Structure of the accepted tokens

The tokens accepted by the statue::initialize_elements macro can be seen as an object with the following fields:

• html (mandatory) - a string literal representing the path to the HTML file, relative to the CARGO_MANIFEST_DIR.
• elements (mandatory) - a sequence of tokens resembling a block expression.
• opts (optional) - a sequence of tokens resembling an object.

For example:

#![allow(unused)]
fn main() {
initialize_elements!(
    html: "index.html",
    elements: {
        let work_area = Single("#work-area");
        let layer_list_div = Single("#layer-list");   
        let save_files_btn = Single("#save-files", RcT);
    },
    opts: {
        window_ret_ty: Some(RcT),
        document_ret_ty: None
    }
);
}

For ease of parsing,

• all of the fields must appear in the same order as shown above. The html field must be the first one, the elements field must be the second one, and the opts field, if present, must be the last one.
• trailing commas are not allowed.