Created
January 17, 2016 18:22
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Making `Lens<Whole, Part>` into a functor
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| struct Lens<A, B> { | |
| let get: A -> B | |
| let set: (B, A) -> A | |
| func map <C> (f: B -> C) -> Lens<A, C> { | |
| return Lens( | |
| get: { f(get($0)) }, | |
| set: { set(f($0), $1) } | |
| ) | |
| } | |
| } | |
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