Ross put it better than I ever could :) yes this is what I meant Sent from Supmenow.com
On Wed, Apr 6, 2016 at 1:45 PM -0700, "Ross O'Brien" <narrativium+sw...@gmail.com> wrote: It's not the same topic. Let's take an example: suppose we have a data structure for a graph of nodes and edges, where the nodes and edges are indexed and both have values. So we have a Graph<NodeIndex : Hashable, EdgeIndex : Hashable, NodeValue, EdgeValue>.Now suppose we want a shortest path from one node to another, and we have a data structure to represent that. Now we have a Path<NodeIndex : Hashable, EdgeIndex : Hashable, NodeValue, EdgeValue>. They both have the same 'generic signature'. If you're navigating a Graph<String, Int, City, Motorway>, you're going to want a Path<String, Int, City, Motorway> as output. Right now you might write that as:func shortestPath<NodeIndex, EdgeIndex, NodeValue, EdgeValue>(graph:Graph<NodeIndex, EdgeIndex, NodeValue, EdgeValue>, startNode: NodeIndex, endNode: NodeIndex> -> Path<NodeIndex, EdgeIndex, NodeValue, EdgeValue> It might save a fair amount of typing if we had a generic equivalent to both typealias and associatedtype. associatedgenerics GraphElements = <NodeIndex : Hashable, EdgeIndex : Hashable, NodeValue, EdgeValue>func shortestPath<GraphElements>(graph: Graph<GraphElements>, startNode<GraphElements.NodeIndex>, endNode<GraphElements.NodeIndex>) -> Path<GraphElements> genericalias NavigationGraphElements = GraphElements<String, Int, City, Motorway> typealias NavigationGraph = Graph<NavigationGraphElements>// navigationGraph.shortestPath() now returns a Path<NavigationGraphElements>// this last part is closest to the proposal under review. On Wed, Apr 6, 2016 at 9:05 PM, Milos Rankovic via swift-evolution <swift-evolution@swift.org> wrote: Chris Lattner has a proposal under review on this topic. milos On 6 Apr 2016, at 20:41, James Campbell via swift-evolution <swift-evolution@swift.org> wrote: This was inspired from the topic about moving where clauses out of parameter lists. Certain generics get very long winded, I was wondering if we could create some sort of alias for generics. func anyCommonElements <T: SequenceType, U: SequenceType where T.Generator.Element: Equatable, T.Generator.Element == U.Generator.Element> (lhs: T, _ rhs: U) -> Bool could be shared across functions like so: genericalias SequencesWithSameElements<T, U> = <T: SequenceType, U: SequenceType where T.Generator.Element: Equatable, T.Generator.Element == U.Generator.Element> func anyCommonElements <SequencesWithSameElements> (lhs: T, _ rhs: U) -> Bool func == <SequencesWithSameElements> (lhs: T, _ rhs: U) -> Bool ___________________________________ James⎥ ja...@supmenow.com⎥supmenow.com Sup Runway East 10 Finsbury Square London EC2A 1AF _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
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