Be mindful of Clojure's binding - Chas Emerick - Muck and Brass - The Diigo Meta page

• 05 Nov 09
  

  Carlos Santos

  clojure binding tips programming

• 04 Nov 09
  

  Damon Snyder

  clojure

• 03 Nov 09
  

  Javier Neira

  clojure binding concurrency lazy issues

  • Binding is thread-local

    
    
    

    This is super-simple, and it's the first thing that one learns upon encountering binding for the first time

  • (pmap

    • 

      Javier Neira on 2009-11-03

      parallel map (create multiple threads others than actual)
  • 5 more annotations...
  • • 

      • 

        Javier Neira on 2009-11-03

        parallel map -creates multiples threads-
    • The problem here is that adder is being invoked in threads other than the thread that is establishing the binding on *foo*; therefore, the value of *foo* within adder is always the default, 5.
    • One of the great things about Clojure is you can "do concurrency" using a variety of easy-to-use primitives (e.g. pmap is absolutely the cat's nuts, in that it's a dead-simple way to almost-transparently parallelize computation over a dataset)
    • things like pmap have so little ceremony that it's easy to forget the basics.
    • Notice that some-fn is now explicitly capturing the bound value of the *foo* var; this ensures that, regardless of when and where or on which thread the lazy seq is materialized, the values it contains are what were bound by the caller of some-fn. This is almost always what you want to have happen.

Public Stiky Notes

• 
  Javier Neira on 2009-11-03
  parallel map (create multiple threads others than actual)
• 
  Javier Neira on 2009-11-03
  parallel map -creates multiples threads-

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