Re: [Chicken-users] DBI

[Graham Fawcett]

On Thu, Feb 28, 2008 at 10:30 AM, Peter Bex <address@hidden> wrote:
> On Thu, Feb 28, 2008 at 10:05:58AM -0500, Graham Fawcett wrote:
>  > >  Why the thunk? (why not directly the port?)
>  >
>  > Laziness: it avoids the overhead of setting up the input port if it's
>  > not required. You might want to iterate over a set of (id, name, blob)
>  > records and only open the blob if the name meets some criteria that
>  > are local to the app (i.e. can't be expressed in a WHERE clause).
>
>  You can make a 'smart' custom port that only really opens the blob when
>  you first read from it (it has to be a custom port anyway, so this is
>  not too much extra work).  This makes for a more convenient API, IMHO.

That's true. I was going to argue that it doesn't have to be a custom
port (some interfaces may return a TCP port to consume the blob, for
example) and that I'd rather not add an extra layer. But using a
custom port would also ensure that the right cleanup code was called,
and that's a big win. The custom-port is a good solution.

G