RE: A Modest Proposal

["Doug Olson" <dlolson@lbl.gov>]

I vote in favor of Dave's proposal. -- Doug

> -----Original Message-----
> From: David M. Malon [mailto:malon@anl.gov]
> Sent: Wednesday, June 10, 1998 9:27 AM
> To: challenge@sseos.lbl.gov
> Cc: malon@anl.gov
> Subject: A Modest Proposal
>
>
> I'm in the middle of tracking down a bug in which the Query
> Object - Query
> Estimator duo throw an exception when PercentComplete() is
> invoked--someone
> thinks the query state has become invalid before the iterator has
> received
> all the data.  That's not what I'm writing about, but it motivates this
> note.
>
> -> I propose that accessor functions like PercentComplete, and
> even things
> -> like minNumEvents, should NOT throw exceptions.
>
>    They should instead return "innocuous" values, and we should
> document our
>    way out of any inconsistencies.  I realize that one could make an
>    argument for notifying the user that her query doesn't exist, rather
>    than telling her that it's 0% complete, but if we force a user to wrap
>    every effort to retrieve an integer from our components in
> try/catch blocks,
>    and kill her code whenever anything goes even slightly awry if
> she fails to
>    do so, we will win no fans (...and I want people to LIKE us; well, me,
>    anyway).
>
>    Consider the single line
>
>  cout<<"iterator returned "<<OOI.numFiles()<<" and
> "<<OOI.numRefs()<<" refs.";
>
>    Do we want to require that the user write:
>
> ************************************************
>
>    int nFiles = 0;
>    int nRefs = 0;
>    cout<<"iterator returned ";
>    try {
>     nFiles = OOI.numFiles();
>    }
>    catch(...) {
> //   "Switch" block to set nFiles or terminate cleanly, depending
> upon the
> //   particular exception, should go here.
>    }
>    cout<<nFiles<<" and ";
>    try {
>     nRefs = OOI.numRefs();
>    }
>    catch(...) {
> //   "Switch" block to set nFiles or terminate cleanly, depending
> upon the
> //   particular exception, should go here.
>    }
>    cout<<nRefs<<" refs.";
>
> ************************************************
>
>    Imagine doing this every time you want to touch a datum!  No one wants
>    to code like this, and I don't believe that doing so improves software
>    quality.
>
>    I am happy to propose that users wrap query construction,
> estimation, and
>    execution in try/catch blocks, but simple accessors?
>
> What do you think?
>
> David
>
>
>