objcio / functional-swift

Issue repository for the Functional Swift book
http://www.objc.io/books/fpinswift
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Phrasing error in book #125

Closed ghost closed 5 years ago

ghost commented 7 years ago

I think this might need to be re-phrased as it is both right and wrong.

“The problem is that addition only works on Int values”

Excerpt From: Chris Eidhof. “Functional Swift.” iBooks. Section: Optional binding re-visited

This might be a bit misleading, because addition is an overloaded function, so it depends where it is used. With Int's it is true

public func +(lhs: Int, rhs: Int) -> Int

but elsewhere...

public func +<RRC1 : RangeReplaceableCollection, RRC2 : RangeReplaceableCollection where RRC1.Iterator.Element == RRC2.Iterator.Element>(lhs: RRC1, rhs: RRC2) -> RRC1

let a = [1,2,3] let b = [2,3,4] let c = a + b


The book is great so far. Thanks for the effort.