Change the semantics of Required
Summary: This is a redesign, based on a suggestion from Alexx.
The core concept here is that I should be able to define a "Required" Property that has no default value in the Model. When I create/edit an Instance, that Instance should be visibly "invalid" until I fill in a value.
This is really a small Epic; here's the outline.
- Make sure there is a way to check
isUsingDefault on a Required value.
- Add a new
Requires Instance Value flag Property.
- In the Model Designer, add a new checkbox to each Required Property, labeled something like "No default -- Instances must fill this in", hooked into
Requires Instance Value.
- Add an "isFullyValid" method on Thing, which checks whether all of its values are Valid. Iff an Instance Property has
Requires Instance Value and it isUsingDefault, then it is considered invalid, and marks the Thing as invalid.
- Enhance ThingInfo to carry the isFullyValid flag to the client.
- When looking at a Thing, iff it is not fully valid and I can edit it, the Edit button should turn red, and probably have "!" appended, to indicate that this Thing needs editing.
- In the Instance and Advanced Editors, if a Property value is not valid, it should show up initially as an error, the same way it is if I give an invalid value.
- These same errors should highlight any Required fields that need to be filled in when I initially create the Thing.
