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CHAIN COMMAND
o.
1 -
Use
the
sy~tem
console
input
~e~ue~ts
so
that
input can be
supplied from the intermediate
file.
Each
time
an
input
request
is
made
by
a command that is invoked
by
the CHAIN
process, the next line from the
intermediate
file
will
be
read
and
passed
to
the command.
As far as the command is
conce~ned,
it is receiving its
input
information
from
the
operator at
the
console.
The
CHAIN. command only intercepts console input via the
MOOS stlstem function
I t .
KEVIN" (see section 25. 2L
The~e.pore,
only
programs
(commands
or user-written programs) that use
this system
function
will
receive
their
input
Trom
the
intermediate
file.
Programs
which contain their own input
routines, or which use the device independent
lID
functions
(see
section
25.3)
can be invoked by the CHAIN process,
but
tne
subsequent input
to
those
programs
must
be
supplied
manuall~
via the console.
Tbe
CHAIN command cannot be invoked from within a CHAIN
process unless
it
is
invoked
from
the
last
line
of
the
intermediate
file.
An
er~or
message will be displayed
if
oth-er t1Jpes oT CHAIN command recursion are attempted.
The CHAIN command.will continue
to
supply
information
from
the
intermediate
file
until
the
end
of the File is
encounte-red.
If, at that point,
the next input i'-equest
from
the
console
is
bq
the
MDOS·
command interpreter, the
CHAIN
process will be properly terminated ..
MDOS
~ill
be re-entered,
"
and
commands will again be accepted
f~om
the operator at the
console.
I:r,
however,
the
end of the
intermediate
file
is
encountered while
a
program
is re~uesting
console input,
t'en
the CHAIN p-rocess is aborted, an error message is
displayedl
and
the
cur-rently
active program will be
s~opped.
Control
will then be given to
the MDOS
command interpreter.
The diskette in drive zero must
remain
in
throughout
the
execution
of
the CHAIN process,
ReF"
file is compiled from drives other than zero.
drive
zero
even
i:r
the
6.2
Tag
DeTinition, Assignment,
and Substitution
The
CHAIN
arguments
that
command
follow
line
can
be
parameterized
the
CHAIN file specification.
argument has the
rollo~ing
format:
<tag:>Ch<value:>;'J
with
Each
~here
<tag:> is the name
b~
which the argument
is
reTerenced
within
the
CHAIN file, and <value:> is the value assigned to
that argument.
As many
ar9ument~
as fit on the command
line
can
be
specified.
Multiple arguments must be separated
by
commas.
Tags may be from one
to
thirty-two
characters
in
length
and
can contain any displayable character except the
Page
\
\
"~
06-02
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