Major new feature set: comprehensive support for events, watching, callbacks, and dependencies
- Parameterized methods can now declare `depends(p,q)` to indicate that they depend on parameters `p` and `q` (defaulting to all parameters)
- Parameterized methods can depend on subobjects with `depends(p.param,q.param.r)`, where `p.param` indicates dependencies on all parameters of `p` and `q.param.r` indicates a dependency on parameter `r` of `q`.
- Functions and methods can `watch` parameter values, re-running when those values change or when an explicit trigger is issued, and can unwatch them later if needed.
- Multiple events can be batched to trigger callbacks only once for a coordinated set of changes
Other new features:
- Added support in ObjectSelector for selecting lists and dicts (268)
- Added pandas DataFrame and Series parameter types (285)
- Added support for regular expression validation to String Parameter (241, 245)
For more details, you can see a [full list of changes since the previous release](https://github.com/ioam/param/compare/v1.8.0...v1.7.0).