[Semediawiki-user] Nested queries

[Peter R. <zoo...@gm...>]

I've just developed a technique for nesting queries I haven't seen
anywhere before, using templates to format a subquery – this example
queries pages with [[attribute::value]] set for a property called
"property" - then, assuming the value of that property is a page,
queries the resulting page for a property called "subproperty" and
returns its value.

{{#ask:
  {{#ask: [[attribute::value]]
    | ?property=
    | format=list
    | mainlabel=-
    | sep={{pipes}}
    | intro={{OpenBrackets}}
    | outro={{ClosedBrackets}}
  }}
  | ?subproperty
}}

Is this something that can be done more easily some other way? Or is
this just a hack that would ordinarily be filed under "Things that are
not possible", specifically
http://semantic-mediawiki.org/wiki/Help:Selecting_pages#Subqueries_for_properties
? I've never quite understood what case "subquery for property" was
describing, but I couldn't find a better way to do this sort of thing
using either property chains ([[attribute1.attribute2::value]] etc) or
standard sub queries ([[attribute::<q>[[attribute2::value]]</q>]] … if
it's new, would it be worth adding it to the documentation?

Cheers –
P