Merge pull request swiftlang#174 from dabelknap/closures

Add closure captures, and allow for bodiless closures.

Author: allevato

Sources/SwiftFormatPrettyPrint/PrettyPrint.swift

@@ -465,6 +465,7 @@ public class PrettyPrinter {
       print("[SPACE Size: \(size) Length: \(length)]")
 
     case .reset:
+      printDebugIndent()
       print("[RESET]")
 
     case .comment(let comment):

Sources/SwiftFormatPrettyPrint/TokenStreamCreator.swift

@@ -200,27 +200,29 @@ private final class TokenStreamCreator: SyntaxVisitor {
 
   override func visit(_ node: FunctionCallArgumentSyntax) {
     after(node.colon, tokens: .break)
-
-      before(node.firstToken, tokens: .open)
-      if let trailingComma = node.trailingComma {
-        after(trailingComma, tokens: .close, .break)
-      } else {
-        after(node.lastToken, tokens: .close)
-      }
-      super.visit(node)
+    before(node.firstToken, tokens: .open)
+    if let trailingComma = node.trailingComma {
+      after(trailingComma, tokens: .close, .break)
+    } else {
+      after(node.lastToken, tokens: .close)
+    }
+    super.visit(node)
   }
 
   override func visit(_ node: ClosureExprSyntax) {
     before(node.firstToken, tokens: .reset)
     if let signature = node.signature {
       before(signature.firstToken, tokens: .break(offset: 2))
-      before(node.statements.firstToken, tokens: .newline(offset: 2), .open(.consistent, 0))
+      if node.statements.count > 0 {
+        after(signature.inTok, tokens: .newline(offset: 2), .open(.consistent, 0))
+      } else {
+        after(signature.inTok, tokens: .break(size: 0, offset: 2), .open(.consistent, 0))
+      }
       before(node.rightBrace, tokens: .break(offset: -2), .close)
     } else {
-      before(node.statements.firstToken, tokens: .break(offset: 2), .open(.consistent, 0))
+      after(node.leftBrace, tokens: .break(offset: 2), .open(.consistent, 0))
       before(node.rightBrace, tokens: .break(offset: -2), .close)
     }
-
     super.visit(node)
   }
 
@@ -230,19 +232,33 @@ private final class TokenStreamCreator: SyntaxVisitor {
   }
 
   override func visit(_ node: ClosureSignatureSyntax) {
-    before(node.firstToken, tokens: .open(.inconsistent, 2))
-    after(node.input?.lastToken, tokens: .break)
+    before(node.firstToken, tokens: .open(.inconsistent, 0))
+    after(node.capture?.lastToken, tokens: .break)
+    before(node.input?.firstToken, tokens: .open)
+    after(node.input?.lastToken, tokens: .close, .break)
     after(node.output?.lastToken, tokens: .break)
     after(node.throwsTok, tokens: .break)
     after(node.lastToken, tokens: .close)
     super.visit(node)
   }
 
   override func visit(_ node: ClosureCaptureSignatureSyntax) {
+    after(node.leftSquare, tokens: .break(size: 0, offset: 2), .open(.consistent, 0))
+    before(node.rightSquare, tokens: .break(size: 0, offset: -2), .close)
     super.visit(node)
   }
 
   override func visit(_ node: ClosureCaptureItemSyntax) {
+    before(node.firstToken, tokens: .open)
+    after(node.specifier?.lastToken, tokens: .break)
+    before(node.assignToken, tokens: .break)
+    after(node.assignToken, tokens: .break)
+    if let trailingComma = node.trailingComma {
+      before(trailingComma, tokens: .close)
+      after(trailingComma, tokens: .break)
+    } else {
+      after(node.lastToken, tokens: .close)
+    }
     super.visit(node)
   }
 
@@ -1398,7 +1414,7 @@ private final class TokenStreamCreator: SyntaxVisitor {
         if index > 0 || isStartOfFile {
           if token.withoutTrivia().text == "}" {
             if let previousToken = token.previousToken,
-               previousToken.withoutTrivia().text == "{" {
+              (["{", "in"].contains { $0 == previousToken.withoutTrivia().text }) {
               // do nothing
             } else {
               appendToken(.newline)

Tests/SwiftFormatPrettyPrintTests/FunctionCallTests.swift

@@ -75,7 +75,7 @@ public class FunctionCallTests: PrettyPrintTestCase {
       })
       funcCall(closure: {
         s1, s2, s3, s4, s5, s6, s7, s8, s9, s10
-          in
+        in
         return s1
       })
       funcCall(
@@ -164,4 +164,60 @@ public class FunctionCallTests: PrettyPrintTestCase {
 
     assertPrettyPrintEqual(input: input, expected: expected, linelength: 40)
   }
+
+  public func testClosureCapture() {
+    let input =
+      """
+      let a = funcCall() { [weak self] (a: Int) in
+        return a + 1
+      }
+      let a = funcCall() { [weak self, weak a = self.b] (a: Int) in
+        return a + 1
+      }
+      let b = funcCall() { [unowned self, weak delegate = self.delegate!] (a: Int, b: String) -> String in
+        return String(a) + b
+      }
+      """
+
+    let expected =
+      """
+      let a = funcCall() { [weak self] (a: Int) in
+        return a + 1
+      }
+      let a = funcCall() {
+        [weak self, weak a = self.b] (a: Int) in
+        return a + 1
+      }
+      let b = funcCall() {
+        [unowned self, weak delegate = self.delegate!]
+        (a: Int, b: String) -> String in
+        return String(a) + b
+      }
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 60)
+  }
+
+  public func testBodilessClosure() {
+    let input =
+      """
+      let a = funcCall() { s1, s2 in
+        // Move along, nothing here to see
+      }
+      let a = funcCall() { s1, s2 in }
+      """
+
+
+    let expected =
+      """
+      let a = funcCall() { s1, s2 in
+        // Move along, nothing here to see
+      }
+      let a = funcCall() { s1, s2 in }
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 60)
+  }
 }