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[stdlib] Used map and guard for nil handling #241

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Merged
merged 1 commit into from
Dec 6, 2015
Merged

[stdlib] Used map and guard for nil handling #241

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5 changes: 2 additions & 3 deletions stdlib/public/core/Algorithm.swift
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Expand Up @@ -177,9 +177,8 @@ public struct EnumerateGenerator<
///
/// - Requires: No preceding call to `self.next()` has returned `nil`.
public mutating func next() -> Element? {
let b = base.next()
if b == nil { return .None }
return .Some((index: count++, element: b!))
guard let b = base.next() else { return .None }
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This could be implemented using Optional.map:

public mutating func next() -> Element? {
  return base.next().map { (index: count++, element: $0) }
}

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-1 from me on this one because of side effects inside map().

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@gribozavr Changed it to guard let. What side effect it cause?

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The increment in index++ was side effect.

return .Some((index: count++, element: b))
}
}

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3 changes: 1 addition & 2 deletions stdlib/public/core/Collection.swift
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Expand Up @@ -765,8 +765,7 @@ public struct PermutationGenerator<
///
/// - Requires: No preceding call to `self.next()` has returned `nil`.
public mutating func next() -> Element? {
let result = indices.next()
return result != nil ? seq[result!] : .None
return indices.next().map { seq[$0] }
}
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Ditto:

public mutating func next() -> Element? {
  return indices.next().map { seq[$0] }
}

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This part LGTM.


/// Construct a *generator* over a permutation of `elements` given
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