Memory game tutorial, 'Polishing the Tile': Where is the value of open_curtain coming from?

[runiq]

I'm going through the tutorial and I kind of got stuck on the Polishing the Tile chapter. In it, there's the Boolean open_curtain property which appears to default to false, but nowhere in the code is it explicitly set to false. I've tried looking through the Slint docs for 'default values' or 'default property values', to no avail. Can someone explain where the default value of false for open_curtain is coming from?

[ogoffart]

When a property is not set, it is initialized to the default value of the type, which for book, is false.

It's true that the docs don't say that, we should fix that.

[runiq]

Thanks, that clears it up. :) Is this the place where Default is derived for the Boolean value type in Slint?

[ogoffart]

Well, not really. bool implements Default in rust, and the property of type bool will ceate a Property whose default value will be the one of the Default trait.

There are other places where we determine what's the default value, for example in

slint/internal/compiler/expression_tree.rs

Line 1211 in 718e4df

pub fn default_value_for_type(ty: &Type) -> Expression {

[runiq]

Ah, thanks! Looks like it's this one:

slint/internal/compiler/expression_tree.rs

Line 1237 in 718e4df

Type::Bool => Expression::BoolLiteral(false),

[ogoffart]

I added some docs in #2993