Haskellian fmap

src/func.rs

@@ -70,6 +70,12 @@ pub trait Functor: WeakFunctor {
     }
 }
 
+pub fn fmap<'a, T: 'a + Functor, A: 'a, B: 'a>(
+    f: impl 'a + FnOnce(A) -> B,
+) -> impl FnOnce(T::F<'a, A>) -> T::F<'a, B> {
+    move |fa| T::fmap(f, fa)
+}
+
 pub trait ApplicativeSeq: Functor {
     fn seq<'a, A: 'a, B: 'a>(
         ff: Self::F<'a, impl 'a + FnOnce(A) -> B>,