Various improvements related to .Ex and .Rv:

[mandoc.git] / roff.7

diff --git a/roff.7 b/roff.7
index 48e16dd905bd3a752306fbb123cde150de1f0858..bc2f24e45b3fb115321e60bda8fd60c9fda7badf 100644 (file)
--- a/roff.7
+++ b/roff.7
@@ -1,7 +1,7 @@
-.\"    $Id: roff.7,v 1.46 2013/12/26 02:43:18 schwarze Exp $
+.\"    $Id: roff.7,v 1.55 2014/07/07 11:35:06 schwarze Exp $

 .\"
 .\" Copyright (c) 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
 .\"
 .\" Copyright (c) 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>

-.\" Copyright (c) 2010, 2011, 2013 Ingo Schwarze <schwarze@openbsd.org>
+.\" Copyright (c) 2010, 2011, 2013, 2014 Ingo Schwarze <schwarze@openbsd.org>

 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above
 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above


@@ -15,7 +15,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"

-.Dd $Mdocdate: December 26 2013 $
+.Dd $Mdocdate: July 7 2014 $

 .Dt ROFF 7
 .Os
 .Sh NAME
 .Dt ROFF 7
 .Os
 .Sh NAME


@@ -409,24 +409,27 @@ and the number of arguments is not checked.
 Append to a macro definition.
 The syntax of this request is the same as that of
 .Sx \&de .
 Append to a macro definition.
 The syntax of this request is the same as that of
 .Sx \&de .

-It is currently ignored by
-.Xr mandoc 1 ,
-as are its children.

 .Ss \&ami
 Append to a macro definition, specifying the macro name indirectly.
 The syntax of this request is the same as that of
 .Sx \&dei .
 .Ss \&ami
 Append to a macro definition, specifying the macro name indirectly.
 The syntax of this request is the same as that of
 .Sx \&dei .

-It is currently ignored by
-.Xr mandoc 1 ,
-as are its children.

 .Ss \&am1
 Append to a macro definition, switching roff compatibility mode off
 during macro execution.
 The syntax of this request is the same as that of
 .Sx \&de1 .
 .Ss \&am1
 Append to a macro definition, switching roff compatibility mode off
 during macro execution.
 The syntax of this request is the same as that of
 .Sx \&de1 .

-It is currently ignored by
-.Xr mandoc 1 ,
-as are its children.
+Since
+.Xr mandoc 1
+does not implement
+.Nm
+compatibility mode at all, it handles this request as an alias for
+.Sx \&am .
+.Ss \&as
+Append to a user-defined string.
+The syntax of this request is the same as that of
+.Sx \&ds .
+If a user-defined string with the specified name does not yet exist,
+it is set to the empty string before appending.

 .Ss \&cc
 Changes the control character.
 Its syntax is as follows:
 .Ss \&cc
 Changes the control character.
 Its syntax is as follows:


@@ -439,6 +442,12 @@ If
 is not specified, the control character is reset to
 .Sq \&. .
 Trailing characters are ignored.
 is not specified, the control character is reset to
 .Sq \&. .
 Trailing characters are ignored.

+.Ss \&ce
+Center some lines.
+This line-scoped request is intended to take one integer argument,
+specifying how many lines to center.
+Currently, it is ignored including its arguments, and the number
+of arguments is not checked.

 .Ss \&de
 Define a
 .Nm
 .Ss \&de
 Define a
 .Nm


@@ -542,9 +551,13 @@ Define a
 macro, specifying the macro name indirectly.
 The syntax of this request is the same as that of
 .Sx \&de .
 macro, specifying the macro name indirectly.
 The syntax of this request is the same as that of
 .Sx \&de .

-It is currently ignored by
-.Xr mandoc 1 ,
-as are its children.
+The request
+.Pp
+.D1 Pf . Cm \&dei Ar name Op Ar end
+.Pp
+has the same effect as:
+.Pp
+.D1 Pf . Cm \&de No \e* Ns Bo Ar name Bc Op \e* Ns Bq Ar end

 .Ss \&de1
 Define a
 .Nm
 .Ss \&de1
 Define a
 .Nm


@@ -647,6 +660,34 @@ This line-scoped request is intended to have one argument specifying
 the font family to be selected.
 It is a groff extension, and currently, it is ignored including its
 arguments, and the number of arguments is not checked.
 the font family to be selected.
 It is a groff extension, and currently, it is ignored including its
 arguments, and the number of arguments is not checked.

+.Ss \&ft
+Change the font.
+Its syntax is as follows:
+.Pp
+.D1 Pf . Cm \&ft Op Ar font
+.Pp
+The following
+.Ar font
+arguments are supported:
+.Bl -tag -width 4n -offset indent
+.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, may be overridden by macros
+and escape sequences, and is only supported in
+.Xr man 7
+for now.

 .Ss \&hw
 Specify hyphenation points in words.
 This line-scoped request is currently ignored.
 .Ss \&hw
 Specify hyphenation points in words.
 This line-scoped request is currently ignored.


@@ -665,10 +706,67 @@ Its syntax is equivalent to
 .Sx \&if .
 .Ss \&if
 Begins a conditional.
 .Sx \&if .
 .Ss \&if
 Begins a conditional.

-Right now, the conditional evaluates to true
-if and only if it starts with the letter
-.Sy n ,
-indicating processing in nroff style as opposed to troff style.
+This request has the following syntax:
+.Bd -literal -offset indent
+\&.if COND BODY
+.Ed
+.Bd -literal -offset indent
+\&.if COND \e{BODY
+BODY...\e}
+.Ed
+.Bd -literal -offset indent
+\&.if COND \e{\e
+BODY...
+\&.\e}
+.Ed
+.Pp
+COND is a conditional statement.
+Currently,
+.Xr mandoc 1
+supports the following subset of roff conditionals:
+.Bl -bullet
+.It
+If
+.Sq \&!
+is prefixed to COND, the condition is logically inverted.
+.It
+If the first character of COND is
+.Sq n
+.Pq nroff mode
+or
+.Sq o
+.Pq odd page ,
+COND evaluates to true.
+.It
+If the first character of COND is
+.Sq c
+.Pq character available ,
+.Sq d
+.Pq string defined ,
+.Sq e
+.Pq even page ,
+.Sq r
+.Pq register accessed ,
+or
+.Sq t
+.Pq troff mode ,
+COND evaluates to false.
+.It
+If COND starts with a parenthesis or with an optionally signed
+integer number, it is evaluated according to the rules of
+.Sx Numerical expressions
+explained below.
+It evaluates to true if the the result is positive,
+or to false if the result is zero or negative.
+.It
+Otherwise, the first character of COND is regarded as a delimiter
+and COND evaluates to true if the string extending from its first
+to its second occurrence is equal to the string extending from its
+second to its third occurrence.
+.It
+If COND cannot be parsed, it evaluates to false.
+.El
+.Pp

 If a conditional is false, its children are not processed, but are
 syntactically interpreted to preserve the integrity of the input
 document.
 If a conditional is false, its children are not processed, but are
 syntactically interpreted to preserve the integrity of the input
 document.


@@ -686,44 +784,12 @@ will continue to syntactically interpret to the block close of the final
 conditional.
 Sub-conditionals, in this case, obviously inherit the truth value of
 the parent.
 conditional.
 Sub-conditionals, in this case, obviously inherit the truth value of
 the parent.

-This request has the following syntax:
-.Bd -literal -offset indent
-\&.if COND \e{\e
-BODY...
-\&.\e}
-.Ed
-.Bd -literal -offset indent
-\&.if COND \e{ BODY
-BODY... \e}
-.Ed
-.Bd -literal -offset indent
-\&.if COND \e{ BODY
-BODY...
-\&.\e}
-.Ed
-.Bd -literal -offset indent
-\&.if COND \e
-BODY
-.Ed
-.Pp
-COND is a conditional statement.
-roff allows for complicated conditionals; mandoc is much simpler.
-At this time, mandoc supports only
-.Sq n ,
-evaluating to true;
-and
-.Sq t ,
-.Sq e ,
-and
-.Sq o ,
-evaluating to false.
-All other invocations are read up to the next end of line or space and
-evaluate as false.

 .Pp
 If the BODY section is begun by an escaped brace
 .Sq \e{ ,
 .Pp
 If the BODY section is begun by an escaped brace
 .Sq \e{ ,

-scope continues until a closing-brace escape sequence
-.Sq \.\e} .
+scope continues until the end of the input line containing the
+matching closing-brace escape sequence
+.Sq \e} .

 If the BODY is not enclosed in braces, scope continues until
 the end of the line.
 If the COND is followed by a BODY on the same line, whether after a
 If the BODY is not enclosed in braces, scope continues until
 the end of the line.
 If the COND is followed by a BODY on the same line, whether after a


@@ -803,6 +869,23 @@ Otherwise, it only terminates the
 and arguments following it or the
 .Sq \&..
 request are discarded.
 and arguments following it or the
 .Sq \&..
 request are discarded.

+.Ss \&ll
+Change the output line length.
+Its syntax is as follows:
+.Pp
+.D1 Pf . Cm \&ll Op Oo +|- Oc Ns Ar width
+.Pp
+If the
+.Ar width
+argument is omitted, the line length is reset to its previous value.
+The default setting for terminal output is 78n.
+If a sign is given, the line length is added to or subtracted from;
+otherwise, it is set to the provided value.
+Using this request in new manuals is discouraged for several reasons,
+among others because it overrides the
+.Xr mandoc 1
+.Fl O Cm width
+command line option.

 .Ss \&ne
 Declare the need for the specified minimum vertical space
 before the next trap or the bottom of the page.
 .Ss \&ne
 Declare the need for the specified minimum vertical space
 before the next trap or the bottom of the page.


@@ -810,23 +893,19 @@ This line-scoped request is currently ignored.
 .Ss \&nh
 Turn off automatic hyphenation mode.
 This line-scoped request is currently ignored.
 .Ss \&nh
 Turn off automatic hyphenation mode.
 This line-scoped request is currently ignored.

-.Ss \&rm
-Remove a request, macro or string.
-This request is intended to have one argument,
-the name of the request, macro or string to be undefined.
-Currently, it is ignored including its arguments,
-and the number of arguments is not checked.

 .Ss \&nr
 Define or change a register.
 A register is an arbitrary string value that defines some sort of state,
 which influences parsing and/or formatting.
 Its syntax is as follows:
 .Pp
 .Ss \&nr
 Define or change a register.
 A register is an arbitrary string value that defines some sort of state,
 which influences parsing and/or formatting.
 Its syntax is as follows:
 .Pp

-.D1 Pf \. Cm \&nr Ar name Oo +|- Oc Ns Ar value
+.D1 Pf \. Cm \&nr Ar name Oo +|- Oc Ns Ar expression

 .Pp
 .Pp

-The
-.Ar value
-may, at the moment, only be an integer.
+For the syntax of
+.Ar expression ,
+see
+.Sx Numerical expressions
+below.

 If it is prefixed by a sign, the register will be
 incremented or decremented instead of assigned to.
 .Pp
 If it is prefixed by a sign, the register will be
 incremented or decremented instead of assigned to.
 .Pp


@@ -861,6 +940,16 @@ Change point size.
 This line-scoped request is intended to take one numerical argument.
 Currently, it is ignored including its arguments,
 and the number of arguments is not checked.
 This line-scoped request is intended to take one numerical argument.
 Currently, it is ignored including its arguments,
 and the number of arguments is not checked.

+.Ss \&rm
+Remove a request, macro or string.
+Its syntax is as follows:
+.Pp
+.D1 Pf \. Cm \&rm Ar name
+.Ss \&rr
+Remove a register.
+Its syntax is as follows:
+.Pp
+.D1 Pf \. Cm \&rr Ar name

 .Ss \&so
 Include a source file.
 Its syntax is as follows:
 .Ss \&so
 Include a source file.
 Its syntax is as follows:


@@ -929,6 +1018,73 @@ Begin a table, which formats input in aligned rows and columns.
 See
 .Xr tbl 7
 for a description of the tbl language.
 See
 .Xr tbl 7
 for a description of the tbl language.

+.Ss Numerical expressions
+The
+.Sx \&nr ,
+.Sx \&if ,
+and
+.Sx \&ie
+requests accept integer numerical expressions as arguments.
+These are always evaluated using the C
+.Vt int
+type; integer overflow works the same way as in the C language.
+Numbers consist of an arbitrary number of digits
+.Sq 0
+to
+.Sq 9
+prefixed by an optional sign
+.Sq +
+or
+.Sq - .
+.Pp
+The following binary operators are implemented.
+Unless otherwise stated, they behave as in the C language:
+.Pp
+.Bl -tag -width 2n -compact
+.It Ic +
+addition
+.It Ic -
+subtraction
+.It Ic *
+multiplication
+.It Ic /
+division
+.It Ic %
+remainder of division
+.It Ic <
+less than
+.It Ic >
+greater than
+.It Ic ==
+equal to
+.It Ic =
+equal to, same effect as
+.Ic ==
+(this differs from C)
+.It Ic <=
+less than or equal to
+.It Ic >=
+greater than or equal to
+.It Ic <>
+not equal to (corresponds to C
+.Ic != ;
+this one is of limited portability, it is supported by Heirloom roff,
+but not by groff)
+.It Ic &
+logical and (corresponds to C
+.Ic && )
+.It Ic \&:
+logical or (corresponds to C
+.Ic \&|| )
+.It Ic <?
+minimum (not available in C)
+.It Ic >?
+maximum (not available in C)
+.El
+.Pp
+There is no concept of precendence; evaluation proceeds from left to right,
+except when subexpressions are enclosed in parantheses.
+Inside parentheses, whitespace is ignored.

 .Sh ESCAPE SEQUENCE REFERENCE
 The
 .Xr mandoc 1
 .Sh ESCAPE SEQUENCE REFERENCE
 The
 .Xr mandoc 1


@@ -1017,10 +1173,15 @@ Digit width space character.
 Anchor definition; ignored by
 .Xr mandoc 1 .
 .Ss \eB\(aq Ns Ar string Ns \(aq
 Anchor definition; ignored by
 .Xr mandoc 1 .
 .Ss \eB\(aq Ns Ar string Ns \(aq

-Test whether
+Interpolate
+.Sq 1
+if

 .Ar string
 .Ar string

-is a numerical expession; ignored by
-.Xr mandoc 1 .
+conforms to the syntax of
+.Sx Numerical expressions
+explained above and
+.Sq 0
+otherwise.

 .Ss \eb\(aq Ns Ar string Ns \(aq
 Bracket building function; ignored by
 .Xr mandoc 1 .
 .Ss \eb\(aq Ns Ar string Ns \(aq
 Bracket building function; ignored by
 .Xr mandoc 1 .


@@ -1144,9 +1305,13 @@ Vertical motion; ignored by
 .Xr mandoc 1 .
 .Ss \ew\(aq Ns Ar string Ns \(aq
 Interpolate the width of the
 .Xr mandoc 1 .
 .Ss \ew\(aq Ns Ar string Ns \(aq
 Interpolate the width of the

-.Ar string ;
-ignored by
-.Xr mandoc 1 .
+.Ar string .
+The
+.Xr mandoc 1
+implementation assumes that after expansion of user-defined strings, the
+.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
 Output
 .Ar string
 .Ss \eX\(aq Ns Ar string Ns \(aq
 Output
 .Ar string