1EQN(1) General Commands Manual EQN(1)
2
6 eqn - format equations for troff or MathML
7
9 eqn [-rvCNR] [-d xy] [-T name] [-M dir] [-f F] [-s n] [-p n] [-m n]
10 [files...]
11
13 This manual page describes the GNU version of eqn, which is part of the
14 groff document formatting system. eqn compiles descriptions of equa‐
15 tions embedded within troff input files into commands that are under‐
16 stood by troff. Normally, it should be invoked using the -e option of
17 groff. The syntax is quite compatible with Unix eqn. The output of
18 GNU eqn cannot be processed with Unix troff; it must be processed with
19 GNU troff. If no files are given on the command line, the standard
20 input is read. A filename of - causes the standard input to be read.
21 eqn searches for the file eqnrc in the directories given with the -M
23 option first, then in /etc/groff/site-tmac, /etc/groff/site-tmac, and
24 finally in the standard macro directory /usr/share/groff/1.22.3/tmac.
25 If it exists, eqn processes it before the other input files. The -R
26 option prevents this.
27 GNU eqn does not provide the functionality of neqn: it does not support
29 low-resolution, typewriter-like devices (although it may work ade‐
30 quately for very simple input).
31
33 It is possible to have whitespace between a command line option and its
34 parameter.
35 -dxy Specify delimiters x and y for the left and right end, respec‐
37 tively, of in-line equations. Any delim statements in the
38 source file overrides this.
39 -C Recognize .EQ and .EN even when followed by a character other
41 than space or newline. Also, the statement ‘delim on’ is not
42 handled specially.
43 -N Don't allow newlines within delimiters. This option allows eqn
45 to recover better from missing closing delimiters.
46 -v Print the version number.
48 -r Only one size reduction.
50 -mn The minimum point-size is n. eqn does not reduce the size of
52 subscripts or superscripts to a smaller size than n.
53 -Tname The output is for device name. Normally, the only effect of
55 this is to define a macro name with a value of 1; eqnrc uses
56 this to provide definitions appropriate for the output device.
57 However, if the specified device is “MathML”, the output is
58 MathML markup rather than troff commands, and eqnrc is not
59 loaded at all. The default output device is ps.
60 -Mdir Search dir for eqnrc before the default directories.
62 -R Don't load eqnrc.
64 -fF This is equivalent to a gfont F command.
66 -sn This is equivalent to a gsize n command. This option is depre‐
68 cated. eqn normally sets equations at whatever the current
69 point size is when the equation is encountered.
70 -pn This says that subscripts and superscripts should be n points
72 smaller than the surrounding text. This option is deprecated.
73 Normally eqn sets subscripts and superscripts at 70% of the size
74 of the surrounding text.
75
77 Only the differences between GNU eqn and Unix eqn are described here.
78 GNU eqn emits Presentation MathML output when invoked with the
80 -T MathML option.
81 GNU eqn sets the input token "..." as three periods or low dots,
83 rather than the three centered dots of classic eqn. To get three cen‐
84 tered dots, write cdots or cdot cdot cdot.
85 Most of the new features of the GNU eqn input language are based on
87 TeX. There are some references to the differences between TeX and GNU
88 eqn below; these may safely be ignored if you do not know TeX.
89 Controlling delimiters
91 If not in compatibility mode, eqn recognizes
92 delim on
94 to restore the delimiters which have been previously disabled with a
96 call to ‘delim off’. If delimiters haven't been specified, the call
97 has no effect.
98 Automatic spacing
100 eqn gives each component of an equation a type, and adjusts the spacing
101 between components using that type. Possible types are:
102 ordinary an ordinary character such as ‘1’ or ‘
104 x’;
105 operator a large operator such as ‘Σ’;
107 binary a binary operator such as ‘+’;
109 relation a relation such as ‘=’;
111 opening a opening bracket such as ‘(’;
113 closing a closing bracket such as ‘)’;
115 punctuation a punctuation character such as ‘,;
117 inner a subformula contained within brackets;
119 suppress spacing
121 that suppresses automatic spacing adjustment.
122 Components of an equation get a type in one of two ways.
124 type t e
126 This yields an equation component that contains e but that has
127 type t, where t is one of the types mentioned above. For exam‐
128 ple, times is defined as
129 type "binary" \(mu
131 The name of the type doesn't have to be quoted, but quoting pro‐
133 tects from macro expansion.
134 chartype t text
136 Unquoted groups of characters are split up into individual char‐
137 acters, and the type of each character is looked up; this
138 changes the type that is stored for each character; it says that
139 the characters in text from now on have type t. For example,
140 chartype "punctuation" .,;:
142 would make the characters ‘.,;:’ have type punctuation whenever
144 they subsequently appeared in an equation. The type t can also
145 be letter or digit; in these cases chartype changes the font
146 type of the characters. See the Fonts subsection.
147 New primitives
149 big e Enlarges the expression it modifies; intended to have semantics
150 like CSS ‘large’. In troff output, the point size is increased
151 by 5; in MathML output, the expression uses
152 <mstyle mathsize='big'>
154 e1 smallover e2
156 This is similar to over; smallover reduces the size of e1 and
157 e2; it also puts less vertical space between e1 or e2 and the
158 fraction bar. The over primitive corresponds to the TeX \over
159 primitive in display styles; smallover corresponds to \over in
160 non-display styles.
161 vcenter e
163 This vertically centers e about the math axis. The math axis is
164 the vertical position about which characters such as ‘+cq and
165 ‘−’ are centered; also it is the vertical position used for the
166 bar of fractions. For example, sum is defined as
167 { type "operator" vcenter size +5 \(*S }
169 (Note that vcenter is silently ignored when generating MathML.)
171 e1 accent e2
173 This sets e2 as an accent over e1. e2 is assumed to be at the
174 correct height for a lowercase letter; e2 is moved down accord‐
175 ing to whether e1 is taller or shorter than a lowercase letter.
176 For example, hat is defined as
177 accent { "^" }
179 dotdot, dot, tilde, vec, and dyad are also defined using the
181 accent primitive.
182 e1 uaccent e2
184 This sets e2 as an accent under e1. e2 is assumed to be at the
185 correct height for a character without a descender; e2 is moved
186 down if e1 has a descender. utilde is pre-defined using uaccent
187 as a tilde accent below the baseline.
188 split "text"
190 This has the same effect as simply
191 text
193 but text is not subject to macro expansion because it is quoted;
195 text is split up and the spacing between individual characters
196 is adjusted.
197 nosplit text
199 This has the same effect as
200 "text"
202 but because text is not quoted it is subject to macro expansion;
204 text is not split up and the spacing between individual charac‐
205 ters is not adjusted.
206 e opprime
208 This is a variant of prime that acts as an operator on e. It
209 produces a different result from prime in a case such as
210 A opprime sub 1: with opprime the 1 is tucked under the prime as
211 a subscript to the A (as is conventional in mathematical type‐
212 setting), whereas with prime the 1 is a subscript to the prime
213 character. The precedence of opprime is the same as that of bar
214 and under, which is higher than that of everything except accent
215 and uaccent. In unquoted text a ' that is not the first charac‐
216 ter is treated like opprime.
217 special text e
219 This constructs a new object from e using a troff(1) macro named
220 text. When the macro is called, the string 0s contains the out‐
221 put for e, and the number registers 0w, 0h, 0d, 0skern, and
222 0skew contain the width, height, depth, subscript kern, and skew
223 of e. (The subscript kern of an object says how much a sub‐
224 script on that object should be tucked in; the skew of an object
225 says how far to the right of the center of the object an accent
226 over the object should be placed.) The macro must modify 0s so
227 that it outputs the desired result with its origin at the cur‐
228 rent point, and increase the current horizontal position by the
229 width of the object. The number registers must also be modified
230 so that they correspond to the result.
231 For example, suppose you wanted a construct that ‘cancels’ an
233 expression by drawing a diagonal line through it.
234 .EQ
236 define cancel 'special Ca'
237 .EN
238 .de Ca
239 . ds 0s \
240 \Z'\\*(0s'\
241 \v'\\n(0du'\
242 \D'l \\n(0wu -\\n(0hu-\\n(0du'\
243 \v'\\n(0hu'
244 ..
245 Then you could cancel an expression e with cancel { e }
247 Here's a more complicated construct that draws a box round an
249 expression:
250 .EQ
252 define box 'special Bx'
253 .EN
254 .de Bx
255 . ds 0s \
256 \Z'\h'1n'\\*(0s'\
257 \Z'\
258 \v'\\n(0du+1n'\
259 \D'l \\n(0wu+2n 0'\
260 \D'l 0 -\\n(0hu-\\n(0du-2n'\
261 \D'l -\\n(0wu-2n 0'\
262 \D'l 0 \\n(0hu+\\n(0du+2n'\
263 '\
264 \h'\\n(0wu+2n'
265 . nr 0w +2n
266 . nr 0d +1n
267 . nr 0h +1n
268 ..
269 space n
271 A positive value of the integer n (in hundredths of an em) sets
272 the vertical spacing before the equation, a negative value sets
273 the spacing after the equation, replacing the default values.
274 This primitive provides an interface to groff's \x escape (but
275 with opposite sign).
276 This keyword has no effect if the equation is part of a pic pic‐
278 ture.
279 Extended primitives
281 col n { ... }
282 ccol n { ... }
283 lcol n { ... }
284 rcol n { ... }
285 pile n { ... }
286 cpile n { ... }
287 lpile n { ... }
288 rpile n { ... }
289 The integer value n (in hundredths of an em) increases the ver‐
290 tical spacing between rows, using groff's \x escape (the value
291 has no effect in MathML mode). Negative values are possible but
292 have no effect. If there is more than a single value given in a
293 matrix, the biggest one is used.
294 Customization
296 When eqn is generating troff markup, the appearance of equations is
297 controlled by a large number of parameters. They have no effect when
298 generating MathML mode, which pushes typesetting and fine motions down‐
299 stream to a MathML rendering engine. These parameters can be set using
300 the set command.
301 set p n
303 This sets parameter p to value n; n is an integer. For example,
304 set x_height 45
306 says that eqn should assume an x height of 0.45 ems.
308 Possible parameters are as follows. Values are in units of hun‐
310 dredths of an em unless otherwise stated. These descriptions
311 are intended to be expository rather than definitive.
312 minimum_size
314 eqn doesn't set anything at a smaller point-size than
315 this. The value is in points.
316 fat_offset
318 The fat primitive emboldens an equation by overprinting
319 two copies of the equation horizontally offset by this
320 amount. This parameter is not used in MathML mode;
321 instead, fat text uses
322 <mstyle mathvariant='double-struck'>
324 over_hang
326 A fraction bar is longer by twice this amount than the
327 maximum of the widths of the numerator and denominator;
328 in other words, it overhangs the numerator and denomina‐
329 tor by at least this amount.
330 accent_width
332 When bar or under is applied to a single character, the
333 line is this long. Normally, bar or under produces a
334 line whose length is the width of the object to which it
335 applies; in the case of a single character, this tends to
336 produce a line that looks too long.
337 delimiter_factor
339 Extensible delimiters produced with the left and right
340 primitives have a combined height and depth of at least
341 this many thousandths of twice the maximum amount by
342 which the sub-equation that the delimiters enclose
343 extends away from the axis.
344 delimiter_shortfall
346 Extensible delimiters produced with the left and right
347 primitives have a combined height and depth not less than
348 the difference of twice the maximum amount by which the
349 sub-equation that the delimiters enclose extends away
350 from the axis and this amount.
351 null_delimiter_space
353 This much horizontal space is inserted on each side of a
354 fraction.
355 script_space
357 The width of subscripts and superscripts is increased by
358 this amount.
359 thin_space
361 This amount of space is automatically inserted after
362 punctuation characters.
363 medium_space
365 This amount of space is automatically inserted on either
366 side of binary operators.
367 thick_space
369 This amount of space is automatically inserted on either
370 side of relations.
371 x_height
373 The height of lowercase letters without ascenders such as
374 ‘x’.
375 axis_height
377 The height above the baseline of the center of characters
378 such as ‘+’ and ‘−’. It is important that this value is
379 correct for the font you are using.
380 default_rule_thickness
382 This should set to the thickness of the \(ru character,
383 or the thickness of horizontal lines produced with the \D
384 escape sequence.
385 num1 The over command shifts up the numerator by at least this
387 amount.
388 num2 The smallover command shifts up the numerator by at least
390 this amount.
391 denom1 The over command shifts down the denominator by at least
393 this amount.
394 denom2 The smallover command shifts down the denominator by at
396 least this amount.
397 sup1 Normally superscripts are shifted up by at least this
399 amount.
400 sup2 Superscripts within superscripts or upper limits or
402 numerators of smallover fractions are shifted up by at
403 least this amount. This is usually less than sup1.
404 sup3 Superscripts within denominators or square roots or sub‐
406 scripts or lower limits are shifted up by at least this
407 amount. This is usually less than sup2.
408 sub1 Subscripts are normally shifted down by at least this
410 amount.
411 sub2 When there is both a subscript and a superscript, the
413 subscript is shifted down by at least this amount.
414 sup_drop
416 The baseline of a superscript is no more than this much
417 amount below the top of the object on which the super‐
418 script is set.
419 sub_drop
421 The baseline of a subscript is at least this much below
422 the bottom of the object on which the subscript is set.
423 big_op_spacing1
425 The baseline of an upper limit is at least this much
426 above the top of the object on which the limit is set.
427 big_op_spacing2
429 The baseline of a lower limit is at least this much below
430 the bottom of the object on which the limit is set.
431 big_op_spacing3
433 The bottom of an upper limit is at least this much above
434 the top of the object on which the limit is set.
435 big_op_spacing4
437 The top of a lower limit is at least this much below the
438 bottom of the object on which the limit is set.
439 big_op_spacing5
441 This much vertical space is added above and below limits.
442 baseline_sep
444 The baselines of the rows in a pile or matrix are nor‐
445 mally this far apart. In most cases this should be equal
446 to the sum of num1 and denom1.
447 shift_down
449 The midpoint between the top baseline and the bottom
450 baseline in a matrix or pile is shifted down by this much
451 from the axis. In most cases this should be equal to
452 axis_height.
453 column_sep
455 This much space is added between columns in a matrix.
456 matrix_side_sep
458 This much space is added at each side of a matrix.
459 draw_lines
461 If this is non-zero, lines are drawn using the \D escape
462 sequence, rather than with the \l escape sequence and the
463 \(ru character.
464 body_height
466 The amount by which the height of the equation exceeds
467 this is added as extra space before the line containing
468 the equation (using \x). The default value is 85.
469 body_depth
471 The amount by which the depth of the equation exceeds
472 this is added as extra space after the line containing
473 the equation (using \x). The default value is 35.
474 nroff If this is non-zero, then ndefine behaves like define and
476 tdefine is ignored, otherwise tdefine behaves like define
477 and ndefine is ignored. The default value is 0 (This is
478 typically changed to 1 by the eqnrc file for the ascii,
479 latin1, utf8, and cp1047 devices.)
480 A more precise description of the role of many of these parame‐
482 ters can be found in Appendix H of The TeXbook.
483 Macros
485 Macros can take arguments. In a macro body, $n where n is between 1
486 and 9, is replaced by the n-th argument if the macro is called with
487 arguments; if there are fewer than n arguments, it is replaced by noth‐
488 ing. A word containing a left parenthesis where the part of the word
489 before the left parenthesis has been defined using the define command
490 is recognized as a macro call with arguments; characters following the
491 left parenthesis up to a matching right parenthesis are treated as
492 comma-separated arguments; commas inside nested parentheses do not ter‐
493 minate an argument.
494 sdefine name X anything X
496 This is like the define command, but name is not recognized if
497 called with arguments.
498 include "file"
500 copy "file"
501 Include the contents of file (include and copy are synonyms).
502 Lines of file beginning with .EQ or .EN are ignored.
503 ifdef name X anything X
505 If name has been defined by define (or has been automatically
506 defined because name is the output device) process anything;
507 otherwise ignore anything. X can be any character not appearing
508 in anything.
509 undef name
511 Remove definition of name, making it undefined.
512 Besides the macros mentioned above, the following definitions are
514 available: Alpha, Beta, ..., Omega (this is the same as ALPHA, BETA,
515 ..., OMEGA), ldots (three dots on the base line), and dollar.
516 Fonts
518 eqn normally uses at least two fonts to set an equation: an italic font
519 for letters, and a roman font for everything else. The existing gfont
520 command changes the font that is used as the italic font. By default
521 this is I. The font that is used as the roman font can be changed
522 using the new grfont command.
523 grfont f
525 Set the roman font to f.
526 The italic primitive uses the current italic font set by gfont; the
528 roman primitive uses the current roman font set by grfont. There is
529 also a new gbfont command, which changes the font used by the bold
530 primitive. If you only use the roman, italic and bold primitives to
531 changes fonts within an equation, you can change all the fonts used by
532 your equations just by using gfont, grfont and gbfont commands.
533 You can control which characters are treated as letters (and therefore
535 set in italics) by using the chartype command described above. A type
536 of letter causes a character to be set in italic type. A type of digit
537 causes a character to be set in roman type.
538
540 /usr/share/groff/1.22.3/tmac/eqnrc
541 Initialization file.
542
544 MathML is designed on the assumption that it cannot know the exact
545 physical characteristics of the media and devices on which it will be
546 rendered. It does not support fine control of motions and sizes to the
547 same degree troff does. Thus:
548 * eqn parameters have no effect on the generated MathML.
550 * The special, up, down, fwd, and back operations cannot be imple‐
552 mented, and yield a MathML ‘<merror>’ message instead.
553 * The vcenter keyword is silently ignored, as centering on the
555 math axis is the MathML default.
556 * Characters that eqn over troff sets extra large – notably the
558 integral sign – may appear too small and need to have their
559 ‘<mstyle>’ wrappers adjusted by hand.
560 As in its troff mode, eqn in MathML mode leaves the .EQ and .EN delim‐
562 iters in place for displayed equations, but emits no explicit delim‐
563 iters around inline equations. They can, however, be recognized as
564 strings that begin with ‘<math>’ and end with ‘</math>’ and do not
565 cross line boundaries.
566 See the BUGS section for translation limits specific to eqn.
568
570 Inline equations are set at the point size that is current at the
571 beginning of the input line.
572 In MathML mode, the mark and lineup features don't work. These could,
574 in theory, be implemented with ‘<maligngroup>’ elements.
575 In MathML mode, each digit of a numeric literal gets a separate ‘<mn>
577 </mn>’ pair, and decimal points are tagged with ‘<mo></mo>’. This is
578 allowed by the specification, but inefficient.
579
581 groff(1), troff(1), pic(1), groff_font(5), The TeXbook
582
584 Copyright © 1989-2014 Free Software Foundation, Inc.
585 Permission is granted to make and distribute verbatim copies of this
587 manual provided the copyright notice and this permission notice are
588 preserved on all copies.
589 Permission is granted to copy and distribute modified versions of this
591 manual under the conditions for verbatim copying, provided that the
592 entire resulting derived work is distributed under the terms of a per‐
593 mission notice identical to this one.
594 Permission is granted to copy and distribute translations of this man‐
596 ual into another language, under the above conditions for modified ver‐
597 sions, except that this permission notice may be included in transla‐
598 tions approved by the Free Software Foundation instead of in the origi‐
599 nal English.
600Groff Version 1.22.3 4 November 2014 EQN(1)