lilyball/Challenge 2.md

## Challenge 2.md

      
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              Challenge 2.md
            
          
    Challenge #2

Implement a take_while method on Array
take_while runs the block with each element of the Array in turn until it returns false, then it stops and returns an Array of the prior elements.
Example
  Input >> [1,2,3,4].take_while { $0 < 3 }
  Output >> R8: Array<Int> = 2 values {
            [0] = 1
            [1] = 2
          } 

Bonus
Implement take_while as a global struct named TakeWhile that implements SequenceType (like Zip2)
Example
  Input >> Array(TakeWhile([1,2,3,4]) { $0 < 3 })
  Output >> R8: Array<Int> = 2 values {
            [0] = 1
            [1] = 2
          } 

Thanks to @eridius for the suggestion this week!
Post your answers as replies; directly or with a paste-site link.