Sealing and freezing

Note

New with version 0.1.8

While easytree makes it easy to create deeply-nested trees, it can also make it error prone when reading back properties. Sealing and freezing allow to protect trees by restricting some or all mutations to a tree.

	default	sealed	frozen
read an existing node	✅	✅	✅
create a new node	✅	❌	❌
edit a node	✅	✅	❌
delete a node	✅	❌	❌

Sealing

Sealing a tree prevents the user from accidentally creating new nodes; it does allow to edit leaf values.

>>> person = easytree.dict({"name":"Bob", "address":{"city":"New York"}}, sealed=True)
>>> person.name = "Alice" # you can still edit leaf values
>>> person.adress.city    # typo spelling address
AttributeError: sealed node has no attribute 'adress'

You can seal and unseal a tree with the dedicated root-level functions. These functions return a new tree (i.e. these functions are not in-place).

Freezing

Freezing a tree prevents the user from accidentally creating new nodes or changing existing nodes.

>>> person = easytree.dict({"name":"Bob", "address":{"city":"New York"}}, frozen=True)
>>> person.address.city = "Los Angeles"
AttributeError: cannot set attribute 'city' on frozen node

You can freeze and unfreeze a tree with the dedicated root-level functions. These functions return a new tree (i.e. these functions are not in-place).