{id_?} criterion allows all possible joins to be made with environment variables. It therefore behaves as many criteria {id_xxx ?} as possible for the given loop.
For example the loop <BOUCLE_liste(ARTICLES){id_?}>... will be understood as <BOUCLE_liste(ARTICLES){id_article?}{id_rubrique?}{id_secteur?}{id_trad?}{id_mot?}{id_document?}>..., varying according to the possible links, and therefore according to the active plugins. The syntax is therefore much more concise.
For a loop on a given table, the links created take into account:
- the link table if it exists (for example spip_mots_liens for spip_mots)
- objets,id_objet fields otherwise (for example for spip_forum).
Keys objet,id_objet
On a table with the fields objet and id_objet (as spip_forum), both the {objet?} criterion and the {id_objet?} criterion will be applied.
Installing and uninstalling plugins
{id_?} criterion allows to write identical loops whatever the active plugins. Indeed, some plugins create tables and allow additional conditional joins on these tables, but if we integrate these joins in a loop using the identifier of this table {id_table?}, uninstalling this plugin will cause a compilation error. With {id_?} criterion, the joins are done automatically and without error whatever the plugins are, installed or not.
See also
- criterion ?
- The syntax of SPIP’s loops <BOUCLE_cond(ATABLE?)>