127

0127-parsing-performance-pt1/.gitignore

@@ -0,0 +1,5 @@
+.DS_Store
+/.build
+/Packages
+/*.xcodeproj
+xcuserdata/

0127-parsing-performance-pt1/README.md

@@ -0,0 +1,5 @@
+## [Point-Free](https://www.pointfree.co)
+
+> #### This directory contains code from Point-Free Episode: [Parsing Performance: Strings](https://www.pointfree.co/episodes/ep127-parsing-performance-strings)
+>
+> We want to explore the performance of composable parsers, but to do so we must first take a deep dive into the Swift string API. There are multiple abstractions of strings in Swift, each with its own benefits and performance characteristics. We will benchmark them in order to get a scientific basis for comparison, and will describe how to properly write a benchmark.

0127-parsing-performance-pt1/parser-performance.playground/Contents.swift

@@ -0,0 +1,35 @@
+
+let bigString = String.init(repeating: "A", count: 1_000_000)
+
+var copy = bigString
+copy.removeFirst()
+
+var anotherCopy = bigString
+anotherCopy.removeFirst()
+
+let truncatedBigString = bigString.dropFirst() as Substring
+
+bigString.index(after: bigString.startIndex) == truncatedBigString.startIndex
+
+var copy1 = truncatedBigString.dropFirst(100)
+var copy2 = truncatedBigString.dropFirst(1_000)
+var copy3 = truncatedBigString.dropFirst(10_000)
+
+let acuteE1 = "é"
+let acuteE2 = "é"
+acuteE1 == acuteE2
+acuteE1.count
+acuteE2.count
+
+acuteE1.unicodeScalars.count
+acuteE2.unicodeScalars.count
+
+Array(acuteE1.unicodeScalars)
+Array(acuteE2.unicodeScalars)
+
+acuteE1.unicodeScalars.elementsEqual(acuteE2.unicodeScalars)
+
+"🇺"
+"🇸"
+"🇺" + "🇸"
+"\u{1F1FA}\u{1F1F8}"

0127-parsing-performance-pt1/parser-performance.playground/contents.xcplayground

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos' buildActiveScheme='true'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>

0127-parsing-performance-pt1/string-performance/.gitignore

@@ -0,0 +1,5 @@
+.DS_Store
+/.build
+/Packages
+/*.xcodeproj
+xcuserdata/

0127-parsing-performance-pt1/string-performance/.swiftpm/xcode/xcshareddata/xcschemes/string-performance.xcscheme

@@ -0,0 +1,108 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1230"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "string-performance"
+               BuildableName = "string-performance"
+               BlueprintName = "string-performance"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "NO"
+            buildForArchiving = "NO"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "string-performanceTests"
+               BuildableName = "string-performanceTests"
+               BlueprintName = "string-performanceTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "string-performanceTests"
+               BuildableName = "string-performanceTests"
+               BlueprintName = "string-performanceTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Release"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "string-performance"
+            BuildableName = "string-performance"
+            BlueprintName = "string-performance"
+            ReferencedContainer = "container:">
+         </BuildableReference>
+      </BuildableProductRunnable>
+      <CommandLineArguments>
+         <CommandLineArgument
+            argument = "--allow-debug-build"
+            isEnabled = "YES">
+         </CommandLineArgument>
+      </CommandLineArguments>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "string-performance"
+            BuildableName = "string-performance"
+            BlueprintName = "string-performance"
+            ReferencedContainer = "container:">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

0127-parsing-performance-pt1/string-performance/Package.swift

@@ -0,0 +1,23 @@
+// swift-tools-version:5.3
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "string-performance",
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        // .package(url: /* package url */, from: "1.0.0"),
+      .package(name: "Benchmark", url: "https://github.com/google/swift-benchmark", .branch("master"))
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
+        // Targets can depend on other targets in this package, and on products in packages this package depends on.
+        .target(
+            name: "string-performance",
+          dependencies: [.product(name: "Benchmark", package: "Benchmark")]),
+        .testTarget(
+            name: "string-performanceTests",
+            dependencies: ["string-performance"]),
+    ]
+)

0127-parsing-performance-pt1/string-performance/README.md

@@ -0,0 +1,3 @@
+# string-performance
+
+A description of this package.

0127-parsing-performance-pt1/string-performance/Sources/string-performance/Benchmark-Copying.swift

@@ -0,0 +1,28 @@
+import Benchmark
+
+let copyingSuite = BenchmarkSuite(name: "Copying") { suite in
+  let string = String.init(repeating: "A", count: 1_000_000)
+
+  suite.benchmark("String") {
+    var copy = string
+    copy.removeFirst()
+    var copy1 = copy
+    copy1.removeFirst()
+    var copy2 = copy1
+    copy2.removeFirst()
+    var copy3 = copy2
+    copy3.removeFirst()
+  }
+
+  suite.benchmark("Substring") {
+    var copy = string[...]
+    copy.removeFirst()
+    var copy1 = copy
+    copy1.removeFirst()
+    var copy2 = copy1
+    copy2.removeFirst()
+    var copy3 = copy2
+    copy3.removeFirst()
+  }
+}
+

0127-parsing-performance-pt1/string-performance/Sources/string-performance/main.swift

@@ -0,0 +1,6 @@
+import Benchmark
+
+Benchmark.main([
+  copyingSuite,
+])
+

0127-parsing-performance-pt1/string-performance/Tests/LinuxMain.swift

@@ -0,0 +1,7 @@
+import XCTest
+
+import string_performanceTests
+
+var tests = [XCTestCaseEntry]()
+tests += string_performanceTests.allTests()
+XCTMain(tests)

0127-parsing-performance-pt1/string-performance/Tests/string-performanceTests/XCTestManifests.swift

@@ -0,0 +1,9 @@
+import XCTest
+
+#if !canImport(ObjectiveC)
+public func allTests() -> [XCTestCaseEntry] {
+    return [
+        testCase(string_performanceTests.allTests),
+    ]
+}
+#endif

0127-parsing-performance-pt1/string-performance/Tests/string-performanceTests/string_performanceTests.swift

@@ -0,0 +1,47 @@
+import XCTest
+import class Foundation.Bundle
+
+final class string_performanceTests: XCTestCase {
+    func testExample() throws {
+        // This is an example of a functional test case.
+        // Use XCTAssert and related functions to verify your tests produce the correct
+        // results.
+
+        // Some of the APIs that we use below are available in macOS 10.13 and above.
+        guard #available(macOS 10.13, *) else {
+            return
+        }
+
+        let fooBinary = productsDirectory.appendingPathComponent("string-performance")
+
+        let process = Process()
+        process.executableURL = fooBinary
+
+        let pipe = Pipe()
+        process.standardOutput = pipe
+
+        try process.run()
+        process.waitUntilExit()
+
+        let data = pipe.fileHandleForReading.readDataToEndOfFile()
+        let output = String(data: data, encoding: .utf8)
+
+        XCTAssertEqual(output, "Hello, world!\n")
+    }
+
+    /// Returns path to the built products directory.
+    var productsDirectory: URL {
+      #if os(macOS)
+        for bundle in Bundle.allBundles where bundle.bundlePath.hasSuffix(".xctest") {
+            return bundle.bundleURL.deletingLastPathComponent()
+        }
+        fatalError("couldn't find the products directory")
+      #else
+        return Bundle.main.bundleURL
+      #endif
+    }
+
+    static var allTests = [
+        ("testExample", testExample),
+    ]
+}

README.md

@@ -129,3 +129,4 @@ This repository is the home of code written on episodes of
 1. [Generalized Parsing: Part 1](0124-generalized-parsing-pt1)
 1. [Generalized Parsing: Part 2](0125-generalized-parsing-pt2)
 1. [Generalized Parsing: Part 3](0126-generalized-parsing-pt3)
+1. [Parsing Performance: Strings](0127-parsing-performance-pt1)