DESCRIPTION
The
tbl language is a table-formatting language. It is used within
mdoc(7) and
man(7) UNIX manual pages. This manual describes the subset of the
tbl language accepted by the
mandoc(1) utility.
Tables within mdoc(7) or man(7) are enclosed by the ‘TS' and ‘TE' macro tags, whose precise syntax is documented in roff(7). Tables consist of a series of options on a single line, followed by the table layout, followed by data.
For example, the following creates a boxed table with digits centred in the cells.
.TS
tab(:) box;
c5 c5 c5.
1:2:3
4:5:6
.TE
When formatted, the following output is produced:
The tbl implementation in mandoc(1) is currently under development.
TABLE STRUCTURE
Tables are enclosed by the ‘TS' and ‘TE'
roff(7) macros. A table consists of an optional single line of table
Options terminated by a semicolon, followed by one or more lines of
Layout specifications terminated by a period, then
Data. All input must be 7-bit ASCII. Example:
.TS
box tab(:);
c | c
| c | c.
1:2
3:4
.TE
Table data is 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 roff(7), mdoc(7), and man(7) macros such as
.TS
tab(:);
c c c.
1:2:3
.Ao
3:2:1
.Ac
.TE
in the case of mdoc(7) or
.TS
tab(:);
c c c.
.ds ab 2
1:\*(ab:3
.I
3:2:1
.TE
in the case of man(7).
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
Layout is processed. Some options accept arguments enclosed by parenthesis. The following case-insensitive options are available:
-
center
-
This option is not supported by mandoc(1). This may also be invoked with centre.
-
delim
-
Accepts a two-character argument. This option is not supported by mandoc(1).
-
expand
-
This option is not supported by mandoc(1).
-
box
-
Draw a single-line box around the table. This may also be invoked with frame.
-
doublebox
-
Draw a double-line box around the table. This may also be invoked with doubleframe.
-
allbox
-
This option is not supported by mandoc(1).
-
tab
-
Accepts a single-character argument. This character is used as a delimiter between data cells, which otherwise defaults to the tab character.
-
linesize
-
Accepts a natural number (all digits). This option is not supported by mandoc(1).
-
nokeep
-
This option is not supported by mandoc(1).
-
decimalpoint
-
Accepts a single-character argument. This character will be used as the decimal point with the n layout key.
-
nospaces
-
This option is not supported by mandoc(1).
Layout
The table layout follows
Options or a ‘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:
-
c
-
Centre a literal string within its column.
-
r
-
Right-justify a literal string within its column.
-
l
-
Left-justify a literal string within its column.
-
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.
-
s
-
Horizontally span columns from the last non-s data cell. It is an error if spanning columns follow a - or | cell, or come first. This option is not supported by mandoc(1).
-
a
-
Left-justify a literal string and pad with one space.
-
^
-
Vertically span rows from the last non-^ 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.
-
-
-
Replace the data cell (its contents will be lost) with a single horizontal line. This may also be invoked with _.
-
=
-
Replace the data cell (its contents will be lost) with a double horizontal line.
-
|
-
Emit a vertical bar instead of data.
-
||
-
Emit a double-vertical bar instead of data.
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: z, u, e, t, d, b, i, r, and f (followed by b, i, r, 3, 2, or 1). All of these are ignored by mandoc(1).
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:
c10 | l10 | n
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 tab option. If _ or = is specified, a single or double line, respectively, is drawn across the data field. If \- or \= 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 T{, all subsequent lines are included as part of the cell until T} is specified as its own data cell. It may then be followed by a tab (or as designated by tab) or an end-of-line to terminate the row.
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
mandoc(1) utility.