From: Thorsten Ottosen (thorsten.ottosen_at_[hidden])
Date: 2006-04-24 09:47:21
John Maddock wrote:
> Let's start with child access, I can't believe you're not using operator[]
> here. Yes I know it's cute, but it does work well for std::map.
>
> How about:
>
> mymap b;
> b[a][b][c] = 2; // assigns value 2 to node at a/b/c
>
> The way I'm figuring this would work is:
>
> * Accessing a child node with operator[] always succeeds but may point to a
> "ghost" node that doesn't actually exist.
> * Assignment to a node always succeeds, the node gets created if required.
> * Reading from a node throws if the node doesn't exist yet, or if the
> conversion can't be performed.
> * If you read a Boost::optional then it shouldn't throw, and no need for a
> special member function.
>
> I'm assuming that operator [] returns another "property map" by value BTW.
Seems both expensive (unless state is shared using intrisive_ptr), and
impossible, since the returned instance would not know how to change the
original instance.
Are you sure you don't mean "by reference", perhaps overloaded on
const-ness?
-Thorsten