ADD2QDIR

Think about where Internet Basic has been. New let's think about where it could go.
I remember when we all coded:

READ(1,000) KEY="" EXCP=FUGETABOUTIT
FUGETABOUTIT:

The FILE statement makes it much easier and cleaner to code:
FILE (0) POS=BOF. No meaningless EXCP or pointless statement label is necessary.

Getting to the beginning of the file is really a special case. The more general statement is:

READ(OrdDet,0000) KEY=Ornbr$ EXCP=FUGETABOUTIT
FUGETABOUTIT:

The Exception is meaningless because the Order Detail file is keyed by Order Number and Line Number and the READ can never (should never?) succeed.

The POSITION statement makes this construction unnecessary.

POSITION (OrdDet) KEY = Ornbr$

I never code an EXCP on a POSITION statement even though the documentation shows one. The documentation does not specify what conditions could trigger a exception; the only one I can think of is File Not Open and I would want that to cause a crash.

The CLEARFILE statement comes close to addressing the complications of:

ERASE "FILENAME" EXCP=NEXTLINE
NEXTLINE:
CREATE "FILENAME" .....
OPEN (1) "FILENAME"

Sadly the CLEARFILE statement has its own limitations. Recently we learned that CLEARFILE, which does not include an EXCP argument, is oblivious to file contention. If the file being cleared is open by another user, Comet will chop that user off and clear the file. Signature recommends LOCKing the file before clearing it.

Recently I found myself doing a lot of work with files imported into Comet from Windows applications. Internet Basic has a way to add a file to a Comet QDIR from inside an application program, but the method is awkward and results in spaghetti code.

OPEN (1) "FOREIGN" EXCP=OPNERR
. process data here
..
..
OPNERR: !Open fails on file being imported
CREATE "FOREIGN",T,DIR="XXX",EXCP=CRERR
CRERR: !Create error
If EXCP=13 !Ah ha, the file exists
Goto ... !Now it's in the QDIR
Endif

You might be tempted, I was, to code an AGAIN statement to get back to the OPEN. After all that's where all the stuff started. That wont work because it was the CREATE that trip the Exception that triggered the pseudo-create. Sadly you need a label that is almost as useless as the statement labels we used to code for POSITIONs and still do for ERASE/CREATE pairs.

I want an ADD2QDIR that needs no EXCP. Then I can OPEN foreign files without jumping all over the place.