gistfile1.rs

pub type Fun<'a, I, O> = Box<FnMut(I) -> Res<'a, I, O> +'a>;

pub enum Res<'a, I, O> {
  Done(I, O),
  Incomplete(Fun<'a, I, O>)
}

pub trait FMap<I, O, N> {
  fn fmap<'y,F: Fn(O) -> N>(&'y self, f: F) -> Res<'y, I, N>;
}

impl<'z, R, S, T> FMap<R, S, T> for Res<'z, R, S> {
  fn fmap<'y,F: Fn(S) -> T>(&'y self, f: F) -> Res<'y, R, T> {
    match self {
      &Res::Incomplete(ref g) => {
        Res::Incomplete(Box::new(move |input| {
          let tmp = g(input);
          let res = tmp.fmap(f);
          res
        }))
      },
      &Res::Done(i, ref o) => Res::Done(i,f(*o))
    }
  }
}

fn main() {

}

no generics

pub type Fun<'a> = Box<FnMut(u8) -> Res<'a> +'a>;

pub enum Res<'a> {
  Done(u8, u8),
  Incomplete(Fun<'a>)
}

pub trait FMap {
  fn fmap<'y,F: Fn(u8) -> u8>(&'y self, f: F) -> Res<'y>;
}

impl<'z> FMap for Res<'z> {
  fn fmap<'y,F: Fn(u8) -> u8>(&'y self, f: F) -> Res<'y> {
    match self {
      &Res::Incomplete(ref g) => {
        Res::Incomplete(Box::new(move |input| {
          let tmp = g(input);
          let res = tmp.fmap(f);
          res
        }))
      },
      &Res::Done(i, o) => Res::Done(i,f(o))
    }              
  }                
}                  
fn main() {        

}