-dxy

Specify?delimiters?x?and?y?for the left and right end, respectively, of in-line equations. Any?delim?statements in the source file overrides this.

-C

Recognize?.EQ?and?.EN?even when followed by a character other than space or?newline.

-N

Don't allow newlines within delimiters. This option allows eqn to recover better from missing closing delimiters.

-v

Print the version number.

-r

Only one size reduction.

-mn

The minimum point-size is?n.?eqn?will not reduce the size of?subscripts?or?superscripts?to a smaller size than?n.

-Tname

The output is for device?name. The only effect of this is to define a macro name with a value of 1. Typically?eqnrc?will use this to provide definitions appropriate for the output device. The default output device is?ps.

-Mdir

Search?dir?for?eqnrc?before the default directories.

-R

Don't load?eqnrc.

-fF

This is equivalent to a?gfont F?command.

-sn

This is equivalent to a?gsize?n?command. This option is deprecated.?eqn?will normally set equations at whatever the current point size is when the equation is encountered.

-pn

This says that subscripts and superscripts should be?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.

ordinary

an ordinary character such as '1' or 'x'

operator

a large operator such as '>'

binary

a binary operator such as '+'

relation

a relation such as '='

opening

an opening bracket such as '('

closing

a closing bracket such as ')'

punctuation

a punctuation character such as ','

inner

a subformula contained within brackets

suppress

spacing that suppresses automatic spacing adjustment

type?t e

This yields an equation component that contains?e?but that has type?t, where?t?is one of the types mentioned above. For example,?times?is defined as

type "binary" \(mu

The name of the type doesn't have to be quoted, but quoting protects from macro expansion.

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?text?from now on have type?t. For example,

chartype "punctuation" .,;:

would make the characters '.,;:' have type punctuation whenever they subsequently appeared in an equation. The type?t?can also be letter or digit; in these cases?chartype?changes the font type of the characters. See the?Fonts subsection.

e1?smallover?e2

This is similar to?over;?smallover?reduces the size of?e1?and?e2; it also puts less vertical space between?e1?or?e2?and the fraction bar. The?over?primitive corresponds to the TeX?\over?primitive in display styles;?smallover?corresponds to?\over?in non-display styles.

vcenter?e

This vertically centers?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,?sum?is defined as

{ type "operator" vcenter size +5 \(*S }

e1?accent?e2

This sets?e2?as an accent over?e1.?e2?is assumed to be at the correct height for a lowercase letter;?e2?will be moved down according if?e1?is taller or shorter than a lowercase letter. For example,?hat?is defined as

accent { "^" }

dotdot,?dot,?tilde,?vec, and?dyad?are also defined using the accent primitive.

e1?uaccent?e2

This sets?e2?as an accent under?e1.?e2?is assumed to be at the correct height for a character without a descender;?e2?will be moved down if?e1?has a descender. An under-tilde ("utilde") is pre-defined using uaccent as a tilde accent below the baseline.

split?"text"

This has the same effect as

text

but?text?is not subject to macro expansion because it is quoted; text will be split up and the spacing between individual characters will be adjusted.

nosplit?text

This has the same effect as

"text"

but because?text?is not quoted it will be subject to macro expansion; text will not be split up and the spacing between individual characters will not be adjusted.

e?opprime

This is a variant of?prime?that acts as an operator on?e. It produces a different result from?prime?in a case such as?A opprime sub 1: with?opprime?the?1?will be tucked under the prime as a subscript to the?A?(as is conventional in mathematical typesetting), whereas with?prime?the?1?will be a subscript to the prime character. The precedence of?opprime?is the same as that of?bar?and?under, which is higher than that of everything except?accent?and?uaccent. In unquoted text a?'?that is not the first character will be treated like?opprime.

special?text e

This constructs a new object from e using a?troff?macro named?text. When the macro is called, the string?0s?will contain the output for?e, and the number registers?0w,?0h,?0d,?0skern, and?0skew?will contain the?width,?height,?depth,?subscript kern, and?skew?of?e. The?subscript kern?of an object says how much a subscript on that object should be tucked in; the?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?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.

For example, suppose you wanted a construct that 'cancels' an expression by drawing a diagonal line through it.

.EQ
define cancel 'special Ca'
.EN
.de Ca
.  ds 0s \
\Z'\\*(0s'\
\v'\\n(0du'\
\D'l \\n(0wu -\\n(0hu-\\n(0du'\
\v'\\n(0hu'
..

Then you could cancel an expression?e?with?cancel {?e}

Here's a more complicated construct that draws a box round an expression:

.EQ
define box 'special Bx'
.EN
.de Bx
.  ds 0s \
\Z'\h'1n'\\*(0s'\
\Z'\
\v'\\n(0du+1n'\
\D'l \\n(0wu+2n 0'\
\D'l 0 -\\n(0hu-\\n(0du-2n'\
\D'l -\\n(0wu-2n 0'\
\D'l 0 \\n(0hu+\\n(0du+2n'\
'\
\h'\\n(0wu+2n'
.  nr 0w +2n
.  nr 0d +1n
.  nr 0h +1n
..

space?n

A positive value of the integer?n?(in hundredths of an em) sets the vertical spacing before the equation, a negative value sets the spacing after the equation, replacing the default values. This primitive provides an interface to?groff's?\x?escape (but with opposite sign).

This keyword has no effect if the equation is part of a pic picture.

col?n?{?...?}

ccol?n?{?...?}

lcol?n?{?...?}

rcol?n?{?...?}

pile?n?{?...?}

cpile?n?{?...?}

lpile?n?{?...?}

rpile?n?{?...?}

The integer value?n?(in hundredths of an em) increases the vertical spacing between rows, using?groff's?\x?escape. Negative values are possible but have no effect. If there is more than a single value given in a matrix, the biggest one is used.

set?p n

This sets parameter?p?to value?n;?n?is an integer. For example,

set x_height 45

says that?eqn?should assume an x height of 0.45 ems.

minimum_size

eqn?will not set anything at a smaller point-size than this. The value is in points.

fat_offset

The?fat?primitive emboldens an equation by overprinting two copies of the equation horizontally offset by this amount.

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.

accent_width

When?bar?or?under?is applied to a single character, the line will be this long. Normally,?bar?or?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.

delimiter_factor

Extensible delimiters produced with the left and 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.

delimiter_shortfall

Extensible delimiters produced with the left and 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.

null_delimiter_space

This much horizontal space is inserted on each side of a fraction.

script_space

The width of subscripts and superscripts is increased by this amount.

thin_space

This amount of space is automatically inserted after punctuation characters.

medium_space

This amount of space is automatically inserted on either side of binary operators.

thick_space

This amount of space is automatically inserted on either side of relations.

x_height

The height of lowercase letters without ascenders such as 'x'.

axis_height

The height above the baseline of the center of characters such as '+' and '-'. It is important that this value is correct for the font you are using.

default_rule_thickness

This should set to the thickness of the?\(ru?character, or the thickness of horizontal lines produced with the?\D?escape sequence.

num1

The?over?command will shift up the numerator by at least this amount.

num2

The?smallover?command will shift up the numerator by at least this amount.

denom1

The?over?command will shift down the denominator by at least this amount.

denom2

The?smallover?command will shift down the denominator by at least this amount.

sup1

Normally superscripts will be shifted up by at least this amount.

sup2

Superscripts within superscripts or upper limits or numerators of smallover fractions will be shifted up by at least this amount. This is usually less than?sup1.

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.

sub1

Subscripts will normally be shifted down by at least this amount.

sub2

When there is both a subscript and a superscript, the subscript will be shifted down by at least this amount.

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.

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.

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.

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.

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.

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.

big_op_spacing5

This much vertical space will be added above and below limits.

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?num1?and?denom1.

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?axis_height.

column_sep

This much space will be added between columns in a matrix.

matrix_side_sep

This much space will be added at each side of a matrix.

draw_lines

If this is non-zero, lines will be drawn using the?\D?escape sequence, rather than with the?\l?escape sequence and the?\(ru?character.

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?\x). The default value is?85.

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?\x). The default value is?35.

nroff

If this is non-zero, then?ndefine?will behave like?define?and?tdefine?will be ignored, otherwise?tdefine?will behave like?define?and?ndefine?will be ignored. The default value is?0?This is typically changed to?1?by the?eqnrc?file for the?ascii,?latin1,?utf8, and?cp1047?devices.

sdefine?name X anything X

This is like the?define?command, but?name?will not be recognized if called with arguments.

include?"file"

copy?"file"

Include the contents of?file?(include?and?copy?are synonyms). Lines of file beginning with?.EQ?or?.EN?will be ignored.

ifdef?name X anything X

If?name?has been defined by?define?(or has been automatically defined because?name?is the output device) process?anything; otherwise ignore?anything.?X?can be any character not appearing in?anything.

undef?name

Remove definition of?name, making it undefined.

grfont?f

Set the roman font to?f.

/usr/share/groff/1.19.2/tmac/eqnrc

eqn's Initialization file.