as-> is great for when you have to mix thread-first and thread-last. cond-> is g... | Hacker News

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iterati on Oct 26, 2018 | parent | context | favorite | on: Not Lisp again (2009)

as-> is great for when you have to mix thread-first and thread-last.

cond-> is great for building maps where some keys might not be needed:

    (cond-> {:k1 v1}
      v2 (assoc :k2 v2)
      ...)

some-> and some->> I don't use as often, but when mixing in some java code that could throw an NPE, these will avoid that and just return nil early (they short-circuit when getting a nil value).

dustingetz on Oct 27, 2018 [–]

You can next ->> inside ->, took far too many years for me to realize:

    @(-> ctx
        :hypercrud.browser/fiddle
        (reactive/cursor [:fiddle/ident])
        (->> (reactive/fmap name)))

another

    (-> [10 11] 
        (conj 12) 
        (as-> xs (map - xs [3 2 1])) 
        (reverse))

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