#plugin #types

plugin

Lazily evaluated, order-independent plugins for extensible types

11 releases

0.2.6 Apr 22, 2015
0.2.5 Apr 3, 2015
0.2.4 Mar 31, 2015
0.2.2 Feb 28, 2015
0.0.0 Nov 11, 2014

#3 in Multimedia

Download history 2145/week @ 2018-05-27 2493/week @ 2018-06-03 2646/week @ 2018-06-10 2268/week @ 2018-06-17 2717/week @ 2018-06-24 3012/week @ 2018-07-01 2578/week @ 2018-07-08 2512/week @ 2018-07-15 2593/week @ 2018-07-22 2572/week @ 2018-07-29 2641/week @ 2018-08-05 2172/week @ 2018-08-12 2245/week @ 2018-08-19

12,815 downloads per month
Used in 156 crates (18 directly)

MIT license

8KB
113 lines

Plugin

Type-Safe, Lazily Evaluated, Plugins for Extensible Types

Plugins provide a consistent interface for mixin methods. You can use a plugin anywhere you would use a "mixin" trait and an implementation.

Example Usage

// Define a struct.
struct IntPlugin;

// Map it onto an `i32` value.
impl Assoc<i32> for IntPlugin {}

// Define the plugin evaluation function.
// `Extended` is a type that implements `Extensible`.
impl PluginFor<Extended, i32> for IntPlugin {
    fn eval(_: &Extended, _: Phantom<IntPlugin>) -> Option<i32> {
        Some(0i32)
    }
}
assert_eq!(extended.get::<IntPlugin>().unwrap(), 0i32);

To do the same thing with a trait, one could do:

trait IntProducer {
    fn get_int_value(&self) -> Option<i32>;
}

impl IntProducer for Extended {
    fn get_int_value(&self) -> Option<i32> {
        Some(0i32)
    }
}

Although using a raw trait is less code, plugins provide the following advantages:

  • Automatic caching of values. Calling a method again is a constant time operation! This is particularly useful in pipeline structures where only the extensible object is passed around.
  • A consistent interface, which also allows for neater name clash resolution. Two modules that provide PluginX can be differentiated using a module prefix.
e.get::<mod1::PluginX>();
e.get::<mod2::PluginX>();

Dependencies

~29KB