Currently, DumbQL has one-of expressions:

status: [todo, in_progress, done]

When such syntax is applied to numbers:

age: [18, 65]

It's expected that it will check if the value of age falls into range between 18 and 65. But it's not! So, I think we need syntax for numeric ranges. And it should be a bit different from what we have now. For example:

age: [18..65]

or maybe something like this, like in regular expressions:

age: [18-65]

or just like this:

age: 18..65