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.\" Copyright (c) 2014, 2015 Ingo Schwarze <schwarze@openbsd.org>
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.Dd $Mdocdate$
.Dt TBL 7
.Os
.Sh NAME
.Nm tbl
.Nd tbl language reference for mandoc
.Sh DESCRIPTION
The
.Nm tbl
language is a table-formatting language.
It is used within
.Xr mdoc 7
and
.Xr man 7
.Ux
manual pages.
This manual describes the subset of the
.Nm
language accepted by the
.Xr mandoc 1
utility.
.Pp
Tables within
.Xr mdoc 7
or
.Xr man 7
are enclosed by the
.Sq TS
and
.Sq TE
macro tags, whose precise syntax is documented in
.Xr roff 7 .
Tables consist of a series of options on a single line, followed by the
table layout, followed by data.
.Pp
For example, the following creates a boxed table with digits centered in
the cells.
.Bd -literal -offset indent
\&.TS
tab(:) box;
c5 c5 c5.
1:2:3
4:5:6
\&.TE
.Ed
.Pp
When formatted, the following output is produced:
.Bd -filled -offset indent -compact
.TS
tab(:) box;
c5 c5 c5.
1:2:3
4:5:6
.TE
.Ed
.Sh TABLE STRUCTURE
Tables are enclosed by the
.Sq TS
and
.Sq TE
.Xr roff 7
macros.
A table consists of an optional single line of table
.Sx Options
terminated by a semicolon, followed by one or more lines of
.Sx Layout
specifications terminated by a period, then
.Sx Data .
All input must be 7-bit ASCII.
Example:
.Bd -literal -offset indent
\&.TS
box tab(:);
c | c
| c | c.
1:2
3:4
\&.TE
.Ed
.Pp
Table data is
.Em pre-processed ,
that is, data rows are parsed then inserted into the underlying stream
of input data.
This allows data rows to be interspersed by arbitrary
.Xr roff 7 ,
.Xr mdoc 7 ,
and
.Xr man 7
macros such as
.Bd -literal -offset indent
\&.TS
tab(:);
c c c.
1:2:3
\&.Ao
3:2:1
\&.Ac
\&.TE
.Ed
.Pp
in the case of
.Xr mdoc 7
or
.Bd -literal -offset indent
\&.TS
tab(:);
c c c.
\&.ds ab 2
1:\e*(ab:3
\&.I
3:2:1
\&.TE
.Ed
.Pp
in the case of
.Xr man 7 .
.Ss Options
The first line of a table may contain options separated by spaces, tabs,
or commas and terminated by a semicolon.
If the first line does not have a terminating semicolon, it is assumed
that no options are specified and instead a
.Sx Layout
is processed.
Some options require arguments enclosed by parentheses.
The following case-insensitive options are available:
.Bl -tag -width Ds
.It Cm allbox
Draw a single-line box around each table cell.
Currently treated as a synonym for
.Cm box .
.It Cm box
Draw a single-line box around the table.
For GNU compatibility, this may also be invoked with
.Cm frame .
.It Cm center
Center the table instead of left-adjusting it.
Currently ignored.
For GNU compatibility, this may also be invoked with
.Cm centre .
.It Cm decimalpoint
Use the single-character argument as the decimal point with the
.Cm n
layout key.
This is a GNU extension.
.It Cm delim
Use the two characters of the argument as
.Xr eqn 7
delimiters.
Currently unsupported.
.It Cm doublebox
Draw a double-line box around the table.
For GNU compatibility, this may also be invoked with
.Cm doubleframe .
.It Cm expand
Increase the width of the table to the current line length.
Currently ignored.
.It Cm linesize
Draw lines with the point size given by the unsigned integer argument.
Currently ignored.
.It Cm nokeep
Allow page breaks within the table.
This is a GNU extension and currently ignored.
.It Cm nospaces
Ignore leading and trailing spaces in data cells.
This is a GNU extension and currently ignored.
.It Cm nowarn
Suppress warnings about tables exceeding the current line length.
This is a GNU extension and currently ignored.
.It Cm tab
Use the single-character argument as a delimiter between data cells.
By default, the tab character is used.
.El
.Ss Layout
The table layout follows
.Sx Options
or a
.Sq \&T&
macro invocation.
Layout specifies how data rows are displayed on output.
Each layout line corresponds to a line of data; the last layout line
applies to all remaining data lines.
Layout lines may also be separated by a comma.
Each layout cell consists of one of the following case-insensitive keys:
.Bl -tag -width 2n
.It Cm c
Center a literal string within its column.
.It Cm r
Right-justify a literal string within its column.
.It Cm l
Left-justify a literal string within its column.
.It Cm n
Justify a number around its last decimal point.
If the decimal point is not found on the number, it's assumed to trail
the number.
.It Cm s
Horizontally span columns from the last
.No non- Ns Cm s
data cell.
It is an error if spanning columns follow a
.Cm \-
or
.Cm \(ba
cell, or come first.
This option is not supported by
.Xr mandoc 1 .
.It Cm a
Left-justify a literal string and pad with one space.
.It Cm ^
Vertically span rows from the last
.No non- Ns Cm ^
data cell.
It is an error to invoke a vertical span on the first layout row.
Unlike a horizontal spanner, you must specify an empty cell (if it not
empty, the data is discarded) in the corresponding data cell.
.It Cm \-
Replace the data cell (its contents will be lost) with a single
horizontal line.
This may also be invoked with
.Cm _ .
.It Cm =
Replace the data cell (its contents will be lost) with a double
horizontal line.
.It Cm \(ba
Emit a vertical bar instead of data.
.It Cm \(ba\(ba
Emit a double-vertical bar instead of data.
.El
.Pp
Keys may be followed by a set of modifiers.
A modifier is either a modifier key or a natural number for specifying
the minimum width of a column.
The following case-insensitive modifier keys are available:
.Bl -tag -width 2n
.It Cm b
Use a bold font for the contents of this column.
.It Cm d
Move cell content down to the last cell of a vertical span.
Currently ignored.
.It Cm e
Make this column wider to match the maximum width
of any other column also having the
.Cm e
modifier.
.It Cm f
The next character selects the font to use for this column.
See the
.Xr roff 7
manual for supported one-character font names.
.It Cm i
Use an italic font for the contents of this column.
.It Cm m
Specify a cell start macro.
This is a GNU extension and currently unsupported.
.It Cm p
Set the point size to the following unsigned argument,
or change it by the following signed argument.
Currently ignored.
.It Cm v
Set the vertical line spacing to the following unsigned argument,
or change it by the following signed argument.
Currently ignored.
.It Cm t
Do not vertically center cell content in the vertical span,
leave it at the top.
Currently ignored.
.It Cm u
Move cell content up by half a table line.
Currently ignored.
.It Cm w
Specify minimum column width.
Currently ignored.
.It Cm x
After determining the width of all other columns, distribute the
rest of the line length among all columns having the
.Cm x
modifier.
.It Cm z
Do not use this cell for determining the width of this column.
.El
.Pp
For example, the following layout specifies a center-justified column of
minimum width 10, followed by vertical bar, followed by a left-justified
column of minimum width 10, another vertical bar, then a column using
bold font justified about the decimal point in numbers:
.Pp
.Dl c10 | l10 | nfB
.Ss Data
The data section follows the last layout row.
By default, cells in a data section are delimited by a tab.
This behaviour may be changed with the
.Cm tab
option.
If
.Cm _
or
.Cm =
is specified, a single or double line, respectively, is drawn across the
data field.
If
.Cm \e-
or
.Cm \e=
is specified, a line is drawn within the data field (i.e. terminating
within the cell and not draw to the border).
If the last cell of a line is
.Cm T{ ,
all subsequent lines are included as part of the cell until
.Cm T}
is specified as its own data cell.
It may then be followed by a tab
.Pq or as designated by Cm tab
or an end-of-line to terminate the row.
.Sh COMPATIBILITY
This section documents compatibility between mandoc and other
.Nm
implementations, at this time limited to GNU tbl.
.Pp
.Bl -dash -compact
.It
In GNU tbl, comments and macros are disallowed prior to the data block
of a table.
The
.Xr mandoc 1
implementation allows them.
.El
.Sh SEE ALSO
.Xr mandoc 1 ,
.Xr man 7 ,
.Xr mandoc_char 7 ,
.Xr mdoc 7 ,
.Xr roff 7
.Rs
.%A M. E. Lesk
.%T Tbl\(emA Program to Format Tables
.%D June 11, 1976
.Re
.Sh HISTORY
The tbl utility, a preprocessor for troff, was originally written by M.
E. Lesk at Bell Labs in 1975.
The GNU reimplementation of tbl, part of the groff package, was released
in 1990 by James Clark.
A standalone tbl implementation was written by Kristaps Dzonsons in
2010.
This formed the basis of the implementation that is part of the
.Xr mandoc 1
utility.
.Sh AUTHORS
This
.Nm
reference was written by
.An Kristaps Dzonsons Aq Mt kristaps@bsd.lv .