880 lines
18 KiB
Groff
880 lines
18 KiB
Groff
.ig \"-*- nroff -*-
|
|
Copyright (C) 1989-1995 Free Software Foundation, Inc.
|
|
|
|
Permission is granted to make and distribute verbatim copies of
|
|
this manual provided the copyright notice and this permission notice
|
|
are preserved on all copies.
|
|
|
|
Permission is granted to copy and distribute modified versions of this
|
|
manual under the conditions for verbatim copying, provided that the
|
|
entire resulting derived work is distributed under the terms of a
|
|
permission notice identical to this one.
|
|
|
|
Permission is granted to copy and distribute translations of this
|
|
manual into another language, under the above conditions for modified
|
|
versions, except that this permission notice may be included in
|
|
translations approved by the Free Software Foundation instead of in
|
|
the original English.
|
|
..
|
|
.ie \n(.V<\n(.v .ds tx T\h'-.1667m'\v'.224m'E\v'-.224m'\h'-.125m'X
|
|
.el .ds tx TeX
|
|
.\" Like TP, but if specified indent is more than half
|
|
.\" the current line-length - indent, use the default indent.
|
|
.de Tp
|
|
.ie \\n(.$=0:((0\\$1)*2u>(\\n(.lu-\\n(.iu)) .TP
|
|
.el .TP "\\$1"
|
|
..
|
|
.\" The BSD man macros can't handle " in arguments to font change macros,
|
|
.\" so use \(ts instead of ".
|
|
.tr \(ts"
|
|
.TH @G@EQN @MAN1EXT@ "@MDATE@" "Groff Version @VERSION@"
|
|
.SH NAME
|
|
@g@eqn \- format equations for troff
|
|
.SH SYNOPSIS
|
|
.B @g@eqn
|
|
[
|
|
.B \-rvCNR
|
|
]
|
|
[
|
|
.BI \-d cc
|
|
]
|
|
[
|
|
.BI \-T name
|
|
]
|
|
[
|
|
.BI \-M dir
|
|
]
|
|
[
|
|
.BI \-f F
|
|
]
|
|
[
|
|
.BI \-s n
|
|
]
|
|
[
|
|
.BI \-p n
|
|
]
|
|
[
|
|
.BI \-m n
|
|
]
|
|
[
|
|
.IR files \|.\|.\|.
|
|
]
|
|
.SH DESCRIPTION
|
|
This manual page describes the GNU version of
|
|
.BR eqn ,
|
|
which is part of the groff document formatting system.
|
|
.B eqn
|
|
compiles descriptions of equations embedded within
|
|
.B troff
|
|
input files into commands that are understood by
|
|
.BR troff .
|
|
Normally, it should be invoked using the
|
|
.B \-e
|
|
option of
|
|
.BR groff .
|
|
The syntax is quite compatible with Unix eqn.
|
|
The output of GNU eqn cannot be processed with Unix troff;
|
|
it must be processed with GNU troff.
|
|
If no files are given on the command line, the standard input
|
|
will be read.
|
|
A filename of
|
|
.B \-
|
|
will cause the standard input to be read.
|
|
.LP
|
|
.B eqn
|
|
searches for the file
|
|
.B eqnrc
|
|
using the path
|
|
.BR @MACROPATH@ .
|
|
If it exists, eqn will process it before the other input files.
|
|
The
|
|
.B \-R
|
|
option prevents this.
|
|
.LP
|
|
GNU eqn does not provide the functionality of neqn:
|
|
it does not support low-resolution, typewriter-like devices
|
|
(although it may work adequately for very simple input).
|
|
.SH OPTIONS
|
|
.TP
|
|
.B \-C
|
|
Recognize
|
|
.B .EQ
|
|
and
|
|
.B .EN
|
|
even when followed by a character other than space or newline.
|
|
.TP
|
|
.B \-N
|
|
Don't allow newlines within delimiters.
|
|
This option allows
|
|
.B eqn
|
|
to recover better from missing closing delimiters.
|
|
.TP
|
|
.B \-v
|
|
Print the version number.
|
|
.TP
|
|
.B \-r
|
|
Only one size reduction.
|
|
.TP
|
|
.BI \-m n
|
|
The minimum point-size is
|
|
.IR n .
|
|
eqn will not reduce the size of subscripts or superscripts to
|
|
a smaller size than
|
|
.IR n .
|
|
.TP
|
|
.BI \-T name
|
|
The output is for device
|
|
.IR name .
|
|
The only effect of this is to define a macro
|
|
.I name
|
|
with a value of
|
|
.BR 1 .
|
|
Typically
|
|
.B eqnrc
|
|
will use this to provide definitions appropriate for the output device.
|
|
The default output device is
|
|
.BR @DEVICE@ .
|
|
.TP
|
|
.BI \-M dir
|
|
Search
|
|
.I dir
|
|
for
|
|
.B eqnrc
|
|
before the default directories.
|
|
.TP
|
|
.B \-R
|
|
Don't load
|
|
.BR eqnrc .
|
|
.TP
|
|
.BI \-f F
|
|
This is equivalent to a
|
|
.BI gfont\ F
|
|
command.
|
|
.TP
|
|
.BI \-s n
|
|
This is equivalent to a
|
|
.BI gsize\ n
|
|
command.
|
|
This option is deprecated.
|
|
eqn will normally set equations at whatever the current point size
|
|
is when the equation is encountered.
|
|
.TP
|
|
.BI \-p n
|
|
This says that subscripts and superscripts should be
|
|
.I n
|
|
points smaller than the surrounding text.
|
|
This option is deprecated.
|
|
Normally eqn makes sets subscripts and superscripts at 70%
|
|
of the size of the surrounding text.
|
|
.SH USAGE
|
|
Only the differences between GNU eqn and Unix eqn are described here.
|
|
.LP
|
|
Most of the new features of GNU eqn
|
|
are based on \*(tx.
|
|
There are some references to the differences between \*(tx and GNU eqn below;
|
|
these may safely be ignored if you do not know \*(tx.
|
|
.SS Automatic spacing
|
|
.LP
|
|
.B eqn
|
|
gives each component of an equation a type, and adjusts the spacing
|
|
between components using that type.
|
|
Possible types are:
|
|
.TP \w'punctuation'u+2n
|
|
ordinary
|
|
an ordinary character such as 1 or
|
|
.IR x ;
|
|
.TP
|
|
operator
|
|
a large operator such as
|
|
.ds Su \s+5\(*S\s0
|
|
.if \n(.g .if !c\(*S .ds Su the summation operator
|
|
\*(Su;
|
|
.TP
|
|
binary
|
|
a binary operator such as +;
|
|
.TP
|
|
relation
|
|
a relation such as =;
|
|
.TP
|
|
opening
|
|
a opening bracket such as (;
|
|
.TP
|
|
closing
|
|
a closing bracket such as );
|
|
.TP
|
|
punctuation
|
|
a punctuation character such as ,;
|
|
.TP
|
|
inner
|
|
a subformula contained within brackets;
|
|
.TP
|
|
suppress
|
|
spacing that suppresses automatic spacing adjustment.
|
|
.LP
|
|
Components of an equation get a type in one of two ways.
|
|
.TP
|
|
.BI type\ t\ e
|
|
This yields an equation component that contains
|
|
.I e
|
|
but that has type
|
|
.IR t ,
|
|
where
|
|
.I t
|
|
is one of the types mentioned above.
|
|
For example,
|
|
.B times
|
|
is defined as
|
|
.RS
|
|
.IP
|
|
.B
|
|
type "binary" \e(mu
|
|
.RE
|
|
.IP
|
|
The name of the type doesn't have to be quoted, but quoting protects
|
|
from macro expansion.
|
|
.TP
|
|
.BI chartype\ t\ text
|
|
Unquoted groups of characters are split up into individual characters,
|
|
and the type of each character is looked up;
|
|
this changes the type that is stored for each character;
|
|
it says that the characters in
|
|
.I text
|
|
from now on have type
|
|
.IR t .
|
|
For example,
|
|
.RS
|
|
.IP
|
|
.B
|
|
chartype "punctuation" .,;:
|
|
.RE
|
|
.IP
|
|
would make the characters
|
|
.B .,;:
|
|
have type punctuation
|
|
whenever they subsequently appeared in an equation.
|
|
The type
|
|
.I t
|
|
can also be
|
|
.B letter
|
|
or
|
|
.BR digit ;
|
|
in these cases
|
|
.B chartype
|
|
changes the font type of the characters.
|
|
See the Fonts subsection.
|
|
.SS New primitives
|
|
.TP
|
|
.IB e1\ smallover\ e2
|
|
This is similar to
|
|
.BR over ;
|
|
.B smallover
|
|
reduces the size of
|
|
.I e1
|
|
and
|
|
.IR e2 ;
|
|
it also puts less vertical space between
|
|
.I e1
|
|
or
|
|
.I e2
|
|
and the fraction bar.
|
|
The
|
|
.B over
|
|
primitive corresponds to the \*(tx
|
|
.B \eover
|
|
primitive in display styles;
|
|
.B smallover
|
|
corresponds to
|
|
.B \eover
|
|
in non-display styles.
|
|
.TP
|
|
.BI vcenter\ e
|
|
This vertically centers
|
|
.I e
|
|
about the math axis.
|
|
The math axis is the vertical position about which characters
|
|
such as + and - are centered; also it is the vertical position
|
|
used for the bar of fractions.
|
|
For example,
|
|
.B sum
|
|
is defined as
|
|
.RS
|
|
.IP
|
|
.B
|
|
{ type "operator" vcenter size +5 \e(*S }
|
|
.RE
|
|
.TP
|
|
.IB e1\ accent\ e2
|
|
This sets
|
|
.I e2
|
|
as an accent over
|
|
.IR e1 .
|
|
.I e2
|
|
is assumed to be at the correct height for a lowercase letter;
|
|
.I e2
|
|
will be moved down according if
|
|
.I e1
|
|
is taller or shorter than a lowercase letter.
|
|
For example,
|
|
.B hat
|
|
is defined as
|
|
.RS
|
|
.IP
|
|
.B
|
|
accent { "^" }
|
|
.RE
|
|
.IP
|
|
.BR dotdot ,
|
|
.BR dot ,
|
|
.BR tilde ,
|
|
.B vec
|
|
and
|
|
.B dyad
|
|
are also defined using the
|
|
.B accent
|
|
primitive.
|
|
.TP
|
|
.IB e1\ uaccent\ e2
|
|
This sets
|
|
.I e2
|
|
as an accent under
|
|
.IR e1 .
|
|
.I e2
|
|
is assumed to be at the correct height for a character without a descender;
|
|
.I e2
|
|
will be moved down if
|
|
.I e1
|
|
has a descender.
|
|
.B utilde
|
|
is pre-defined using
|
|
.B uaccent
|
|
as a tilde accent below the baseline.
|
|
.TP
|
|
.BI split\ \(ts text \(ts
|
|
This has the same effect as simply
|
|
.RS
|
|
.IP
|
|
.I text
|
|
.RE
|
|
.IP
|
|
but
|
|
.I text
|
|
is not subject to macro expansion because it is quoted;
|
|
.I text
|
|
will be split up and the spacing between individual characters
|
|
will be adjusted.
|
|
.TP
|
|
.BI nosplit\ text
|
|
This has the same effect as
|
|
.RS
|
|
.IP
|
|
.BI \(ts text \(ts
|
|
.RE
|
|
.IP
|
|
but because
|
|
.I text
|
|
is not quoted it will be subject to macro expansion;
|
|
.I text
|
|
will not be split up
|
|
and the spacing between individual characters will not be adjusted.
|
|
.TP
|
|
.IB e\ opprime
|
|
This is a variant of
|
|
.B prime
|
|
that acts as an operator on
|
|
.IR e .
|
|
It produces a different result from
|
|
.B prime
|
|
in a case such as
|
|
.BR A\ opprime\ sub\ 1 :
|
|
with
|
|
.B opprime
|
|
the
|
|
.B 1
|
|
will be tucked under the prime as a subscript to the
|
|
.B A
|
|
(as is conventional in mathematical typesetting),
|
|
whereas with
|
|
.B prime
|
|
the
|
|
.B 1
|
|
will be a subscript to the prime character.
|
|
The precedence of
|
|
.B opprime
|
|
is the same as that of
|
|
.B bar
|
|
and
|
|
.BR under ,
|
|
which is higher than that of everything except
|
|
.B accent
|
|
and
|
|
.BR uaccent .
|
|
In unquoted text a
|
|
.B '
|
|
that is not the first character will be treated like
|
|
.BR opprime .
|
|
.TP
|
|
.BI special\ text\ e
|
|
This constructs a new object from
|
|
.I e
|
|
using a
|
|
.BR @g@troff (@MAN1EXT@)
|
|
macro named
|
|
.IR text .
|
|
When the macro is called,
|
|
the string
|
|
.B 0s
|
|
will contain the output for
|
|
.IR e ,
|
|
and the number registers
|
|
.BR 0w ,
|
|
.BR 0h ,
|
|
.BR 0d ,
|
|
.BR 0skern
|
|
and
|
|
.BR 0skew
|
|
will contain the width, height, depth, subscript kern, and skew of
|
|
.IR e .
|
|
(The
|
|
.I "subscript kern"
|
|
of an object says how much a subscript on that object should be tucked in;
|
|
the
|
|
.I skew
|
|
of an object says how far to the right of the center of the object an
|
|
accent over the object should be placed.)
|
|
The macro must modify
|
|
.B 0s
|
|
so that it will output the desired result with its origin at the current
|
|
point, and increase the current horizontal position by the width
|
|
of the object.
|
|
The number registers must also be modified so that they correspond to the
|
|
result.
|
|
.RS
|
|
.LP
|
|
For example, suppose you wanted a construct that `cancels' an expression
|
|
by drawing a diagonal line through it.
|
|
.IP
|
|
.nf
|
|
.ft B
|
|
.ne 6+\n(.Vu
|
|
\&.EQ
|
|
define cancel 'special Ca'
|
|
\&.EN
|
|
\&.de Ca
|
|
\&.ds 0s \eZ'\e\e*(0s'\ev'\e\en(0du'\eD'l \e\en(0wu -\e\en(0hu-\e\en(0du'\ev'\e\en(0hu'
|
|
\&..
|
|
.ft
|
|
.fi
|
|
.LP
|
|
Then you could cancel an expression
|
|
.I e
|
|
with
|
|
.BI cancel\ {\ e\ }
|
|
.LP
|
|
Here's a more complicated construct that draws a box round an expression:
|
|
.IP
|
|
.nf
|
|
.ft B
|
|
.ne 11+\n(.Vu
|
|
\&.EQ
|
|
define box 'special Bx'
|
|
\&.EN
|
|
\&.de Bx
|
|
\&.ds 0s \eZ'\eh'1n'\e\e*(0s'\e
|
|
\eZ'\ev'\e\en(0du+1n'\eD'l \e\en(0wu+2n 0'\eD'l 0 -\e\en(0hu-\e\en(0du-2n'\e
|
|
\eD'l -\e\en(0wu-2n 0'\eD'l 0 \e\en(0hu+\e\en(0du+2n''\eh'\e\en(0wu+2n'
|
|
\&.nr 0w +2n
|
|
\&.nr 0d +1n
|
|
\&.nr 0h +1n
|
|
\&..
|
|
.ft
|
|
.fi
|
|
.RE
|
|
.SS Customization
|
|
The appearance of equations is controlled by
|
|
a large number of parameters. These can be set using
|
|
the
|
|
.B set
|
|
command.
|
|
.TP
|
|
.BI set\ p\ n
|
|
This sets parameter
|
|
.I p
|
|
to value
|
|
.I n ;
|
|
.I n
|
|
is an integer.
|
|
For example,
|
|
.RS
|
|
.IP
|
|
.B
|
|
set x_height 45
|
|
.RE
|
|
.IP
|
|
says that
|
|
.B eqn
|
|
should assume an x height of 0.45 ems.
|
|
.RS
|
|
.LP
|
|
Possible parameters are as follows.
|
|
Values are in units of hundredths of an em unless otherwise stated.
|
|
These descriptions are intended to be expository rather than
|
|
definitive.
|
|
.TP \w'\fBdefault_rule_thickness'u+2n
|
|
.B minimum_size
|
|
.B eqn
|
|
will not set anything at a smaller point-size than this.
|
|
The value is in points.
|
|
.TP
|
|
.B fat_offset
|
|
The
|
|
.B fat
|
|
primitive emboldens an equation
|
|
by overprinting two copies of the equation
|
|
horizontally offset by this amount.
|
|
.TP
|
|
.B over_hang
|
|
A fraction bar will be longer by twice this amount than
|
|
the maximum of the widths of the numerator and denominator;
|
|
in other words, it will overhang the numerator and
|
|
denominator by at least this amount.
|
|
.TP
|
|
.B accent_width
|
|
When
|
|
.B bar
|
|
or
|
|
.B under
|
|
is applied to a single character,
|
|
the line will be this long.
|
|
Normally,
|
|
.B bar
|
|
or
|
|
.B under
|
|
produces a line whose length is the width of the object to which it applies;
|
|
in the case of a single character,
|
|
this tends to produce a line that looks too long.
|
|
.TP
|
|
.B delimiter_factor
|
|
Extensible delimiters produced with the
|
|
.B left
|
|
and
|
|
.B right
|
|
primitives will have a combined height and depth of at least this many
|
|
thousandths of twice the maximum amount by which the sub-equation that
|
|
the delimiters enclose extends away from the axis.
|
|
.TP
|
|
.B delimiter_shortfall
|
|
Extensible delimiters produced with the
|
|
.B left
|
|
and
|
|
.B right
|
|
primitives will have a combined height and depth
|
|
not less than the difference of
|
|
twice the maximum amount by which the sub-equation that
|
|
the delimiters enclose extends away from the axis
|
|
and this amount.
|
|
.TP
|
|
.B null_delimiter_space
|
|
This much horizontal space is inserted
|
|
on each side of a fraction.
|
|
.TP
|
|
.B script_space
|
|
The width of subscripts and superscripts is increased by this amount.
|
|
.TP
|
|
.B thin_space
|
|
This amount of space is automatically inserted after punctuation
|
|
characters.
|
|
.TP
|
|
.B medium_space
|
|
This amount of space is automatically inserted on either side
|
|
of binary operators.
|
|
.TP
|
|
.B thick_space
|
|
This amount of space is automatically inserted on either side of
|
|
relations.
|
|
.TP
|
|
.B x_height
|
|
The height of lowercase letters without ascenders such as x.
|
|
.TP
|
|
.B axis_height
|
|
The height above the baseline of the center of characters
|
|
such as \(pl and \(mi.
|
|
It is important that this value is correct for the font
|
|
you are using.
|
|
.TP
|
|
.B default_rule_thickness
|
|
This should set to the thickness of the
|
|
.B \e(ru
|
|
character, or the thickness of horizontal lines produced with the
|
|
.B \eD
|
|
escape sequence.
|
|
.TP
|
|
.B num1
|
|
The
|
|
.B over
|
|
command will shift up the numerator by at least this amount.
|
|
.TP
|
|
.B num2
|
|
The
|
|
.B smallover
|
|
command will shift up the numerator by at least this amount.
|
|
.TP
|
|
.B denom1
|
|
The
|
|
.B over
|
|
command will shift down the denominator by at least this amount.
|
|
.TP
|
|
.B denom2
|
|
The
|
|
.B smallover
|
|
command will shift down the denominator by at least this amount.
|
|
.TP
|
|
.B sup1
|
|
Normally superscripts will be shifted up by at least this amount.
|
|
.TP
|
|
.B sup2
|
|
Superscripts within superscripts or upper limits
|
|
or numerators of
|
|
.B smallover
|
|
fractions
|
|
will be shifted up by at least this amount.
|
|
This is usually less than sup1.
|
|
.TP
|
|
.B sup3
|
|
Superscripts within denominators or square roots
|
|
or subscripts or lower limits will be shifted up by at least
|
|
this amount.
|
|
This is usually less than sup2.
|
|
.TP
|
|
.B sub1
|
|
Subscripts will normally be shifted down by at least this amount.
|
|
.TP
|
|
.B sub2
|
|
When there is both a subscript and a superscript, the subscript
|
|
will be shifted down by at least this amount.
|
|
.TP
|
|
.B sup_drop
|
|
The baseline of a superscript will be no more
|
|
than this much amount below the top of the object on
|
|
which the superscript is set.
|
|
.TP
|
|
.B sub_drop
|
|
The baseline of a subscript will be at least this much below
|
|
the bottom of the object on which the subscript is set.
|
|
.TP
|
|
.B big_op_spacing1
|
|
The baseline of an upper limit will be at least this
|
|
much above the top of the object on which the limit is set.
|
|
.TP
|
|
.B big_op_spacing2
|
|
The baseline of a lower limit will be at least this
|
|
much below the bottom of the object on which the limit is set.
|
|
.TP
|
|
.B big_op_spacing3
|
|
The bottom of an upper limit will be at least this much above the
|
|
top of the object on which the limit is set.
|
|
.TP
|
|
.B big_op_spacing4
|
|
The top of a lower limit will be at least this much below
|
|
the bottom of the object on which the limit is set.
|
|
.TP
|
|
.B big_op_spacing5
|
|
This much vertical space will be added above and below limits.
|
|
.TP
|
|
.B baseline_sep
|
|
The baselines of the rows in a pile or matrix will normally be
|
|
this far apart.
|
|
In most cases this should be equal to the sum of
|
|
.B num1
|
|
and
|
|
.BR denom1 .
|
|
.TP
|
|
.B shift_down
|
|
The midpoint between the top baseline and the bottom baseline
|
|
in a matrix or pile will be shifted down by this much from the axis.
|
|
In most cases this should be equal to
|
|
.BR axis_height .
|
|
.TP
|
|
.B column_sep
|
|
This much space will be added between columns in a matrix.
|
|
.TP
|
|
.B matrix_side_sep
|
|
This much space will be added at each side of a matrix.
|
|
.TP
|
|
.B draw_lines
|
|
If this is non-zero, lines will be drawn using the
|
|
.B \eD
|
|
escape sequence, rather than with the
|
|
.B \el
|
|
escape sequence and the
|
|
.B \e(ru
|
|
character.
|
|
.TP
|
|
.B body_height
|
|
The amount by which the height of the equation exceeds this
|
|
will be added as extra space before the line containing the equation
|
|
(using
|
|
.BR \ex .)
|
|
The default value is 85.
|
|
.TP
|
|
.B body_depth
|
|
The amount by which the depth of the equation exceeds this
|
|
will be added as extra space after the line containing the equation
|
|
(using
|
|
.BR \ex .)
|
|
The default value is 35.
|
|
.TP
|
|
.B nroff
|
|
If this is non-zero,
|
|
then
|
|
.B ndefine
|
|
will behave like
|
|
.B define
|
|
and
|
|
.B tdefine
|
|
will be ignored,
|
|
otherwise
|
|
.B tdefine
|
|
will behave like
|
|
.B define
|
|
and
|
|
.B ndefine
|
|
will be ignored.
|
|
The default value is 0
|
|
(This is typically changed to 1 by the
|
|
.B eqnrc
|
|
file for the
|
|
.B ascii
|
|
and
|
|
.B latin1
|
|
devices.)
|
|
.LP
|
|
A more precise description of the role of many of these
|
|
parameters can be found in Appendix H of
|
|
.IR The\ \*(txbook .
|
|
.RE
|
|
.SS Macros
|
|
Macros can take arguments.
|
|
In a macro body,
|
|
.BI $ n
|
|
where
|
|
.I n
|
|
is between 1 and 9,
|
|
will be replaced by the
|
|
.IR n-th
|
|
argument if the macro is called with arguments;
|
|
if there are fewer than
|
|
.I n
|
|
arguments, it will be replaced by nothing.
|
|
A word containing a left parenthesis where the part of the word
|
|
before the left parenthesis has been defined using the
|
|
.B define
|
|
command
|
|
will be recognized as a macro call with arguments;
|
|
characters following the left parenthesis
|
|
up to a matching right parenthesis will be treated as comma-separated
|
|
arguments;
|
|
commas inside nested parentheses do not terminate an argument.
|
|
.TP
|
|
.BI sdefine\ name\ X\ anything\ X
|
|
This is like the
|
|
.B define
|
|
command, but
|
|
.I name
|
|
will not be recognized if called with arguments.
|
|
.TP
|
|
.BI include\ \(ts file \(ts
|
|
Include the contents of
|
|
.IR file .
|
|
Lines of
|
|
.I file
|
|
beginning with
|
|
.B .EQ
|
|
or
|
|
.B .EN
|
|
will be ignored.
|
|
.TP
|
|
.BI ifdef\ name\ X\ anything\ X
|
|
If
|
|
.I name
|
|
has been defined by
|
|
.B define
|
|
(or has been automatically defined because
|
|
.I name
|
|
is the output device)
|
|
process
|
|
.IR anything ;
|
|
otherwise ignore
|
|
.IR anything .
|
|
.I X
|
|
can be any character not appearing in
|
|
.IR anything .
|
|
.SS Fonts
|
|
.B eqn
|
|
normally uses at least two fonts to set an equation:
|
|
an italic font for letters,
|
|
and a roman font for everything else.
|
|
The existing
|
|
.B gfont
|
|
command
|
|
changes the font that is used as the italic font.
|
|
By default this is
|
|
.BR I .
|
|
The font that is used as the roman font can be changed
|
|
using the new
|
|
.B grfont
|
|
command.
|
|
.TP
|
|
.BI grfont\ f
|
|
Set the roman font to
|
|
.IR f .
|
|
.LP
|
|
The
|
|
.B italic
|
|
primitive uses the current italic font set by
|
|
.BR gfont ;
|
|
the
|
|
.B roman
|
|
primitive uses the current roman font set by
|
|
.BR grfont .
|
|
There is also a new
|
|
.B gbfont
|
|
command, which changes the font used by the
|
|
.B bold
|
|
primitive.
|
|
If you only use the
|
|
.BR roman ,
|
|
.B italic
|
|
and
|
|
.B bold
|
|
primitives to changes fonts within an equation,
|
|
you can change all the fonts used by your equations
|
|
just by using
|
|
.BR gfont ,
|
|
.B grfont
|
|
and
|
|
.B gbfont
|
|
commands.
|
|
.LP
|
|
You can control which characters are treated as letters
|
|
(and therefore set in italics) by using the
|
|
.B chartype
|
|
command described above.
|
|
A type of
|
|
.B letter
|
|
will cause a character to be set in italic type.
|
|
A type of
|
|
.B digit
|
|
will cause a character to be set in roman type.
|
|
.SH FILES
|
|
.Tp \w'\fB@MACRODIR@/eqnrc'u+2n
|
|
.B @MACRODIR@/eqnrc
|
|
Initialization file.
|
|
.SH BUGS
|
|
Inline equations will be set at the point size that is current at the
|
|
beginning of the input line.
|
|
.SH "SEE ALSO"
|
|
.BR groff (@MAN1EXT@),
|
|
.BR @g@troff (@MAN1EXT@),
|
|
.BR groff_font (@MAN5EXT@),
|
|
.I The\ \*(txbook
|