_ isSeparator: => whereSeparator isSeparator:

Author: Dave Abrahams

stdlib/private/StdlibCollectionUnittest/LoggingWrappers.swift.gyb

@@ -274,13 +274,13 @@ public struct ${Self}<
   public func split(
     maxSplits: Int = Int.max,
     omittingEmptySubsequences: Bool = true,
-    isSeparator: @noescape (Base.Iterator.Element) throws -> Bool
+    whereSeparator isSeparator: @noescape (Base.Iterator.Element) throws -> Bool
   ) rethrows -> [SubSequence] {
     Log.split[selfType] += 1
     return try base.split(
       maxSplits: maxSplits,
       omittingEmptySubsequences: omittingEmptySubsequences,
-      isSeparator: isSeparator)
+      whereSeparator: isSeparator)
   }
 
   public func _customContainsEquatableElement(

stdlib/public/core/Collection.swift

@@ -1484,15 +1484,17 @@ extension Collection {
   /// that was originally separated by one or more spaces.
   ///
   ///     let line = "BLANCHE:   I don't want realism. I want magic!"
-  ///     print(line.characters.split(isSeparator: { $0 == " " })
+  ///     print(line.characters.split(whereSeparator: { $0 == " " })
   ///                          .map(String.init))
   ///     // Prints "["BLANCHE:", "I", "don\'t", "want", "realism.", "I", "want", "magic!"]"
   ///
   /// The second example passes `1` for the `maxSplits` parameter, so the
   /// original string is split just once, into two new strings.
   ///
-  ///     print(line.characters.split(maxSplits: 1, isSeparator: { $0 == " " })
-  ///                           .map(String.init))
+  ///     print(
+  ///         line.characters.split(
+  ///             maxSplits: 1, whereSeparator: { $0 == " " }
+  ///             ).map(String.init))
   ///     // Prints "["BLANCHE:", "  I don\'t want realism. I want magic!"]"
   ///
   /// The final example passes `false` for the `omittingEmptySubsequences`
@@ -1523,7 +1525,7 @@ extension Collection {
   public func split(
     maxSplits: Int = Int.max,
     omittingEmptySubsequences: Bool = true,
-    isSeparator: @noescape (Iterator.Element) throws -> Bool
+    whereSeparator isSeparator: @noescape (Iterator.Element) throws -> Bool
   ) rethrows -> [SubSequence] {
     // TODO: swift-3-indexing-model - review the following
     _precondition(maxSplits >= 0, "Must take zero or more splits")
@@ -1624,7 +1626,7 @@ extension Collection where Iterator.Element : Equatable {
     return split(
       maxSplits: maxSplits,
       omittingEmptySubsequences: omittingEmptySubsequences,
-      isSeparator: { $0 == separator })
+      whereSeparator: { $0 == separator })
   }
 }
 
@@ -1719,11 +1721,11 @@ extension Collection {
     Builtin.unreachable()
   }
 
-  @available(*, unavailable, message: "Please use split(maxSplits:omittingEmptySubsequences:isSeparator:) instead")
+  @available(*, unavailable, message: "Please use split(maxSplits:omittingEmptySubsequences:whereSeparator:) instead")
   public func split(
     _ maxSplit: Int = Int.max,
     allowEmptySlices: Bool = false,
-    isSeparator: @noescape (Iterator.Element) throws -> Bool
+    whereSeparator isSeparator: @noescape (Iterator.Element) throws -> Bool
   ) rethrows -> [SubSequence] {
     Builtin.unreachable()
   }

stdlib/public/core/ExistentialCollection.swift.gyb

@@ -200,7 +200,7 @@ internal class _AnyRandomAccessCollectionBox<Element>
 
   internal func _split(
     maxSplits: Int, omittingEmptySubsequences: Bool,
-    isSeparator: @noescape (Element) throws -> Bool
+    whereSeparator isSeparator: @noescape (Element) throws -> Bool
   ) rethrows -> [Any${Kind}<Element>] {
     _abstract()
   }
@@ -376,12 +376,12 @@ internal final class _${Kind}Box<S : ${Kind}> : _Any${Kind}Box<S.Iterator.Elemen
 %   for ResultKind in EqualAndWeakerKinds:
   internal override func _split(
     maxSplits: Int, omittingEmptySubsequences: Bool,
-    isSeparator: @noescape (Element) throws -> Bool
+    whereSeparator isSeparator: @noescape (Element) throws -> Bool
   ) rethrows -> [Any${ResultKind}<Element>] {
     return try _base.split(
       maxSplits: maxSplits,
       omittingEmptySubsequences: omittingEmptySubsequences,
-      isSeparator: isSeparator)
+      whereSeparator: isSeparator)
       .map {
         Any${ResultKind}(_box: _${Kind}Box<S.SubSequence>(_base: $0))
       }
@@ -609,12 +609,12 @@ extension Any${Kind} {
   public func split(
     maxSplits: Int = Int.max,
     omittingEmptySubsequences: Bool = true,
-    isSeparator: @noescape (Element) throws -> Bool
+    whereSeparator isSeparator: @noescape (Element) throws -> Bool
   ) rethrows -> [Any${Kind}<Element>] {
     return try _box._split(
       maxSplits: maxSplits,
       omittingEmptySubsequences: omittingEmptySubsequences,
-      isSeparator: isSeparator)
+      whereSeparator: isSeparator)
   }
 
   public func _preprocessingPass<R>(

stdlib/public/core/Sequence.swift

@@ -558,7 +558,7 @@ public protocol Sequence {
   /// - Returns: An array of subsequences, split from this sequence's elements.
   func split(
     maxSplits: Int, omittingEmptySubsequences: Bool,
-    isSeparator: @noescape (Iterator.Element) throws -> Bool
+    whereSeparator isSeparator: @noescape (Iterator.Element) throws -> Bool
   ) rethrows -> [SubSequence]
 
   /// Returns the first element of the sequence that satisfies the given
@@ -859,7 +859,7 @@ extension Sequence {
   public func split(
     maxSplits: Int = Int.max,
     omittingEmptySubsequences: Bool = true,
-    isSeparator: @noescape (Iterator.Element) throws -> Bool
+    whereSeparator isSeparator: @noescape (Iterator.Element) throws -> Bool
   ) rethrows -> [AnySequence<Iterator.Element>] {
     _precondition(maxSplits >= 0, "Must take zero or more splits")
     var result: [AnySequence<Iterator.Element>] = []
@@ -1043,7 +1043,7 @@ extension Sequence where Iterator.Element : Equatable {
     return split(
       maxSplits: maxSplits,
       omittingEmptySubsequences: omittingEmptySubsequences,
-      isSeparator: { $0 == separator })
+      whereSeparator: { $0 == separator })
   }
 }
 

test/1_stdlib/Renames.swift

@@ -61,7 +61,7 @@ func _Collection<C : Collection>(c: C) {
   func fn<T : Collection, U>(_: T, _: U) where T.Generator == U {} // expected-error {{'T' does not have a member type named 'Generator'; did you mean 'Iterator'?}} {{50-59=Iterator}} {{none}} 
   _ = c.generate() // expected-error {{'generate()' has been renamed to 'makeIterator()'}} {{9-17=makeIterator}} {{none}}
   _ = c.underestimateCount() // expected-error {{'underestimateCount()' is unavailable: Removed in Swift 3. Please use underestimatedCount property.}} {{none}}
-  _ = c.split(1) { _ in return true} // expected-error {{'split(_:allowEmptySlices:isSeparator:)' is unavailable: Please use split(maxSplits:omittingEmptySubsequences:isSeparator:) instead}} {{none}}
+  _ = c.split(1) { _ in return true} // expected-error {{split(maxSplits:omittingEmptySubsequences:whereSeparator:) instead}} {{none}}
 }
 
 func _Collection<C : Collection, E>(c: C, e: E) where C.Iterator.Element: Equatable, C.Iterator.Element == E {

test/Constraints/diagnostics.swift

@@ -554,7 +554,7 @@ func r22020088bar(_ p: r22020088P?) {
 
 // <rdar://problem/22288575> QoI: poor diagnostic involving closure, bad parameter label, and mismatch return type
 func f(_ arguments: [String]) -> [ArraySlice<String>] {
-  return arguments.split(maxSplits: 1, omittingEmptySubsequences: false, isSeparator: { $0 == "--" })
+  return arguments.split(maxSplits: 1, omittingEmptySubsequences: false, whereSeparator: { $0 == "--" })
 }