Add support for tries, and do-catch blocks.

Author: dabelknap

Sources/PrettyPrint/TokenStreamCreator.swift

@@ -495,10 +495,31 @@ private final class TokenStreamCreator: SyntaxVisitor {
   }
 
   override func visit(_ node: AsExprSyntax) {
+    before(node.asTok, tokens: .space)
+    after(node.asTok, tokens: .break)
     super.visit(node)
   }
 
   override func visit(_ node: DoStmtSyntax) {
+    after(node.doKeyword, tokens: .space)
+    after(node.body.leftBrace, tokens: .newline(offset: 2), .open(.consistent, 0))
+    before(node.body.rightBrace, tokens: .break(offset: -2), .close)
+    super.visit(node)
+  }
+
+  override func visit(_ node: CatchClauseSyntax) {
+    before(node.catchKeyword, tokens: .space)
+    before(node.pattern?.firstToken, tokens: .break)
+
+    if let whereClause = node.whereClause {
+      before(whereClause.firstToken, tokens: .break(offset: 2), .open(.consistent, 0))
+      before(node.body.leftBrace, tokens: .break(offset: -2), .close)
+    } else {
+      before(node.body.leftBrace, tokens: .break)
+    }
+
+    after(node.body.leftBrace, tokens: .newline(offset: 2), .open(.consistent, 0))
+    before(node.body.rightBrace, tokens: .break(offset: -2), .close)
     super.visit(node)
   }
 
@@ -521,10 +542,13 @@ private final class TokenStreamCreator: SyntaxVisitor {
   }
 
   override func visit(_ node: IsExprSyntax) {
+    before(node.isTok, tokens: .space)
+    after(node.isTok, tokens: .break)
     super.visit(node)
   }
 
   override func visit(_ node: TryExprSyntax) {
+    before(node.expression.firstToken, tokens: .break)
     super.visit(node)
   }
 
@@ -702,10 +726,6 @@ private final class TokenStreamCreator: SyntaxVisitor {
     super.visit(node)
   }
 
-  override func visit(_ node: CatchClauseSyntax) {
-    super.visit(node)
-  }
-
   override func visit(_ node: DotSelfExprSyntax) {
     super.visit(node)
   }
@@ -868,6 +888,7 @@ private final class TokenStreamCreator: SyntaxVisitor {
   }
 
   override func visit(_ node: IsTypePatternSyntax) {
+    after(node.isKeyword, tokens: .break)
     super.visit(node)
   }
 

Tests/PrettyPrinterTests/TryCatchTests.swift

@@ -0,0 +1,104 @@
+public class TryCatchTests: PrettyPrintTestCase {
+  public func testBasicTries() {
+    let input =
+      """
+      let a = try possiblyFailingFunc()
+      let a = try? possiblyFailingFunc()
+      let a = try! possiblyFailingFunc()
+      """
+
+    let expected =
+      """
+      let a = try possiblyFailingFunc()
+      let a = try? possiblyFailingFunc()
+      let a = try! possiblyFailingFunc()
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 40)
+  }
+
+  public func testDoTryCatch() {
+    let input =
+      """
+      do {
+        try thisFuncMightFail()
+      } catch error1 {
+        print("Nope")
+      }
+      do {
+        try thisFuncMightFail()
+      } catch error1 {
+        print("Nope")
+      } catch error2(let someVar) {
+        print(someVar)
+        print("Don't do it!")
+      }
+      do {
+        try thisFuncMightFail()
+      } catch is ABadError{
+        print("Nope")
+      }
+      """
+
+    let expected =
+      """
+      do {
+        try thisFuncMightFail()
+      } catch error1 {
+        print("Nope")
+      }
+      do {
+        try thisFuncMightFail()
+      } catch error1 {
+        print("Nope")
+      } catch error2(let someVar) {
+        print(someVar)
+        print("Don't do it!")
+      }
+      do {
+        try thisFuncMightFail()
+      } catch is ABadError {
+        print("Nope")
+      }
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 40)
+  }
+
+  public func testCatchWhere() {
+    let input =
+      """
+      do {
+        try thisFuncMightFail()
+      } catch error1 where error1 is ErrorType {
+        print("Nope")
+      }
+      do {
+        try thisFuncMightFail()
+      } catch error1 where error1 is LongerErrorType {
+        print("Nope")
+      }
+      """
+
+    let expected =
+      """
+      do {
+        try thisFuncMightFail()
+      } catch error1 where error1 is ErrorType {
+        print("Nope")
+      }
+      do {
+        try thisFuncMightFail()
+      } catch error1
+        where error1 is LongerErrorType
+      {
+        print("Nope")
+      }
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 45)
+  }
+}