Re: Generator "Cleanup" Question

Cp200205@[EMAIL PROTECTED]
 wrote:
>> The fetching of the result sequence is not really a logical
>> part of the generation of events from the result sequence,
>> hence combining that (and the free of the result sequence)
>> into a single procedure may not be the way to go.
> 
> I thought it work kind of well:
> 
> every person := dbi_conn_find(conn, "SELECT * FROM people") do
>     displayPerson(person)
> 
> That prevented me from having to deal with having a var for storing the
> result, doing the actual query, and freeing the query when I was done
> with it.

Oh, I know, that is attractive.  And you can still write dbi_conn_find()
that way for the situation where you want all results displayed.  Or,
write
a procedure that applies displayPerson to every result:

    applyToRes(conn, "SELECT * FROM people", displayPerson)

    procedure applyToRes(conn, sql, func)
        res := dbi_conn_query(conn, sql)
        every func(dbi_result_fetch_next_table(res))
        dbi_result_free(res)
    end

which has the same drawback as the original [only works 'right' when
you want all of them displayed].  *But* consider the following version:

    procedure applyToRes(conn, sql, func, limit)
       res := dbi_conn_query(conn, sql)
       if \limit then
           every func(dbi_result_fetch_next_table(res))\limit
       else
           every func(dbi_result_fetch_next_table(res))
       dbi_result_free(res)
    end

so, if you want only the first result:

    applyToRes(conn, "SELECT * FROM people", displayPerson, 1)

Of course, once you allow this, then you could more efficiently write:

    procedure applyToRes(conn, sql, func, limit)
        if \limit then sql ||:= " LIMIT "||limit
        res := dbi_conn_query(conn, sql)
        every func(dbi_result_fetch_next_table(res))
        dbi_result_free(res)
    end

> However, I see now that's not possible, so I'll just omit the function
> and use:
> 
> res := dbi_conn_query(conn, "SELECT * FROM people")
> every person := dbi_result_fetch_next_table(res) do
>   displayPerson(person)
> dbi_result_free(res)
> 
> Add's two more lines and a declared var, no huge deal, just though the
> other was rather nice.

You can also write:

  res := dbi_conn_query(conn, "SELECT * FROM people")
  every displayPerson(dbi_result_fetch_next_table(res))
  dbi_result_free(res)

which gets rid of one variable (just a different one than before).

And, if you're feeling perverse, consider:

   res := dbi_conn_query(conn, "SELECT * FROM people")
   every displayPerson(
           (dbi_result_fetch_next_table|dbi_result_free)(res))

which works if dbi_result_free() always fails.  Not
that I'd wish that on any sane human, mind you...

-- 
Steve Wampler -- swampler@[EMAIL PROTECTED]
 gods that smiled on your birth are now laughing out loud.