Merge pull request swiftlang#138 from google/throwing-functions

Support throws/rethrows in function decls.

Author: dabelknap

Sources/SwiftFormatPrettyPrint/TokenStreamCreator.swift

@@ -767,6 +767,8 @@ private final class TokenStreamCreator: SyntaxVisitor {
   }
 
   override func visit(_ node: FunctionDeclSyntax) {
+    before(node.firstToken, tokens: .open(.inconsistent, 0))
+
     if let attributes = node.attributes {
       before(node.firstToken, tokens: .space(size: 0), .open(.consistent, 0))
       after(attributes.lastToken, tokens: .open)
@@ -790,6 +792,7 @@ private final class TokenStreamCreator: SyntaxVisitor {
       before(body.rightBrace, tokens: .break(offset: -2), .close)
     }
 
+    after(node.lastToken, tokens: .close)
     super.visit(node)
   }
 
@@ -824,6 +827,7 @@ private final class TokenStreamCreator: SyntaxVisitor {
   }
 
   override func visit(_ node: FunctionSignatureSyntax) {
+    before(node.throwsOrRethrowsKeyword, tokens: .break)
     before(node.output?.firstToken, tokens: .break)
     super.visit(node)
   }

Tests/SwiftFormatPrettyPrintTests/FunctionDeclTests.swift

@@ -73,6 +73,39 @@ public class FunctionDeclTests: PrettyPrintTestCase {
     assertPrettyPrintEqual(input: input, expected: expected, linelength: 50)
   }
 
+  public func testFunctionDeclThrows() {
+    let input =
+      """
+      func myFun(var1: Int) throws -> Double {
+        print("Hello World")
+        return 1.0
+      }
+      func reallyLongName(var1: Int, var2: Double, var3: Bool) throws -> Double {
+        print("Hello World")
+        return 1.0
+      }
+      """
+
+    let expected =
+      """
+      func myFun(var1: Int) throws -> Double {
+        print("Hello World")
+        return 1.0
+      }
+      func reallyLongName(
+        var1: Int,
+        var2: Double,
+        var3: Bool
+      ) throws -> Double {
+        print("Hello World")
+        return 1.0
+      }
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 50)
+  }
+
   public func testFunctionGenericParameters() {
     let input =
     """