форматировать таблицы в документах groff (format tables in groff documents)
Описание (Description)
The GNU implementation of tbl is part of the groff(1) document
formatting system. tbl is a troff(1) preprocessor that
translates descriptions of tables embedded within a roff(7) input
files into the language understood by troff(1). It copies the
contents of each file to the standard output stream, except that
lines between .TS and .TE are interpreted as table descriptions.
While GNU tbl's input syntax is highly compatible with AT&T tbl,
the output tbl produces cannot be processed by AT&T troff; GNU
troff (or a troff implementing relevant GNU extensions) must be
used. Normally, tbl is not executed directly by the user, but
invoked by specifying the -t option to groff(1). If no file
operands are given on the command line, or if file is '-', the
standard input stream is read.
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
The table format specification is mandatory; it determines
the number of columns in the table. Each cell in a column
is classified by being centered, left-aligned, numeric
(aligned to a decimal point), and so on. 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 in table data are separated by a tab character by default.
That can be changed by the global option tab(c), where c is an
arbitrary character.
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 sub-
columns (hence the name of the key character) in
combination with L; they are called sub-columns because
A items are indented by 1n relative to L entries.
Example:
.TS
tab(;);
ln,an.
item one;1
sub-item two;2
sub-item three;3
.T&
ln,an.
item eleven;11
sub-item twenty-two;22
sub-item thirty-three;33
.TE
Result:
item one 1
sub-item two 2
sub-item three 3
item eleven 11
sub-item twenty-two 22
sub-item thirty-three 33
c,C Center item within the column.
l,L Left-justify item within the column.
n,N Numerically justify item in the column; that is, align
columns of numbers vertically at the units place. If
there are 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 are 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
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 │ │
├─────┤ │
│ r │ foo │
├─────┼────────┤
│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 controls).
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 (this 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 Call named macro before outputting table cell text (GNU
tbl only). 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. 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 roff 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 multi-digit
number 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
neighbors. 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 neighbors.
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 neighbors).
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{' at the end of a line and finished with 'T}' at the
start of a line. Further column data can follow the end of a
text block on the same line.
Text blocks are formatted as was the text prior to the table,
modified as applicable by column specifiers. Specifically, the
key characters 'a', 'c', 'l', 'n', and 's' determine a text
block's alignment within its cell, but not its adjustment. You
can add an .na or .ad request to the beginning of a text block to
alter its adjustment distinctly from other text in the document.
If 'w' or 'x' column 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. If necessary, you can
also control the text block width by inserting an .ll request
right after 'T{'. Because a diversion is used to format the text
block, its width is subsequently available in the register \n[dl]
.
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.
Using tbl macros within conditional input (that is, contingent
upon an .if, .ie, .el, or .while request) can result in
misleading line numbers in subsequent diagnostics. tbl
unconditionally injects its output into the source document, but
the conditional branch containing it may not be taken, and if it
is not, the .lf requests that tbl injects to restore the source
line number cannot take effect. Consider copying the input line
counter register .c and restoring its value at a convenient
location after applicable arithmetic.
Interaction with eqn
tbl(1) should always be called before eqn(1) (groff(1)
automatically takes care of the correct order of preprocessors).
Don't call the EQ and EN macros within tables; instead, set up
delimiters in your eqn input and use the delim() table option so
that tbl will recognize them.
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.
Using 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's 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.
