Null handling in Rhai

[Goffen]

Hi there! Thanks for an excellent crate!

I have a question regarding nulls in Rhai:

Is it supported? How do i use it?

I want my users to be able to check for null/None/nil or whatever the notion is. Some values that i feed them are missing and I want the option for them to also return null/missing.

I've read somewhere that Option gets set to null in Rhai if it's None. But if i print the value as a string it say tyhe type of it is "core::option::Option" which seems correct I guess? But I cant use that type in an if-statement.

When i try some statements with null in Rhai playground i get an error on simple let q = null; saying null is reserved.

[Goffen]

I've found one thing that i can almost work with: the unit-type.

If i feed the scope with unit type the user (creating the expression) can then use the ?? to use a default value. But its very limited

[schungx]

Well, () takes the place of nulls in Rhai.

If you want to push an Optiom to the scope, you can try unwrap,_or(Dy namic::UNIT).

Using the unit type to indicate missing or unavailable information is idiomatic. Many standard library functions do so.

[Goffen]

Oki!

Is there any easy way to check if the variable is of unit-type?

In ideal world for me users could use if var { ... do stuff } else { .. nope its unit-type }

But I guess i would need type_of(var) == '()' ?

[schungx]

Just if x == ()

In ideal world for me users could use if var { ... do stuff } else { .. nope its unit-type }

This is JavaScript and its weird truthy/falsy values. Extremely confusing to novice users so I'd suggest not.

[Goffen]

Ah! Ok thank you!