Merge pull request #21 from natecook1000/all_scalars

Add an `AllScalars` collection

Author: natecook1000

Sources/Util/AllScalars.swift

@@ -0,0 +1,45 @@
+extension Unicode.Scalar {
+ public struct AllScalars: RandomAccessCollection {
+ // Unicode scalar values are in two discontiguous blocks:
+ // 0...0xD7FF and 0xE000...0x10FFFF
+ internal static var lowerSectionFirstValue: Int { 0 }
+ internal static var lowerSectionLastValue: Int { 0xD7FF }
+ internal static var upperSectionFirstValue: Int { 0xE000 }
+ internal static var upperSectionLastValue: Int { 0x10FFFF }
+ 
+ internal static var surrogateRangeCount: Int {
+ (upperSectionFirstValue - lowerSectionLastValue) - 1
+ }
+ 
+ internal func toContiguous(_ i: Int) -> Int {
+ i >= Self.upperSectionFirstValue
+ ? i - Self.surrogateRangeCount
+ : i
+ }
+ 
+ internal func fromContiguous(_ i: Int) -> Int {
+ i > Self.lowerSectionLastValue
+ ? i + Self.surrogateRangeCount
+ : i
+ }
+ 
+ public var startIndex: Int { 0 }
+ public var endIndex: Int { toContiguous(Self.upperSectionLastValue + 1) }
+ 
+ public subscript(position: Int) -> Unicode.Scalar {
+ Unicode.Scalar(UInt32(fromContiguous(position)))!
+ }
+ 
+ public func _customIndexOfEquatableElement(_ scalar: Unicode.Scalar) -> Int?? {
+ toContiguous(Int(scalar.value))
+ }
+ 
+ public func _customContainsEquatableElement(_: Unicode.Scalar) -> Bool? {
+ true
+ }
+ }
+ 
+ public static var allScalars: AllScalars {
+ AllScalars()
+ }
+}

Tests/UtilTests/AllScalarsTests.swift

@@ -0,0 +1,35 @@
+import XCTest
+@testable import Util
+
+let allScalars = Unicode.Scalar.allScalars
+
+class AllScalarsTests: XCTestCase {
+ func testCollectionConformance() {
+ let calculatedCount = (0...0xD7FF).count + (0xE000...0x10FFFF).count
+ XCTAssertEqual(calculatedCount, allScalars.count)
+ XCTAssertEqual(calculatedCount, allScalars.reduce(0, { sum, _ in sum + 1 }))
+ }
+ 
+ func testIndexOf() throws {
+ for scalar in "béड🥰 \u{0} \u{D7FF} \u{E000} \u{10FFFF}".unicodeScalars {
+ let i = try XCTUnwrap(allScalars.firstIndex(of: scalar))
+ XCTAssertEqual(scalar, allScalars[i])
+ }
+ }
+ 
+ func testProperties() throws {
+ let whitespaces = allScalars.filter { $0.properties.isWhitespace }
+ XCTAssertEqual(25, whitespaces.count)
+ 
+ let numericIndices = allScalars
+ .indices
+ .filter { allScalars[$0].properties.numericType == .decimal }
+ XCTAssertEqual(650, numericIndices.count)
+ 
+ let digitSum = try numericIndices
+ .map { try XCTUnwrap(allScalars[$0].properties.numericValue) }
+ .reduce(0, +)
+ XCTAssertEqual(2925, digitSum)
+ XCTAssertEqual(4.5, digitSum / Double(numericIndices.count))
+ }
+}