A '''deep [dict%|%dictionary]''' is a dictionary in which each each key has the
same representation it would have in a standard [dict%|%dictionary], and each
value is a [deep list]:  It is either another deep dictionary or simple
value, which is represented as a list containing only one item.  Because it is
often useful to assign multiple values to an entry, that one item is itself a
list of values.



** See Also **

   [scripted dict]:   Scripting a deep dict in a manner similar to [scripted list].



** Description **

** Implementations **

   [ycl%|%ycl dict deep]:   Provides `get`, `merge`, `pretty`, and `set`.



** Description **

Another way to define deep dictionary is as a [deep list] that represents a
[tree]:  Each value, is a branch that and may or may not have subordinate
branches.

A '''deep dictionary''' can be unambiguously merged into another deep
dictionary.

The key benefit of a deep dictionary is that the structure is self-describing:
In contrast with a standard [dict%|%dictionary], it is possible to determine
whether a value is a leaf node or an intermediate node.  A value that is a list
with more than one item is additional structure, whereas a value that is a list
with only one item does not.

Unlike a standard Tcl dictionary, a '''deep dictionary''' is suitable for
communicating an ordered tree without prior agreement between the parties about
the exact shape of the tree.


'''Example''':


======
{key 1} {{
    {value 1}
    {value 2}
}}
{key 2} {
    {key 2a} {{{value 3}}}
    {key 2b} {{
        {value 4}
        {value 5}
    }}
}
======










<<categories>> deep list