result builder (#53)

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.1
+// swift-tools-version:5.4
 
 import PackageDescription
 

SwiftyAttributes.podspec

@@ -26,5 +26,5 @@ Pod::Spec.new do |s|
   s.tvos.deployment_target = '9.0'
   s.watchos.deployment_target = '2.0'
 
-  s.swift_versions = ['5.0', '5.1']
+  s.swift_versions = ['5.0', '5.1', '5.4']
 end

SwiftyAttributes.xcodeproj/project.pbxproj

@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		9E04C4D126EA09A5009BA429 /* SwiftyAttributedStringBuilder.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9E04C4D026EA09A5009BA429 /* SwiftyAttributedStringBuilder.swift */; };
 		9E0DA889229B2F8600E29BFD /* UIKit+SwiftyAttributes.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9E0DA888229B2F8600E29BFD /* UIKit+SwiftyAttributes.swift */; };
 		9E0DA88E229B34D800E29BFD /* UIKit+SwiftyAttributes_Tests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9E0DA88D229B34D800E29BFD /* UIKit+SwiftyAttributes_Tests.swift */; };
 		9E28077022A424320097CE8A /* NSString+macOS.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9E28076F22A424320097CE8A /* NSString+macOS.swift */; };
@@ -74,6 +75,7 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		9E04C4D026EA09A5009BA429 /* SwiftyAttributedStringBuilder.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = SwiftyAttributedStringBuilder.swift; path = common/SwiftyAttributedStringBuilder.swift; sourceTree = "<group>"; };
 		9E0DA888229B2F8600E29BFD /* UIKit+SwiftyAttributes.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "UIKit+SwiftyAttributes.swift"; sourceTree = "<group>"; };
 		9E0DA88D229B34D800E29BFD /* UIKit+SwiftyAttributes_Tests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "UIKit+SwiftyAttributes_Tests.swift"; sourceTree = "<group>"; };
 		9E28076F22A424320097CE8A /* NSString+macOS.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "NSString+macOS.swift"; sourceTree = "<group>"; };
@@ -249,6 +251,7 @@
 				9EB6D1A222A1CAC200D00CFC /* NSString+SwiftyAttributes.swift */,
 				C05082241DFA72F700D39B3B /* Operators.swift */,
 				C05082251DFA72F700D39B3B /* String+SwiftyAttributes.swift */,
+				9E04C4D026EA09A5009BA429 /* SwiftyAttributedStringBuilder.swift */,
 				C05082261DFA72F700D39B3B /* TextEffect.swift */,
 				C05082271DFA72F700D39B3B /* VerticalGlyphForm.swift */,
 				C05082281DFA72F700D39B3B /* WritingDirection.swift */,
@@ -479,6 +482,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				9E04C4D126EA09A5009BA429 /* SwiftyAttributedStringBuilder.swift in Sources */,
 				C050822A1DFA72F700D39B3B /* Attribute.swift in Sources */,
 				C050822F1DFA72F700D39B3B /* Operators.swift in Sources */,
 				C050822E1DFA72F700D39B3B /* NSMutableAttributedString+SwiftyAttributes.swift in Sources */,

SwiftyAttributes/Sources/common/NSAttributedString+SwiftyAttributes.swift

@@ -28,6 +28,18 @@ extension NSAttributedString {
         self.init(string: str, attributes: dictionary(from: attrs))
     }
 
+    #if swift(>=5.4)
+    /**
+     Creates a new `NSAttributedString` with the specified attributes.
+     
+     - parameter    str:                The string for the new attributed string.
+     - parameter    swiftyAttributes:   The attributes for the new attributed string.
+     */
+    public convenience init(string str: String, @SwiftyAttributedStringBuilder swiftyAttributes attrs: () -> [NSAttributedString.Key: Any]) {
+        self.init(string: str, attributes: attrs())
+    }
+    #endif
+
     /**
      Returns an attributed string with the specified attributes added.
 
@@ -40,6 +52,20 @@ extension NSAttributedString {
         return mutable
     }
 
+    #if swift(>=5.4)
+    /**
+     Returns an attributed string with the specified attributes added.
+
+     - parameter    attributes:     The attributes to add to the new attributed string.
+     - returns:                     An `NSMutableAttributedString` with the new attributes applied.
+     */
+    public func withAttributes(@SwiftyAttributedStringBuilder _ attributes: () -> [NSAttributedString.Key: Any]) -> NSMutableAttributedString {
+        let mutable = mutableCopy() as! NSMutableAttributedString
+        mutable.addAttributes(attributes(), range: NSRange(location: 0, length: length))
+        return mutable
+    }
+    #endif
+
     /**
      Returns an attributed string with the specified attribute added.
      

SwiftyAttributes/Sources/common/String+SwiftyAttributes.swift

@@ -20,6 +20,18 @@ extension String {
         return attributedString.withAttributes(attributes)
     }
 
+    #if swift(>=5.4)
+    /**
+     Returns an attributed string with the specified attributes added.
+
+     - parameter    attributes:     The attributes to add to the new attributed string.
+     - returns:                     An `NSMutableAttributedString` with the new attributes applied.
+     */
+    public func withAttributes(@SwiftyAttributedStringBuilder _ attributes: () -> [NSAttributedString.Key: Any]) -> NSMutableAttributedString {
+        return attributedString.withAttributes(attributes)
+    }
+    #endif
+
     /**
      Returns an attributed string with the specified attribute added.
 

SwiftyAttributes/Sources/common/SwiftyAttributedStringBuilder.swift

@@ -0,0 +1,46 @@
+//
+//  SwiftyAttributedStringBuilder.swift
+//  SwiftyAttributes
+//
+//  Created by Roman Podymov on 09/09/21.
+//  Copyright © 2021 Roman Podymov. All rights reserved.
+//
+
+#if swift(>=5.4)
+import Foundation
+
+public protocol AttributesProvider {
+    var attributes: [Attribute] { get }
+}
+
+extension Attribute: AttributesProvider {
+    public var attributes: [Attribute] { [self] }
+}
+
+extension Array: AttributesProvider where Element == Attribute {
+    public var attributes: [Attribute] { self }
+}
+
+@resultBuilder
+public struct SwiftyAttributedStringBuilder {
+    public static func buildBlock(_ components: AttributesProvider...) -> [Attribute] {
+        components.flatMap { $0.attributes }
+    }
+
+    public static func buildEither(first components: [AttributesProvider]) -> [Attribute] {
+        components.flatMap { $0.attributes }
+    }
+
+    public static func buildEither(second components: [AttributesProvider]) -> [Attribute] {
+        components.flatMap { $0.attributes }
+    }
+
+    public static func buildOptional(_ components: [Attribute]?) -> [Attribute] {
+        components?.flatMap { $0.attributes } ?? []
+    }
+
+    public static func buildFinalResult(_ components: [Attribute]) -> [NSAttributedString.Key: Any] {
+        dictionary(from: components)
+    }
+}
+#endif

SwiftyAttributesTests/NSAttributedString_Tests.swift

@@ -17,6 +17,42 @@ class NSAttributedString_Tests: XCTestCase {
         XCTAssertEqual(subject, expected)
     }
 
+    #if swift(>=5.4)
+    func testInit_withSwiftyAttributedStringBuilder() {
+        let shouldAddStrokeWidth = true
+        let subject = NSAttributedString(string: "Hello World") {
+            Attribute.strokeColor(.green)
+            if let link = URL(string: "").map { Attribute.link($0) } {
+                link
+            }
+            if shouldAddStrokeWidth {
+                Attribute.strokeWidth(3)
+            } else {
+                Attribute.strokeColor(.yellow)
+            }
+        }
+        let expected = NSAttributedString(string: "Hello World", attributes: [.strokeColor: Color.green, .strokeWidth: 3])
+        XCTAssertEqual(subject, expected)
+    }
+
+    func testWithAttributes_SwiftyAttributedStringBuilder() {
+        let shouldAddStrokeWidth = true
+        let subject = NSAttributedString(string: "Hello World").withAttributes {
+            Attribute.strokeColor(.green)
+            if let link = URL(string: "").map { Attribute.link($0) } {
+                link
+            }
+            if shouldAddStrokeWidth {
+                Attribute.strokeWidth(3)
+            } else {
+                Attribute.strokeColor(.yellow)
+            }
+        }
+        let expected = NSAttributedString(string: "Hello World", attributes: [.strokeColor: Color.green, .strokeWidth: 3])
+        XCTAssertEqual(subject, expected)
+    }
+    #endif
+
     func testSubstringFromRange() {
         let str = "Hello".withStrikethroughColor(.blue).withUnderlineStyle(.patternDash)
         str.addAttributes([.backgroundColor(.brown)], range: 0 ..< 3)

SwiftyAttributesTests/SwiftyAttributes_Tests.swift

@@ -11,6 +11,25 @@ import SwiftyAttributes
 
 class SwiftyAttributesTests: XCTestCase {
 
+    #if swift(>=5.4)
+    func testString_withAttributes_SwiftyAttributedStringBuilder() {
+        let shouldAddStrokeWidth = true
+        let subject = "Hello".withAttributes {
+            Attribute.strokeColor(.green)
+            if let link = URL(string: "").map { Attribute.link($0) } {
+                link
+            }
+            if shouldAddStrokeWidth {
+                Attribute.strokeWidth(3)
+            } else {
+                Attribute.strokeColor(.yellow)
+            }
+        }
+        let expected = NSAttributedString(string: "Hello", attributes: [.strokeColor: Color.green, .strokeWidth: 3])
+        XCTAssertEqual(subject, expected)
+    }
+    #endif
+
     func testString_withAttribute() {
         let subject = "Hello".withAttribute(.strokeWidth(4))
         let expected = NSAttributedString(string: "Hello", attributes: [.strokeWidth: NSNumber(value: 4)])