Forum OpenACS Q&A: ad_form skips on_submit and after_submit code

Hi everyone,
I have a problem with the following tcl code, which I am working on for a school project: it builds a form which should pass the entries to another script, but when the user submits the values it just reloads the page, in spite of the ad_returnredirect instruction (which links to an existing file). On a further inspection, I noticed that no lines from the on_submit and after_submit blocks are executed.
What I really can't understand is that everything works fine if I take out the parameter declaration from ad_page_contract and replace it with a fixed value for istruttori_id...

ad_page_contract {
Inserimento Orario Settimanale
} {
istruttori_id:integer
}

set caption [db_string query "select a.nome || ' ' || a.cognome from scg_istruttori a where a.istruttori_id = :istruttori_id"]
set prev_page "Orario di $caption"
set page_title "Pianifica l'orario settimanale"

set context [list [list index {Scuola Guida}] [list istruttori-list {Lista Istruttori}] [list orari-list?istruttori_id=$istruttori_id $prev_page] $page_title]

ad_form -name orari \
-has_edit 1 \
-form {

{max_dow:integer(select)
{options {{"Lunedì - Sabato" "6"} {"Lunedì - Venerdì" "5"} } }
{label "Giorni"}
{html {size 1}}
}

{ora1:text
{label "Ora inizio mattino"}
{html {size 7} }
}

{ora2:text
{label "Ora fine mattino"}
{html {size 7} }
}

{ora3:text
{label "Ora inizio pomeriggio"}
{html {size 7} }
}

{ora4:text
{label "Ora fine pomeriggio"}
{html {size 7} }
}

} -on_submit {

#instructions

} -after_submit {

ad_returnredirect "orari-inse-q?max_dow=$max_dow&ora1=$ora1&ora2=$ora2&ora3=$ora3&ora4=$ora4"
ad_script_abort

}

Thank you very much, it works now ;)

Re Dave's comment on proper usage, I would love to learn how to use ad_form, but the documentation I have found seems light on examples, the ad_form code seemed a bit dense to read and understand on its own, and therefore a long sit-down and read-thru and pondering seemed called for, and I have never found the time to do that. Could someone be generous enough to post a good example or two showing some significant functionality in a page that obtains and processes input? That will be a fast way to learn, and I would be very, very grateful. Or if there is documentation with examples somewhere that would also be great to learn about. Thanks!!

See for a collection of articles as well under: https://openacs.org/rubick/