Actually, this feature is useful only
when the type of values (the type V_) is a reference type, to avoid using has just
followed by at to get the corresponding value with the very best performances.
If there is as yet no key k in the dictionary,
enter it with item v. Otherwise overwrite the item associated with key k.
As the put procedure actually uses is_equal, you may consider to use fast_put for expanded
objects as well while trying to get the very best performances.
Remove entry k (which may exist or not before this call).
As the remove procedure actually uses is_equal, you may consider to use fast_remove for expanded
objects as well while trying to get the very best performances.
Internal storage capacity of the dictionary is initialized using the
Default_size value. Then, tuning of needed storage capacity is performed automatically
according to usage. If you are really sure that your dictionary is always really bigger than
Default_size, you may consider to use with_capacity to save some execution time.
May be used to save some execution time if one is sure that storage size will rapidly become
really bigger than Default_size.
When first remove occurs, storage size may naturally become
smaller than medium_size. Afterall, tuning of storage size is done automatically according to
usage.