Macro typst_func 

macro_rules! typst_func {
    (
        // The literal function name from the Typst scope,
        // usually from the source file.
        $str_name:literal,
        // Attributes.
        $( #[$attr:meta] )*
        $vis:vis struct $struct_name:ident
        // Lifetimes and generics.
        $(< $( $generic:tt $( : $bound:tt $(+ $_bound:tt )* )? ),+ >)? {}$(,)?
        // Positional args
        $(
            positional_args {
                // Optional positional args.
                $(
                    $( #[$positional_attr:meta] )*
                    $positional_vis:vis $positional_arg:ident: $positional_type:ty
                ),*$(,)?
            }$(,)?
        )?
        // Named args.
        $(
            named_args {
                $(
                    $( #[$named_attr:meta] )*
                    $named_vis:vis $named_arg:ident: $named_type:ty
                ),*$(,)?
            }$(,)?
        )?
    ) => { ... };
}

Helper macro for creating Typst function struct with TypstFunc trait implementation.

Example

use bevy::prelude::*;
use velyst::prelude::*;

typst_func!(
    // The literal function name from the Typst scope,
    // usually from the source file.
    "button",
    /// A button function from Typst.
    #[derive(Component, Reflect)]
    #[reflect(Component)]
    struct ButtonFunc<T: TypstValue> {},
    // Positional arguments, order matters here!
    positional_args {
        /// Label size.
        size: f64,
        custom_data: T,
        /// Button label.
        #[reflect(ignore)]
        label: String,
    },
    // Named arguments, order doesn't really matters here.
    named_args {
        icon_index: u32,
        #[reflect(ignore)]
        icon_label: String,
    },
);

Arguments can be also omitted if there aren’t any:

use velyst::typst_func;
typst_func!("empty", struct EmptyFunc {});