%    Copyright (C) 1991 Silvio Levy
%     
%    This file is free software: you can redistribute it and/or modify
%    it under the terms of the GNU General Public License as published by
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%    This file is distributed in the hope that it will be useful,
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%    GNU General Public License for more details.
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\input amstex
\documentstyle{amsppt}
\nologo
\hsize=6.5in
\vsize=9in
\widowpenalty=10000
\clubpenalty=10000

\input greekmacros
\greekdelims

\font\sc=cmcsc10
\def\LaTeX{{\rm L\kern-.36em\raise.3ex\hbox{\sc a}\kern-.15em
    T\kern-.1667em\lower.7ex\hbox{E}\kern-.125emX}}
\def\plus{\math{}+{}\math}
\def\.#1{{\tt #1}}
\def\disp#1{\line{\tt #1\hfil}}
\def\angles#1{{$\langle$\rm #1$\rangle$}}
\chardef\!`\\
\chardef\~`\~
\chardef\{`\{
\chardef\}`\}
\chardef\#`\#
\def\begineight{\smallskip\bgroup\eightpoint}
\def\endeight{\par\egroup\smallskip}

\def\verbatim{\begingroup
  \def\do##1{\catcode`##1=12 } \dospecials
  \parskip 0pt \parindent 0pt
  \catcode`\ =13 \catcode`\^^M=13
  \tt \catcode`\?=0 \verbatimdefs \verbatimgobble}
{\catcode`\^^M=13{\catcode`\ =13\gdef\verbatimdefs{\def^^M{\ \par}\let =\ }} %
  \gdef\verbatimgobble#1^^M{}}
\def\beginverbatim{\smallskip\begingroup\verbatim}
\def\endverbatim{\endgroup\endgroup\smallskip}

\topmatter
\title Using Greek Fonts with \TeX\endtitle
\author Silvio Levy \endauthor
\affil
  Princeton University \\
  Fine Hall, Washington Road\\
  Princeton, NJ, 08544\\
  (\.{levy\@princeton.edu})
\endaffil
\endtopmatter
\document

\abovedisplayskip6pt plus3pt minus3pt
\belowdisplayskip6pt plus3pt minus3pt
\abovedisplayshortskip0pt plus3pt
\belowdisplayshortskip4pt plus3pt minus4pt

In this document I hope to show that typesetting Greek in \TeX\
using the \.{gr} family of fonts can be as easy as typesetting
English text, and leads to equally good results.
This is meant to be a tutorial, not an exhaustive discussion;
some \TeX nical remarks that should be useful after the reader
has acquired some familiarity with the fonts are printed in fine
print.

\heading
The Alphabet
\endheading

In order to typeset Greek text, you need to go into ``Greek mode.''
This is achieved by typing \.{\!begingreek} anywhere in your document;
Greek mode will remain in effect until you type a matching \.{\!endgreek}.
While in Greek mode, the letters `a' to `z' and `A' to `Z' come out
as Greek letters, according to the following code:
\display
\hbox{\valign
  {\hbox to 10pt{\hfil\strut$#$\hfil}&\hbox to 10pt{\hfil\strut\tt#\hfil}\cr
  a&a\cr b&b\cr g&g\cr d&d\cr e&e\cr z&z\cr h&h\cr j&j\cr
  i&i\cr k&k\cr l&l\cr m&m\cr n&n\cr x&x\cr o&o\cr p&p\cr
  r&r\cr c&s\cr t&t\cr u&u\cr f&f\cr q&q\cr y&y\cr w&w\cr}}
\enddisplay

There is no digamma yet.  The same character `s' will print as
`$c$' or `$s$', depending on its position in a word.

\begineight
The system does this by accessing a ligature of `s' with any other
letter that follows it.  If, for some reason, you want to print
an initial/medial sigma by itself (as in the table above), or
at the end of a word, you should type `c'.
\endeight

Try to typeset some simple text now.  Create a file
containing the following lines:

\beginverbatim
\input greekmacros	% where \begingreek and other commands are defined
This is English text.
\begingreek
This is Greek text.
\endgreek
?endverbatim

When you \TeX\ this file, you get the following gibberish:
\display
\hbox{
This is English text.
\begingreek
This is Greek text.
\endgreek
}
\enddisplay

If you say \.{\!greekdelims} near the top of your file,
the character \.{\$} can be used
in place of both \.{\!begingreek} and \.{\!endgreek}.  The control
sequence \.{\!math} takes on the former meaning of \.{\$}.

\heading
Accents and Breathings
\endheading

To get an acute, grave or circumflex accent over a vowel,
type \.{'}, \.{`} or \.{\~}, respectively, before the vowel.
To get a rough or smooth breathing, type \.{<} or \.{>} before
the vowel (or rho) and any accent that it may have.  To get an iota
subscript, type \.{|} {\it after\/} the vowel.  A diaeresis is
represented by \.{"}, and if accompanied by an accent it can come
before or after the accent.

For example, \hbox{\.{>en >arq\~h| >\~hn <o l'ogos}}
gives \hbox{$>en >arq~h| >~hn <o l'ogos$}.
Neat, ain't it?

\begineight
Accents and breathings, too, are typeset by means of ligatures: a
vowel with a breathing, an accent and iota subscript, for example,
is realized as a four-character ligature.  The only exception is
when a breathing is followed by a grave accent, in which case the
breathing\plus accent combination is typeset as a \TeX\ \.{\!accent}
over the vowel.  This means that words containing such combinations
cannot be hyphenated in (standard) \TeX; but this is not a problem
because, with the exception of very rare cases of crasis, all such words
are monosyllables.
\endeight

\heading
Punctuation
\endheading

Here's the table of correspondences for punctuation:
\display
\hbox{\valign
  {\hbox to 15pt{\hfil\strut$#$\hfil}&\hbox to 15pt{\hfil\strut\tt#\hfil}\cr
  .&.\cr ,&,\cr ;&;\cr :&:\cr !&!\cr ?&?\cr ''&''\cr ((&((\cr ))&))\cr}}
\enddisplay
The last three entries represent the apostrophe and quotations marks.
The other available non-letters are the ten digits, parentheses,
brackets, hyphen, em- and en-dashes, slash, percent sign, asterisk,
plus and equal signs.  All of these are accessible in the same way as
under plain \TeX.  In a future release there will be tick marks for
numbers (\math\hbox{$a$}'=1\math, \math{}_\prime\hbox{$a$}=1000\math).

\heading
Hyphenation
\endheading

A hyphenation table for both modern and ancient Greek is currently
being debugged.  For now one can use plain \TeX\ with its (English)
hyphenation table, which gives the right results about 90\% of the
time (amazing, isn't it?).  Be sure to proofread your text carefully,
unless you've turned hyphenation off.

\begineight
In standard \TeX, only one hyphenation dictionary can be used in
a job.  Thus, even with a Greek hyphenation table, a file that
combines Greek and English text is likely to be incorrectly
hyphenated.  Michael Ferguson's extension to \TeX\ handles multiple
hyphenation tables, and hyphenates words containing \.{\!accent}s
(cf.~the previous fine print paragraph).
\endeight

\heading
Interaction with other macros
\endheading

While in Greek mode you can do just about everything that you can
outside: go into math mode, create boxes, alignments, and so on.
The file \.{greekmacros.tex} sets things up so that in Greek mode
the control sequences \.{\!tt} and \.{\!bf} switch to a
typewriter and a bold Greek font, respectively: thus
\.{\{\!tt s''>agap\~w\}} gives \hbox{$\tt s''>agap~w$}.  (Try it.)
On the other hand, there are no ``italic'' or slanted Greek fonts,
so \.{\!it} and \.{\!sl} will give you the same fonts as outside
Greek mode.  The various constructions under
\AmSTeX\ and \LaTeX\ for increasing or decreasing point sizes don't
work yet; they will in a future release.

The characters that form diacritics (\.{<}, \.{>},
\.{'}, \.{`}, \.{\~}, \.{"} and \.{|}) are treated differently
depending on whether or not you're in Greek mode.  More exactly,
under plain \TeX\ these characters (with the exception of
\.{\~}) have a \.{\!catcode} of 12: they print as themselves, 
and they cannot appear in control words.  But in Greek mode
\.{'}, \.{`}, \.{\~}, \.{"} and \.{|} are ``letters'', that is,
they have a \.{\!catcode} of 11, while \.{<} and \.{>} are
active, with a \.{\!catcode} of 13.  This may be important even
for beginners because it means that \.{'}, for example, can be taken
as part of a control word.  Thus the sequence
\beginverbatim
\begingreek
\line{wm'ega\hfil'alfa}
\endgreek
?endverbatim
\noindent
will cause an error message about an
undefined control sequence \.{\!hfil'alfa}, instead of printing
\display
$\line{wm'ega\hfil 'alfa}$
\enddisplay
as you might expect.  (I hope classicists will forgive this use
of the modern Greek one-accent system.) The solution, of course,
is to remember to add a blank after the \.{\!hfil}.

\begineight
A more subtle problem arises when you use Greek text in macro
arguments, if the arguments are scanned while you're outside Greek
mode.  This is because \TeX\ assigns \.{\!catcode}s to tokens
as it first reads them, so when the argument is plugged into
the body of the macro the characters above have the wrong 
\.{\!catcode}.  If the legendary Jonathan Horatio Quick were
to write
\display
\hbox{\.{%
\!def\!hellenize\#1\{\!begingreek \#1\!endgreek\}
\!hellenize\{d'uo >`h tre\~is,\}}}
\enddisplay
he would be unpleasantly surprised by the following output:
\display
\def\hellenize#1{\begingreek #1\endgreek}
\hbox{\hellenize{d'uo >`h tre~is,}}
\enddisplay
which can be explained as follows: the \.{\~}, which should be
a letter, is seen as an active character, and expands to a blank
as in plain \TeX; while the breathing, which should be active,
is not, and in particular it doesn't do the right thing when
next to the grave accent.  Solutions to this problem require a
bit of wizardry, and will not be discussed here; see, for example,
Reinhard Wonneberger's article in the October, 1986 issue of
{\it TUGboat}, especially pages 179--180.
\endeight
\end