[development] Retrieving form values during intial form rendering

[Syscrusher]

I'm really stumped with what I thought would be a simple thing, and I'm finally
asking for some help. This is in Drupal 5.

I have a form that is *not* node-related, that needs to be able to do the
equivalent of a preview, in that it needs to be rendered with its default
values being the fields from its previous submission. Sounds simple, right?

Here's what's happening, though: My form gets built fine during HTTP GET, with
#default_value being set appropriately. The user submits the form, and $_POST
gets the right data. That data is passed to hook_form_validate() and then
to hook_form_submit(). So far, so good.

But when I get to hook_form(), the $_POST is no longer set, because of the
drupal_goto() that results from hook_form_submit(). So I wondered, "Where does
my data get stored?" Apparently, I wondered this like everyone else, because
the Forms API handbook page says:

  "The practical upshot to this is that many developers immediately find
   themselves asking the question of "where does my data get stored?".
   The answer is simply that it doesn't. You put your $form data together,
   perhaps loading your object from the database and filling in
   #default_values, the form builder then checks this against what
   was posted."

Loading from the database isn't an option, because these happen to be search
parameters that aren't stored in the database. Most of the extant Drupal code
I looked at for an example doesn't apply to my situation, because they all
use $node->foo to store their data. My module is managing an app-specific
table that isn't connected with nodes in any way, and the particular form in
question is a query rather than data entry, so I don't have a table where I
can put the data.

Now, I think I can probably solve this using $_SESSION, but that seems so...
inelegant. I've got to believe someone has solved this before, and that there
is a "Drupally-correct" standard way to do what I need to do, which is simply
to have a form that defaults to its previous values each time it's rendered
after a POST operation (but not a GET).

Can anyone tell me what I'm overlooking, or point me toward one of your own
modules that does this that would serve as an example?

Many thanks.

Scott

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