Crate enum_derive_2018

This crate provides several macros for deriving some useful methods for unitary enums (i.e. enums where variants do not have payloads) and unary enums.

Feature flags

• std (enabled by default) — disable to make the library #![no_std].

Using with and without macro_attr!

All of the macros are designed to be used with the macro-attr-2018 crate, though they can be used independent of it. The following:

macro_attr! {
    #[derive(Copy, Clone, Debug, IterVariants!(Vars))]
    enum ItAintRight { BabeNo, NoNo, BoyBoy }
}

can also be written as

#[derive(Copy, Clone, Debug)]
enum ItAintRight { BabeNo, NoNo, BoyBoy }

IterVariants! { (Vars) enum ItAintRight { BabeNo, NoNo, BoyBoy } }

Macros

EnumDisplay

Derives Display for an unitary enum, which outputs the name of the variant.

EnumFromInner

Derives From<T> for each variant’s payload, assuming all variants are unary.

EnumFromStr

Derives FromStr for an unitary enum. It requires an exact match of the variant name.

EnumInnerAsTrait

Derives a method for an unary enum returning a borrowed pointer to the inner value, cast to a trait object.

IterVariantNames

Derives iter_variant_names() for an unitary enum, which returns an iterator over the string names of the variants of the enum in lexical order.

IterVariants

Derives iter_variants() for an unitary enum, which returns an iterator over the variants of the enum in lexical order.

NextVariant

Derives next_variant(&self) for an unitary enum, which returns the next variant, or None when called for the last.

PrevVariant

Derives prev_variant(&self) for an unitary enum, which returns the previous variant, or None when called for the first.

Structs

ParseEnumError

The FromStr derived implementations error type.