\documentclass{article}

\usepackage{hyperref,bookmark}
\hypersetup{colorlinks=true,linkcolor=blue,urlcolor=blue,pdfencoding=auto}
\usepackage{parskip}
\usepackage{amsmath}

\ifdefined\XeTeXrevision
  \usepackage[no-math]{fontspec}
  \setmainfont{Linux Libertine O}
  \usepackage[libertine,slantedGreek]{newtxmath}
\else\ifdefined\luatexversion
  \usepackage{fontspec}
  \setmainfont{Linux Libertine O}
  \usepackage[libertine,slantedGreek]{newtxmath}
\else
  \usepackage[utf8]{inputenc}
  \usepackage[LGR,T1]{fontenc}
  \usepackage{textcomp}
  % \usepackage{lmodern}
  % \usepackage{gfsdidot}
  % \usepackage{kerkis}
  \usepackage{newtxtext,newtxmath}
  \usepackage{substitutefont}
  \substitutefont{LGR}{\rmdefault}{artemisia}
  \usepackage{isomath}
\fi\fi

% No section numbers but PDF bookmarks for sections
\setcounter{secnumdepth}{0}

% load alphabeta after math setup and encoding setup!
\usepackage{alphabeta}

% Avoid warnigns with PDF string generation for "alphabeta" commands:

% let \TextOrMath (from fixltx2e) return the "text" argument:
\pdfstringdefDisableCommands{%
  \let\TextOrMath\@firstoftwo%
}

% \varstigma is not defined with Xe/LuaTeX:
\providecommand*{\varstigma}{$\oslash$}


\begin{document}

\title{The \emph{alphabeta} package}
\author{Günter Milde}
\maketitle

With the \emph{alphabeta} package, you can write Greek letters ``by name''
or as literal Unicode characters in both, ``text'' and ``math'' mode. The
mode determines whether the letters are taken from the text or math font.
Just like Latin letters, the Greek counterparts are by default italic in
math mode (capital letters upright without \emph{fixmath} or
\emph{\href{http://www.ctan.org/pkg/isomath}{isomath}}) and upright in text:


\begin{quote}
  Text: L \Gamma{} l \gamma,
  emphasized text: \emph{L \Gamma{} l \gamma},
  mathematics: $ L \ \Gamma \ l \ \gamma $
\end{quote}

This makes it easy to write a single Greek symbol (like \Psi{} or \mu{}) or
a \lambda\omicron\gamma\omicron\varsigma{} in non-Greek text as well as
ISO-conforming formulas with upright symbols for constants like $A =
\text{\pi} r^2$ instead of $A = \pi r^2$.\footnote{%
  The \emph{\href{http://www.ctan.org/pkg/isomath}{isomath}} package
  documentation describes more alternatives for upright Greek symbols in
  math mode.}

\section{Tests and examples}

\subsection{Greek alphabet}

Greek letters via Latin transscription in LGR font encoding:

\begin{quote}
  \ensuregreek{A B G D E Z H J I K L M N X O P R S T U F Q Y W}\\
  \ensuregreek{a b g d e z h j i k l m n x o p r s c t u f q y w}
\end{quote}

Greek letters via default macros without language/font-encoding switch:

\begin{quote}
  \Alpha{} \Beta{} \Gamma{} \Delta{} \Epsilon{} \Zeta{} \Eta{} \Theta{}
  \Iota{} \Kappa{} \Lambda{} \Mu{} \Nu{} \Xi{} \Omicron{} \Pi{} \Rho{}
  \Sigma{} \Tau{} \Upsilon{} \Phi{} \Chi{} \Psi{} \Omega{}
  \\
  \alpha{} \beta{} \gamma{} \delta{} \epsilon{} \zeta{} \eta{} \theta{}
  \iota{} \kappa{} \lambda{} \mu{} \nu{} \xi{} \omicron{} \pi{} \rho{}
  \sigma{} \varsigma{} \tau{} \upsilon{} \phi{} \chi{} \psi{} \omega{}
  \\
  \digamma{} \Digamma{} \stigma{} \varstigma{}%
     \footnote{\texttt{\textbackslash varstigma} is not defined with Xe/LuaTeX.}
  \koppa{} \qoppa{} \Qoppa{}
  \Stigma{} \Sampi{} \sampi{}
\end{quote}

Greek letters via Unicode input without language/font-encoding switch:

\begin{quote}
  Α Β Γ Δ Ε Ζ Η Θ Ι Κ Λ Μ Ν Ξ Ο Π Ρ Σ Τ Υ Φ Χ Ψ Ω\\
  α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ σ ς τ υ φ χ ψ ω\\
  ϝ Ϝ ϛ ϟ ϙ Ϙ Ϛ Ϡ ϡ
\end{quote}


\subsection{\ensuregreek{%
    Ἑλληνικά (\<\Epsilon\lambda\lambda\eta\nu\iota\kappa\'\alpha{})}
  in PDF strings}

With the alphabeta package, you get Greek letters in both, the document body
and PDF metadata generated by hyperref if the input uses Unicode literals or
macros. Wrapping in \verb+\ensuregreek+ ensures the right placement of the
accents and breathings (before, not above capital letters). With LICR input
(accent macros + symbol macros), non-standard diacritics are missing in the
PDF data, as hyperref's PU encoding currently does not support polytonic
Greek. (Here, the dasia is dropped at the start of the word in parentheses in
the PDF toc. The warning ``\texttt{Glyph not defined in PU encoding,
removing `\textbackslash<' on input line 145.}'' is written to the log.)

Warnings like \texttt{Token not allowed in a PDF string
(Unicode): removing `\textbackslash TextOrMath ' on input line 145.}
can be ignored or avoided with the preamble code:

\begin{verbatim}
\pdfstringdefDisableCommands{%
  \let\TextOrMath\@firstoftwo%
}
\end{verbatim}


\subsection{Greek in math $\Gamma = \sin\alpha / \cos{\beta}$}

In the main document, Greek in math mode should work as usual:

\[\Gamma = \frac{\sin\alpha}{\cos{\beta}}.
\]

With 8-bit TeX, literal Greek Unicode characters are supported also in
mathematical mode (for XeTeX/LuaTeX use unicode-math):

\[  Γ = \frac{\sin α}{\cos{β}}.
\]

Greek letters in math (there are no math macros for Greek letters wich exist
with similar shape in the Latin alphabet):

Input as macro:

\begin{align*}
  &
  % \Alpha{} \Beta{}
  \Gamma{} \Delta{}
  % \Epsilon{} \Zeta{} \Eta{}
  \Theta{}
  % \Iota{} \Kappa{}
  \Lambda{}
  % \Mu{} \Nu{}
  \Xi{}
  % \Omicron{}
  \Pi{}
  % \Rho{}
  \Sigma{}
  % \Tau{}
  \Upsilon{} \Phi{}
  % \Chi{}
  \Psi{} \Omega{}
\\&
  \alpha{} \beta{} \gamma{} \delta{} \epsilon{} \zeta{} \eta{} \theta{}
  \iota{} \kappa{} \lambda{} \mu{} \nu{} \xi{}
  % \omicron{}
  \pi{} \rho{}
  \sigma{} \varsigma{} \tau{} \upsilon{} \phi{} \chi{} \psi{} \omega{}
  \, \digamma{}
\end{align*}

Input as Unicode literals (with XeTeX/LuaTeX, this requires the unicode-math
package):

\begin{align*} & Γ ΔΘΛΞΠΣΥ ΦΨ Ω \\
               & αβγδεζηθικλμνξπρσςτ υφχψω \, ϝ
\end{align*}


PDF strings do not know math mode. The content of a formula or equation is
evaluated in text mode with non-valid commands discarded (and warnings
written to the log). This works resonably well for simple formulas (but not,
e.g., for super-/subscripts). With the \emph{alphabeta} package, it works
also for Greek letters.


\subsection{Diacritics}

Accent macros are set up for use with the generic macros by definition of
``TextComposite'' commands.

Diacritics (except the dialytika) should placed
before capital letters and dropped with MakeUppercase:

\ensuregreek{
\<{\alpha} \>{\epsilon} \"'{\iota} \>`{\eta}
\'<{\omicron} \~<{\upsilon} \~>{\omega}
\\
\<{\Alpha} \>{\Epsilon} \'{\Iota} \>`{\Eta}
\'<{\Omicron} \~<{\Upsilon} \~>{\Omega}
\\
\MakeUppercase{%
 \<{\alpha} \>{\epsilon} \"'{\iota} \>`\eta{}
 \'<{\omicron} \~<{\upsilon} \~>{\omega}
}}

\subsection{Limitations}

With 8-bit TeX, the following limitations known from
\emph{\href{textalpha-test.pdf}{textalpha}} apply if the current font
encoding is not LGR:

\begin{itemize}

\item Composition of diacritics (like \verb+\>\'+) fails:

      \<{\alpha} \>{\epsilon} \"'{\iota} \>`\eta{}
      \'<{\omicron} \~<{\upsilon} \~>{\omega}

      Long names (like \verb+\accdasiaoxia+) work in any font encoding,
      however they do not select precomposed characters (the difference
      becomes obvious if you drag-and-drop text from the PDF version of this
      document):
      %
      \ensuregreek{\<'\alpha{} \accdasia\acctonos\alpha{} \accdasiaoxia\alpha{}}
      (LGR) vs. \accdasiaoxia\alpha{} (T1)

\item MakeUppercase fails with composite diacritics in other font encodings.
      % \MakeUppercase{%
      %  \<\alpha{} \>\epsilon{} \'\iota{} \`\eta{} \~\upsilon{}
      % }

\item There is no kerning between Greek letters, if the font encoding is not
      LGR: compare \ensuregreek{\Alpha\Upsilon\Alpha} (LGR) to \Alpha\Upsilon\Alpha (T1).
      Because of this (and for proper hyphenation), use of the Babel package
      and correct language setting is recommended for Greek quotes.

\end{itemize}

The \verb+\ensuregreek+ macro ensures that the argument is typeset with a
font encoding supporting Greek. This keeps kerning (if the kerning pair is
inside the argument, \ensuregreek{\Alpha\Upsilon\Alpha}), and allows
iterative accent macros where pre-composed characters are selected
(\ensuregreek{\<'\alpha}).

\end{document}
