let-like syntactic abstraction

[ghost]

A let-like macro for declaring fetches withouth worrying about dependencies:

(flet [posts (latest-posts 10)
       post-scores (u/traverse score posts)
       authors (u/traverse user posts)]
 (map (fn [post score author]
        (merge post {:author author :score score})) 
      posts 
      post-scores 
      authors))        

which will be translated to calls to the combinators under the hood, resolving the data dependencies based on the code.