On Mar 9, 2011, at 9:43 AM, Andrey Somov wrote:
> Hi all,
> I have found the following comment in the source (couch_db.hrl):
>
> % Tree::term() is really a tree(), but we don't want to require R13B04 yet
> -type branch() :: {Key::term(), Value::term(), Tree::term()}.
>
> Does it mean that CouchDB includes its own copy of gb_trees.erl ?
> Does it mean that CouchDB implements its own tree but the interface is
> identical to gb_trees.erl and it will be changed once R13B04 is required ?
>
>
> -
> Andrey
Hi Andrey, neither. It simply means that the third element of a branch() is of
type tree(). The reason for comment is that recursive type specifications are
not supported in Erlang/OTP releases prior to R13B04, so I fell back to calling
it a term() instead.
The tree() data structure being described is a custom data structure
implemented entirely in couch_key_tree.erl. It's used to store document
revision histories. Best,
Adam
