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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 consists of space-separated option keys and
modifiers 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 accept arguments enclosed by parenthesis.
The following case-insensitive options are available:
.Bl -tag -width Ds
.It Cm center
This option is not supported by
.Xr mandoc 1 .
This may also be invoked with
.Cm centre .
.It Cm delim
Accepts a two-character argument.
This option is not supported by
.Xr mandoc 1 .
.It Cm expand
This option is not supported by
.Xr mandoc 1 .
.It Cm box
Draw a single-line box around the table.
This may also be invoked with
.Cm frame .
.It Cm doublebox
Draw a double-line box around the table.
This may also be invoked with
.Cm doubleframe .
.It Cm allbox
This option is not supported by
.Xr mandoc 1 .
.It Cm tab
Accepts a single-character argument.
This character is used as a delimiter between data cells, which otherwise
defaults to the tab character.
.It Cm linesize
Accepts a natural number (all digits).
This option is not supported by
.Xr mandoc 1 .
.It Cm nokeep
This option is not supported by
.Xr mandoc 1 .
.It Cm decimalpoint
Accepts a single-character argument.
This character will be used as the decimal point with the
.Cm n
layout key.
.It Cm nospaces
This option is not supported by
.Xr mandoc 1 .
.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 Ds
.It Cm c
Centre 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:
.Cm z ,
.Cm u ,
.Cm e ,
.Cm t ,
.Cm d ,
.Cm f ,
.Cm b ,
.Cm i ,
.Cm b ,
and
.Cm i .
All of these are ignored by
.Xr mandoc 1 .
.Pp
For example, the following layout specifies a centre-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
justified about the decimal point in numbers:
.Pp
.Dl c10 | l10 | n
.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 partial
.Nm
reference was written by
.An Kristaps Dzonsons Aq kristaps@bsd.lv .
