the referenced fields of an expression
Avoids some cases where use of various expression functions which
normally trigger all attributes to be requested, yet can be pre-computed
during prepare stages, cause non-provider fields to be listed in
the referenced columns and accordingly prevent expression compilation.
Notably this can occur when using an expression like:
aggregate( .... , filter:=
"some_child_field"=attribute(@atlas_feature, 'some_atlas_field_name') )
where the whole attribute(@atlas_feature....) part is a constant
static value and can be compiled down to a trivial, index-friendly
"some_child_field"=### filter for the aggregate provider request.
Ultimately giving a big performance boost to the atlas!
"field=value" type expression, and for condensing a list of similar
expressions to an equivalent "field IN (value, value2,...)" expression
wherever possible
For the c++ api dox this expands to "\c nullptr" (the
\c directive indicates a code literal value), and for sipify/Python
it expands to ``None`` (`` is sphinx annotation for literal values)
Makes for nicer dox for both c++ and Python!
All your uses of toUtf8().data() actually just need a const char*
So use constData() that is semantically more correct, and documented
to be faster.
From http://doc.qt.io/qt-5/qbytearray.html#data
"For read-only access, constData() is faster because it never
causes a deep copy to occur."
Checks whether a function declaration has parameters that are
top level const.
const values in declarations do not affect the signature of a
function, so they should not be put there.
- nodes() return the list of all nodes
- findNodes<T> returns a list of the nodes matching the class
Also drops the regexp for finding form attrs in the value-relation
expressions.
Other minor fixes as suggested in the PR review.
