gistfile1.txt

module Seq

#light

let merge (s1:seq<'a>) (s2:seq<'a>) =
    let rec innerMerge s1 s2 =
        seq {
            match s1, s2 with
            | LazyList.Cons(h1, t1), LazyList.Cons(h2, t2) -> 
                yield h1
                yield h2
                yield! innerMerge s1 s2
            | LazyList.Cons(h1, t1), LazyList.Nil -> 
                yield h1
                yield! innerMerge s1 s2
            | LazyList.Nil, LazyList.Cons(h2, t2) -> 
                yield h2
                yield! innerMerge s1 s2
            | LazyList.Nil, LazyList.Nil ->
                yield! innerMerge s1 s2
        }
    innerMerge (LazyList.ofSeq s1) (LazyList.ofSeq s2)