Use Swift 4 features

.travis.yml

@@ -1,10 +1,15 @@
 matrix:
   include:
     - os: osx
-      osx_image: xcode9.3
+      osx_image: xcode9.4
       env: SWIFT_VERSION=4.1
+    - os: osx
+      osx_image: xcode10
+      env: SWIFT_VERSION=4.2
     - os: linux
       env: SWIFT_VERSION=4.1
+    - os: linux
+      env: SWIFT_VERSION=4.2
 language: generic
 sudo: required
 dist: trusty

CHANGELOG.md

@@ -16,11 +16,13 @@
 
 ### New Features
 
- _None_
+_None_
 
 ### Internal Changes
 
- _None_
+- Updated the codebase to use Swift 4 features.  
+  [David Jennes](https://github.com/djbe)
+  [#239](https://github.com/stencilproject/Stencil/pull/239)
 
 
 ## 0.12.1

Sources/Errors.swift

@@ -37,11 +37,6 @@ public struct TemplateSyntaxError : Error, Equatable, CustomStringConvertible {
   public init(_ description: String) {
     self.init(reason: description)
   }
-
-  public static func ==(lhs:TemplateSyntaxError, rhs:TemplateSyntaxError) -> Bool {
-    return lhs.description == rhs.description && lhs.token == rhs.token && lhs.stackTrace == rhs.stackTrace
-  }
-
 }
 
 extension Error {
@@ -67,11 +62,16 @@ open class SimpleErrorReporter: ErrorReporter {
     func describe(token: Token) -> String {
       let templateName = token.sourceMap.filename ?? ""
       let location = token.sourceMap.location
-      let highlight = "\(String(Array(repeating: " ", count: location.lineOffset)))^\(String(Array(repeating: "~", count: max(token.contents.count - 1, 0))))"
-
-      return "\(templateName)\(location.lineNumber):\(location.lineOffset): error: \(templateError.reason)\n"
-        + "\(location.content)\n"
-        + "\(highlight)\n"
+      let highlight = """
+        \(String(Array(repeating: " ", count: location.lineOffset)))\
+        ^\(String(Array(repeating: "~", count: max(token.contents.count - 1, 0))))
+        """
+
+      return """
+        \(templateName)\(location.lineNumber):\(location.lineOffset): error: \(templateError.reason)
+        \(location.content)
+        \(highlight)
+        """
     }
 
     var descriptions = templateError.stackTrace.reduce([]) { $0 + [describe(token: $1)] }

Sources/Filters.swift

@@ -74,15 +74,19 @@ func indentFilter(value: Any?, arguments: [Any?]) throws -> Any? {
   var indentWidth = 4
   if arguments.count > 0 {
     guard let value = arguments[0] as? Int else {
-      throw TemplateSyntaxError("'indent' filter width argument must be an Integer (\(String(describing: arguments[0])))")
+      throw TemplateSyntaxError("""
+        'indent' filter width argument must be an Integer (\(String(describing: arguments[0])))
+        """)
     }
     indentWidth = value
   }
 
   var indentationChar = " "
   if arguments.count > 1 {
     guard let value = arguments[1] as? String else {
-      throw TemplateSyntaxError("'indent' filter indentation argument must be a String (\(String(describing: arguments[1]))")
+      throw TemplateSyntaxError("""
+        'indent' filter indentation argument must be a String (\(String(describing: arguments[1]))
+        """)
     }
     indentationChar = value
   }

Sources/Include.swift

@@ -10,7 +10,11 @@ class IncludeNode : NodeType {
     let bits = token.components()
 
     guard bits.count == 2 || bits.count == 3 else {
-      throw TemplateSyntaxError("'include' tag requires one argument, the template file to be included. A second optional argument can be used to specify the context that will be passed to the included file")
+      throw TemplateSyntaxError("""
+        'include' tag requires one argument, the template file to be included. \
+        A second optional argument can be used to specify the context that will \
+        be passed to the included file
+        """)
     }
 
     return IncludeNode(templateName: Variable(bits[1]), includeContext: bits.count == 3 ? bits[2] : nil, token: token)

Sources/Parser.swift

@@ -98,7 +98,10 @@ public class TokenParser {
     if suggestedFilters.isEmpty {
       throw TemplateSyntaxError("Unknown filter '\(name)'.")
     } else {
-      throw TemplateSyntaxError("Unknown filter '\(name)'. Found similar filters: \(suggestedFilters.map({ "'\($0)'" }).joined(separator: ", ")).")
+      throw TemplateSyntaxError("""
+        Unknown filter '\(name)'. \
+        Found similar filters: \(suggestedFilters.map({ "'\($0)'" }).joined(separator: ", ")).
+        """)
     }
   }
 

Sources/Tokenizer.swift

@@ -114,21 +114,4 @@ public enum Token : Equatable {
       return sourceMap
     }
   }
-
-}
-
-
-public func == (lhs: Token, rhs: Token) -> Bool {
-  switch (lhs, rhs) {
-  case let (.text(lhsValue, lhsAt), .text(rhsValue, rhsAt)):
-    return lhsValue == rhsValue && lhsAt == rhsAt
-  case let (.variable(lhsValue, lhsAt), .variable(rhsValue, rhsAt)):
-    return lhsValue == rhsValue && lhsAt == rhsAt
-  case let (.block(lhsValue, lhsAt), .block(rhsValue, rhsAt)):
-    return lhsValue == rhsValue && lhsAt == rhsAt
-  case let (.comment(lhsValue, lhsAt), .comment(rhsValue, rhsAt)):
-    return lhsValue == rhsValue && lhsAt == rhsAt
-  default:
-    return false
-  }
 }

Sources/Variable.swift

@@ -128,10 +128,6 @@ public struct Variable : Equatable, Resolvable {
   }
 }
 
-public func ==(lhs: Variable, rhs: Variable) -> Bool {
-  return lhs.variable == rhs.variable
-}
-
 /// A structure used to represet range of two integer values expressed as `from...to`.
 /// Values should be numbers (they will be converted to integers).
 /// Rendering this variable produces array from range `from...to`.