Options and IOs and Iteratees, oh my! If you've poked around at Scala you've seen it--the ubiquitous for-comprehension sprinkled through idiomatic Scala code. As it turns out, what looks like a bit of syntactic sugar to ease prosaic list manipulation is actually a super powerful structure for abstracting away all kinds of common operations in a safe and maintainable way. It allows you to take full advantage of type safety and pushes the work of setting up boilerplate to the compiler. We'll break down exactly what's going on in a for-comprehension and explore some of the wild and wonderful structures that can be used within one. You'll leave with a deeper understanding of the real-world benefits of functional programming. Or, to put it another way: for { attendees <-><-> attendee } yourFpKnowledge <- you.knowledgeOfFunctionalProgramming getOrElse beginner } yield { expand(yourFpKnowledge) }

1. Journey to the Heart of the For-Yield
Kelsey Gilmore-Innis
http://nerd.kelseyinnis.com
@kelseyinnis
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2. VAN
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4. What have you done for me lately?
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18. flatten compose map
flatMap
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19. flatMap!
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27. Enter Option
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28. Enter Option
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29. Enter Option
blergh!
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30. blergh.
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34. Smokey, this is not ‘Nam.
There are rules.
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35. the
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word

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43. Other m-words
•Iteratee
•Reader
•Writer
•State
•IO
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44. But, but...
•I don’t wanna fail fast!
•|@|
•Chocolate in my peanut butter? Peanut
butter in my chocolate?
•.toSeq, monad transformers
•It’s inside out!
•traverse & sequence
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