enum_convert

A Rust procedural macro library for deriving automatic conversions between enums variants.

Features

• EnumFrom: Derive From<Source> for AnnotatedEnum
• EnumInto: Derive From<AnnotatedEnum> for Target
• Support for multiple source/target enums
• Flexible variant name mapping (one-to-many, many-to-one)
• Field-level mapping for named struct variants
• Automatic type conversion for fields via .into()

Usage

EnumFrom - Convert from source enums to annotated target enum

use enum_convert::EnumFrom;

enum Source {
    Unit,
    Tuple(i32, String),
    Struct { x: i32, y: i32 }
}

#[derive(EnumFrom)]
#[enum_from(Source)]
enum Target {
    #[enum_from]  // Maps from Source::Unit
    Unit,
    #[enum_from]  // Maps from Source::Tuple with type conversion
    Tuple(i64, String),
    #[enum_from]  // Maps from Source::Struct with type conversion
    Struct { x: f64, y: f64 },
    Extra  // This variant has no mapping
}

// Usage
let source = Source::Tuple(42, "hello".to_string());
let target: Target = source.into();

EnumInto - Convert from annotated source enum to target enums

use enum_convert::EnumInto;

#[derive(EnumInto)]
#[enum_into(Target)]
enum Source {
    Unit,  // Maps to Target::Unit
    #[enum_into(Target::Different)]  // Maps to Target::Different
    Variant(i32),
}

enum Target {
    Unit,
    Different(i64),
    Extra
}

// Usage
let source = Source::Variant(42);
let target: Target = source.into();

Advanced Features

Multiple source/target enums

#[derive(EnumFrom)]
#[enum_from(FirstSource, SecondSource)]
enum Target {
    #[enum_from(FirstSource, SecondSource::Empty)]
    Unit,
    #[enum_from(FirstSource)]
    Data(String),
}

Field mapping

#[derive(EnumFrom)]
#[enum_from(Source)]
enum Target {
    #[enum_from]
    Record {
        #[enum_from(Source::name)]  // Maps Source::name to Target::title
        title: String,
        value: i32,
    }
}