Macro rocket_dyn_templates::minijinja::context

macro_rules! context {
    () => { ... };
    (
        $($key:ident $(=> $value:expr)?),*
        $(, .. $ctx:expr),* $(,)?
    ) => { ... };
    (
        $(.. $ctx:expr),* $(,)?
    ) => { ... };
}

Creates a template context from keys and values or merging in another value.

let ctx = context!{
    name => "Peter",
    location => "World",
};

Alternatively if the variable name matches the key name it can be omitted:

let name = "Peter";
let ctx = context!{ name };

The return value is a Value.

Note that context! can also be used recursively if you need to create nested objects:

let ctx = context! {
    nav => vec![
        context!(path => "/", title => "Index"),
        context!(path => "/downloads", title => "Downloads"),
        context!(path => "/faq", title => "FAQ"),
    ]
};

Additionally the macro supports a second syntax that can merge other contexts or values. In that case one or more values need to be passed with a leading .. operator. This is useful to supply extra values into render in a common place. The order of precedence is left to right:

let ctx = context! { a => "A" };
let ctx = context! { ..ctx, ..context! {
    b => "B"
}};

// or

let ctx = context! {
    a => "A",
    ..context! {
        b => "B"
    }
};

The merge works with an value, not just values created by the context! macro and is performed lazy. This means it also works with dynamic StructObjects.