## Script (Python) "doFormSearch"
##parameters=REQUEST
##title=Pre-process form variables, then return catalog query results.
##
vars = REQUEST.form
form_vars = {}
skip_vars = []
select_vars = ( 'review_state'
              , 'Subject'
              , 'portal_type'
              )
date_vars = ('created',
             )
epoch = DateTime('1970/01/01 00:00:01 GMT')

for k, v in vars.items():

    if k in select_vars:
        if same_type( v, [] ):
            v = filter( None, v )
        if not v:
            continue

    if k in date_vars:
        if v == epoch and vars.get(k+'_usage') == 'range:min':
            skip_vars.append(k+'_usage')
            continue

    form_vars[ k ] = v

for k in skip_vars:
    del form_vars[k]

return context.portal_catalog( form_vars )