\documentclass[a4paper]{article}
% \usepackage{textcomp}
% \usepackage{hyperref,bookmark}
\usepackage{parskip}
% \usepackage{booktabs}

\usepackage[LGR]{fontenc}
\usepackage{fontspec}
% \setmainfont{DejaVu Serif}
% \setsansfont{DejaVu Sans}
% \usepackage{libertineotf}
\setmainfont{Linux Libertine O}
\setsansfont{Linux Biolinum O}
% \setmainfont{FreeSerif}
% \setmainfont{Droid Sans}

% Declare the font encoding and Greek LICR definitions:
\usepackage{textalpha}

% Optionally load the xunicode package:
% \newcommand{\UTFencname}{\LastDeclaredEncoding}
% \usepackage{xunicode}

% Accent+Unicode character: proof of concept:
\DeclareTextCompositeCommand{\accpsiliperispomeni}{\LastDeclaredEncoding}{α}{ἆ}


\begin{document}

\section*{Greek LICR definitions with XeTeX/LuaTeX}

The \verb|textalpha| package from the greek-fontenc bundle is a convenient way to
load Greek LICR macros for use anywhere in the document and with any
TeX engine supporting the e-TeX extensions (pdfTeX, XeTeX, or LuaTeX).
With XeTeX or LuaTeX, it loads the file greek-euenc.def.

Typesetting Greek texts requires a font containing Greek letters. With the
XeTeX or LuaTeX engines, the user should ensure that the choosen font
contains the required glyphs (the default Latin Modern fonts have only
capital Greek letters). Examples for suitable fonts are the “Deja Vu” or
the “Linux Libertine” OpenType fonts.

\section{LICR input}

The example from \texttt{usage.tex} in \emph{babel-greek} input
using the LICR macros:

\begin{quote}
  \textTau\'\textiota{}
  \textphi\'\texteta\textiota\textfinalsigma\texterotimatiko{}
  \<\textIota\textdelta\`\textomega\textnu{}
  \>\textepsilon\textnu\texttheta\'\textepsilon\textdelta\textepsilon{}
  \textpi\textalpha\~\textiota\textdelta\'\'
  \>\textepsilon\textlambda\textepsilon\textupsilon\texttheta\'\textepsilon\textrho\textalpha\textnu\\
  \texttau\`\textalpha\textfinalsigma{}
  \textpi\textlambda\texteta\textsigma\'\textiota\textomicron\textnu{}
  \textNu\'\textupsilon\textmu\textphi\textalpha\textfinalsigma{}
  \textsigma\texttau\textepsilon\textphi\textalpha\textnu\textomicron\~\textupsilon\textsigma\textalpha\textnu{},
  \textSigma\'\textomega\textsigma\texttau\textrho\textalpha\texttau\textepsilon{},\\
  \>\textepsilon\textrho\~\textomega\textnu{}
  \'\textalpha\textpi\~\texteta\textlambda\texttheta\textepsilon\textfinalsigma{}
  \textepsilon\>\textupsilon\texttheta\'\textupsilon\textfinalsigma\texterotimatiko{}
\end{quote}

\subsection{Greek alphabet}

Greek letters via LICR macros:


\textAlpha{} \textBeta{} \textGamma{} \textDelta{} \textEpsilon{}
\textZeta{} \textEta{} \textTheta{} \textIota{} \textKappa{}
\textLambda{} \textMu{} \textNu{} \textXi{} \textOmicron{} \textPi{}
\textRho{} \textSigma{} \textTau{} \textUpsilon{} \textPhi{}
\textChi{} \textPsi{} \textOmega{}

\textalpha{} \textbeta{} \textgamma{} \textdelta{} \textepsilon{}
\textzeta{} \texteta{} \texttheta{} \textiota{} \textkappa{}
\textlambda{} \textmu{} \textnu{} \textxi{} \textomicron{} \textpi{}
\textrho{} \textsigma{} \texttau{} \textupsilon{}
\textphi{} \textchi{} \textpsi{} \textomega{}

The small sigma is set with a different
glyph if it ends a word:

\begin{itemize}
  \item[\textsigma]       textsigma
  \item[\textfinalsigma]  textfinalsigma or textvarsigma
\end{itemize}

In the Latin transcription, the letter `s' stands for \verb|\textautosigma|
which automatically chooses the glyph according to the position.

\subsection{Additional Greek symbols}

\textkoppa{}      textkoppa                 \\ % ϟ
\textqoppa{}      textqoppa (archaic koppa) \\ % ϙ
\textQoppa{}      textQoppa (archaic Koppa) \\ % Ϙ
\textstigma{}     textstigma                \\ % ϛ
% \textvarstigma{}  textvarstigma \\ % no separate Unicode character
\textStigma{}     textStigma (Sigma-Tau-Ligature in CB-fonts)%
\footnote{the name “stigma” originally applied to a medieval sigma-tau
         ligature, whose shape was confusably similar to the cursive
         digamma}                      \\ % Ϛ
\textsampi{}      textsampi  \\ % ϡ
\textSampi{}      textSampi  \\ % Ϡ
\textdigamma{}  textdigamma  \\ % ϝ (\digamma used by amsmath!)
\textDigamma{}  textDigamma  \\ % Ϝ
% numeral signs: http://en.wikipedia.org/wiki/Greek_numerals
\textdexiakeraia{}    textdexiakeraia  \\ % ʹ
\textaristerikeraia{} textaristerikeraia \\ % ͵

Mathematical notation uses variant shapes for pi, kappa, rho, theta, and phi
as additional symbols. These variations have no syntactic meaning in Greek
text and are not given separate code-points in the LGR text encoding. Some
text fonts use the variant shapes in place of the “regular” ones.

TeX's concept of “standard” vs. “variant” symbols does not map to the
distinction between “Greek Letter ...” vs. “Greek Symbol ...” in the
Unicode standard:

\begin{tabular}{cccc}
math symbol & Unicode «letter» & var math symbol & Unicode «symbol» \\
$\pi$      & π & $\varpi$       & ϖ \\
$\rho$     & ρ & $\varrho$      & ϱ \\
$\theta$   & θ & $\vartheta$    & ϑ \\
$\epsilon$ & ε & $\varepsilon$  & ϵ \\
$\phi$     & φ & $\varphi$      & ϕ \\
$\beta$    & β & \emph{missing} & ϐ \\
$\kappa$   & κ & \emph{missing} & ϰ \\
$\Theta$   & Θ & \emph{missing} & ϴ \\
\end{tabular}

\subsection{Diacritics}

Greek diacritcs can be input by named macro or symbol macro. Named macros
are defined in xunicode-greek.sty for \verb|\LastDeclaredEncoding| (here
\LastDeclaredEncoding).

\acctonos\textalpha       \'\textalpha{}  \acctonos       x\'x
\accvaria\textalpha       \`\textalpha{}  \accvaria       x\`x
\accdialytika\textiota    \"\textiota{}   \accdialytika   x\"x
\accperispomeni\textalpha \~\textalpha{}  \accperispomeni x\~x
\accpsili\textalpha       \>\textalpha{}  \accpsili       x\>x
\accdasia\textalpha       \<\textalpha{}  \accdasia       x\<x

There are currently no defintions for accent macros combined with literal
unicode characters. Combining diacritical characters are used in the output.

\acctonos α       \'α
\accvaria α       \`α
\accdialytika ι   \"ι
\accperispomeni α \~α
\accpsili α       \>α
\accdasia α       \<α


Please mail a feature request if there is demand for definitions selecting
precomposed characters. 
As proof of concept, this document defines a composite command for 
alpha with psili and perispomeni. Compare \<~α with \>~α.



Composite commands for combined diacritics are defined in
“greek-fontenc.def”, also for the \verb|\LastDeclaredEncoding|. There are
composite definitions for all precomposed characters, the fallback
definition uses combining characters:

\accdialytikatonos\textiota{}     \"'\textiota{} \"\'\textiota{}
\accdialytikatonos x              \"'x           \"\'x
\accdialytikavaria\textiota{}     \"`\textiota{} \"\`\textiota{}
\accdialytikavaria x              \"`x           \"\`x
\accdialytikaperispomeni\textiota{} \~"\textiota{} \~\"\textiota{}
\accdialytikaperispomeni x        \~"x           \~\"x

\accdasiaoxia\textiota{}          \<'\textiota{} \<\'\textiota{}
\accdasiaoxia x                   \<'x           \<\'x
\accdasiavaria\textiota{}         \<`\textiota{} \<\`\textiota{}
\accdasiavaria x                  \<`x           \<\`x
\accdasiaperispomeni\textiota{}   \~<\textiota{} \~\<\textiota{}
\accdasiaperispomeni x            \~<x           \~\<x

\accpsilioxia\textiota{}          \>'\textiota{} \>\'\textiota{}
\accpsilioxia x                   \>'x           \>\'x
\accpsilivaria\textiota{}         \>`\textiota{} \>\`\textiota{}
\accpsilivaria x                  \>`x           \>\`x
\accpsiliperispomeni\textiota{}   \~>\textiota{} \~\>\textiota{}
\accpsiliperispomeni x            \~>x           \~\>x

Problems: Composite diacritics with breathings overlap when set using two
combining characters (in the tested fonts).


Upcasing with \verb|\MakeUppercase| drops diacritics (except
dialytika and sub-iota):

\MakeUppercase{
\accdialytikatonos\textiota       \"'\textiota{}  \accdialytikatonos x       \"'x
\accdialytikavaria\textiota       \"`\textiota{}  \accdialytikavaria x       \"`x
\accdialytikaperispomeni\textiota \~"\textiota{}  \accdialytikaperispomeni x \~"x
}

\MakeUppercase{
\accdasiaoxia\textiota            \<'\textiota{}  \accdasiaoxia x            \<'x
\accdasiavaria\textiota           \<`\textiota{}  \accdasiavaria x           \<`x
\accdasiaperispomeni\textiota     \~<\textiota{}  \accdasiaperispomeni x     \~<x
}

\MakeUppercase{
\accpsilioxia\textiota            \>'\textiota{}  \accpsilioxia x           \>'x
\accpsilivaria\textiota           \>`\textiota{}  \accpsilivaria x          \>`x
\accpsiliperispomeni\textiota     \~>\textiota{}  \accpsiliperispomeni x    \~>x
}


However, when the tonos, varia, and perispomeni accents are input using the
symbol macros (\verb|\' \` \~|), they behave like standard accents with
XeTeX/LuaTeX. If these accents should be dropped by MakeUppercase, they must
be input as named macro:

\MakeUppercase{
\acctonos\textalpha       \'\textalpha{}  \acctonos       x\'x
\accvaria\textalpha       \`\textalpha{}  \accvaria       x\`x
\accperispomeni\textalpha \~\textalpha{}  \accperispomeni x\~x
}


The sub-iota is input after the base letter.
Ligature definitions in the 8-bit LGR fonts ensure that precomposed
characters are used. This does not work with Unicode fonts:\footnote{%
  When copy/pasting generated output from the “evince” PDF
  viewer, the COMBINING GREEK YPOGEGRAMMENI is merged with the base
  character. A capital letter + combining ypogegrammeni results in GREEK
  CAPITAL LETTER ... WITH [.. AND] PROSGEGRAMMENI). This indicates that for
  a subfix (in contrast to post-fix) prosgegrammeni, the combining
  \emph{ypogegrammeni} could be used together with a captial base letter.}

\textalpha\ypogegrammeni{} x\ypogegrammeni{} \textAlpha\prosgegrammeni{}
X\prosgegrammeni, see also the \emph{Greek extended} Unicode block below.

Both, the standard LaTeX and the “xunicode” composite mechanism require
the first part of a composite definition to be a macro requiring one
argument.  I.e. selecting pre-defined characters with sub-iota would require
prefix \verb|\accypogegrammeni| and \verb|\accprosgegrammeni| accent
macros and composite definitions for all combination of letters and letters
with diacritic and sub-iota.

\subsection{Greek and Coptic Unicode block}

Greek symbols from the Greek and Coptic Unicode block are fully supported:

% NR    Unicode Name                                       %   babel name, UCS name
% 0370  GREEK CAPITAL LETTER HETA                          % Ͱ
% 0371  GREEK SMALL LETTER HETA                            % ͱ
% 0372  GREEK CAPITAL LETTER ARCHAIC SAMPI                 % Ͳ
% 0373  GREEK SMALL LETTER ARCHAIC SAMPI                   % Ͳ
\textnumeralsigngreek{} % ʹ \anwtonos, \textdexiakeraia
\textnumeralsignlowergreek{} % ͵ \katwtonos, \textaristerikeraia,
% 0376  GREEK CAPITAL LETTER PAMPHYLIAN DIGAMMA            % Ͷ
% 0377  GREEK SMALL LETTER PAMPHYLIAN DIGAMMA              % ͷ

\textcompwordmark\ypogegrammeni{} % ͺ \textsubiota{\empty}
% 037B  GREEK SMALL REVERSED LUNATE SIGMA SYMBOL           %
% 037C  GREEK SMALL DOTTED LUNATE SIGMA SYMBOL             %
% 037D  GREEK SMALL REVERSED DOTTED LUNATE SIGMA SYMBOL    %
\texterotimatiko{} % ; \textquestion

\acctonos\textcompwordmark{} % ΄
\"'\textcompwordmark{} % ΅
\'\textAlpha{} % Ά
\textanoteleia{} % · \anoteleia
\'\textEpsilon{} % Έ
\'\textEta{} % Ή
\'\textIota{} % Ί
\'\textOmicron{} % Ό
\'\textUpsilon{} % Ύ
\'\textOmega{} % Ώ
\'"\textiota{} % ΐ

\textAlpha{} % Α
\textBeta{} % Β
\textGamma{} % Γ
\textDelta{} % Δ
\textEpsilon{} % Ε
\textZeta{} % Ζ
\textEta{} % Η
\textTheta{} % Θ
\textIota{} % Ι
\textKappa{} % Κ
\textLambda{} % Λ
\textMu{} % Μ
\textNu{} % Ν
\textXi{} % Ξ
\textOmicron{} % Ο
\textPi{} % Π
\textRho{} % Ρ
\textSigma{} % Σ
\textTau{} % Τ
\textUpsilon{} % Υ
\textPhi{} % Φ
\textChi{} % Χ
\textPsi{} % Ψ
\textOmega{} % Ω

\"\textIota{} % Ϊ
\"\textUpsilon{} % Ϋ
\'\textalpha{} % ά
\'\textepsilon{} % έ
\'\texteta{} % ή
\'\textiota{} % ί
\"'\textupsilon{} % ΰ

\textalpha{} % α
\textbeta{} % β
\textgamma{} % γ
\textdelta{} % δ
\textepsilon{} % ε
\textzeta{} % ζ
\texteta{} % η
\texttheta{} % θ
\textiota{} % ι
\textkappa{} % κ
\textlambda{} % λ
\textmu{} % μ \textmugreek
\textnu{} % ν
\textxi{} % ξ
\textomicron{} % ο
\textpi{} % π
\textrho{} % ρ
\textvarsigma{} % ς
\textsigma{} % σ
\texttau{} % τ
\textupsilon{} % υ
\textphi{} % φ
\textchi{} % χ
\textpsi{} % ψ
\textomega{} % ω

\"\textiota{} % ϊ
\"\textupsilon{} % ϋ
\'\textomicron{} % ό
\'\textupsilon{} % ύ
\'\textomega{} % ώ

\textQoppa{} % Ϙ
\textqoppa{} % ϙ
\textStigma{} % Ϛ \Stigma
\textstigma{} % ϛ \stigma
\textDigamma{} % Ϝ \Digamma
\textdigamma{} % ϝ \ddigamma
%03DE GREEK LETTER KOPPA                      % Ϟ \textKoppagreek
\textkoppa{} % ϟ \koppa, \textqoppa [sic!]
\textSampi{} % Ϡ \Sampi
\textsampi{} % ϡ \sampi


\subsection{Greek Extended Unicode block}

Characters from the Greek Extended Unicode block are only partially
supported, accented characters with sub-iota currently use a combining
prosgegrammeni or ypogegrammeni character.

For comparision, the LICR macro is followed by the corresponding literal
Unicode character:

\>\textalpha   ἀ
\<\textalpha   ἁ
\>`\textalpha  ἂ
\<`\textalpha  ἃ
\>'\textalpha  ἄ
\<'\textalpha  ἅ
\~>\textalpha  ἆ
\~<\textalpha  ἇ
\>\textAlpha   Ἀ
\<\textAlpha   Ἁ
\>`\textAlpha  Ἂ
\<`\textAlpha  Ἃ
\>'\textAlpha  Ἄ
\<'\textAlpha  Ἅ
\~>\textAlpha  Ἆ
\~<\textAlpha  Ἇ

\>\textepsilon   ἐ
\<\textepsilon   ἑ
\>`\textepsilon  ἒ
\<`\textepsilon  ἓ
\>'\textepsilon  ἔ
\<'\textepsilon  ἕ
\>\textEpsilon   Ἐ
\<\textEpsilon   Ἑ
\>`\textEpsilon  Ἒ
\<`\textEpsilon  Ἓ
\>'\textEpsilon  Ἔ
\<'\textEpsilon  Ἕ

\>\texteta   ἠ
\<\texteta   ἡ
\>`\texteta  ἢ
\<`\texteta  ἣ
\>'\texteta  ἤ
\<'\texteta  ἥ
\~>\texteta  ἦ
\~<\texteta  ἧ
\>\textEta   Ἠ
\<\textEta   Ἡ
\>`\textEta  Ἢ
\<`\textEta  Ἣ
\>'\textEta  Ἤ
\<'\textEta  Ἥ
\~>\textEta  Ἦ
\~<\textEta  Ἧ

\>\textiota   ἰ
\<\textiota   ἱ
\>`\textiota  ἲ
\<`\textiota  ἳ
\>'\textiota  ἴ
\<'\textiota  ἵ
\~>\textiota  ἶ
\~<\textiota  ἷ
\>\textIota   Ἰ
\<\textIota   Ἱ
\>`\textIota  Ἲ
\<`\textIota  Ἳ
\>'\textIota  Ἴ
\<'\textIota  Ἵ
\~>\textIota  Ἶ
\~<\textIota  Ἷ

\>\textomicron   ὀ
\<\textomicron   ὁ
\>`\textomicron  ὂ
\<`\textomicron  ὃ
\>'\textomicron  ὄ
\<'\textomicron  ὅ
\>\textOmicron   Ὀ
\<\textOmicron   Ὁ
\>`\textOmicron  Ὂ
\<`\textOmicron  Ὃ
\>'\textOmicron  Ὄ
\<'\textOmicron  Ὅ

\>\textupsilon   ὐ
\<\textupsilon   ὑ
\>`\textupsilon  ὒ
\<`\textupsilon  ὓ
\>'\textupsilon  ὔ
\<'\textupsilon  ὕ
\~>\textupsilon  ὖ
\~<\textupsilon  ὗ
\<\textUpsilon   Ὑ
\<`\textUpsilon  Ὓ
\<'\textUpsilon  Ὕ
\~<\textUpsilon  Ὗ

\>\textomega   ὠ
\<\textomega   ὡ
\>`\textomega  ὢ
\<`\textomega  ὣ
\>'\textomega  ὤ
\<'\textomega  ὥ
\~>\textomega  ὦ
\~<\textomega  ὧ
\>\textOmega   Ὠ
\<\textOmega   Ὡ
\>`\textOmega  Ὢ
\<`\textOmega  Ὣ
\>'\textOmega  Ὤ
\<'\textOmega  Ὥ
\~>\textOmega  Ὦ
\~<\textOmega  Ὧ

\`\textalpha    ὰ
\'\textalpha    ά
\`\textepsilon  ὲ
\'\textepsilon  έ
\`\texteta      ὴ
\'\texteta      ή
\`\textiota     ὶ
\'\textiota     ί
\`\textomicron  ὸ
\'\textomicron  ό
\`\textupsilon  ὺ
\'\textupsilon  ύ
\`\textomega    ὼ
\'\textomega    ώ

\>\textalpha\ypogegrammeni    ᾀ
\<\textalpha\ypogegrammeni    ᾁ
\>`\textalpha\ypogegrammeni   ᾂ
\<`\textalpha\ypogegrammeni   ᾃ
\>'\textalpha\ypogegrammeni   ᾄ
\<'\textalpha\ypogegrammeni   ᾅ
\~>\textalpha\ypogegrammeni   ᾆ
\~<\textalpha\ypogegrammeni   ᾇ
\>\textAlpha\prosgegrammeni   ᾈ
\<\textAlpha\prosgegrammeni   ᾉ
\>`\textAlpha\prosgegrammeni  ᾊ
\<`\textAlpha\prosgegrammeni  ᾋ
\>'\textAlpha\prosgegrammeni  ᾌ
\<'\textAlpha\prosgegrammeni  ᾍ
\~>\textAlpha\prosgegrammeni  ᾎ
\~<\textAlpha\prosgegrammeni  ᾏ

\>\texteta\ypogegrammeni    ᾐ
\<\texteta\ypogegrammeni    ᾑ
\>`\texteta\ypogegrammeni   ᾒ
\<`\texteta\ypogegrammeni   ᾓ
\>'\texteta\ypogegrammeni   ᾔ
\<'\texteta\ypogegrammeni   ᾕ
\~>\texteta\ypogegrammeni   ᾖ
\~<\texteta\ypogegrammeni   ᾗ
\>\textEta\prosgegrammeni   ᾘ
\<\textEta\prosgegrammeni   ᾙ
\>`\textEta\prosgegrammeni  ᾚ
\<`\textEta\prosgegrammeni  ᾛ
\>'\textEta\prosgegrammeni  ᾜ
\<'\textEta\prosgegrammeni  ᾝ
\~>\textEta\prosgegrammeni  ᾞ
\~<\textEta\prosgegrammeni  ᾟ

\>\textomega\ypogegrammeni    ᾠ
\<\textomega\ypogegrammeni    ᾡ
\>`\textomega\ypogegrammeni   ᾢ
\<`\textomega\ypogegrammeni   ᾣ
\>'\textomega\ypogegrammeni   ᾤ
\<'\textomega\ypogegrammeni   ᾥ
\~>\textomega\ypogegrammeni   ᾦ
\~<\textomega\ypogegrammeni   ᾧ
\>\textOmega\prosgegrammeni   ᾨ
\<\textOmega\prosgegrammeni   ᾩ
\>`\textOmega\prosgegrammeni  ᾪ
\<`\textOmega\prosgegrammeni  ᾫ
\>'\textOmega\prosgegrammeni  ᾬ
\<'\textOmega\prosgegrammeni  ᾭ
\~>\textOmega\prosgegrammeni  ᾮ
\~<\textOmega\prosgegrammeni  ᾯ

\u\textalpha                      ᾰ
\=\textalpha                      ᾱ
\`\textalpha\ypogegrammeni        ᾲ
\textalpha\ypogegrammeni          ᾳ
\'\textalpha\ypogegrammeni        ᾴ
\~\textalpha                      ᾶ
\~\textalpha\ypogegrammeni        ᾷ
\u\textAlpha                      Ᾰ
\=\textAlpha                      Ᾱ
\`\textAlpha                      Ὰ
\'\textAlpha                      Ά
\textAlpha\prosgegrammeni         ᾼ
\>\textcompwordmark               ᾽
\textcompwordmark\prosgegrammeni  ι
\>\textcompwordmark               ᾿

\accperispomeni\textcompwordmark  ῀
\"\~\textcompwordmark             ῁
\`\texteta\ypogegrammeni          ῂ
\texteta\ypogegrammeni            ῃ
\'\texteta\ypogegrammeni          ῄ
\~\texteta                        ῆ
\~\texteta\ypogegrammeni          ῇ
\`\textEpsilon                    Ὲ
\'\textEpsilon                    Έ
\`\textEta                        Ὴ
\'\textEta                        Ή
\textEta\prosgegrammeni           ῌ
\>`\textcompwordmark              ῍
\>'\textcompwordmark              ῎
\~>\textcompwordmark              ῏

\u\textiota                       ῐ
\=\textiota                       ῑ
\`"\textiota                      ῒ
\'"\textiota                      ΐ
\~\textiota                       ῖ
\~"\textiota                      ῗ
\u\textIota                       Ῐ
\=\textIota                       Ῑ
\`\textIota                       Ὶ
\'\textIota                       Ί
\<`\textcompwordmark              ῝
\>'\textcompwordmark              ῞
\~<\textcompwordmark              ῟

\u\textupsilon                    ῠ
\=\textupsilon                    ῡ
\`"\textupsilon                   ῢ
\'"\textupsilon                   ΰ
\>\textrho                        ῤ
\<\textrho                        ῥ
\~\textupsilon                    ῦ
\~"\textupsilon                   ῧ
\u\textUpsilon                    Ῠ
\=\textUpsilon                    Ῡ
\`\textUpsilon                    Ὺ
\'\textUpsilon                    Ύ
\<\textRho                        Ῥ
\`"\textcompwordmark              ῭
\'"\textcompwordmark              ΅
\accvaria\textcompwordmark        `

\`\textomega\ypogegrammeni        ῲ
\textomega\ypogegrammeni          ῳ
\'\textomega\ypogegrammeni        ῴ
\~\textomega                      ῶ
\~\textomega\ypogegrammeni        ῷ
\`\textOmicron                    Ὸ
\'\textOmicron                    Ό
\`\textOmega                      Ὼ
\'\textOmega                      Ώ
\textOmega\prosgegrammeni         ῼ
\accoxia\textcompwordmark         ´
\<\textcompwordmark               ῾

Ancient Greek Numbers are missing in most fonts (including Libertine and
Deja Vu). The “FreeSerif” font works fine.

\textpentedeka    % GREEK ACROPHONIC ATTIC FIFTY
\textpentehekaton % GREEK ACROPHONIC ATTIC FIVE HUNDRED
\textpenteqilioi  % GREEK ACROPHONIC ATTIC FIVE THOUSAND
\textpentemuria   % GREEK ACROPHONIC ATTIC FIFTY THOUSAND

If the LGR font encoding is loaded via «fontenc» in the document preamble,
Ancient Greek Numbers (as well as any other character) from LGR encoded
8-bit TeX fonts can be used after a font-encoding switch. babel-greek
defines the \verb|\textgreek| command for this purpose:

\providecommand*{\textgreek}[1]{\leavevmode{%
  \fontfamily{cmr}\fontencoding{LGR}\selectfont#1}%
}

\textgreek{
\textpentedeka    % GREEK ACROPHONIC ATTIC FIFTY
\textpentehekaton % GREEK ACROPHONIC ATTIC FIVE HUNDRED
\textpenteqilioi  % GREEK ACROPHONIC ATTIC FIVE THOUSAND
\textpentemuria   % GREEK ACROPHONIC ATTIC FIFTY THOUSAND
}

\section{Latin transcription}

The \verb|\textgreek| macro and LGR encoded fonts can also be used for the
input of Greek letters via the \emph{Latin transcription} provided by this
font encoding, e.g. «logos» becomes «\textgreek{logos}»
and «\verb|\>aupn\'ia|»
becomes «\textgreek{\>aupn\'ia}» (capitalized
«\textgreek{\MakeUppercase{\>aupn\'ia}}»). For details of the Latin
transliteration see the teubner package or the file usage.pdf from the
babel-greek package.

Mark, that you cannot use Unicode input with LGR encoded fonts except when
running in 8-bit compatibility mode because of the incompatibility between
Xe/LuaTeX and the inputenc package.

LICR macros work in both, Unicode font encoding and LGR: compare
\>\textIota\textalpha\textnu\textomicron\textupsilon\textalpha
\textrho\acctonos\textiota\textomicron\textupsilon{} (Unicode font set up
via fontspec) vs. 
\textgreek{\>\textIota\textalpha\textnu\textomicron\textupsilon\textalpha
           \textrho\acctonos\textiota\textomicron\textupsilon}
(LGR-encoded 8-bit font set up via NFSS commands, see \emph{The LaTeX font
guide} [fntguide.pdf]).

\end{document}
