Lib.rs

Enhanced Fieldless Enumerations and Associated Array Types

In Rust, enumerations can contain data fields which is a powerful language feature. However not all enums have data fields. Fieldless enums are simply a list of variants. This crate provides many features for fieldless enums which are difficult or impossible to provide for enums with data fields.

This crate contains a single item: the enhanced_enum! macro which generates an enum.

enhanced_enum::enhanced_enum!(YourEnum { A, B, C });

Translates to:

pub enum YourEnum {
A,
B,
C
}

impl YourEnum {
...
}

/// Custom wrapper around an array of length `YourEnum::len()`.
/// This array can only be indexed by `YourEnum`.
pub struct YourEnumArray<T> {
...
}

Features

• Enhanced enums implement many common traits:

• Debug, Display,
• Copy, Clone,
• PartialEq, Eq, PartialOrd, Ord,
• Hash

• Iterate through all variants of your enhanced enum with YourEnum::iter().

• Count the number of variants with YourEnum::count() or YourEnum::len().

• Make an array which can only be indexed by your enum. The enhanced_enum! macro generates a wrapper around a standard array, and this custom array type implements a very similar API to a standard array. The name of the new array type is the enum name with the word "Array" appended.

• Convert between integers, strings, and enhanced enums.

• YourEnum::try_from(usize) Also works with u32 and 64.
• YourEnum::try_from(&str) Note that the string must exactly match a variant name, or else this returns an error.
• your_enum as usize.
• your_enum.to_string() -> String
• your_enum.to_str() -> &'static str

• Interface with Python via the pyo3 library. Currently this only implements a converting from python strings to rust. This is optionally compiled. To opt-in: build the enhanced_enum crate using the feature flag "pyo3".

Examples

A histogram for counting DNA nucleotides. This re-implements the example from the documentation for the Trait std::ops::Index.

enhanced_enum::enhanced_enum!(Nucleotide {
A,
C,
G,
T,
});

let nucleotide_count = NucleotideArray::<usize>::new_with(|x| match x {
Nucleotide::A => 14,
Nucleotide::C => 9,
Nucleotide::G => 10,
Nucleotide::T => 12
});
assert_eq!(nucleotide_count[Nucleotide::A], 14);
assert_eq!(nucleotide_count[Nucleotide::C], 9);
assert_eq!(nucleotide_count[Nucleotide::G], 10);
assert_eq!(nucleotide_count[Nucleotide::T], 12);