Nullable type used for attribute value could omit the attribute if value.isNull

[schveiguy]

I currently have some types that have nullable values that come from a database.

Let's say it's an id that's either null or not.

Nullable!int othertable_id;

If I want to display an editor to this id, I can do this in diet:

input(type='number', value=othertable_id)

The resulting html code shows value="Nullable.null", which works OK for this integer, but is a bit messy (and technically be interpreted as text in some browsers).

Because there isn't a type that evaluates to false or some value, it's hard to do this in one statement. For example:

input(type='number', value=(othertable_id.isNull ? false : othtertable_id)) // error

However, a nice addition to diet would be to treat a Nullable value that is null as a "false" in terms of erasing the attribute. I don't think this should impact existing code, since you likely have to sanitize something like this with if statements.

I think this can come in handy in a lot of places, since html has many spots where the absence of an attribute means something different than the presence.