> 2018/10/02 4:48、Kirk Brooks via 4D_Tech <[email protected]>のメール:
>
> Just to be clear about what you're saying here - let's say I populate a
> large object, $bigObj, with some complex data. I might create a handle to a
> collection within it as you describe:
>
> $myCol:=$bigObj.a.b.c[2].someRef
in this example, it is not clear whether someRef is an object, collection, or a
scaler value,
so let's focus on its parent c which is obviously a collection.
> $c:=$bigObj.a.b.c
$c would be a direct reference of the collection,
so $c[2] would point directly to the 3rd element of this collection which is a
sub-sub property of $bigObj.
suppose we do something like
$o:=New object("foo";"bar")
$c.push($o)
we add $o to this collection ($bigObj.a.b.c) without touching its root object.
not only that, we can directly modify a property of this object even after it
has been joined to another object or collection.
$o.foo:="not bar"
changes the value of $bigObj.a.b.c[3].foo
> This makes it easy to, say, iterate through each element. Beyond
> convenience are you saying this is more efficient than using the full dot
> notation?
it depends on how frequently you force 4D to evaluate dot notation.
for example.
> For each($e;$myCol)
>
> End for each
as opposed to
> For each($e;$myObj.a.b.c)
>
> End for each
is not that different, because $myObj.a.b.c is only evaluated once.
same with
> Use ($myObj.a.b.c)
>
> End use
but if you know you are going to use the same sub-sub-sub object or collection
multiple times,
it makes no sense to have 4D re-evaluate the same static dot notation path over
and over again.
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