Make importer protocol.

Sources/LibMakeColors/Importers/Importer.swift

@@ -0,0 +1,5 @@
+protocol Importer {
+    init(source: String) throws
+
+    func read() throws -> [String: ColorDef]
+}

Sources/LibMakeColors/Importers/List/ListImporter.swift

@@ -0,0 +1,36 @@
+import Foundation
+
+struct ListImporter: Importer {
+    let input: String
+
+    init(source: String) {
+        input = source
+    }
+
+    func read() throws -> [String: ColorDef] {
+        let scanner = Scanner(string: try readInput())
+        scanner.charactersToBeSkipped = .whitespaces
+
+        return try scanner.colorList()
+    }
+
+    func readInput() throws -> String {
+        if input == "-" {
+            return try readStdin()
+        }
+
+        let url = URL(fileURLWithPath: input)
+        return try String(contentsOf: url)
+    }
+
+    func readStdin() throws -> String {
+        guard
+            let data = try FileHandle.standardInput.readToEnd(),
+            let input = String(data: data, encoding: .utf8)
+        else {
+            throw Errors.cannotReadStdin
+        }
+
+        return input
+    }
+}

Sources/LibMakeColors/Importers/List/Scanner+ColorParser.swift

@@ -110,7 +110,7 @@ extension Scanner {
 
     func colorLine() -> (String, ColorDef)? {
         guard
-            let name = self.name(),
+            let name = name(),
             let def = colorDef(),
             endOfLine()
         else {
@@ -168,7 +168,7 @@ extension Scanner {
     func commaSeparated() -> [UInt8]? {
         var result: [UInt8] = []
         repeat {
-            guard let component = self.component() else {
+            guard let component = component() else {
                 return nil
             }
             result.append(component)

Sources/LibMakeColors/MakeColors.swift

@@ -66,10 +66,8 @@ public final class MakeColors: ParsableCommand, Context {
     public init() {}
 
     public func run() throws {
-        let scanner = Scanner(string: try readInput())
+        let importer = ListImporter(source: input)
-        scanner.charactersToBeSkipped = .whitespaces
+        let data = try importer.read()
-
-        let data = try scanner.colorList()
 
         if dump {
             try dump(data: data)
@@ -81,26 +79,6 @@ public final class MakeColors: ParsableCommand, Context {
         try writeOutput(fileWrapper)
     }
 
-    func readInput() throws -> String {
-        if input == "-" {
-            return try readStdin()
-        }
-
-        let url = URL(fileURLWithPath: input)
-        return try String(contentsOf: url)
-    }
-
-    func readStdin() throws -> String {
-        guard
-            let data = try FileHandle.standardInput.readToEnd(),
-            let input = String(data: data, encoding: .utf8)
-        else {
-            throw Errors.cannotReadStdin
-        }
-
-        return input
-    }
-
     func dump(data: [String: ColorDef]) throws {
         for (key, color) in data.sorted() {
             let resolved = try data.resolve(key)