Update Swift.g4 for swift 4.1

pmd-swift/src/main/antlr4/net/sourceforge/pmd/lang/swift/antlr4/Swift.g4

@@ -894,11 +894,14 @@ platformCondition
  : 'os' '(' operatingSystem ')'
  | 'arch' '(' architecture ')'
  | 'swift' '(' '>=' swiftVersion ')'
+ | 'canImport' '(' moduleName ')'
+ | 'targetEnvironment' '(' 'simulator' ')'
  ;
 
 operatingSystem: 'OSX' | 'iOS' | 'watchOS' | 'tvOS' ;
 architecture: 'i386' | 'x86_64' | 'arm' | 'arm64' ;
 swiftVersion: FloatingPointLiteral ;
+moduleName: IdentifierCharacters ;
 
 lineControlStatement: '#sourceLocation' '(' 'file' ':' fileName ',' 'line' ':' lineNumber ')'
  | '#sourceLocation' '(' ')' ;

pmd-swift/src/test/java/net/sourceforge/pmd/cpd/SwiftTokenizerTest.java

@@ -30,7 +30,7 @@ public class SwiftTokenizerTest extends AbstractTokenizerTest {
 
     @Test
     public void tokenizeTest() throws IOException {
-        this.expectedTokenCount = 4217;
+        this.expectedTokenCount = 4239;
         super.tokenizeTest();
     }
 }

pmd-swift/src/test/resources/net/sourceforge/pmd/cpd/BTree.swift

@@ -1003,3 +1003,13 @@ class MyClass {
 let myClass = MyClass()
 //myClass.delegate = View() // error: cannot assign value of type 'View' to type '(View & MyProtocol)?'
 myClass.delegate = ViewSubclass()
+
+// 4.1 conditional
+
+#if canImport(SomeModule)
+let someModuleImportedVersion = SomeModule.version
+#endif
+
+#if targetEnvironment(simulator)
+print("code only compiled for simulator")
+#endif