calc: TeX and LaTeX Language Modes
7.8.3 TeX and LaTeX Language Modes
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The ‘d T’ (‘calc-tex-language’) command selects the conventions of “math
mode” in Donald Knuth’s TeX typesetting language, and the ‘d L’
(‘calc-latex-language’) command selects the conventions of “math mode”
in LaTeX, a typesetting language that uses TeX as its formatting engine.
Calc’s LaTeX language mode can read any formula that the TeX language
mode can, although LaTeX mode may display it differently.
Formulas are entered and displayed in the appropriate notation;
‘sin(a/b)’ will appear as ‘\sin\left( {a \over b} \right)’ in TeX mode
and ‘\sin\left(\frac{a}{b}\right)’ in LaTeX mode. Math formulas are
often enclosed by ‘$ $’ signs in TeX and LaTeX; these should be omitted
when interfacing with Calc. To Calc, the ‘$’ sign has the same meaning
it always does in algebraic formulas (a reference to an existing entry
on the stack).
Complex numbers are displayed as in ‘3 + 4i’. Fractions and
quotients are written using ‘\over’ in TeX mode (as in ‘{a \over b}’)
and ‘\frac’ in LaTeX mode (as in ‘\frac{a}{b}’); binomial coefficients
are written with ‘\choose’ in TeX mode (as in ‘{a \choose b}’) and
‘\binom’ in LaTeX mode (as in ‘\binom{a}{b}’). Interval forms are
written with ‘\ldots’, and error forms are written with ‘\pm’. Absolute
values are written as in ‘|x + 1|’, and the floor and ceiling functions
are written with ‘\lfloor’, ‘\rfloor’, etc. The words ‘\left’ and
‘\right’ are ignored when reading formulas in TeX and LaTeX modes. Both
‘inf’ and ‘uinf’ are written as ‘\infty’; when read, ‘\infty’ always
translates to ‘inf’.
Function calls are written the usual way, with the function name
followed by the arguments in parentheses. However, functions for which
TeX and LaTeX have special names (like ‘\sin’) will use curly braces
instead of parentheses for very simple arguments. During input, curly
braces and parentheses work equally well for grouping, but when the
document is formatted the curly braces will be invisible. Thus the
printed result is ‘sin 2x’ but ‘sin(2 + x)’.
The TeX specific unit names (
Predefined Units) will not use
the ‘tex’ prefix; the unit name for a TeX point will be ‘pt’ instead of
‘texpt’, for example.
Function and variable names not treated specially by TeX and LaTeX
are simply written out as-is, which will cause them to come out in
italic letters in the printed document. If you invoke ‘d T’ or ‘d L’
with a positive numeric prefix argument, names of more than one
character will instead be enclosed in a protective commands that will
prevent them from being typeset in the math italics; they will be
written ‘\hbox{NAME}’ in TeX mode and ‘\text{NAME}’ in LaTeX mode. The
‘\hbox{ }’ and ‘\text{ }’ notations are ignored during reading. If you
use a negative prefix argument, such function names are written ‘\NAME’,
and function names that begin with ‘\’ during reading have the ‘\’
removed. (Note that in this mode, long variable names are still written
with ‘\hbox’ or ‘\text’. However, you can always make an actual
variable name like ‘\bar’ in any TeX mode.)
During reading, text of the form ‘\matrix{ ... }’ is replaced by ‘[
... ]’. The same also applies to ‘\pmatrix’ and ‘\bmatrix’. In LaTeX
mode this also applies to ‘\begin{matrix} ... \end{matrix}’,
‘\begin{bmatrix} ... \end{bmatrix}’, ‘\begin{pmatrix} ...
\end{pmatrix}’, as well as ‘\begin{smallmatrix} ... \end{smallmatrix}’.
The symbol ‘&’ is interpreted as a comma, and the symbols ‘\cr’ and ‘\\’
are interpreted as semicolons. During output, matrices are displayed in
‘\matrix{ a & b \\ c & d}’ format in TeX mode and in ‘\begin{pmatrix} a
& b \\ c & d \end{pmatrix}’ format in LaTeX mode; you may need to edit
this afterwards to change to your preferred matrix form. If you invoke
‘d T’ or ‘d L’ with an argument of 2 or -2, then matrices will be
displayed in two-dimensional form, such as
\begin{pmatrix}
a & b \\
c & d
\end{pmatrix}
This may be convenient for isolated matrices, but could lead to
expressions being displayed like
\begin{pmatrix} \times x
a & b \\
c & d
\end{pmatrix}
While this wouldn’t bother Calc, it is incorrect LaTeX. (Similarly for
TeX.)
Accents like ‘\tilde’ and ‘\bar’ translate into function calls
internally (‘tilde(x)’, ‘bar(x)’). The ‘\underline’ sequence is treated
as an accent. The ‘\vec’ accent corresponds to the function name ‘Vec’,
because ‘vec’ is the name of a built-in Calc function. The following
table shows the accents in Calc, TeX, LaTeX and “eqn” (described in the
next section):
Calc TeX LaTeX eqn
---- --- ----- ---
acute \acute \acute
Acute \Acute
bar \bar \bar bar
Bar \Bar
breve \breve \breve
Breve \Breve
check \check \check
Check \Check
dddot \dddot
ddddot \ddddot
dot \dot \dot dot
Dot \Dot
dotdot \ddot \ddot dotdot
DotDot \Ddot
dyad dyad
grave \grave \grave
Grave \Grave
hat \hat \hat hat
Hat \Hat
Prime prime
tilde \tilde \tilde tilde
Tilde \Tilde
under \underline \underline under
Vec \vec \vec vec
VEC \Vec
The ‘=>’ (evaluates-to) operator appears as a ‘\to’ symbol: ‘{A \to
B}’. TeX defines ‘\to’ as an alias for ‘\rightarrow’. However, if the
‘=>’ is the top-level expression being formatted, a slightly different
notation is used: ‘\evalto A \to B’. The ‘\evalto’ word is ignored by
Calc’s input routines, and is undefined in TeX. You will typically want
to include one of the following definitions at the top of a TeX file
that uses ‘\evalto’:
\def\evalto{}
\def\evalto#1\to{}
The first definition formats evaluates-to operators in the usual way.
The second causes only the B part to appear in the printed document; the
A part and the arrow are hidden. Another definition you may wish to use
is ‘\let\to=\Rightarrow’ which causes ‘\to’ to appear more like Calc’s
‘=>’ symbol. Evaluates-To Operator, for a discussion of
‘evalto’.
The complete set of TeX control sequences that are ignored during
reading is:
\hbox \mbox \text \left \right
\, \> \: \; \! \quad \qquad \hfil \hfill
\displaystyle \textstyle \dsize \tsize
\scriptstyle \scriptscriptstyle \ssize \ssize
\rm \bf \it \sl \roman \bold \italic \slanted
\cal \mit \Cal \Bbb \frak \goth
\evalto
Note that, because these symbols are ignored, reading a TeX or LaTeX
formula into Calc and writing it back out may lose spacing and font
information.
Also, the “discretionary multiplication sign” ‘\*’ is read the same
as ‘*’.
The TeX version of this manual includes some printed examples at the
end of this section.
Info Catalog
calc: C FORTRAN Pascal
calc: Language Modes
calc: Eqn Language Mode