v0.26.2

Compare Source

• #​337: Fix missing generic impls for EnumTryAs
• #​334: Support prefix in AsRefStr. Technically a breaking change,
  but prefix was just added in 0.26.0 so it's a newer feature and it makes the feature more consisent in general.

v0.26.1

• #​325: use core instead of std in VariantArray.

v0.26.0

Breaking Changes

• The EnumVariantNames macro has been renamed VariantNames. The deprecation warning should steer you in
  the right direction for fixing the warning.
• The Iterator struct generated by EnumIter now has new bounds on it. This shouldn't break code unless you manually
  added the implementation in your code.
• Display now supports format strings using named fields in the enum variant. This should be a no-op for most code.
  However, if you were outputting a string like "Hello {field}", this will now be interpretted as a format string.
• EnumDiscriminant now inherits the repr and discriminant values from your main enum. This makes the discriminant type
  closer to a mirror of the original and that's always the goal.

New features

• The VariantArray macro has been added. This macro adds an associated constant VARIANTS to your enum. The constant
  is a &'static [Self] slice so that you can access all the variants of your enum. This only works on enums that only
  have unit variants.

  use strum::VariantArray;
  
  #[derive(Debug, VariantArray)]
  enum Color {
    Red,
    Blue,
    Green,
  }
  
  fn main() {
    println!("{:?}", Color::VARIANTS); // prints: ["Red", "Blue", "Green"]
  }

• The EnumTable macro has been experimentally added. This macro adds a new type that stores an item for each variant
  of the enum. This is useful for storing a value for each variant of an enum. This is an experimental feature because
  I'm not convinced the current api surface area is correct.

  use strum::EnumTable;
  
  #[derive(Copy, Clone, Debug, EnumTable)]
  enum Color {
    Red,
    Blue,
    Green,
  }
  
  fn main() {
    let mut counts = ColorTable::filled(0);
    for color in &[Color::Red, Color::Red, Color::Green]] {
      counts[color] += 1;
    }
  
    assert_eq!(counts[Color::Red], 2);
    assert_eq!(counts[Color::Blue], 0);
    assert_eq!(counts[Color::Green], 1);
  }

• Display has 2 new features:

  • the strum(prefix = "some_value") attribute on an enum now allows you to prepend a string onto every
    variant when you serialize it.

  • Custom to_string and serialize attributes now support string interopolation on serialization.

PR's Merged

• #​322: avoid collisions on std::fmt::Debug
• #​321: avoid conflicts with consecutive underscores.
• #​314: add additional bounds to EnumIterator
• #​311: add FusedIterator bounds to EnumIterator
• #​297: New macro, add VariantArray
• #​296: adds prefix attribute to To/From String macros.
• #​294: use named enum fields in to_string macro.
• #​288: discriminant enums now inherit the repr from the original enum.
• #​279: Add EnumTable macro to generate a mapping between fieldless variants and data.