Derive Macro VariantDescriptors

#[derive(VariantDescriptors)]

A derive procedural macro for the VariantDescriptors trait.

This macro generates an implementation of the VariantDescriptors trait for an enum. The trait provides two methods:

1. variant_names_with_token_counts: Returns a Vec containing tuples, each with a string representation of a variant’s name and its token count.

2. variant_name_with_token_count: Takes an enum variant as input and returns a tuple with the variant’s name as a string and its token count.

Note: This macro will panic if it is used on anything other than an enum.

Usage

#[derive(VariantDescriptors)]
enum MyEnum {
    Variant1,
    Variant2,
}

This will generate the following:

impl VariantDescriptors for MyEnum {
    fn variant_names_with_token_counts() -> Vec<(String, usize)> {
        vec![
            (String::from("Variant1"), /* token count of "Variant1" */),
            (String::from("Variant2"), /* token count of "Variant2" */),
        ]
    }

    fn variant_name_with_token_count(&self) -> (String, usize) {
        match self {
            Self::Variant1 => (String::from("Variant1"), /* token count of "Variant1" */),
            Self::Variant2 => (String::from("Variant2"), /* token count of "Variant2" */),
        }
    }
}

The actual token count is computed during compile time using the calculate_token_count function.