Validations must allow parametrization

[fpuga]

We will need validations to check if a value is between two numbers. Right now it's not possible to implement this.

We need rules like

between

[oandregal]

Thinking out loud here for further reference:

after a 1-minute research, I see no obvious way to create such a rule (as well as other interesting ones, ie: the UNIQUE), because those rules use values only known in executing time. The case you suggest, for example, may need to know the values of other fields in the same form, which may vary depending on the user actions. I though we could benefit from something like DomainValues, but it may be not enough as it caches the values every time a form is opened.

Plus -and not sure yet if both are related- we need to provide a way for the developer to hook their own checks into isSaveable().

[fpuga]

I agree with have the hooks.

But the user case that i'm pointed in this case is about fixed values set in the xml

[oandregal]

If the value is know and no change along the life of the app, it's easy.

In such a case, I'd bet for having 3 independent and compatible new rules (for example <EQUALS>, <MIN> and <MAX>) which allow us to implement all use cases for ranges: "x greater than y", "x greater or equals than y", "x lower than y", "x between min and max", etc. Would need assessing how that may be related to the validation of data types such as integer_positive or double_positive, which would make easier the XML parsing.

May be useful reviewing how SLD implements and concatenate rules and filters for inspiration.

[fpuga]

I agree with your approach.

I'm bit scary of reinvent the wheel as there are thousands of domain specific language over there and we are creating another one.

[oandregal]

In case it's useful: https://github.com/navtable/navtableforms/wiki/RFC01NTFormsUserDefinedDomainRules