gtbl - format tables for troff
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.
- -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.
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.
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.
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
geqn(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.
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.
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 gtroff(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.
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 gtbl 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.
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 L×C/(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{’.
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.
gtbl(1) should always be called before geqn(1) (groff(1)
automatically takes care of the correct order of preprocessors).
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.
gtbl uses register, string, macro and diversion names
beginning with the digit 3. When using gtbl you should
avoid using any names beginning with a 3.
Since gtbl 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 gtbl can be wrapped
into a macro because gtbl sees the input earlier than gtroff.
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 gtbl itself: It only sees
‘\$1’, ‘\$2’, etc., and therefore can't
recognize the decimal point.
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.
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.