[boost] [Containers] Should flat_* expose implementation vector?

Subject: [boost] [Containers] Should flat_* expose implementation vector?
From: Phil Endecott (spam_from_boost_dev_at_[hidden])
Date: 2011-08-05 20:32:29

Dear All,

Should Ion's proposed flat_set, flat_map etc. expose the underlying 
vector that they use as their implementation?

Pros: it lets the user efficiently load and save the content, and 
implement algorithms that cannot be done via the flat_* interface.

Cons: it lets the user break the invariants.

Const access to the impl is another possibility.

Related to that: could the implementation type be a template 
parameter?  Example: could one implement a flat_set on top of a 
stable_vector?  (Is that useful?)  And/or: should flat_* actually be 
adaptors that take a reference to their underlying implementation?

Regards,  Phil.