Function resolve 

pub fn resolve(
    text: &str,
    slots: &[InterpolationSlot],
    scope: &Scope<'_>,
) -> String

Replace every {...} token in text with what its scope holds.

slots is the placeholder catalog the parser recorded on the element the string came from, which is what tells a fragment parameter apart from a global signal of the same name.

The rules:

• InterpolationSlot::Row - the iteration record’s field. A field the record does not have resolves empty and is reported through Scope::missing_row_field. With no row scope the placeholder is left standing for the <for> walk that has one.
• InterpolationSlot::RowIndex - the iteration index, or left standing outside a row scope.
• InterpolationSlot::Arg - the instantiating argument, else empty. A Global naming a declared parameter resolves the same way, which is how an argument shadows a global signal of that name.
• InterpolationSlot::Global - the global signal, or the iteration record’s field of that name when no signal is set, which is what makes the bare {field} spelling work inside a <for> body.
• InterpolationSlot::SelfField / InterpolationSlot::ParentField - empty. Per-entity properties have no consumer yet.