878 lines
18 KiB
Groff
878 lines
18 KiB
Groff
.ig \"-*- nroff -*-
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Copyright (C) 1989-2000 Free Software Foundation, Inc.
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Permission is granted to make and distribute verbatim copies of
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this manual provided the copyright notice and this permission notice
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are preserved on all copies.
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Permission is granted to copy and distribute modified versions of this
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manual under the conditions for verbatim copying, provided that the
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entire resulting derived work is distributed under the terms of a
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permission notice identical to this one.
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Permission is granted to copy and distribute translations of this
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manual into another language, under the above conditions for modified
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versions, except that this permission notice may be included in
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translations approved by the Free Software Foundation instead of in
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the original English.
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..
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.ie \n(.V<\n(.v .ds tx T\h'-.1667m'\v'.224m'E\v'-.224m'\h'-.125m'X
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.el .ds tx TeX
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.\" Like TP, but if specified indent is more than half
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.\" the current line-length - indent, use the default indent.
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.de Tp
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.ie \\n(.$=0:((0\\$1)*2u>(\\n(.lu-\\n(.iu)) .TP
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.el .TP "\\$1"
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..
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.\" The BSD man macros can't handle " in arguments to font change macros,
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.\" so use \(ts instead of ".
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.tr \(ts"
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.TH @G@EQN @MAN1EXT@ "@MDATE@" "Groff Version @VERSION@"
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.SH NAME
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@g@eqn \- format equations for troff
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.SH SYNOPSIS
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.nr a \n(.j
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.ad l
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.nr i \n(.i
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.in +\w'\fB@g@eqn 'u
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.ti \niu
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.B @g@eqn
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.de OP
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.ie \\n(.$-1 .RI "[\ \fB\\$1\fP" "\\$2" "\ ]"
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.el .RB "[\ " "\\$1" "\ ]"
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..
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.OP \-rvCNR
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.OP \-d cc
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.OP \-T name
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.OP \-M dir
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.OP \-f F
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.OP \-s n
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.OP \-p n
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.OP \-m n
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.RI "[\ " files\|.\|.\|. "\ ]"
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.br
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.ad \na
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.PP
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It is possible to have whitespace between a command line option and its
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parameter.
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.SH DESCRIPTION
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This manual page describes the GNU version of
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.BR eqn ,
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which is part of the groff document formatting system.
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.B eqn
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compiles descriptions of equations embedded within
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.B troff
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input files into commands that are understood by
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.BR troff .
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Normally, it should be invoked using the
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.B \-e
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option of
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.BR groff .
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The syntax is quite compatible with Unix eqn.
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The output of GNU eqn cannot be processed with Unix troff;
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it must be processed with GNU troff.
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If no files are given on the command line, the standard input
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will be read.
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A filename of
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.B \-
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will cause the standard input to be read.
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.LP
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.B eqn
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searches for the file
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.B eqnrc
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using the path
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.BR @MACROPATH@ .
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If it exists, eqn will process it before the other input files.
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The
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.B \-R
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option prevents this.
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.LP
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GNU eqn does not provide the functionality of neqn:
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it does not support low-resolution, typewriter-like devices
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(although it may work adequately for very simple input).
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.SH OPTIONS
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.TP
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.B \-C
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Recognize
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.B .EQ
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and
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.B .EN
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even when followed by a character other than space or newline.
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.TP
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.B \-N
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Don't allow newlines within delimiters.
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This option allows
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.B eqn
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to recover better from missing closing delimiters.
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.TP
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.B \-v
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Print the version number.
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.TP
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.B \-r
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Only one size reduction.
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.TP
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.BI \-m n
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The minimum point-size is
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.IR n .
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eqn will not reduce the size of subscripts or superscripts to
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a smaller size than
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.IR n .
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.TP
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.BI \-T name
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The output is for device
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.IR name .
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The only effect of this is to define a macro
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.I name
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with a value of
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.BR 1 .
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Typically
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.B eqnrc
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will use this to provide definitions appropriate for the output device.
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The default output device is
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.BR @DEVICE@ .
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.TP
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.BI \-M dir
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Search
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.I dir
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for
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.B eqnrc
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before the default directories.
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.TP
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.B \-R
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Don't load
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.BR eqnrc .
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.TP
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.BI \-f F
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This is equivalent to a
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.BI gfont\ F
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command.
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.TP
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.BI \-s n
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This is equivalent to a
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.BI gsize\ n
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command.
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This option is deprecated.
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eqn will normally set equations at whatever the current point size
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is when the equation is encountered.
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.TP
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.BI \-p n
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This says that subscripts and superscripts should be
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.I n
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points smaller than the surrounding text.
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This option is deprecated.
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Normally eqn makes sets subscripts and superscripts at 70%
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of the size of the surrounding text.
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.SH USAGE
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Only the differences between GNU eqn and Unix eqn are described here.
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.LP
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Most of the new features of GNU eqn
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are based on \*(tx.
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There are some references to the differences between \*(tx and GNU eqn below;
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these may safely be ignored if you do not know \*(tx.
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.SS Automatic spacing
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.LP
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.B eqn
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gives each component of an equation a type, and adjusts the spacing
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between components using that type.
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Possible types are:
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.TP \w'punctuation'u+2n
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ordinary
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an ordinary character such as 1 or
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.IR x ;
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.TP
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operator
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a large operator such as
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.ds Su \s+5\(*S\s0
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.if \n(.g .if !c\(*S .ds Su the summation operator
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\*(Su;
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.TP
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binary
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a binary operator such as +;
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.TP
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relation
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a relation such as =;
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.TP
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opening
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a opening bracket such as (;
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.TP
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closing
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a closing bracket such as );
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.TP
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punctuation
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a punctuation character such as ,;
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.TP
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inner
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a subformula contained within brackets;
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.TP
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suppress
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spacing that suppresses automatic spacing adjustment.
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.LP
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Components of an equation get a type in one of two ways.
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.TP
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.BI type\ t\ e
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This yields an equation component that contains
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.I e
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but that has type
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.IR t ,
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where
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.I t
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is one of the types mentioned above.
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For example,
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.B times
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is defined as
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.RS
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.IP
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.B
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type "binary" \e(mu
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.RE
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.IP
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The name of the type doesn't have to be quoted, but quoting protects
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from macro expansion.
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.TP
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.BI chartype\ t\ text
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Unquoted groups of characters are split up into individual characters,
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and the type of each character is looked up;
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this changes the type that is stored for each character;
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it says that the characters in
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.I text
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from now on have type
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.IR t .
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For example,
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.RS
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.IP
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.B
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chartype "punctuation" .,;:
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.RE
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.IP
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would make the characters
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.B .,;:
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have type punctuation
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whenever they subsequently appeared in an equation.
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The type
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.I t
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can also be
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.B letter
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or
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.BR digit ;
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in these cases
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.B chartype
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changes the font type of the characters.
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See the Fonts subsection.
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.SS New primitives
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.TP
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.IB e1\ smallover\ e2
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This is similar to
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.BR over ;
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.B smallover
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reduces the size of
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.I e1
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and
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.IR e2 ;
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it also puts less vertical space between
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.I e1
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or
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.I e2
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and the fraction bar.
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The
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.B over
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primitive corresponds to the \*(tx
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.B \eover
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primitive in display styles;
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.B smallover
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corresponds to
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.B \eover
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in non-display styles.
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.TP
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.BI vcenter\ e
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This vertically centers
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.I e
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about the math axis.
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The math axis is the vertical position about which characters
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such as + and - are centered; also it is the vertical position
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used for the bar of fractions.
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For example,
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.B sum
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is defined as
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.RS
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.IP
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.B
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{ type "operator" vcenter size +5 \e(*S }
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.RE
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.TP
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.IB e1\ accent\ e2
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This sets
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.I e2
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as an accent over
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.IR e1 .
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.I e2
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is assumed to be at the correct height for a lowercase letter;
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.I e2
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will be moved down according if
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.I e1
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is taller or shorter than a lowercase letter.
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For example,
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.B hat
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is defined as
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.RS
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.IP
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.B
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accent { "^" }
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.RE
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.IP
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.BR dotdot ,
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.BR dot ,
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.BR tilde ,
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.B vec
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and
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.B dyad
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are also defined using the
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.B accent
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primitive.
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.TP
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.IB e1\ uaccent\ e2
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This sets
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.I e2
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as an accent under
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.IR e1 .
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.I e2
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is assumed to be at the correct height for a character without a descender;
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.I e2
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will be moved down if
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.I e1
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has a descender.
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.B utilde
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is pre-defined using
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.B uaccent
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as a tilde accent below the baseline.
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.TP
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.BI split\ \(ts text \(ts
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This has the same effect as simply
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.RS
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.IP
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.I text
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.RE
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.IP
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but
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.I text
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is not subject to macro expansion because it is quoted;
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.I text
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will be split up and the spacing between individual characters
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will be adjusted.
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.TP
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.BI nosplit\ text
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This has the same effect as
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.RS
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.IP
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.BI \(ts text \(ts
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.RE
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.IP
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but because
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.I text
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is not quoted it will be subject to macro expansion;
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.I text
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will not be split up
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and the spacing between individual characters will not be adjusted.
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.TP
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.IB e\ opprime
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This is a variant of
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.B prime
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that acts as an operator on
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.IR e .
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It produces a different result from
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.B prime
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in a case such as
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.BR A\ opprime\ sub\ 1 :
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with
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.B opprime
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the
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.B 1
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will be tucked under the prime as a subscript to the
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.B A
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(as is conventional in mathematical typesetting),
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whereas with
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.B prime
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the
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.B 1
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will be a subscript to the prime character.
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The precedence of
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.B opprime
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is the same as that of
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.B bar
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and
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.BR under ,
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which is higher than that of everything except
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.B accent
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and
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.BR uaccent .
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In unquoted text a
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.B '
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that is not the first character will be treated like
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.BR opprime .
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.TP
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.BI special\ text\ e
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This constructs a new object from
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.I e
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using a
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.BR @g@troff (@MAN1EXT@)
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macro named
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.IR text .
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|
When the macro is called,
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the string
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.B 0s
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will contain the output for
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.IR e ,
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and the number registers
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.BR 0w ,
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.BR 0h ,
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.BR 0d ,
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.BR 0skern
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and
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.BR 0skew
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will contain the width, height, depth, subscript kern, and skew of
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.IR e .
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(The
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.I "subscript kern"
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of an object says how much a subscript on that object should be tucked in;
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the
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.I skew
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of an object says how far to the right of the center of the object an
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accent over the object should be placed.)
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The macro must modify
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.B 0s
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so that it will output the desired result with its origin at the current
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point, and increase the current horizontal position by the width
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of the object.
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The number registers must also be modified so that they correspond to the
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result.
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.RS
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.LP
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|
For example, suppose you wanted a construct that `cancels' an expression
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by drawing a diagonal line through it.
|
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.IP
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.nf
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.ft B
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.ne 6+\n(.Vu
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\&.EQ
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define cancel 'special Ca'
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\&.EN
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\&.de Ca
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\&.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'
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\&..
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.ft
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.fi
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.LP
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Then you could cancel an expression
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.I e
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with
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.BI cancel\ {\ e\ }
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.LP
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Here's a more complicated construct that draws a box round an expression:
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.IP
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.nf
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.ft B
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.ne 11+\n(.Vu
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\&.EQ
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define box 'special Bx'
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\&.EN
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\&.de Bx
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\&.ds 0s \eZ'\eh'1n'\e\e*(0s'\e
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\eZ'\ev'\e\en(0du+1n'\eD'l \e\en(0wu+2n 0'\eD'l 0 -\e\en(0hu-\e\en(0du-2n'\e
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\eD'l -\e\en(0wu-2n 0'\eD'l 0 \e\en(0hu+\e\en(0du+2n''\eh'\e\en(0wu+2n'
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\&.nr 0w +2n
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\&.nr 0d +1n
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\&.nr 0h +1n
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\&..
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.ft
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.fi
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.RE
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.SS Customization
|
|
The appearance of equations is controlled by
|
|
a large number of parameters. These can be set using
|
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the
|
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.B set
|
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command.
|
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.TP
|
|
.BI set\ p\ n
|
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This sets parameter
|
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.I p
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to value
|
|
.I n ;
|
|
.I n
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|
is an integer.
|
|
For example,
|
|
.RS
|
|
.IP
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|
.B
|
|
set x_height 45
|
|
.RE
|
|
.IP
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|
says that
|
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.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
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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;
|
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in other words, it will overhang the numerator and
|
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denominator by at least this amount.
|
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.TP
|
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.B accent_width
|
|
When
|
|
.B bar
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or
|
|
.B under
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is applied to a single character,
|
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the line will be this long.
|
|
Normally,
|
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.B bar
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or
|
|
.B under
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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.
|
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.TP
|
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.B delimiter_factor
|
|
Extensible delimiters produced with the
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.B left
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and
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.B right
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primitives will have a combined height and depth of at least this many
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thousandths of twice the maximum amount by which the sub-equation that
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the delimiters enclose extends away from the axis.
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.TP
|
|
.B delimiter_shortfall
|
|
Extensible delimiters produced with the
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.B left
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and
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.B right
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primitives will have a combined height and depth
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not less than the difference of
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twice the maximum amount by which the sub-equation that
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the delimiters enclose extends away from the axis
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and this amount.
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.TP
|
|
.B null_delimiter_space
|
|
This much horizontal space is inserted
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|
on each side of a fraction.
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.TP
|
|
.B script_space
|
|
The width of subscripts and superscripts is increased by this amount.
|
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.TP
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|
.B thin_space
|
|
This amount of space is automatically inserted after punctuation
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|
characters.
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.TP
|
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.B medium_space
|
|
This amount of space is automatically inserted on either side
|
|
of binary operators.
|
|
.TP
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.B thick_space
|
|
This amount of space is automatically inserted on either side of
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|
relations.
|
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.TP
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.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
|
|
.BR ascii ,
|
|
.BR latin1 ,
|
|
.BR utf8 ,
|
|
and
|
|
.B cp1047
|
|
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
|