Re: [boost] [property tree][review]

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