[unix-history] / usr / doc / trofftut / tt07

.NH
Strings
.PP
Obviously if a paper contains a large number of occurrences
of an acute accent over a letter `e',
typing
.BD \eo"e\e\'"
for each \*e
would be a great nuisance.
.PP
Fortunately,
.UL troff
provides a way in which you can store an arbitrary
collection of text in a `string',
and thereafter use the string name as a shorthand
for its contents.
Strings are one of several
.UL troff
mechanisms whose judicious use
lets you type a document
with less effort and organize
it
so that extensive format changes
can be made with few editing changes.
.PP
A reference to a string is replaced by whatever
text
the string was defined as.
Strings are defined with the command
.BD .ds .
The line
.P1
\&^ds e \eo"e\e'"
.P2
defines the string
.BD e
to have the value
.BD \eo"e\e\'"
.PP
String names may be either one or two characters long,
and are referred to by
.BD \e*x
for one character names or
.BD \e*(xy
for two character names.
Thus to get
t\*el\*ephone,
given the definition of the string
.BD e
as above,
we can say
t\e*el\e*ephone.
.PP
If a string must begin with blanks, define it as
.P1
\&.ds xx "      text
.P2
The double quote signals the beginning of the definition.
There is no trailing quote;
the end of the line terminates the string.
.PP
A string may actually be several lines long;
if
.UL troff
encounters a 
.BD \e
at the end of
.ul
any
line, it is thrown away and the next line
added to the current one.
So you can make a long string simply by ending each line
but the last with a backslash:
.P1
\&^ds xx this \e
is a very \e
long string
.P2
.PP
Strings may be defined in terms of other strings, or even in terms of themselves;
we will discuss some of these possibilities later.
Commit	Line	Data
8340f87c BJ	1	.NH
	2	Strings
	3	.PP
	4	Obviously if a paper contains a large number of occurrences
	5	of an acute accent over a letter `e',
	6	typing
	7	.BD \eo"e\e\'"
	8	for each \*e
	9	would be a great nuisance.
	10	.PP
	11	Fortunately,
	12	.UL troff
	13	provides a way in which you can store an arbitrary
	14	collection of text in a `string',
	15	and thereafter use the string name as a shorthand
	16	for its contents.
	17	Strings are one of several
	18	.UL troff
	19	mechanisms whose judicious use
	20	lets you type a document
	21	with less effort and organize
	22	it
	23	so that extensive format changes
	24	can be made with few editing changes.
	25	.PP
	26	A reference to a string is replaced by whatever
	27	text
	28	the string was defined as.
	29	Strings are defined with the command
	30	.BD .ds .
	31	The line
	32	.P1
	33	\&^ds e \eo"e\e'"
	34	.P2
	35	defines the string
	36	.BD e
	37	to have the value
	38	.BD \eo"e\e\'"
	39	.PP
	40	String names may be either one or two characters long,
	41	and are referred to by
	42	.BD \e*x
	43	for one character names or
	44	.BD \e*(xy
	45	for two character names.
	46	Thus to get
	47	t\el\ephone,
	48	given the definition of the string
	49	.BD e
	50	as above,
	51	we can say
	52	t\eel\eephone.
	53	.PP
	54	If a string must begin with blanks, define it as
	55	.P1
	56	\&.ds xx " text
	57	.P2
	58	The double quote signals the beginning of the definition.
	59	There is no trailing quote;
	60	the end of the line terminates the string.
	61	.PP
	62	A string may actually be several lines long;
	63	if
	64	.UL troff
65	encounters a
66	.BD \e
67	at the end of
68	.ul
69	any
70	line, it is thrown away and the next line
71	added to the current one.
72	So you can make a long string simply by ending each line
73	but the last with a backslash:
74	.P1
75	\&^ds xx this \e
76	is a very \e
77	long string
78	.P2
79	.PP
80	Strings may be defined in terms of other strings, or even in terms of themselves;
81	we will discuss some of these possibilities later.