Refactor Sequential and Parallel

Author: juliohm

src/transforms/parallel.jl

@@ -94,7 +94,7 @@ end
 Create a [`Parallel`](@ref) transform with
 `[transform₁, transform₂, …, transformₙ]`.
 """
-∥(t1, t2) = Parallel([t1, t2])
-∥(t1, t2::Parallel) = Parallel([t1; t2.transforms])
-∥(t1::Parallel, t2) = Parallel([t1.transforms; t2])
-∥(t1::Parallel, t2::Parallel) = Parallel([t1.transforms; t2.transforms])
+∥(t1::Transform, t2::Transform) = Parallel([t1, t2])
+∥(t1::Transform, t2::Parallel)  = Parallel([t1; t2.transforms])
+∥(t1::Parallel, t2::Transform)  = Parallel([t1.transforms; t2])
+∥(t1::Parallel, t2::Parallel)   = Parallel([t1.transforms; t2.transforms])

src/transforms/sequential.jl

@@ -37,7 +37,7 @@ end
 Create a [`Sequential`](@ref) transform with
 `[transform₁, transform₂, …, transformₙ]`.
 """
-→(t1, t2) = Sequential([t1, t2])
-→(t1, t2::Sequential) = Sequential([t1; t2.transforms])
-→(t1::Sequential, t2) = Sequential([t1.transforms; t2])
+→(t1::Transform, t2::Transform)   = Sequential([t1, t2])
+→(t1::Transform, t2::Sequential)  = Sequential([t1; t2.transforms])
+→(t1::Sequential, t2::Transform)  = Sequential([t1.transforms; t2])
 →(t1::Sequential, t2::Sequential) = Sequential([t1.transforms; t2.transforms])