Merge pull request #2 from RougeWare/feature/NSRange

Added subscript using `NSRange`
RougeWare · May 20, 2020 · 3bd0d7e · 3bd0d7e
2 parents c2abe76 + d1e195b
commit 3bd0d7e
Show file tree

Hide file tree

Showing 2 changed files with 59 additions and 0 deletions.
diff --git a/Sources/StringIntegerAccess/String + Integer access.swift b/Sources/StringIntegerAccess/String + Integer access.swift
@@ -127,3 +127,45 @@ public extension StringProtocol {
         self[PartialRangeThrough(index(range.upperBound))]
     }
 }
+
+
+
+#if canImport(ObjectiveC) // NSRange seems to only exist on platforms where there's Obj-C
+import Foundation
+
+
+
+public extension StringProtocol {
+
+    /// Allows you to subscript a string with a `NSRange`
+    ///
+    /// These are equivalent:
+    /// ```
+    /// let mySubstring: Substring?
+    /// if range.length >= 0,
+    ///     let range = Range(nsRange, in: myString)
+    /// {
+    ///     mySubstring = myString[range]
+    /// }
+    /// else {
+    ///     mySubstring = nil
+    /// }
+    /// ```
+    /// ```
+    /// let mySubstring = myString[nsRange]
+    /// ```
+    ///
+    /// - Parameter range: A range of valid indices of characters in the string. `location` must be less than `count`
+    ///                    (exclusive), and `length` must be less than `count` (inclusive). If `length` is longer than
+    ///                    `count`, or if `location` pushes the upper bound outside this string, or if `length` is
+    ///                    negative, this returns `nil`.
+    /// - Returns: The characters at the given index-range in this string
+    @inlinable
+    @available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+    subscript(_ range: NSRange) -> SubSequence? {
+        return range.length < 0
+            ? nil
+            : Range(range, in: self).map { self[$0] }
+    }
+}
+#endif
diff --git a/Tests/StringIntegerAccessTests/StringIntegerAccessTests.swift b/Tests/StringIntegerAccessTests/StringIntegerAccessTests.swift
@@ -1,6 +1,8 @@
 import XCTest
 @testable import StringIntegerAccess
 
+
+
 final class StringIntegerAccessTests: XCTestCase {
     func testGetCharacterWithIntSubscript() {
         XCTAssertEqual("Hello, World!"[0], "H")
@@ -11,6 +13,7 @@ final class StringIntegerAccessTests: XCTestCase {
 
 
     func testGetSubstringWithIntClosedRangeSubscript() {
+        XCTAssertEqual("Hello, World!"[0...12], "Hello, World!")
         XCTAssertEqual("Hello, World!"[0...1], "He")
         XCTAssertEqual("Hello, World!"[1...5], "ello,")
         XCTAssertEqual("Hello, World!"[12...12], "!")
@@ -19,6 +22,7 @@ final class StringIntegerAccessTests: XCTestCase {
 
 
     func testGetSubstringWithIntRangeSubscript() {
+        XCTAssertEqual("Hello, World!"[0..<13], "Hello, World!")
         XCTAssertEqual("Hello, World!"[0..<1], "H")
         XCTAssertEqual("Hello, World!"[1..<5], "ello")
         XCTAssertEqual("Hello, World!"[12..<12], "")
@@ -53,6 +57,19 @@ final class StringIntegerAccessTests: XCTestCase {
         XCTAssertEqual("Hello, World!"[...12], "Hello, World!")
     }
 
+
+    @available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+    func testGetSubstringWithNSRangeSubscript() {
+        XCTAssertEqual("Hello, World!"[NSRange(location: 0, length: 13)], "Hello, World!")
+        XCTAssertEqual("Hello, World!"[NSRange(location: 0, length: 1)], "H")
+        XCTAssertEqual("Hello, World!"[NSRange(location: 1, length: 4)], "ello")
+        XCTAssertEqual("Hello, World!"[NSRange(location: 12, length: 0)], "")
+        XCTAssertEqual("Hello, World!"[NSRange(location: 11, length: 1)], "d")
+        XCTAssertEqual("Hello, World!"[NSRange(location: 11, length: 2)], "d!")
+        XCTAssertNil("Hello, World!"[NSRange(location: 5, length: -5)])
+        XCTAssertNil("Hello, World!"[NSRange(location: 11, length: 999)])
+    }
+
 
     static var allTests = [
         ("testGetCharacterWithIntSubscript", testGetCharacterWithIntSubscript),