delegate-display 1.0.2

Lets you derive Display and Debug traits by delegating them to the only member of 0..1-member structs & enums.

use delegate_display::{DelegateDebug, DelegateDisplay};
use std::fmt;

// Input
#[derive(DelegateDebug, DelegateDisplay)]
enum MyEnum {
  Foo,
  Bar(SomeType),
  Qux { baz: SomeType }, 
}

// Generated output
impl fmt::Display for MyEnum {
  // Equivalent implementation for Debug & for structs
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
    match self {
      Self::Foo => f.write_str("Foo"),
      Self::Bar(value) => fmt::Display::fmt(value, f),
      Self::Qux { baz } => fmt::Display::fmt(baz, f),    
    }
  }
}

See module-level documentation for more examples, what's allowed and what isn't.