I've recently developed a hierarchical associative array (http://doc.hammurapi.com/dokuwiki/doku.php?id=products:common:concurrent:property_set) to serve as a data backbone in a flow execution engine. It's not anything groundbreaking, just a collection class which can be handy is some situations.
This class has the following features which can be interesting for the community:
- Lazy, asynchronous and delayed computation of values.
- Data (objects) and behavior (invocation) entries.
- Concurrency through read/write lock.
- Data type conversion.
- Forward-only change propagation, copy-on-access.
- Hierarchical structure, mounting, sub-setting.
Best regards, Pavel.