.\" @(#)tt12 6.1 (Berkeley) 5/23/86
macro to leave two extra inches of space just before section 1,
The cleanest way to do that is to test inside the
and add some space if it is.
command provides the conditional test
just before the heading line is output:
^if \e\en(SH=1 ^sp 2i \e" first section only
can be any arithmetic or logical expression.
If the condition is logically true, or arithmetically greater than zero,
the rest of the line is treated as if
If the condition is false, or zero or negative,
the rest of the line is skipped.
It is possible to do more than one command if a condition is true.
Suppose several operations are to be done before section 1.
One possibility is to define a macro
if we are about to do section 1
--- processing for section 1 ---
An alternate way is to use the
^if \e\en(SH=1 \e{--- processing
must occur in the positions shown
or you will get unexpected extra lines in your output.
an `if-else' construction,
which we will not go into here.
A condition can be negated by preceding it with
we get the same effect as above (but less clearly) by using
other conditions that can be tested with
For example, is the current page even or odd?
^if o ^tl 'odd page title''- % -'
^if e ^tl '- % -''even page title'
gives facing pages different titles and page numbers on the
outside edge when used inside an appropriate new page macro.
which tell you whether the formatter is
Finally, string comparisons may be made in an
^if 'string1'string2' stuff
The character separating the strings can be anything
not contained in either string.
The strings themselves can reference strings with