Type Alias Capability 

pub type Capability = Box<dyn for<'a> Pass<Parse<'a>>>;

A capability pass, boxed for Language::pipeline.

A capability is a pass_lang::Pass over a Parse, named by its Pass::name. Implement the pass for every lifetime — impl<'a> Pass<Parse<'a>> for MyPass — and box it as a Capability; the language then runs it whenever its schematic includes that name.

Examples

use lang_forge::pass_lang::{Outcome, Pass, PassError};
use lang_forge::{Capability, Parse};

struct CountNodes(usize);

impl<'a> Pass<Parse<'a>> for CountNodes {
    fn name(&self) -> &'static str {
        "count-nodes"
    }

    fn run(&mut self, parse: &mut Parse<'a>) -> Result<Outcome, PassError> {
        self.0 = parse.tree().descendants().count();
        Ok(Outcome::Unchanged)
    }
}

let capability: Capability = Box::new(CountNodes(0));
assert_eq!(capability.name(), "count-nodes");

Aliased Type

pub struct Capability(/* private fields */);