[unix-history] / usr / doc / trofftut / tt05

.NH
Tabs
.PP
Tabs
(the \s8ASCII\s0 `horizontal tab' character)
can be used to produce output in columns,
or to set the horizontal position of output.
Typically
tabs are used only in unfilled text.
Tab stops are set by default every half inch from the
current indent,
but
can be changed by the
.BD .ta
command.
To set stops every inch, for example,
.P1
^ta 1i 2i 3i 4i 5i 6i
.P2
.PP
Unfortunately the stops are left-justified only
(as on a typewriter),
so lining up columns of right-justified numbers can be painful.
If you have many numbers,
or if you need more complicated table layout,
.ul
don't
use
.UL troff 
directly;
use the
.UL tbl
program described in [3].
.PP
For a handful of numeric columns, you can do it this way:
Precede every number by enough blanks to make it line up
when typed.
.P1
^nf
^ta 1i 2i 3i
\0\01\0\fItab\fR\0\0\02\0\fItab\fR\0\0\03
\040\0\fItab\fR\0\050\0\fItab\fR\0\060
700\0\fItab\fR\0800\0\fItab\fR\0900
^fi
.P2
Then change each leading blank into the string
.BD \e0 .
This is a character that does not print, but that has
the same width as a digit.
When printed, this will produce
.P1
.ta 1i 2i 3i
\0\01	\0\02	\0\03
\040	\050	\060
700	800	900
.P2
.PP
It is also possible to fill up tabbed-over space with
some character other than blanks by setting the `tab replacement character'
with the
.BD .tc
command:
.P1
^ta 1.5i 2.5i
^tc \e(ru	(\e(ru is "\(ru")
Name \fItab\fR Age \fItab\fR 
.P2
produces
.P1 3
.ta 1.5i 2.5i
.tc \(ru
Name	 Age 	
.tc
.P2
To reset the tab replacement character to a blank, use
.BD .tc
with no argument.
(Lines can also be drawn with the
.BD \el
command, described in Section 6.)
.PP
.UL troff
also provides a very general mechanism called `fields'
for setting up complicated columns.
(This is used by
.UL tbl ).
We will not go into it in this paper.
Commit	Line	Data
8340f87c BJ	1	.NH
	2	Tabs
	3	.PP
	4	Tabs
	5	(the \s8ASCII\s0 `horizontal tab' character)
	6	can be used to produce output in columns,
	7	or to set the horizontal position of output.
	8	Typically
	9	tabs are used only in unfilled text.
	10	Tab stops are set by default every half inch from the
	11	current indent,
	12	but
	13	can be changed by the
	14	.BD .ta
	15	command.
	16	To set stops every inch, for example,
	17	.P1
	18	^ta 1i 2i 3i 4i 5i 6i
	19	.P2
	20	.PP
	21	Unfortunately the stops are left-justified only
	22	(as on a typewriter),
	23	so lining up columns of right-justified numbers can be painful.
	24	If you have many numbers,
	25	or if you need more complicated table layout,
	26	.ul
	27	don't
	28	use
	29	.UL troff
	30	directly;
	31	use the
	32	.UL tbl
	33	program described in [3].
	34	.PP
	35	For a handful of numeric columns, you can do it this way:
	36	Precede every number by enough blanks to make it line up
	37	when typed.
	38	.P1
	39	^nf
	40	^ta 1i 2i 3i
	41	\0\01\0\fItab\fR\0\0\02\0\fItab\fR\0\0\03
	42	\040\0\fItab\fR\0\050\0\fItab\fR\0\060
	43	700\0\fItab\fR\0800\0\fItab\fR\0900
	44	^fi
	45	.P2
	46	Then change each leading blank into the string
	47	.BD \e0 .
	48	This is a character that does not print, but that has
	49	the same width as a digit.
	50	When printed, this will produce
	51	.P1
	52	.ta 1i 2i 3i
	53	\0\01 \0\02 \0\03
	54	\040 \050 \060
	55	700 800 900
	56	.P2
	57	.PP
	58	It is also possible to fill up tabbed-over space with
	59	some character other than blanks by setting the `tab replacement character'
	60	with the
	61	.BD .tc
	62	command:
	63	.P1
	64	^ta 1.5i 2.5i
65	^tc \e(ru (\e(ru is "\(ru")
66	Name \fItab\fR Age \fItab\fR
67	.P2
68	produces
69	.P1 3
70	.ta 1.5i 2.5i
71	.tc \(ru
72	Name Age
73	.tc
74	.P2
75	To reset the tab replacement character to a blank, use
76	.BD .tc
77	with no argument.
78	(Lines can also be drawn with the
79	.BD \el
80	command, described in Section 6.)
81	.PP
82	.UL troff
83	also provides a very general mechanism called `fields'
84	for setting up complicated columns.
85	(This is used by
86	.UL tbl ).
87	We will not go into it in this paper.