Macro ecs::components

macro_rules! components {
    {
            $(#[$attr:meta])*
            struct $Name:ident;
        } => { ... };
    {
            #[builder($Builder:ident)]
            $(#[$attr:meta])*
            struct $Name:ident {
                $(#[$kind:ident] $field_name:ident : $field_ty:ty),+
            }
        } => { ... };
    {
            $(#[$attr:meta])*
            struct $Name:ident {
                $(#[$kind:ident] $field_name:ident : $field_ty:ty),+
            }
        } => { ... };
    {
            #[builder($Builder:ident)]
            $(#[$attr:meta])*
            struct $Name:ident {
                $(#[$kind:ident] $field_name:ident : $field_ty:ty),+,
            }
        } => { ... };
    {
            $(#[$attr:meta])*
            struct $Name:ident {
                $(#[$kind:ident] $field_name:ident : $field_ty:ty),+,
            }
        } => { ... };
}