src/func.rs

@@ -70,12 +70,6 @@ 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>,

src/func/classes/compositionclass.rs

@@ -53,3 +53,17 @@ impl<U: ApplicativeLA2, V: ApplicativeLA2> ApplicativeLA2 for CompositionClass<U
         U::la2(|ua, ub| V::la2(f, ua, ub), fa, fb)
     }
 }
+
+pub fn compose<'a>(f: impl 'a + Fn(i16) -> i32, g: impl 'a + Fn(i8) -> i16) -> impl 'a + Fn(i8) -> i32 {
+    move |x| f(g(x))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_compose() {
+        assert_eq!(compose(|x| (x + 5).into(), |x| (x + 3).into())(2), 10);
+    }
+}