Motorola EXORdisk II User Manual page 83

CHAIN COMMAND 6.2 -- Tag Definition, Assignment, and Substitution
per i
0
d (.), the comma (,), the spa c e ( )
lOT"
the per
c
en
t
s
i g
n
(%).
A
tag's value can be any series of displayable
chaT"acters with the exception of the percent sign. A tag is
given a value
b~
following the tag's name
~ith
the value
enclosed in percent signs.
IT
no percent sign follows a
tag's name, it is assigned a null value. FaT' example, the
command line
CHAIN TFILE;LIST!DAY%17%!TIME%02:30%
defines three tags: LIST, DAY and TIME. The tag LIST is
assigned a null valuei the tag
DAY
is given the value
17;
the
tag
TIME
is given the value
02:30.
CHAIN allows
t~o
uses to be made of tags.
First, tests
can
be performed within the CHAIN file to determine
whetheT"
or not
a
specific tag has been specified on the CHAIN command
line. Second, the value of a tag can be substituted for a
tag's occurrence within the
CHAIN
file. Thus, using the
above example, the
CHAIN file could contain a test ror the
presence of the tag LIST to determine
if
the
CHAIN
process
will produce output to
a printer.
The values of the tags DAY
and
TIME
could be substituted in one Gf the heading lines
that may be produced by the CHAIN process.
So
rar
in the discussion, the value
or
a tag has not
been used. The existence of a tag can be tested regardless
of a tag's
~alue.
A
iag's value is substituted ror each
occurrence or·th.e tag's name contained between two delimiting
percent signs. The following example will illustrate tag
substitution. I~ a
CHAIN .pile contains these statements:
RASM
TESTPROGiH7.0PTIONi.
PROGRAM ASSEMBLED ON
Y.DATE%
EXBIN TESTPROGi.STARrl.
then the tags OPTION,
respective values put
delimiting peT"cent signs
intermediate file. If
CHAIN at its invocation,
would be compiled:
DATE, and START will have their
in place
Or
their tag names and the
before each line is written into the
no tags were specified for the above
then the following inteT"mediate file
RASM TESTPROGiH
PROGRAM ASSEMBLED ON
EXBIN
TESTPROG
If the
tags were given initiai values via the CHAIN command
1 ine as:
OPTIONi.XLGi.,DATEI.JANUARY 8,
1978i.,STARTl.i 10007.
then the following intermediate rile would be compiled:
Page '06-03