TBL
Section: User Commands (1)
Updated: 17 March 2021
Page Index
NAME
tbl - format tables for troff
SYNOPSIS
[
-Cv ]
[
file
...]
DESCRIPTION
This manual page describes the GNU version of
tbl,
which is part of the groff document formatting system.
tbl
compiles descriptions of tables embedded within
troff
input files into commands that are understood by
troff.
Normally, it should be invoked using the
-t
option of
groff.
It is highly compatible with Unix
tbl.
The output generated by GNU
tbl
cannot be processed with Unix
troff;
it must be processed with GNU
troff.
If no files are given on the command line or a filename of
-
is given, the standard input is read.
OPTIONS
- -C
-
Enable compatibility mode to
recognize
.TS
and
.TE
even when followed by a character other than space or newline.
Leader characters (\a) are handled as interpreted.
- -v
-
Print the version number.
LANGUAGE OVERVIEW
tbl
expects to find table descriptions wrapped in the
.TS
(table start) and
.TE
(table end) macros.
Within each such table sections, another table can be defined by
using the request
.T&
before the final command
.TE.
Each table definition has the following structure:
- Global options
-
This is optional.
This table part can use several of these options distributed in 1 or
more lines.
The
global option part
must always be finished by a
semi-colon ; .
- Table format specification
-
This part must be given, it is not optional.
It determines the number of columns (cells) of the table.
Moreover each cell is classified by being central, left adjusted, or
numerical, etc.
This specification can have several lines, but must be finished by a
dot .
at the end of the last line.
After each cell definition,
column specifiers
can be appended, but that's optional.
Cells are separated by a tab character by default.
That can be changed by the
global option
tab(c),
where
c
is an arbitrary character.
SIMPLE EXAMPLES
The easiest table definition is.
-
.TS
c c c .
This is centered
Well, this also
.TE
By using
c c
c,
each cell in the whole table will be centered.
The separating character is here the default
tab.
The result is
-
| This | is | centered
|
| Well, | this | also
|
This definition is identical to
-
.TS
tab(@);
ccc.
This@is@centered
Well,@this@also
.TE
Here, the separating tab character is changed to the letter
@.
Moreover a title can be added and the centering directions can be
changed to many other formats:
-
.TS
tab(@);
c s s
l c n .
Title
left@centers@123
another@number@75
.TE
The result is
-
Title
|
| left | centers | 123
|
| another | number | 75
|
Here
l
means
left-justified,
and
n
means
numerical,
which is here
right-justified.
USAGE
Global options
The line immediately following the
.TS
macro may contain any of the following global options (ignoring the
case of characters - Unix tbl only accepts options with all
characters lowercase or all characters uppercase), separated by
spaces, tabs, or commas:
- allbox
-
Enclose each item of the table in a box.
- box
-
Enclose the table in a box.
- center
-
Center the table (default is left-justified).
The alternative keyword name
centre
is also recognized (this is a GNU tbl extension).
- decimalpoint(c)
-
Set the character to be recognized as the decimal point in numeric
columns (GNU tbl only).
- delim(xy)
-
Use
x
and~y
as start and end delimiters for
eqn(1).
- doublebox
-
Enclose the table in a double box.
- doubleframe
-
Same as doublebox (GNU tbl only).
- expand
-
Make the table as wide as the current line length (providing a column
separation factor).
Ignored if one or more 'x' column specifiers are used (see
below).
-
In case the sum of the column widths is larger than the current line length,
the column separation factor is set to zero; such tables extend into the
right margin, and there is no column separation at all.
- frame
-
Same as box (GNU tbl only).
- linesize(n)
-
Set lines or rules (e.g. from
box)
in
n-point
type.
- nokeep
-
Don't use diversions to prevent page breaks (GNU tbl only).
Normally
tbl
attempts to prevent undesirable breaks in boxed tables by using diversions.
This can sometimes interact badly with macro packages' own use of
diversions---when footnotes, for example, are used.
- nospaces
-
Ignore leading and trailing spaces in data items (GNU tbl only).
- nowarn
-
Turn off warnings related to tables exceeding the current line width
(GNU tbl only).
- tab(x)
-
Use the character
x
instead of a tab to separate items in a line of input data.
The global options must end with a semicolon.
There might be whitespace between an option and its argument in
parentheses.
Table format specification
After global options come lines describing the format of each line of
the table.
Each such format line describes one line of the table itself, except
that the last format line (which you must end with a period) describes
all remaining lines of the table.
A single-key character describes each column of each line of the table.
Key characters can be separated by spaces or tabs.
You may run format specifications for multiple lines together on the
same line by separating them with commas.
You may follow each key character with specifiers that determine the
font and point size of the corresponding item, that determine column
width, inter-column spacing, etc.
The longest format line defines the number of columns in the table;
missing format descriptors at the end of format lines are assumed to
be~L.
Extra columns in the data (which have no corresponding format entry)
are ignored.
The available key characters are:
- a,A
-
Center longest line in this column and then left-justifies all other
lines in this column with respect to that centered line.
The idea is to use such alphabetic subcolumns (hence the name of the
key character) in combination with~
L;
they are called subcolumns because
A~items
are indented by~1n relative to
L~entries.
Example:
-
-
.TS
tab(;);
ln,an.
item one;1
subitem two;2
subitem three;3
.T&
ln,an.
item eleven;11
subitem twentytwo;22
subitem thirtythree;33
.TE
-
Result:
-
-
| item one | 1
|
| subitem two | 2
|
| subitem three | 3
|
| item eleven | 11
|
| subitem twentytwo | 22
|
| subitem thirtythree | 33
|
- c,C
-
Center item within the column.
- l,L
-
Left-justify item within the column.
- n,N
-
Numerically justify item in the column: Units positions of numbers are
aligned vertically.
If there is one or more dots adjacent to a digit, use the rightmost one for
vertical alignment.
If there is no dot, use the rightmost digit for vertical alignment;
otherwise, center the item within the column.
Alignment can be forced to a certain position using '\&';
if there is one or more instances of this special (non-printing)
character present within the data, use the leftmost one for alignment.
Example:
-
-
.TS
n.
1
1.5
1.5.3
abcde
a\&bcde
.TE
-
Result:
-
-
-
If numerical entries are combined with
L
or
R~entries
- this can happen if the table format is changed with
.T&
-
center the widest
number
(of the data entered under the
N~specifier
regime) relative to the widest
L
or
R~entry,
preserving the alignment of all numerical entries.
Contrary to
A~type
entries, there is no extra indentation.
-
Using equations (to be processed with
eqn)
within columns which use the
N~specifier
is problematic in most cases due to
tbl's
algorithm for finding the vertical alignment, as described above.
Using the global
delim
option, however, it is possible to make
tbl
ignore the data within
eqn
delimiters for that purpose.
- r,R
-
Right-justify item within the column.
- s,S
-
Span previous item on the left into this column.
Not allowed for the first column.
- ^
-
Span down entry from previous row in this column.
Not allowed for the first row.
- _,-
-
Replace this entry with a horizontal line.
Note that '_' and '-' can be used for table fields only,
not for column separator lines.
- =
-
Replace this entry with a double horizontal line.
Note that '=' can be used for table fields only,
not for column separator lines.
- |
-
The corresponding column becomes a vertical rule (if two of these are
adjacent, a double vertical rule).
A vertical bar to the left of the first key letter or to the right of
the last one produces a line at the edge of the table.
To change the data format within a table, use the
.T&
command (at the start of a line).
It is followed by format and data lines (but no global options)
similar to the
.TS
request.
Column specifiers
Here are the specifiers that can appear in suffixes to column key
letters (in any order):
- b,B
-
Short form of
fB
(make affected entries bold).
- d,D
-
Start an item that vertically spans rows,
using the '^' column specifier or '\^' data item,
at the bottom of its range rather
than vertically centering it (GNU tbl only).
Example:
-
-
.TS
tab(;) allbox;
l l
l ld
r ^
l rd.
0000;foobar
T{
1111
.br
2222
T};foo
r;
T{
3333
.br
4444
T};bar
\^;\^
.TE
-
Result:
-
-
| 0000 | foobar
|
1111
2222
| foo
|
| r |
3333
4444
| bar
|
|
- e,E
-
Make equally-spaced columns.
All columns marked with this specifier get the same width; this happens
after the affected column widths have been computed (this means that the
largest width value rules).
- f,F
-
Either of these specifiers may be followed by a font name (either one or two
characters long), font number (a single digit), or long name in parentheses
(the last form is a GNU tbl extension).
A one-letter font name must be separated by one or more blanks from whatever
follows.
- i,I
-
Short form of
fI
(make affected entries italic).
- m,M
-
This is a GNU tbl extension.
Either of these specifiers may be followed by a macro name
(either one or two characters long),
or long name in parentheses.
A one-letter macro name must be separated by one or more blanks from
whatever follows.
The macro which name can be specified here must be defined before
creating the table.
It is called just before the table's cell text is output.
As implemented currently, this macro is only called if block input is
used, that is, text between 'T{' and 'T}'.
The macro should contain only simple
troff
requests to change the text block formatting, like text adjustment,
hyphenation, size, or font.
The macro is called
after
other cell modifications like
b,
f
or
v
are output.
Thus the macro can overwrite other modification specifiers.
- p,P
-
Followed by a number, this does a point size change for the affected fields.
If signed, the current point size is incremented or decremented (using
a signed number instead of a signed digit is a GNU tbl extension).
A point size specifier followed by a column separation number must be
separated by one or more blanks.
- t,T
-
Start an item vertically spanning rows at the top of its range rather than
vertically centering it.
- u,U
-
Move the corresponding column up one half-line.
- v,V
-
Followed by a number, this indicates the vertical line spacing to be
used in a multi-line table entry.
If signed, the current vertical line spacing is incremented or
decremented (using a signed number instead of a signed digit is a GNU
tbl extension).
A vertical line spacing specifier followed by a column separation
number must be separated by one or more blanks.
No effect if the corresponding table entry isn't a text block.
- w,W
-
Minimum column width value.
Must be followed either by a
troff(1)
width expression in parentheses or a unitless integer.
If no unit is given, en units are used.
Also used as the default line length for included text blocks.
If used multiple times to specify the width for a particular column,
the last entry takes effect.
- x,X
-
An expanded column.
After computing all column widths without an
x~specifier,
use the remaining line width for this column.
If there is more than one expanded column, distribute the remaining
horizontal space evenly among the affected columns (this is a GNU
extension).
This feature has the same effect as specifying a minimum column width.
- z,Z
-
Ignore the corresponding column for width-calculation purposes, this
is, don't use the fields but only the specifiers of this column to
compute its width.
A number suffix on a key character is interpreted as a column
separation in en units (multiplied in proportion if the
expand
option is on - in case of overfull tables this might be zero).
Default separation is 3n.
The column
specifier~x
is mutually exclusive with
e
and~w
(but
e
is not mutually exclusive
with~w);
if specified multiple times for a particular column, the last entry takes
effect:
x~unsets
both
e
and~w,
while either
e
or
w
overrides~x.
Table data
The format lines are followed by lines containing the actual data for the
table, followed finally by
.TE.
Within such data lines, items are normally separated by tab characters
(or the character specified with the
tab
option).
Long input lines can be broken across multiple lines if the last
character on the line is '\' (which vanishes after
concatenation).
Note that
tbl
computes the column widths line by line, applying \w on each entry
which isn't a text block.
As a consequence, constructions like
-
.TS
c,l.
\s[20]MM
MMMM
.TE
fail; you must either say
-
.TS
cp20,lp20.
MM
MMMM
.TE
or
-
.TS
c,l.
\s[20]MM
\s[20]MMMM
.TE
A dot starting a line, followed by anything but a digit is handled as
a troff command, passed through without changes.
The table position is unchanged in this case.
If a data line consists of only '_' or '=', a single
or double line, respectively, is drawn across the table at that point;
if a single item in a data line consists of only '_' or
'=', then that item is replaced by a single or double line,
joining its neighbours.
If a data item consists only of '\_' or '\=',
a single or double line, respectively, is drawn across the field at
that point which does not join its neighbours.
A data item consisting only of '\Rx' ('x' any
character) is replaced by repetitions of character 'x' as wide
as the column (not joining its neighbours).
A data item consisting only of '\^' indicates that the
field immediately above spans downward over this row.
Text blocks
A text block can be used to enter data as a single entry which would
be too long as a simple string between tabs.
It is started with 'T{' and closed with 'T}'.
The former must end a line, and the latter must start a line, probably
followed by other data columns (separated with tabs or the character
given with the
tab
global option).
By default, the text block is formatted with the settings which were
active before entering the table, possibly overridden by the
m,
v,
and
w
tbl specifiers.
For example, to make all text blocks ragged-right, insert
.na
right before the starting
.TS
(and
.ad
after the table).
If either 'w' or 'x' specifiers are not given for
all
columns of a text block span, the default length of the text block (to
be more precise, the line length used to process the text block
diversion) is computed as LmuC/(N+1), where 'L' is the
current line length, 'C' the number of columns spanned by the
text block, and 'N' the total number of columns in the table.
Note, however, that the actual diversion width as returned in register
\n[dl]
is used eventually as the text block width.
If necessary, you can also control the text block width with a direct
insertion of a
.ll
request right after 'T{'.
Miscellaneous
The number register
\n[TW]
holds the table width; it can't be used within the table itself
but is defined right before calling
.TE
so that this macro can make use of it.
tbl
also defines a macro
.T#
which produces the bottom and side lines of a boxed table.
While
tbl
does call this macro itself at the end of the table, it can be used by
macro packages to create boxes for multi-page tables by calling it within the
page footer.
An example of this is shown by the
-ms
macros which provide this functionality if a table starts with
.TS H
instead of the standard call to the
.TS
macro.
INTERACTION WITH EQN
tbl(1)
should always be called before
eqn(1)
(
groff(1)
automatically takes care of the correct order of preprocessors).
GNU TBL ENHANCEMENTS
There is no limit on the number of columns in a table, nor any limit on the
number of text blocks.
All the lines of a table are considered in deciding column widths, not just
the first 200.
Table continuation
(
.T&)
lines are not restricted to the first 200 lines.
Numeric and alphabetic items may appear in the same column.
Numeric and alphabetic items may span horizontally.
tbl
uses register, string, macro and diversion names beginning with the digit~3.
When using
tbl
you should avoid using any names beginning with a~3.
GNU TBL WITHIN MACROS
Since
tbl
defines its own macros (right before each table) it is necessary to use
an 'end-of-macro' macro.
Additionally, the escape character has to be switched off.
Here an example.
-
.eo
.de ATABLE ..
.TS
allbox tab(;);
cl.
\$1;\$2
.TE
...
.ec
.ATABLE A table
.ATABLE Another table
.ATABLE And "another one"
Note, however, that not all features of
tbl
can be wrapped into a macro because
tbl
sees the input earlier than
troff.
For example, number formatting with vertically aligned decimal points
fails if those numbers are passed on as macro parameters because
decimal point alignment is handled by
tbl
itself: It only sees '\$1', '\$2', etc., and
therefore can't recognize the decimal point.
BUGS
You should use
.TS H/
.TH
in conjunction with a supporting macro package for
all
multi-page boxed tables.
If there is no header that you wish to appear at the top of each page
of the table, place the
.TH
line immediately after the format section.
Do not enclose a multi-page table within keep/release macros,
or divert it in any other way.
A text block within a table must be able to fit on one page.
The
bp
request cannot be used to force a page-break in a multi-page table.
Instead, define
BP
as follows
-
.de BP
. ie '\\n(.z'' .bp \\$1
. el \!.BP \\$1
..
and use
BP
instead of
bp.
Using \a directly in a table to get leaders does not work (except in
compatibility mode).
This is correct behaviour: \a is an
uninterpreted
leader.
To get leaders use a real leader, either by using a control A or like
this:
-
.ds a \a
.TS
tab(;);
lw(1i) l.
A\*a;B
.TE
A leading and/or trailing '|' in a format line, such as
-
|l r|.
gives output which has a 1n~space between the resulting
bordering vertical rule and the content of the adjacent column,
as in
-
.TS
tab(#);
|l r|.
left column#right column
.TE
If it is desired to have zero space (so that the rule touches
the content), this can be achieved by introducing extra "dummy"
columns, with no content and zero separation, before and/or after,
as in
-
.TS
tab(#);
r0|l r0|l.
#left column#right column#
.TE
The resulting "dummy" columns are invisible and have zero width;
note that such columns usually don't work with TTY devices.
REFERENCE
Lesk, M.E.: "TBL - A Program to Format Tables".
For copyright reasons it cannot be included in the groff distribution,
but copies can be found with a title search on the World Wide Web.
SEE ALSO
groff(1),
troff(1)