mandoc/roff.7 - diff

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Diff for /mandoc/roff.7 between version 1.92 and 1.109

version 1.92, 2017/06/14 22:51:25

version 1.109, 2018/12/16 00:17:02

Line 1

.\" $Id$

.\"

.\" Permission to use, copy, modify, and distribute this software for any

.\" purpose with or without fee is hereby granted, provided that the above

Line 39 or

code.

To properly format such manuals, the

.Xr mandoc 1

utility supports a tiny subset of

utility supports a subset of

.Nm

requests and escapes.

Only these requests and escapes supported by

Even though this manual page lists all

.Nm

requests, it only has partial information about requests not supported by

.Xr mandoc 1

are documented in the present manual,

and about language features that do not matter for manual pages.

together with the basic language syntax shared by

.Nm ,

.Xr mdoc 7 ,

and

.Xr man 7 .

For complete

.Nm

manuals, consult the

Line 86 character, and, in certain circumstances, the tab char

Line 83 character, and, in certain circumstances, the tab char

The backslash character

.Sq \e

indicates the start of an escape sequence, used for example for

.Sx Comments ,

.Sx Comments

.Sx Special Characters ,

.Sx Predefined Strings ,

and

user-defined strings defined using the

.Sx Special Characters .

.Sx ds

request.

For a listing of escape sequences, consult the

.Sx ESCAPE SEQUENCE REFERENCE

below.

Line 139 One-letter backslash escape.

Line 132 One-letter backslash escape.

See

.Xr mandoc_char 7

for a complete list.

.Ss Text Decoration

.Ss Font Selection

Terms may be text-decorated using the

.Sq \ef

.Xr mdoc 7

escape followed by an indicator: B (bold), I (italic), R (regular), or P

and

(revert to previous mode).

.Xr man 7

A numerical representation 3, 2, or 1 (bold, italic, and regular,

documents, fonts are usually selected with macros.

respectively) may be used instead.

The

The indicator or numerical representative may be preceded by C

.Ic \ef

(constant-width), which is ignored.

escape sequence and the

.Ic \&ft

request can be used to manually change the font,

but this is not recommended in

.Xr mdoc 7

documents.

Such manual font changes are overridden by many subsequent macros.

.Pp

The two-character indicator

The following fonts are supported:

.Sq BI

requests a font that is both bold and italic.

It may not be portable to old roff implementations.

.Pp

.Bl -tag -width CW -offset indent -compact

.It Cm B

Bold font.

.It Cm BI

A font that is both bold and italic.

.It Cm CB

Bold constant width font.

Same as

.Cm B

in terminal output.

.It Cm CI

Italic constant width font.

Same as

.Cm I

in terminal output.

.It Cm CR

Regular constant width font.

Same as

.Cm R

in terminal output.

.It Cm CW

An alias for

.Cm CR .

.It Cm I

Italic font.

.It Cm P

Return to the previous font.

If a macro caused a font change since the last

.Ic \ef

eascape sequence or

.Ic \&ft

request, this returns to the font before the last font change in

the macro rather than to the font before the last manual font change.

.It Cm R

Roman font.

This is the default font.

.It Cm 1

An alias for

.Cm R .

.It Cm 2

An alias for

.Cm I .

.It Cm 3

An alias for

.Cm B .

.It Cm 4

An alias for

.Cm BI .

.El

.Pp

Examples:

.Bl -tag -width Ds -offset indent -compact

.It Li \efBbold\efR

Line 163 Write in \fIitalic\fP, then return to previous font mo

Line 209 Write in \fIitalic\fP, then return to previous font mo

.It Li \ef(BIbold italic\efP

Write in \f(BIbold italic\fP, then return to previous font mode.

.El

.Pp

Text decoration is

.Em not

recommended for

.Xr mdoc 7 ,

which encourages semantic annotation.

.Ss Predefined Strings

Predefined strings, like

.Sx Special Characters ,

mark special output glyphs.

Predefined strings are escaped with the slash-asterisk,

.Sq \e* :

single-character

.Sq \e*X ,

two-character

.Sq \e*(XX ,

and N-character

.Sq \e*[N] .

.Pp

Examples:

.Bl -tag -width Ds -offset indent -compact

.It Li \e*(Am

Two-letter ampersand predefined string.

.It Li \e*q

One-letter double-quote predefined string.

.El

.Pp

Predefined strings are not recommended for use,

as they differ across implementations.

Those supported by

.Xr mandoc 1

are listed in

.Xr mandoc_char 7 .

Manuals using these predefined strings are almost certainly not portable.

.Ss Whitespace

Whitespace consists of the space character.

In text lines, whitespace is preserved within a line.

Line 206 Unescaped trailing spaces are stripped from text line

Line 218 Unescaped trailing spaces are stripped from text line

literal context.

In general, trailing whitespace on any input line is discouraged for

reasons of portability.

In the rare case that a blank character is needed at the end of an

In the rare case that a space character is needed at the end of an

input line, it may be forced by

.Sq \e\ \e& .

.Pp

Line 225 Many requests and macros support scaled widths for the

Line 237 Many requests and macros support scaled widths for the

The syntax for a scaled width is

.Sq Li [+-]?[0-9]*.[0-9]*[:unit:] ,

where a decimal must be preceded or followed by at least one digit.

Negative numbers, while accepted, are truncated to zero.

.Pp

The following scaling units are accepted:

.Pp

Line 341 Macros are provided by the

Line 352 Macros are provided by the

and

.Xr man 7

languages and can be defined by the

.Sx \&de

.Ic \&de

request.

When called, they follow the same syntax as requests, except that

macro arguments may optionally be quoted by enclosing them

Line 447 compatibility mode at all, it handles this request as

Line 458 compatibility mode at all, it handles this request as

.It Ic \&as Ar stringname Op Ar string

Append to a user-defined string.

The syntax of this request is the same as that of

.Sx \&ds .

.Ic \&ds .

If a user-defined string with the specified name does not yet exist,

it is set to the empty string before appending.

.It Ic \&as1 Ar stringname Op Ar string

Line 539 This is a groff extension and currently ignored.

Line 550 This is a groff extension and currently ignored.

.It Ic \&ch Ar macroname Op Ar dist

Change a trap location.

Currently ignored.

.It Ic \&char Ar glyphname Op Ar string

.It Ic \&char Ar glyph Op Ar string

Define a new glyph.

Define or redefine the ASCII character or character escape sequence

Currently unsupported.

.Ar glyph

to be rendered as

.Ar string ,

which can be empty.

Only partially supported in

.Xr mandoc 1 ;

may interact incorrectly with

.Ic \&tr .

.It Ic \&chop Ar stringname

Remove the last character from a macro, string, or diversion.

Currently unsupported.

Line 665 produces

Line 683 produces

.Pp

in the input stream, and thus in the output: \fI\^XtFree\^\fP.

Each occurrence of \e\e$* is replaced with all the arguments,

joined together with single blank characters.

joined together with single space characters.

The variant \e\e$@ is similar, except that each argument is

individually quoted.

.Pp

Since macros and user-defined strings share a common string table,

defining a macro

Line 917 This is a Heirloom extension and currently ignored.

Line 937 This is a Heirloom extension and currently ignored.

Conditionally define a special font.

This is a groff extension and currently ignored.

.It Ic \&ft Op Ar font

Change the font.

Change the font; see

The following

.Sx Font Selection .

The

.Ar font

arguments are supported:

argument defaults to

.Bl -tag -width 4n -offset indent

.Cm P .

.It Cm B , BI , 3 , 4

switches to

.Sy bold

font

.It Cm I , 2

switches to

.Em underlined

font

.It Cm R , CW , 1

switches to normal font

.It Cm P No "or no argument"

switches back to the previous font

.El

.Pp

This request takes effect only locally and may be overridden

by macros and escape sequences.

.It Ic \&ftr Ar newname Op Ar oldname

Translate font name.

This is a groff extension and currently ignored.

Line 1037 is

Line 1042 is

.Sq o

.Pq odd page ,

it evaluates to true.

it evaluates to true, and the

.Ar body

starts with the next character.

.It

If the first character of

.Ar condition

.Sq c

.Pq character available ,

.Sq e

.Pq even page ,

.Sq t

Line 1051 is

Line 1056 is

.Sq v

.Pq vroff mode ,

it evaluates to false.

it evaluates to false, and the

.Ar body

starts with the next character.

.It

If the first character of

.Ar condition

.Sq c

.Pq character available ,

it evaluates to true if the following character is an ASCII character

or a valid character escape sequence, or to false otherwise.

The

.Ar body

starts with the character following that next character.

.It

If the first character of

.Ar condition

.Sq d ,

it evaluates to true if the rest of

.Ar condition

Line 1219 While evaluating the

Line 1237 While evaluating the

the unit suffixes described below

.Sx Scaling Widths

are ignored.

.It Ic \&it Ar expression macro

.It Ic \&itc Ar expression macro

Set an input line trap, not counting lines ending with \ec.

Currently unsupported.

.It Ic \&IX Ar class keystring

Line 1346 Currently unsupported.

Line 1364 Currently unsupported.

Temporarily turn off line numbering.

Currently unsupported.

.It Ic \&nop Ar body

Execute the rest of the input line as a request or macro line.

Execute the rest of the input line as a request, macro, or text line,

Currently unsupported.

skipping the

.It Ic \&nr Ar register Oo Cm + Ns | Ns Cm - Oc Ns Ar expression

.Ic \&nop

request and any space characters immediately following it.

This is mostly used to indent text lines inside macro definitions.

.It Ic \&nr Ar register Oo Cm + Ns | Ns Cm - Oc Ns Ar expression Op Ar stepsize

Define or change a register.

A register is an arbitrary string value that defines some sort of state,

which influences parsing and/or formatting.

Line 1360 below.

Line 1381 below.

If it is prefixed by a sign, the register will be

incremented or decremented instead of assigned to.

.Pp

The

.Ar stepsize

is used by the

.Ic \en+

auto-increment feature.

It remains unchanged when omitted while changing an existing register,

and it defaults to 0 when defining a new register.

.Pp

The following

.Ar register

is handled specially:

Line 1471 This is a groff extension and currently ignored.

Line 1500 This is a groff extension and currently ignored.

.It Ic \&rchar Ar glyph ...

Remove glyph definitions.

Currently unsupported.

.It Ic \&rd Op Ar prompt Op Ar agument ...

.It Ic \&rd Op Ar prompt Op Ar argument ...

Read from standard input.

Currently ignored.

.It Ic \&recursionlimit Ar maxrec maxtail

Set the maximum stack depth for recursive macros.

This is a Heirloom extension and currently ignored.

.It Ic \&return Op Ar twice

Exit a macro and return to the caller.

Exit the presently executed macro and return to the caller.

Currently unsupported.

The argument is currently ignored.

.It Ic \&rfschar Ar font glyph ...

Remove font-specific fallback glyph definitions.

Currently unsupported.

Line 1528 This is a Heirloom extension and currently ignored.

Line 1557 This is a Heirloom extension and currently ignored.

Change the soft hyphen character.

Currently ignored.

.It Ic \&shift Op Ar number

Shift macro arguments.

Shift macro arguments

Currently unsupported.

.Ar number

times, by default once: \e\e$i becomes what \e\e$i+number was.

Also decrement \en(.$ by

.Ar number .

.It Ic \&sizes Ar size ...

Define permissible point sizes.

This is a groff extension and currently ignored.

Line 1594 Ignored because insecure.

Line 1626 Ignored because insecure.

Re-start a table layout, retaining the options of the prior table

invocation.

See

.Sx \&TS .

.Ic \&TS .

.It Ic \&ta Op Ar width ... Op Cm T Ar width ...

Set tab stops.

Each

Line 1615 Currently unsupported.

Line 1647 Currently unsupported.

.It Ic \&TE

End a table context.

See

.Sx \&TS .

.Ic \&TS .

.It Ic \&ti Oo Cm + Ns | Ns Cm - Oc Ns Ar width

Break the output line and indent the next output line by

.Ar width .

Line 1718 This is a Heirloom extension and currently ignored.

Line 1750 This is a Heirloom extension and currently ignored.

Set a page location trap.

Currently unsupported.

.It Ic \&while Ar condition body

Repeated execution while a condition is true.

Repeated execution while a

Currently unsupported.

.Ar condition

is true, with syntax similar to

.Ic \&if .

Currently implemented with two restrictions: cannot nest,

and each loop must start and end in the same scope.

.It Ic \&write Oo \(dq Oc Ns Ar string

Write to an open file.

Ignored because insecure.

Line 1735 This is a Heirloom extension and currently ignored.

Line 1771 This is a Heirloom extension and currently ignored.

.El

.Ss Numerical expressions

The

.Sx \&nr ,

.Ic \&nr ,

.Sx \&if ,

.Ic \&if ,

and

.Sx \&ie

.Ic \&ie

requests accept integer numerical expressions as arguments.

These are always evaluated using the C

.Vt int

Line 1826 described in the

Line 1862 described in the

.Sx LANGUAGE SYNTAX

section above.

.Pp

A backslash followed by any character not listed here

.Xr mandoc 1 ,

a backslash followed by any character not listed here

simply prints that character itself.

.Ss \e<newline>

.Bl -tag -width Ds

.It Ic \e<newline>

A backslash at the end of an input line can be used to continue the

logical input line on the next physical input line, joining the text

on both lines together as if it were on a single input line.

.Ss \e<space>

.It Ic \e<space>

The escape sequence backslash-space

.Pq Sq \e\ \&

is an unpaddable space-sized non-breaking space character; see

.Sx Whitespace .

.Ss \e\(dq

.It Ic \e!

Embed text up to and including the end of the input line into the

current diversion or into intermediate output without interpreting

requests, macros, and escapes.

Currently unsupported.

.It Ic \e\(dq

The rest of the input line is treated as

.Sx Comments .

.Ss \e%

.It Ic \e#

Line continuation with comment.

Discard the rest of the physical input line and continue the logical

input line on the next physical input line, joining the text on

both lines together as if it were on a single input line.

This is a groff extension.

.It Ic \e$ Ns Ar arg

Macro argument expansion, see

.Ic \&de .

.It Ic \e%

Hyphenation allowed at this point of the word; ignored by

.Xr mandoc 1 .

.Ss \e&

.It Ic \e&

Non-printing zero-width character; see

.Sx Whitespace .

.Ss \e\(aq

.It Ic \e\(aq

Acute accent special character; use

.Sq \e(aa

.Ic \e(aa

instead.

.Ss \e( Ns Ar cc

.It Ic \e( Ns Ar cc

.Sx Special Characters

with two-letter names, see

.Xr mandoc_char 7 .

.Ss \e*[ Ns Ar name ]

.It Ic \e)

Zero-width space transparent to end-of-sentence detection;

ignored by

.Xr mandoc 1 .

.It Ic \e*[ Ns Ar name Ns Ic \&]

Interpolate the string with the

.Ar name ;

.Ar name .

see

.Sx Predefined Strings

and

.Sx ds .

For short names, there are variants

.No \e* Ns Ar c

.Ic \e* Ns Ar c

and

.No \e*( Ns Ar cc .

.Ic \e*( Ns Ar cc .

.Ss \e,

.Pp

One string is predefined on the

.Nm

language level:

.Ic \e*(.T

expands to the name of the output device,

for example ascii, utf8, ps, pdf, html, or markdown.

.Pp

Macro sets traditionally predefine additional strings which are not

portable and differ across implementations.

Those supported by

.Xr mandoc 1

are listed in

.Xr mandoc_char 7 .

.Pp

Strings can be defined, changed, and deleted with the

.Ic \&ds ,

.Ic \&as ,

and

.Ic \&rm

requests.

.It Ic \e,

Left italic correction (groff extension); ignored by

.Xr mandoc 1 .

.Ss \e-

.It Ic \e-

Special character

.Dq mathematical minus sign .

.Ss \e/

.It Ic \e/

Right italic correction (groff extension); ignored by

.Xr mandoc 1 .

.Ss \e[ Ns Ar name ]

.It Ic \e:

Breaking the line is allowed at this point of the word

without inserting a hyphen.

.It Ic \e?

Embed the text up to the next

.Ic \e?

into the current diversion without interpreting requests, macros,

and escapes.

This is a groff extension and currently unsupported.

.It Ic \e[ Ns Ar name Ns Ic \&]

.Sx Special Characters

with names of arbitrary length, see

.Xr mandoc_char 7 .

.Ss \e^

.It Ic \e^

One-twelfth em half-narrow space character, effectively zero-width in

.Xr mandoc 1 .

.Ss \e`

.It Ic \e_

Underline special character; use

.Ic \e(ul

instead.

.It Ic \e`

Grave accent special character; use

.Sq \e(ga

.Ic \e(ga

instead.

.Ss \e{

.It Ic \e{

Begin conditional input; see

.Sx if .

.Ic \&if .

.Ss \e\(ba

.It Ic \e\(ba

One-sixth em narrow space character, effectively zero-width in

.Xr mandoc 1 .

.Ss \e}

.It Ic \e}

End conditional input; see

.Sx if .

.Ic \&if .

.Ss \e~

.It Ic \e~

Paddable non-breaking space character.

.Ss \e0

.It Ic \e0

Digit width space character.

.Ss \eA\(aq Ns Ar string Ns \(aq

.It Ic \eA\(aq Ns Ar string Ns Ic \(aq

Anchor definition; ignored by

.Xr mandoc 1 .

.Ss \eB\(aq Ns Ar string Ns \(aq

.It Ic \ea

Leader character; ignored by

.Xr mandoc 1 .

.It Ic \eB\(aq Ns Ar string Ns Ic \(aq

Interpolate

.Sq 1

Line 1911 conforms to the syntax of

Line 2001 conforms to the syntax of

explained above and

.Sq 0

otherwise.

.Ss \eb\(aq Ns Ar string Ns \(aq

.It Ic \eb\(aq Ns Ar string Ns Ic \(aq

Bracket building function; ignored by

.Xr mandoc 1 .

.Ss \eC\(aq Ns Ar name Ns \(aq

.It Ic \eC\(aq Ns Ar name Ns Ic \(aq

.Sx Special Characters

with names of arbitrary length.

.Ss \ec

.It Ic \ec

When encountered at the end of an input text line,

the next input text line is considered to continue that line,

even if there are request or macro lines in between.

No whitespace is inserted.

.Ss \eD\(aq Ns Ar string Ns \(aq

.It Ic \eD\(aq Ns Ar string Ns Ic \(aq

Draw graphics function; ignored by

.Xr mandoc 1 .

.Ss \ed

.It Ic \ed

Move down by half a line; ignored by

.Xr mandoc 1 .

.Ss \ee

.It Ic \eE

Escape character intended to not be interpreted in copy mode.

.Xr mandoc 1 ,

it does the same as

.Ic \e

itself for now.

.It Ic \ee

Backslash special character.

.Ss \eF[ Ns Ar name ]

.It Ic \eF[ Ns Ar name Ns Ic \&]

Switch font family (groff extension); ignored by

.Xr mandoc 1 .

For short names, there are variants

.No \eF Ns Ar c

.Ic \eF Ns Ar c

and

.No \eF( Ns Ar cc .

.Ic \eF( Ns Ar cc .

.Ss \ef[ Ns Ar name ]

.It Ic \ef[ Ns Ar name Ns Ic \&]

Switch to the font

.Ar name ,

see

.Sx Text Decoration .

.Sx Font Selection .

For short names, there are variants

.No \ef Ns Ar c

.Ic \ef Ns Ar c

and

.No \ef( Ns Ar cc .

.Ic \ef( Ns Ar cc .

.Ss \eg[ Ns Ar name ]

An empty name

.Ic \ef[]

defaults to

.Ic \efP .

.It Ic \eg[ Ns Ar name Ns Ic \&]

Interpolate the format of a number register; ignored by

.Xr mandoc 1 .

For short names, there are variants

.No \eg Ns Ar c

.Ic \eg Ns Ar c

and

.No \eg( Ns Ar cc .

.Ic \eg( Ns Ar cc .

.Ss \eH\(aq Ns Oo +|- Oc Ns Ar number Ns \(aq

.It Ic \eH\(aq Ns Oo +|- Oc Ns Ar number Ns Ic \(aq

Set the height of the current font; ignored by

.Xr mandoc 1 .

.Ss \eh\(aq Ns Ar width Ns \(aq

.It Ic \eh\(aq Ns Oo Cm \&| Oc Ns Ar width Ns Ic \(aq

Horizontal motion relative to the current position.

Horizontal motion.

If the vertical bar is given, the motion is relative to the current

indentation.

Otherwise, it is relative to the current position.

The default scaling unit is

.Cm m .

.Ss \ek[ Ns Ar name ]

.It Ic \ek[ Ns Ar name Ns Ic \&]

Mark horizontal input place in register; ignored by

.Xr mandoc 1 .

For short names, there are variants

.No \ek Ns Ar c

.Ic \ek Ns Ar c

and

.No \ek( Ns Ar cc .

.Ic \ek( Ns Ar cc .

.Ss \eL\(aq Ns Ar number Ns Oo Ar c Oc Ns \(aq

.It Ic \eL\(aq Ns Ar number Ns Oo Ar c Oc Ns Ic \(aq

Vertical line drawing function; ignored by

.Xr mandoc 1 .

.Ss \el\(aq Ns Ar width Ns Oo Ar c Oc Ns \(aq

.It Ic \el\(aq Ns Ar width Ns Oo Ar c Oc Ns Ic \(aq

Draw a horizontal line of

.Ar width

using the glyph

.Ar c .

.Ss \eM[ Ns Ar name ]

.It Ic \eM[ Ns Ar name Ns Ic \&]

Set fill (background) color (groff extension); ignored by

.Xr mandoc 1 .

For short names, there are variants

.No \eM Ns Ar c

.Ic \eM Ns Ar c

and

.No \eM( Ns Ar cc .

.Ic \eM( Ns Ar cc .

.Ss \em[ Ns Ar name ]

.It Ic \em[ Ns Ar name Ns Ic \&]

Set glyph drawing color (groff extension); ignored by

.Xr mandoc 1 .

For short names, there are variants

.No \em Ns Ar c

.Ic \em Ns Ar c

and

.No \em( Ns Ar cc .

.Ic \em( Ns Ar cc .

.Ss \eN\(aq Ns Ar number Ns \(aq

.It Ic \eN\(aq Ns Ar number Ns Ic \(aq

Character

.Ar number

on the current font.

.Ss \en[ Ns Ar name ]

.It Ic \en Ns Oo +|- Oc Ns Ic \&[ Ns Ar name Ns Ic \&]

Interpolate the number register

.Ar name .

For short names, there are variants

.No \en Ns Ar c

.Ic \en Ns Ar c

and

.No \en( Ns Ar cc .

.Ic \en( Ns Ar cc .

.Ss \eo\(aq Ns Ar string Ns \(aq

If the optional sign is specified,

the register is first incremented or decremented by the

.Ar stepsize

that was specified in the relevant

.Ic \&nr

request, and the changed value is interpolated.

.It Ic \eO Ns Ar digit , Ic \eO[5 Ns arguments Ns Ic \&]

Suppress output.

This is a groff extension and currently unsupported.

With an argument of

.Ic 1 , 2 , 3 ,

.Ic 4 ,

it is ignored.

.It Ic \eo\(aq Ns Ar string Ns Ic \(aq

Overstrike, writing all the characters contained in the

.Ar string

to the same output position.

In terminal and HTML output modes,

only the last one of the characters is visible.

.Ss \ep

.It Ic \ep

Break the output line at the end of the current word.

.Ss \eR\(aq Ns Ar name Oo +|- Oc Ns Ar number Ns \(aq

.It Ic \eR\(aq Ns Ar name Oo +|- Oc Ns Ar number Ns Ic \(aq

Set number register; ignored by

.Xr mandoc 1 .

.Ss \eS\(aq Ns Ar number Ns \(aq

.It Ic \er

Move up by one line; ignored by

.Xr mandoc 1 .

.It Ic \eS\(aq Ns Ar number Ns Ic \(aq

Slant output; ignored by

.Xr mandoc 1 .

.Ss \es\(aq Ns Oo +|- Oc Ns Ar number Ns \(aq

.It Ic \es\(aq Ns Oo +|- Oc Ns Ar number Ns Ic \(aq

Change point size; ignored by

.Xr mandoc 1 .

Alternative forms

.No \es Ns Oo +|- Oc Ns Ar n ,

.Ic \es Ns Oo +|- Oc Ns Ar n ,

.No \es Ns Oo +|- Oc Ns \(aq Ns Ar number Ns \(aq ,

.Ic \es Ns Oo +|- Oc Ns Ic \(aq Ns Ar number Ns Ic \(aq ,

.No \es Ns [ Oo +|- Oc Ns Ar number ] ,

.Ic \es[ Ns Oo +|- Oc Ns Ar number Ns Ic \&] ,

and

.No \es Ns Oo +|- Oc Ns [ Ar number Ns ]

.Ic \es Ns Oo +|- Oc Ns Ic \&[ Ns Ar number Ns Ic \&]

are also parsed and ignored.

.Ss \et

.It Ic \et

Horizontal tab; ignored by

.Xr mandoc 1 .

.Ss \eu

.It Ic \eu

Move up by half a line; ignored by

.Xr mandoc 1 .

.Ss \eV[ Ns Ar name ]

.It Ic \eV[ Ns Ar name Ns Ic \&]

Interpolate an environment variable; ignored by

.Xr mandoc 1 .

For short names, there are variants

.No \eV Ns Ar c

.Ic \eV Ns Ar c

and

.No \eV( Ns Ar cc .

.Ic \eV( Ns Ar cc .

.Ss \ev\(aq Ns Ar number Ns \(aq

.It Ic \ev\(aq Ns Ar number Ns Ic \(aq

Vertical motion; ignored by

.Xr mandoc 1 .

.Ss \ew\(aq Ns Ar string Ns \(aq

.It Ic \ew\(aq Ns Ar string Ns Ic \(aq

Interpolate the width of the

.Ar string .

The

Line 2049 implementation assumes that after expansion of user-de

Line 2170 implementation assumes that after expansion of user-de

.Ar string

only contains normal characters, no escape sequences, and that each

character has a width of 24 basic units.

.Ss \eX\(aq Ns Ar string Ns \(aq

.It Ic \eX\(aq Ns Ar string Ns Ic \(aq

Output

.Ar string

as device control function; ignored in nroff mode and by

.Xr mandoc 1 .

.Ss \ex\(aq Ns Ar number Ns \(aq

.It Ic \ex\(aq Ns Ar number Ns Ic \(aq

Extra line space function; ignored by

.Xr mandoc 1 .

.Ss \eY[ Ns Ar name ]

.It Ic \eY[ Ns Ar name Ns Ic \&]

Output a string as a device control function; ignored in nroff mode and by

.Xr mandoc 1 .

For short names, there are variants

.No \eY Ns Ar c

.Ic \eY Ns Ar c

and

.No \eY( Ns Ar cc .

.Ic \eY( Ns Ar cc .

.Ss \eZ\(aq Ns Ar string Ns \(aq

.It Ic \eZ\(aq Ns Ar string Ns Ic \(aq

.Ar string

with zero width and height; ignored by

.Xr mandoc 1 .

.Ss \ez

.It Ic \ez

Output the next character without advancing the cursor position.

.El

.Sh COMPATIBILITY

The

.Xr mandoc 1

implementation of the

.Nm

language is intentionally incomplete.

language is incomplete.

Unimplemented features include:

Major unimplemented features include:

.Pp

.Bl -dash -compact

.It

For security reasons,

.Xr mandoc 1

never reads or writes external files except via

.Sx \&so

.Ic \&so

requests with safe relative paths.

.It

There is no automatic hyphenation, no adjustment to the right margin,

and no centering; the output is always set flush-left.

and very limited support for centering; the output is always set flush-left.

.It

Support for setting tabulator positions

Support for setting tabulator and leader characters is missing,

and tabulator and leader characters is missing,

and support for manually changing indentation is limited.

.It

The

Line 2102 output media.

Line 2223 output media.

.It

Width measurements are implemented in a crude way

and often yield wrong results.

Explicit movement requests and escapes are ignored.

Support for explicit movement requests and escapes is limited.

.It

There is no concept of output pages, no support for floats,

graphics drawing, and picture inclusion;

terminal output is always continuous.

.It

Requests regarding color, font families, and glyph manipulation

Requests regarding color, font families, font sizes,

are ignored.

and glyph manipulation are ignored.

Font support is very limited.

Kerning is not implemented, and no ligatures are produced.

.It

Line 2117 The

Line 2238 The

.Qq \(aq

macro control character does not suppress output line breaks.

.It

Diversions are not implemented,

Diversions and environments are not implemented,

and support for traps is very incomplete.

.It

While recursion is supported,

Use of macros is not supported inside

.Sx \&while

.Xr tbl 7

loops are not.

code.

.El

.Pp

The special semantics of the

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