refactor style parsing

CHANGELOG.md

@@ -13,6 +13,9 @@
 #### Changed
 - Styles are applied sorted by specificity #5
 
+#### Fixed
+- Fixed nested style references
+
 [Commits](https://github.com/yonaskolb/XcodeGen/compare/0.1.0...0.2.0)
 
 ## 0.1.0

README.md

@@ -66,7 +66,7 @@ styles:
   - [Hot Reloading](#hot-reloading)
 - [🎨 Theme](#theme)
   - [Style Selectors](#style-selectors)
-  - [Included Styles](#included-styles)
+  - [Styles References](#style-references)
   - [View hierarchy styles](#view-hierarchy-styles)
   - [Style Context](#style-context)
 - [🖌 Style Properties](#style-properties)
@@ -186,9 +186,9 @@ styles:
 
 Styles will be applied in order of specificity, so the more specific a style is (more selectors), the later it will be applied.
 
-### Included Styles
+### Style references
 
-Each style may also have a `styles` array that is an array of other inherited styles, who's properties will also be applied.
+Each style may also have a `styles` array that is an array of other inherited styles, who's properties will also be applied without overwriting anything.
 
 ```yml
 styles:

Stylist/Style.swift

@@ -17,6 +17,24 @@ public class Style: Equatable {
         self.subStyles = subStyles
     }
 
+    init(dictionary: [String: Any]) throws {
+        var properties: [StylePropertyValue] = []
+        var subStyles: [String: Style] = [:]
+
+        for (propertyName, value) in dictionary {
+
+            if let subDictionary = value as? [String: Any] {
+                let style = try Style(dictionary: subDictionary)
+                subStyles[propertyName] = style
+                continue
+            }
+
+            properties.append(try StylePropertyValue(string: propertyName, value: value))
+        }
+        self.properties = properties.sorted { $0.name < $1.name }
+        self.subStyles = subStyles
+    }
+
     public static func == (lhs: Style, rhs: Style) -> Bool {
         return lhs.properties == rhs.properties
             && lhs.subStyles == rhs.subStyles

Stylist/Theme.swift

@@ -52,69 +52,59 @@ extension Theme {
     public init(dictionary: [String: Any]) throws {
         var styles: [StyleSelector] = []
         var variables: [String: Any] = dictionary["variables"] as? [String: Any] ?? [:]
-        let stylesDictionary = (dictionary["styles"] as? [String: Any]) ?? [:]
-
-        for (key, value) in stylesDictionary {
-            if var styleDictionary = value as? [String: Any] {
-                if let styles = styleDictionary["styles"] as? [String] {
-                    for style in styles {
-                        if let sharedStyle = stylesDictionary[style] as? [String: Any] {
-                            for (styleKey, styleValue) in sharedStyle {
-                                if styleDictionary[styleKey] == nil {
-                                    styleDictionary[styleKey] = styleValue
-                                }
-                            }
-                        } else {
-                            throw ThemeError.invalidStyleReference(style: key, reference: style)
-                        }
-                    }
-                    styleDictionary["styles"] = nil
-                }
-
-                func parseStyle(dictionary: [String: Any]) throws -> Style {
+        var stylesDictionary = (dictionary["styles"] as? [String: Any]) ?? [:]
 
-                    var properties: [StylePropertyValue] = []
-                    var subStyles: [String: Style] = [:]
+        var visitedStyles: Set<String> = []
 
-                    for (propertyName, value) in dictionary {
+        func getResolvedStyle(_ style: String, from parentStyle: String) throws -> [String: Any] {
+            guard !visitedStyles.contains(style) else {
+                throw ThemeError.styleReferenceCycle(references: visitedStyles)
+            }
+            visitedStyles.insert(style)
 
-                        if let subDictionary = value as? [String: Any] {
-                            let style = try parseStyle(dictionary: subDictionary)
-                            subStyles[propertyName] = style
-                            continue
+            guard var styleDictionary = stylesDictionary[style] as? [String: Any] else {
+                throw ThemeError.invalidStyleReference(style: parentStyle, reference: style)
+            }
+            if let styles = styleDictionary["styles"] as? [String] {
+                for subStyleName in styles {
+                    let subStyle = try getResolvedStyle(subStyleName, from: style)
+                    for (styleKey, styleValue) in subStyle {
+                        if styleDictionary[styleKey] == nil {
+                            styleDictionary[styleKey] = styleValue
                         }
+                    }
+                }
+            }
+            styleDictionary["styles"] = nil
 
-                        func resolveVariable(_ value: Any) throws -> Any {
-                            var propertyValue = value
-                            if let string = propertyValue as? String, string.hasPrefix("$") {
-                                var variableName = string.trimmingCharacters(in: CharacterSet(charactersIn: "$"))
-                                let parts = variableName.components(separatedBy: ":")
-                                if parts.count > 1 {
-                                    variableName = parts[0]
-                                }
-                                guard let variable = variables[variableName] else {
-                                    throw ThemeError.invalidVariable(name: propertyName, variable: variableName)
-                                }
-                                propertyValue = variable
-                                if parts.count > 1 {
-                                    propertyValue = "\(propertyValue):" + Array(parts.dropFirst()).joined(separator: ":")
-                                }
-                            }
-                            return propertyValue
-                        }
+            for (key, value) in styleDictionary {
 
-                        let propertyValue = try resolveVariable(value)
-                        properties.append(try StylePropertyValue(string: propertyName, value: propertyValue))
+                if let string = value as? String, string.hasPrefix("$") {
+                    var variableName = string.trimmingCharacters(in: CharacterSet(charactersIn: "$"))
+                    let parts = variableName.components(separatedBy: ":")
+                    if parts.count > 1 {
+                        variableName = parts[0]
+                    }
+                    guard let variable = variables[variableName] else {
+                        throw ThemeError.invalidVariable(name: key, variable: variableName)
+                    }
+                    var variableValue = variable
+                    if parts.count > 1 {
+                        variableValue = "\(variableValue):" + Array(parts.dropFirst()).joined(separator: ":")
                     }
-                   
-                    return try Style(properties: properties, subStyles: subStyles)
+
+                    styleDictionary[key] = variableValue
                 }
-                let style = try parseStyle(dictionary: styleDictionary)
-                let styleSelector = try StyleSelector(selector: key, style: style)
-                styles.append(styleSelector)
             }
+            return styleDictionary
         }
-        self.styles = styles.sorted()
+
         self.variables = variables
+        self.styles = try stylesDictionary.keys.map { selector in
+            visitedStyles = []
+            let resolvedStyleDictionary = try getResolvedStyle(selector, from: "")
+            let style = try Style(dictionary: resolvedStyleDictionary)
+            return try StyleSelector(selector: selector, style: style)
+        }.sorted()
     }
 }

Stylist/ThemeError.swift

@@ -13,6 +13,7 @@ public enum ThemeError: Error, Equatable {
     case decodingError
     case invalidVariable(name: String, variable: String)
     case invalidStyleReference(style: String, reference: String)
+    case styleReferenceCycle(references: Set<String>)
     case invalidPropertyState(name: String, state: String)
     case invalidDevice(name: String, device: String)
     case invalidSizeClass(name: String, sizeClass: String)

Tests/ThemeDecodingTests.swift

@@ -43,10 +43,13 @@ class ThemeDecodingTests: XCTestCase {
     func testStyleInheriting() throws {
         let string = """
         styles:
+          main:
+            styles: [primary]
+            color: green
           primary:
             tintColor: red
           header:
-            styles: [primary]
+            styles: [main]
             textColor: blue
         """
 
@@ -55,9 +58,14 @@ class ThemeDecodingTests: XCTestCase {
         let expectedTheme = Theme(
             styles: [
                 try StyleSelector(selector: "header", style: Style(properties: [
+                    StylePropertyValue(name: "color", value: "green"),
                     StylePropertyValue(name: "textColor", value: "blue"),
                     StylePropertyValue(name: "tintColor", value: "red"),
                     ])),
+                try StyleSelector(selector: "main", style: Style(properties: [
+                    StylePropertyValue(name: "color", value: "green"),
+                    StylePropertyValue(name: "tintColor", value: "red"),
+                    ])),
                 try StyleSelector(selector: "primary", style: Style(properties: [
                     StylePropertyValue(name: "tintColor", value: "red"),
                     ])),
@@ -207,8 +215,8 @@ class ThemeDecodingTests: XCTestCase {
 
     func testThemeDecodingErrors() throws {
 
-        func themeString(style: String = "testStyle", property: String? = nil) throws {
-            var theme = ""
+        func parseTheme(theme: String = "", style: String = "testStyle", property: String? = nil) throws {
+            var theme = theme
             if let property = property {
                 theme += "\nstyles:\n  \(style):\n    \(property)"
             }
@@ -224,39 +232,49 @@ class ThemeDecodingTests: XCTestCase {
         }
 
         expectError(ThemeError.invalidVariable(name: "prop", variable: "variable")) {
-            try themeString(property: "prop: $variable")
+            try parseTheme(property: "prop: $variable")
         }
 
         expectError(ThemeError.invalidStyleReference(style: "testStyle", reference: "invalid")) {
-            try themeString(property: "styles: [invalid]")
+            try parseTheme(property: "styles: [invalid]")
         }
 
         expectError(ThemeError.invalidPropertyState(name: "color", state: "invalid")) {
-            try themeString(property: "color:invalid: red")
+            try parseTheme(property: "color:invalid: red")
         }
 
         expectError(ThemeError.invalidDevice(name: "color", device: "invalid")) {
-            try themeString(property: "color(device:invalid): red")
+            try parseTheme(property: "color(device:invalid): red")
         }
 
         expectError(ThemeError.invalidStyleContext("color(invalid)")) {
-            try themeString(property: "color(invalid): red")
+            try parseTheme(property: "color(invalid): red")
         }
 
         expectError(ThemeError.invalidStyleContext("color(invalid:ipad)")) {
-            try themeString(property: "color(invalid:ipad): red")
+            try parseTheme(property: "color(invalid:ipad): red")
         }
 
         expectError(ThemeError.invalidStyleSelector("InvalidClass")) {
-            try themeString(style: "InvalidClass", property: "color: red")
+            try parseTheme(style: "InvalidClass", property: "color: red")
         }
 
         expectError(ThemeError.invalidStyleSelector("Module.class.style.invalid")) {
-            try themeString(style: "Module.class.style.invalid", property: "color: red")
+            try parseTheme(style: "Module.class.style.invalid", property: "color: red")
         }
 
         expectError(ThemeError.invalidStyleSelector("Module.Invalid")) {
-            try themeString(style: "Module.Invalid", property: "color: red")
+            try parseTheme(style: "Module.Invalid", property: "color: red")
+        }
+
+        expectError(ThemeError.styleReferenceCycle(references: ["one", "two"])) {
+            try parseTheme(theme: """
+                styles:
+                    one:
+                        styles: [two]
+                    two:
+                        styles: [one]
+                """)
         }
     }