Macro register_templates

macro_rules! register_templates {
    {
        $(
            extra = { $( $extra_template:expr ),* $(,)? };
        )?

        $(
            // Match any attribute on the function, such as #[doc], #[allow(dead_code)], etc.
            $( #[ $attr:meta ] )*
            // The function name
            pub fn $name:ident
                // Optional list of generics. Taken from
                // https://newbedev.com/rust-macro-accepting-type-with-generic-parameters
                $(< $( $lt:tt $( : $clt:tt $(+ $dlt:tt )* )? ),+ >)?
                // Type of context taken by the template
                ( $param:ty )
            {
                // The name of the template file
                $template:expr
            }
        )*
    } => { ... };
}

Macro that helps generating helper function that renders a specific template with a strongly-typed context. It also register the template in a static array to help detecting missing templates at startup time.

The syntax looks almost like a function to confuse syntax highlighter as little as possible.