Trait boulder::Generatable

source · [−]
pub trait Generatable {
    type Generator: Generator<Output = Self>;

    fn generator() -> Self::Generator;
}
Expand description

A type that has an associated default Generator

This trait is implemented via the Generatable derive macro. It cannot be directly implemented because the library itself provides a blanket implementation from a more complex underlying trait MiniGeneratable, which is not currently documented.

This restriction may be removed in a future version; much of the complexity in this module stems from lacking generic associated types on stable.

Required Associated Types

A default choice of Generator for this type.

Required Methods

Return this object’s generator.

Example

use boulder::{Generatable, Generator};

struct FooGenerator {
  a: i32
};

impl Generator for FooGenerator {
  type Output = Foo;
  fn generate(&mut self) -> Foo {
    self.a += 1;
    Foo { a: self.a }
  }
}

struct Foo {
  a: i32
};

impl Generatable for Foo {
  type Generator = FooGenerator;
  fn generator() -> Self::Generator {
    FooGenerator { a: 0 }
  }
}

let mut g = Foo::generator();
assert_eq!(g.generate().a, 1);
assert_eq!(g.generate().a, 2);

Implementors