NAME
tbl - format tables for troff
SYNOPSIS
[files ...]
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.
USAGE
tbl expects to find table descriptions wrapped in the .TS (table start)
and .TE (table end) macros.
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).
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:
1
1.5
1.5.3
abcde
abcde
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.
= Replace this entry with a double horizontal line.
| 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 vertically spanning rows at the bottom of its
range rather than vertically centering it (GNU tbl only).
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 Minimal 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 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{’.
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
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)