\chapterbegin Chapter 9. \TeX's Roman Fonts

When you're typing a manuscript for \TeX, you need to know what symbols
are available. The plain \TeX\ format of Appendix@B is based on the
Computer Modern fonts, which provide the characters needed to typeset a
wide variety of documents. It's time now to discuss what a person can do
with plain \TeX\ when typing straight text. We've already touched on some of
the slightly subtle things---for example, dashes and quotation marks
were considered in Chapter@2, and certain kinds of accents appeared in the
examples of Chapters 3 and@6. The purpose of this chapter is to give a
more systematic summary of the possibilities, by putting all the facts
together.

Let's begin with the rules for the normal roman font (|\rm| or |\tenrm|);
plain \TeX\ will use this font for everything unless you specify
otherwise. Most of the ordinary symbols that you need are readily available
and you can type them in the ordinary way: There's nothing special about
$$\halign{\indent#\hfil\cr
the letters |A| to |Z| and |a| to |z|\cr
the digits |0| to |9|\cr
common punctuation marks |: ; ! ? ( ) [ ] ` ' - * / . ,|\cr}$$
↑(letters) ↑(digits) ↑(punctuation)
except that \TeX\ recognizes certain combinations as ↑{ligatures}:
$$\halign{\indent#\hfil\ produces &#\hfil&
\qquad#\hfil\ produces &#\hfil&
\qquad#\hfil\ produces &#\hfil\cr
|ff|&ff;&|ffi|&ffi;&|``|&``\thinspace\cr
|fi|&fi;&|ffl|&ffl;&|''|&''\thinspace\cr
|fl|&fl;&|--|&--\thinspace;&|---|&---\thinspace.\cr}$$
You can also type |+|, |=|, |<|, and |>|, to get the corresponding
symbols +, =, <, and >; but it's much better to use these characters
only in math mode, i.e., enclosed between two |$| signs, since that tells
\TeX\ to insert the proper spacing for mathematics. Math mode is
explained later; for now, it's just a good idea to remember that formulas
and text should be segregated. A non-mathematical hyphen and a non-mathematical
slash should be specified by typing `|-|' and `|/|' outside of mathematics
mode, but subtraction and division should be specified by typing `|-|' and
`|/|' between |$|@signs.
↑(Colon)
↑(Semicolon)
↑(Exclamation point)
↑(Question mark)
↑(Parentheses)
↑(Brackets)
↑(Apostrophe) ↑(Reverse apostrophe)
↑(Hamza, see apostrophe) ↑(Ain, see reverse apostrophe)
↑(Hyphen) ↑(Dash)
↑(Asterisk)
↑(Virgule, see slash)
↑(Solidus, see slash)
↑(Shilling sign, see slash)
↑(Slash)
↑(Period) ↑(Full stop, see period)
↑(Comma)
↑(Plus sign)
↑(Equals sign)
↑(Less than sign)
↑(Greater than sign)

The previous paragraph covers 81 of the 94 visible characters of standard
ascii; so your keyboard probably contains at least 13 more symbols, and
you should learn to watch out for the remaining ones, since they are special.
Five of these are pre\"empted by plain \TeX; if your manuscript requires
the symbols
\ttbegin
$    #    %    &    @
\ttend
↑(dollar sign) ↑(sharp sign, see hash mark) ↑(number sign, see hash mark)
↑(hash mark) ↑(percent sign) ↑(ampersand) ↑(at sign)
you should remember to type them as
\ttbegin
{\$} {\#} {\%} {\&} {\@}
\ttend
(or you can leave off the curly braces, if you take care not to lose
a blank space that might come next). Plain \TeX\ also reserves the five
symbols
\ttbegin
\    {    }    ↑    _
\ttend
↑(backslash) ↑(braces) ↑(curly braces, see braces) ↑(caret, see circumflex)
↑(circumflex) ↑(underline)
but you probably don't mind losing these, since they don't appear in
normal copy; braces and backslashes are available via control sequences
in math mode.

\goodbreak
There are three remaining special characters in the standard ascii set:
\ttbegin
"    |vert    ~
\ttend
Again, you don't really want them. \ (Double-quote marks should be
replaced either by |``| or by |''|\thinspace; vertical lines are needed only
in math mode; tildes are needed only as accents.)
↑(double-quote mark) ↑(vertical line, see norm) ↑(norm symbol) ↑(tilde)

Scholarly publications in English often refer to other languages, so
plain \TeX\ makes it possible to typeset the most commonly used ↑{accents}:
$$\halign{\indent\hbox to 50pt{#\hfil}&\hbox to 35pt{#\hfil}&#\hfil\cr
Type&to get\cr
\noalign{\smallskip}
|\`o|&\`o&(grave accent)\cr
|\'o|&\'o&(acute accent)\cr
|\↑o|&\↑o&(circumflex or ``hat'')\cr
|\"o|&\"o&(umlaut or diaresis)\cr
|\~o|&\~o&(tilde or ``squiggle'')\cr
|\=o|&\=o&(macron or ``bar'')\cr
|\.o|&\.o&(dot accent)\cr
|\v o|&\v o&(h\'a\v cek or ``hook'')\cr
|\u o|&\u o&(breve accent)\cr
|\H o|&\H o&(long Hungarian umlaut)\cr
|\t oo|&\t oo&(tie-after accent)\cr}$$
↑(:`) ↑(grave accent)
↑(:') ↑(acute accent)
↑(:caret) ↑(circumflex accent) ↑(hat accent)
↑(:") ↑(umlaut accent) ↑(diaresis)
↑(:tilde) ↑(tilde accent) ↑(squiggle accent)
↑(:=) ↑(macron accent) ↑(bar accent)
↑(:.) ↑(dot accent)
↑(:v) ↑(h\'a\v cek accent) ↑(hook accent)
↑(:u) ↑(breve accent)
↑(:H) ↑(Hungarian umlaut)
↑(:t) ↑(tie-after accent)
Within the font, such accents are designed to appear at the right height
for the letter `o'; but you can use them over any letter, and \TeX\ will
raise an accent that is supposed to be taller. Notice that spaces are needed
in the last four cases, to separate the control sequences from the letters
that follow. You could, however, type `|\H{o}|' in order to avoid putting a
space in the midst of a word.

\medbreak
Plain \TeX\ also provides three accents that go underneath:
$$\halign{\indent\hbox to 50pt{#\hfil}&\hbox to 35pt{#\hfil}&#\hfil\cr
Type&to get\cr
\noalign{\smallskip}
|\c o|&\c o&(cedilla accent)\cr
|\d o|&\d o&(dot-under accent)\cr
|\b o|&\b o&(bar-under accent)\cr}$$
↑(:c) ↑(cedilla accent)
↑(:d) ↑(dot-under accent) ↑(emphatics, see dot-under)
↑(:b) ↑(bar-under accent)
And there are a few special letters:
$$\halign{\indent\hbox to 50pt{#\hfil}&\hbox to 35pt{\oldtenrm#\hfil}&#\hfil\cr
Type&to get\cr
\noalign{\smallskip}
|\oe,\OE|&\oe,\thinspace\OE&(French ligature OE)\cr
|\ae,\AE|&\ae,\thinspace\AE&(Latin and Scandinavian ligature AE)\cr
|\aa,\AA|&\aa,\thinspace\AA&(Scandinavian A-with-circle)\cr
|\o,\O|&\o,\thinspace\O&(Scandinavian O-with-slash)\cr
|\l,\L|&\l,\thinspace\L&(Polish suppressed-L)\cr
|\ss|&\ss&(German ``es-zet'' or sharp S)\cr}$$
↑(Scandinavian letters) ↑(sharp S) ↑(es-zet) ↑(German) ↑(Polish)
↑(Norwegian) ↑(Danish) ↑(Swedish) ↑(Icelandic) ↑(suppressed-L)
The |\rm| font contains also the ↑{dotless letters} `\i' and `\j',
which you can obtain by typing `|\i|' and `|\j|'. These are needed because
`i' and `j' should lose their dots when they gain an accent. For example,
the right way to obtain `m\=\i n\u us' is to type \hbox{`|m\=\i n\u us|'}
or `|m\={\i}n\u{u}s|'.

This completes our summary of the |\rm| font. Exactly the same conventions
apply to |\bf|, |\sl|, and |\it|, so you don't have to do things differently
when you're using a different typeface. For example, |\bf\"o| yields
{\bf\"o} and |\it\&| yields {\it\&}.  Isn't that nice?

\danger However, |\tt| is slightly different. You will be glad to know that
|ff|, |fi|, and so on are not treated as ligatures when you're using
↑{typewriter type}; nor do you get ligatures from dashes and quote marks.
That's fine, because ordinary dashes and ordinary double-quotes are
appropriate when you're trying to imitate a typewriter. Most of the
accents are available too. But |\H|, |\l|, |\L|, and |\t| cannot be
used---the typewriter font contains other symbols in their place.
\ (See Appendix@F.)

\exercise What's the non-naive way to type `na\"\i ve'\thinspace? 
\answer |na\"\i ve| or |na{\"\i}ve| or |na\"{\i}ve|.

\exercise List some English words that contain accented letters.
\answer Belov\`ed proteg\'e r\↑ole co\"ordinator: souffl\'es, cr\↑epes,
p\↑at\'es, etc.

\exercise How would you type `{\oldtenrm
\AE sop's \OE uvres} en fran\c cais'\thinspace?
\answer |\AE sop's \OE uvres en fran\c cais|.

\exercise Explain what to type in order to get the sentence

\line{{\sl Commentarii Academ\ae\ Petropolitan\ae\/} is now
{\sl Akademi\t\i a Nauk SSSR, Doklady}.}
\answer |{\sl Commentarii Academ\ae\ Petropolitan\ae\/} is now|\hfil\linebreak
|{\sl Akademi\t\i a Nauk SSSR, Doklady}.|

\exercise And how would you specify the names
Ernesto ↑{Ces\`aro},
P\'al ↑{Erd\H os},
\O ystein ↑{Ore},
Stanis\l aw \'Swierczkowski, ↑(Swiercz...)
Serge\u\i\ \t Iur'ev, ↑(Iur'ev)
Mu\d hammad ibn M\↑us\↑a ↑{al-Khw\↑arizm\↑\i}?
\answer |Ernesto Ces\`aro,
P\'al Erd\H os,
\O ystein Ore,
Stanis\l aw \'Swier%|\linebreak|czkowski,
Serge\u\i\ \t Iur'ev,
Mu\d hammad ibn M\↑us\↑a al-Khw\↑arizm\↑\i.|

\dangerexercise Devise a way to typeset {\tt P\'al Erd{\bf\H{\tt o}}s}
in typewriter type.
\answer The proper umlaut is |\H|, which isn't available in |\tt|, so
it's necessary to borrow the accent from another font. For example,
\hbox{|{\tt P\'al Erd{\bf\H{\tt o}}s}|}.

The following symbols come out looking exactly the same whether you are using
|\rm|, |\sl|, |\bf|, |\it|, or |\tt|:
$$\halign{\indent#\hfil\ &\hfil#\hfil&#\hfil\cr
Type&to get\cr
\noalign{\smallskip}
|\dag|&\dag&(dagger or obelisk)\cr
|\ddag|&\ddag&(double dagger or diesis)\cr
|\section|&\section&(section number sign)\cr
|\P|&\P&(paragraph sign or pilcrow)\cr
|\copyright|&\copyright&(copyright sign)\cr
|\sterling|&\sterling&(British pound sign)\cr}$$
↑(dagger) ↑(double dagger) ↑(obelisk) ↑(obelus, see obelisk) ↑(diesis)
↑(section number sign) ↑(paragraph sign) ↑(pilcrow) ↑(copyright sign)
↑(British pound sign) ↑(pound sterling)
(They appear in just one style because plain \TeX\ gets them from the
math symbols font. Lots of other symbols are needed for mathematics;
we will study them later.)

\danger Appendix B shows that plain \TeX\ handles most of the accents
by using \TeX's ↑{*accent} primitive. For example, |\'| is equivalent
to |{\accent14 #1}|, where |#1| is the argument being accented.
The general rule is that |\accent|\<number> puts
an accent over the next character; the \<number> tells where that accent
appears in the current font. The accent is assumed to be properly
positioned for a character whose height equals the ↑{x-height} of the
current font; taller or shorter characters cause the accent to be raised
or lowered, taking due account of the slantedness of the fonts of accenter
and accentee. The width of the final construction is the width of the
accented character, regardless of the width of the accent.
Mode-independent commands like font changes may appear between the accent
number and the character to be accented, but grouping operations must not
intervene.  If no suitable character is found, the accent will appear by
itself as if you had said |\char|\<number> instead of |\accent|\<number>.
For example, |\'{}| produces \'{}.

\dangerexercise Why do you think plain \TeX\ defines |\'| to be
`|{\accent14 #1}|' instead of simply `|\accent14 |'\thinspace? \ (Why the extra
braces, and why the argument |#1|?)
\answer The extra braces keep font changes local. An argument makes the
use of |\'| more consistent with the use of other accents like |\.|, which
are manufactured from other characters without using the |\accent|
primitive.

\danger It's important to remember that these conventions we have discussed
for accents and special letters are not built into \TeX\ itself; they belong
only to the plain \TeX\ format, which uses the Computer Modern fonts. Quite
different conventions will be appropriate when other fonts are involved;
format designers should provide rules for how to obtain accents and
special characters in their particular systems. Plain \TeX\ works well
enough when accents are infrequent, but the conventions of this chapter
are by no means recommended for large-scale applications of \TeX\ to
other languages. For example, a well-designed \TeX\ font for ↑{French}
would probably treat accents as ligatures, so that one could |e'crire
de cette nai"ve manie`re en franc/aise| without backslashes. (See the
remarks about Norwegian in Chapter@8.)
↑(foreign languages)

\chapterend

Let's do it after the high Roman fashion.
\author WILLIAM ↑{SHAKESPEARE}, {\sl Antony \&\ Cleopatra\/} %
  (Act IV, Scene 13) % line 87

\bigskip

English is a straightforward, frank, honest, open-hearted, no-nonsense language,
which has little truck with such devilish devious devices as accents;
indeed U.S. editors and printers are often thrown into a dither
when a foreign word insinuates itself into the language.
However there is one word on which Americans seem to have closed ranks,
printing it confidently, courageously, and almost invariably
complete with accent---the cheese presented to us as M\"unster.
\smallskip
Unfortunately, ↑{Munster} doesn't take an accent.
\author WAVERLEY ↑{ROOT}, in the {\sl International Herald Tribune\/} (1982)
	% Tuesday 18 May 82 page 8

\eject