Error Analysis Phase
Restart
Procedure
Final
Program
Summary
After
an
error has
been
deteced
in a statement,
and
the
appropriate
error
code
has
been
typed,
the
original error
statement
is
typed.
If
switch 3
is
off,
the
car-
riage
is
returned
and
the
program
halts to
wait
for a
corrected
statement
to
be
typed
in. After reviewing
the
erroneous
statement
and
the
error
code
or codes
indicated,
you
can,
in
most
cases,
make
an
immediate
correction to
the
statement.
Type
the
correct
statement
(followed
by
a
record
mark),
then
press
the
release
and.
start
keys.
The
program
resumes
by
analyzing
the
statement
just
typed
to
determine
if
any
errors still exist.
If
the
statement
is correct,
the
program
will
begin
analyzing
the
next
statement
in
the
FORTRAN
program.
In
some cases,
it
may
not
be
possible to re-enter a
corrected
statement
with-
out
certain modifications
because
part
of
the
statement
has
already
been
proc-
essed as a correct statement.
For
example,
if
an
error is discovered
in
a transfer
statement
(GO
TO),
you
must
enter
the
correct
statement
with
a
statement
num-
ber
to avoid error
STNO
4,
or
enter
it
twice
without
a
statement
number.
(The
program
considers
the
first
part
of
the
GO
TO
to
be
correct,
and
requires
that
any
statement
following a transfer
statement
must
contain a
statement
number).
When
a
statement
containing a
statement
number
is partially processed
due
to
an
error, you
cannot
re-enter
the
statement
with
the
statement
number
be-
cause an error
STNO
2 will result.
In
an erroneous
DIMENSION
statement, for example
DIMENSION
C ( N ),
the
C
is
stored as a
nonsubscripted
variable
and
cannot
be
used
later
in
the
program
as a
subscripted
variable.
In
case of
C(
10,N),
the
C is
stored
as a one-di-
mensioned variable.
Restart
of
the
Pre-Compiler is necessary.
For
expressions involving involution
(raising
to a
power),
the
exponent
cannot
have
an
involution operation.
For
example, A * *
(B
* *
2.
+.1)
will result
in
erroneous operation
of
the
Pre-Compiler. This restriction also applies to
the
arithmetic expression
in
an
IF
statement.
There
is
no
check
for
the
termination
of
a
DO
loop.
If
a dimension specifica-
tion exceeds
the
capacity of
the
storage, erroneous results will follow.
If
an
immediate
correction
cannot
be
made,
you
can
resume
testing
of
the
next
statement
by
manually
branching
to
BEGIN
(see
RESTART
PROCEDURES).
It
is
important
to
note
that
if
a
new
source
program
is
being
punched,
by-
passing
the
error correction routine will result in
the
incorrect
statement
being
punched
into
the
output
tape
or cards.
The
normal operation of
the
Pre-Compiler
program
is to
type
incorrect
statements only.
If
you
require
a
typed
copy
of
all statements,
turn
on
program
switch
1.
You
may
find
it
necessary
during
processing to
interrupt
the
normal
operation
of
the
program.
To
allow such interruptions,
the
following re-entry points, given
by
symbolic
label
and
storage location, are available:
CLEAR
location 01208:
The
symbol
table
and
table
of
statement
numbers
referenced
by
DO statements are cleared.
CLEAR
is
the
restart
point
for a
new
program
to
be
tested.
INITL
location 01340:
The
table
of
statement
numbers
referenced
by
DO statements is cleared.
BEGIN
location 01472: No tables
are
cleared,
but
the
program
will con-
tinue to
read
source
program
statements.
BEGIN
is
the
normal
entry
point
for
restarting
after
a check stop
or
other
interruptions
of
the
Pre-Compiler.
After
the
END
statement
in
a source
program
has
been
processed
by
the
Pre-
Compiler program, a final
program
summary
is
typed
on
the
console typewriter.
The
FORTRAN
Pre-Compiler Program 75
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