Crate enum_group

Enum Group

enum-group is a simple derive macro crate that helps enum types to group their variants. Annotate an enum with #[derive(EnumGroup)], and mark variants some group label names with #[groups(label1, label2)] will auto generate function is_label1 and is_label2. These functions will tell you if a variant of the enum belongs to this grouping.

Example

use enum_group::EnumGroup;

#[derive(EnumGroup)]
enum Number {
    #[groups(odd)]
    One,

    #[groups(even, prime)]
    Two,

    #[groups(odd, prime)]
    Three,

    Unknown(usize)
}

// will auto generate function `fn is_odd(&self) -> bool`
assert!(Number::One.is_odd());
assert!(!Number::Two.is_odd());
assert!(Number::Three.is_odd());
assert!(!Number::Unknown(0).is_odd());

// will auto generate function `fn is_even(&self) -> bool`
assert!(!Number::One.is_even());
assert!(Number::Two.is_even());
assert!(!Number::Three.is_even());
assert!(!Number::Unknown(0).is_even());

// will auto generate function `fn is_prime(&self) -> bool`
assert!(!Number::One.is_prime());
assert!(Number::Two.is_prime());
assert!(Number::Three.is_prime());
assert!(!Number::Unknown(0).is_prime());

Usage Restrictions

Each character of the group label name for each variant must be alphanumeric or _.

Panic

use enum_group::EnumGroup;

#[derive(EnumGroup)]
enum Number {
    // #[groups(odd_&)] groups attribute ident can only contain the characters a-zA-Z0-9_
    // #[groups(_odd)] groups attribute ident must starts wtih characters a-zA-Z
    // #[groups(odd_)] groups attribute ident must ends wtih characters a-zA-Z
    // #[groups()] must have group ident in groups attribute
    One,
}

Derive Macros

EnumGroup