding{OT1}{}{}
Some author commands need to change their definition depending on
which encoding is currently in use. For example, in the OT1
encoding, the letter `Æ' is in slot "1D, whereas in the T1
encoding it is in slot "C6. So the definition of \AE has to
change depending on whether the current encoding is OT1 or T1.
The following commands allow this to happen.
\DeclareTextCommand {<cmd>} {<encoding>}
[<num>] [<default>] {<definition>}
This command is like \newcommand, except that it defines a
command which is specific to one encoding. For example, the
definition of \k in the T1 encoding is:
\DeclareTextCommand{\k}{T1}[1]
{\oalign{\null#1\crcr\hidewidth\char12}}
\DeclareTextCommands takes the same optional arguments as
\newcommand.
The resulting command is
robust, even if the code in <definition> is fragile.
It does not produce an error if the command has already
been defined but logs the redefinition in the transcript file.
\ProvideTextCommand {<cmd>} {<encoding>}
[<num>] [<default>] {<definition>}
This command is the same as \DeclareTextCommand, except that
if <cmd> is already defined in encoding <encoding>, then the
definition is ignored.
\DeclareTextSymbol {<cmd>} {<encoding>} {<slot>}
This command defines a text symbol with slot <slot> in the
encoding. For example, the definition of \ss in the OT1 encoding
is:
\DeclareTextSymbol{\ss}{OT1}{25}
It does not produce an error if the command has already
been defined but logs the redefinition in the transcript file.
\DeclareTextAccent {<cmd>} {<encoding>} {<slot>}
This command declares a text accent, with the accent taken from slot
<slot> in the encoding. For example, the definition of \" in
the OT1 encoding is:
\DeclareTextAccent{\"}{OT1}{127}
It does not produce an error if the command has already
been defined but logs the redefinition in the transcript file.
\DeclareTextComposite {<cmd>} {<encoding>} {<letter>}
{<slot>}
This command declares that the composite letter formed from applying
<cmd> to <letter> is defined to be simply slot <slot> in the
encoding. The <letter> should be a single letter (such as a) or
a single command (such as \i).
For example, the definition of \'{a}
in the T1 encoding could be declared like this:
\DeclareTextComposite{\'}{T1}{a}{225}
The <cmd> will normally have been previously declared
for this encoding, either by using
\DeclareTextAccent, or as a one-argument \DeclareTextCommand.
\DeclareTextCompositeCommand {<cmd>} {<encoding>} {<letter>}
{<definition>}
This is a more general form of \DeclareTextComposite, which allows
for an arbitrary <definition>, not just a <slot>. The main use
for this is to allow accents on i to act like accents on \i, for
example:
\DeclareTextCompositeCommand{\'}{OT1}{i}{\'\i}
It has the same restrictions as \DeclareTextComposite.
\LastDeclaredEncoding
This holds the name of the last encoding declared via
\DeclareFontEncoding (this should also be the currently most
efficient encoding). It can be used in the <encoding> argument
of the above declarations in place of explicitly mentioning the
encoding, e.g.
\DeclareFontEncoding{T1}{}{}
\DeclareTextAccent{\`}{\LastDeclaredEncoding}{0}
\DeclareTextAccent{\'}{\LastDeclaredEncoding}{1}
This can be useful in cases where encoding files sharing common code
are generated from one source.