[Kaleidoscope] Clang-format the Kaleidoscope tutorials.

Also reduces changes between tutorial chapters.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245472 91177308-0d34-0410-b5e6-96231b3b80d8

9 files changed, 594 insertions, 466 deletions

diff --git a/examples/Kaleidoscope/Chapter2/CMakeLists.txt b/examples/Kaleidoscope/Chapter2/CMakeLists.txt
index fed3f4b78c7..a02faa22130 100644
--- a/examples/Kaleidoscope/Chapter2/CMakeLists.txt
+++ b/examples/Kaleidoscope/Chapter2/CMakeLists.txt
@@ -1,3 +1,5 @@
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-unused-private-field")
+
 add_kaleidoscope_chapter(Kaleidoscope-Ch2
   toy.cpp
   )
diff --git a/examples/Kaleidoscope/Chapter2/Makefile b/examples/Kaleidoscope/Chapter2/Makefile
index 1a9b94ce541..fa27e6e0668 100644
--- a/examples/Kaleidoscope/Chapter2/Makefile
+++ b/examples/Kaleidoscope/Chapter2/Makefile
@@ -10,4 +10,6 @@ LEVEL = ../../..
 TOOLNAME = Kaleidoscope-Ch2
 EXAMPLE_TOOL = 1
 
+LLVM_CXXFLAGS := -Wno-unused-private-field
+
 include $(LEVEL)/Makefile.common
diff --git a/examples/Kaleidoscope/Chapter2/toy.cpp b/examples/Kaleidoscope/Chapter2/toy.cpp
index 789caabce0f..9ecf75d3467 100644
--- a/examples/Kaleidoscope/Chapter2/toy.cpp
+++ b/examples/Kaleidoscope/Chapter2/toy.cpp
@@ -15,14 +15,16 @@ enum Token {
   tok_eof = -1,
 
   // commands
-  tok_def = -2, tok_extern = -3,
+  tok_def = -2,
+  tok_extern = -3,
 
   // primary
-  tok_identifier = -4, tok_number = -5
+  tok_identifier = -4,
+  tok_number = -5
 };
 
-static std::string IdentifierStr;  // Filled in if tok_identifier
-static double NumVal;              // Filled in if tok_number
+static std::string IdentifierStr; // Filled in if tok_identifier
+static double NumVal;             // Filled in if tok_number
 
 /// gettok - Return the next token from standard input.
 static int gettok() {
@@ -37,12 +39,14 @@ static int gettok() {
     while (isalnum((LastChar = getchar())))
       IdentifierStr += LastChar;
 
-    if (IdentifierStr == "def") return tok_def;
-    if (IdentifierStr == "extern") return tok_extern;
+    if (IdentifierStr == "def")
+      return tok_def;
+    if (IdentifierStr == "extern")
+      return tok_extern;
     return tok_identifier;
   }
 
-  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
+  if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+
     std::string NumStr;
     do {
       NumStr += LastChar;
@@ -55,13 +59,14 @@ static int gettok() {
 
   if (LastChar == '#') {
     // Comment until end of line.
-    do LastChar = getchar();
+    do
+      LastChar = getchar();
     while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
-    
+
     if (LastChar != EOF)
       return gettok();
   }
-  
+
   // Check for end of file.  Don't eat the EOF.
   if (LastChar == EOF)
     return tok_eof;
@@ -84,32 +89,40 @@ public:
 
 /// NumberExprAST - Expression class for numeric literals like "1.0".
 class NumberExprAST : public ExprAST {
+  double Val;
+
 public:
-  NumberExprAST(double Val) {}
+  NumberExprAST(double Val) : Val(Val) {}
 };
 
 /// VariableExprAST - Expression class for referencing a variable, like "a".
 class VariableExprAST : public ExprAST {
   std::string Name;
+
 public:
   VariableExprAST(const std::string &Name) : Name(Name) {}
 };
 
 /// BinaryExprAST - Expression class for a binary operator.
 class BinaryExprAST : public ExprAST {
+  char Op;
+  std::unique_ptr<ExprAST> LHS, RHS;
+
 public:
   BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
-                std::unique_ptr<ExprAST> RHS) {}
+                std::unique_ptr<ExprAST> RHS)
+      : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
 };
 
 /// CallExprAST - Expression class for function calls.
 class CallExprAST : public ExprAST {
   std::string Callee;
   std::vector<std::unique_ptr<ExprAST>> Args;
+
 public:
   CallExprAST(const std::string &Callee,
               std::vector<std::unique_ptr<ExprAST>> Args)
-    : Callee(Callee), Args(std::move(Args)) {}
+      : Callee(Callee), Args(std::move(Args)) {}
 };
 
 /// PrototypeAST - This class represents the "prototype" for a function,
@@ -118,17 +131,21 @@ public:
 class PrototypeAST {
   std::string Name;
   std::vector<std::string> Args;
+
 public:
   PrototypeAST(const std::string &Name, std::vector<std::string> Args)
-    : Name(Name), Args(std::move(Args)) {}
-  
+      : Name(Name), Args(std::move(Args)) {}
 };
 
 /// FunctionAST - This class represents a function definition itself.
 class FunctionAST {
+  std::unique_ptr<PrototypeAST> Proto;
+  std::unique_ptr<ExprAST> Body;
+
 public:
   FunctionAST(std::unique_ptr<PrototypeAST> Proto,
-              std::unique_ptr<ExprAST> Body) {}
+              std::unique_ptr<ExprAST> Body)
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
 };
 } // end anonymous namespace
 
@@ -140,9 +157,7 @@ public:
 /// token the parser is looking at.  getNextToken reads another token from the
 /// lexer and updates CurTok with its results.
 static int CurTok;
-static int getNextToken() {
-  return CurTok = gettok();
-}
+static int getNextToken() { return CurTok = gettok(); }
 
 /// BinopPrecedence - This holds the precedence for each binary operator that is
 /// defined.
@@ -152,10 +167,11 @@ static std::map<char, int> BinopPrecedence;
 static int GetTokPrecedence() {
   if (!isascii(CurTok))
     return -1;
-  
+
   // Make sure it's a declared binop.
   int TokPrec = BinopPrecedence[CurTok];
-  if (TokPrec <= 0) return -1;
+  if (TokPrec <= 0)
+    return -1;
   return TokPrec;
 }
 
@@ -171,19 +187,39 @@ std::unique_ptr<PrototypeAST> ErrorP(const char *Str) {
 
 static std::unique_ptr<ExprAST> ParseExpression();
 
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return Error("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
 /// identifierexpr
 ///   ::= identifier
 ///   ::= identifier '(' expression* ')'
 static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
   std::string IdName = IdentifierStr;
-  
-  getNextToken();  // eat identifier.
-  
+
+  getNextToken(); // eat identifier.
+
   if (CurTok != '(') // Simple variable ref.
     return llvm::make_unique<VariableExprAST>(IdName);
-  
+
   // Call.
-  getNextToken();  // eat (
+  getNextToken(); // eat (
   std::vector<std::unique_ptr<ExprAST>> Args;
   if (CurTok != ')') {
     while (1) {
@@ -192,7 +228,8 @@ static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
       else
         return nullptr;
 
-      if (CurTok == ')') break;
+      if (CurTok == ')')
+        break;
 
       if (CurTok != ',')
         return Error("Expected ')' or ',' in argument list");
@@ -202,28 +239,8 @@ static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
 
   // Eat the ')'.
   getNextToken();
-  
-  return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
-}
-
-/// numberexpr ::= number
-static std::unique_ptr<ExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return std::move(Result);
-}
 
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken();  // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-  
-  if (CurTok != ')')
-    return Error("expected ')'");
-  getNextToken();  // eat ).
-  return V;
+  return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
 }
 
 /// primary
@@ -232,10 +249,14 @@ static std::unique_ptr<ExprAST> ParseParenExpr() {
 ///   ::= parenexpr
 static std::unique_ptr<ExprAST> ParsePrimary() {
   switch (CurTok) {
-  default: return Error("unknown token when expecting an expression");
-  case tok_identifier: return ParseIdentifierExpr();
-  case tok_number:     return ParseNumberExpr();
-  case '(':            return ParseParenExpr();
+  default:
+    return Error("unknown token when expecting an expression");
+  case tok_identifier:
+    return ParseIdentifierExpr();
+  case tok_number:
+    return ParseNumberExpr();
+  case '(':
+    return ParseParenExpr();
   }
 }
 
@@ -246,31 +267,33 @@ static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
   // If this is a binop, find its precedence.
   while (1) {
     int TokPrec = GetTokPrecedence();
-    
+
     // If this is a binop that binds at least as tightly as the current binop,
     // consume it, otherwise we are done.
     if (TokPrec < ExprPrec)
       return LHS;
-    
+
     // Okay, we know this is a binop.
     int BinOp = CurTok;
-    getNextToken();  // eat binop
-    
+    getNextToken(); // eat binop
+
     // Parse the primary expression after the binary operator.
     auto RHS = ParsePrimary();
-    if (!RHS) return nullptr;
-    
+    if (!RHS)
+      return nullptr;
+
     // If BinOp binds less tightly with RHS than the operator after RHS, let
     // the pending operator take RHS as its LHS.
     int NextPrec = GetTokPrecedence();
     if (TokPrec < NextPrec) {
-      RHS = ParseBinOpRHS(TokPrec+1, std::move(RHS));
-      if (!RHS) return nullptr;
+      RHS = ParseBinOpRHS(TokPrec + 1, std::move(RHS));
+      if (!RHS)
+        return nullptr;
     }
-    
+
     // Merge LHS/RHS.
-    LHS = llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS),
-                                           std::move(RHS));
+    LHS =
+        llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
   }
 }
 
@@ -279,8 +302,9 @@ static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
 ///
 static std::unique_ptr<ExprAST> ParseExpression() {
   auto LHS = ParsePrimary();
-  if (!LHS) return nullptr;
-  
+  if (!LHS)
+    return nullptr;
+
   return ParseBinOpRHS(0, std::move(LHS));
 }
 
@@ -292,28 +316,28 @@ static std::unique_ptr<PrototypeAST> ParsePrototype() {
 
   std::string FnName = IdentifierStr;
   getNextToken();
-  
+
   if (CurTok != '(')
     return ErrorP("Expected '(' in prototype");
-  
+
   std::vector<std::string> ArgNames;
   while (getNextToken() == tok_identifier)
     ArgNames.push_back(IdentifierStr);
   if (CurTok != ')')
     return ErrorP("Expected ')' in prototype");
-  
+
   // success.
-  getNextToken();  // eat ')'.
-  
-  return llvm::make_unique<PrototypeAST>(std::move(FnName),
-                                         std::move(ArgNames));
+  getNextToken(); // eat ')'.
+
+  return llvm::make_unique<PrototypeAST>(FnName, std::move(ArgNames));
 }
 
 /// definition ::= 'def' prototype expression
 static std::unique_ptr<FunctionAST> ParseDefinition() {
-  getNextToken();  // eat def.
+  getNextToken(); // eat def.
   auto Proto = ParsePrototype();
-  if (!Proto) return nullptr;
+  if (!Proto)
+    return nullptr;
 
   if (auto E = ParseExpression())
     return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
@@ -324,8 +348,8 @@ static std::unique_ptr<FunctionAST> ParseDefinition() {
 static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
   if (auto E = ParseExpression()) {
     // Make an anonymous proto.
-    auto Proto = llvm::make_unique<PrototypeAST>("",
-                                                 std::vector<std::string>());
+    auto Proto =
+        llvm::make_unique<PrototypeAST>("", std::vector<std::string>());
     return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
   }
   return nullptr;
@@ -333,7 +357,7 @@ static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
 
 /// external ::= 'extern' prototype
 static std::unique_ptr<PrototypeAST> ParseExtern() {
-  getNextToken();  // eat extern.
+  getNextToken(); // eat extern.
   return ParsePrototype();
 }
 
@@ -374,11 +398,20 @@ static void MainLoop() {
   while (1) {
     fprintf(stderr, "ready> ");
     switch (CurTok) {
-    case tok_eof:    return;
-    case ';':        getNextToken(); break;  // ignore top-level semicolons.
-    case tok_def:    HandleDefinition(); break;
-    case tok_extern: HandleExtern(); break;
-    default:         HandleTopLevelExpression(); break;
+    case tok_eof:
+      return;
+    case ';': // ignore top-level semicolons.
+      getNextToken();
+      break;
+    case tok_def:
+      HandleDefinition();
+      break;
+    case tok_extern:
+      HandleExtern();
+      break;
+    default:
+      HandleTopLevelExpression();
+      break;
     }
   }
 }
@@ -393,7 +426,7 @@ int main() {
   BinopPrecedence['<'] = 10;
   BinopPrecedence['+'] = 20;
   BinopPrecedence['-'] = 20;
-  BinopPrecedence['*'] = 40;  // highest.
+  BinopPrecedence['*'] = 40; // highest.
 
   // Prime the first token.
   fprintf(stderr, "ready> ");
diff --git a/examples/Kaleidoscope/Chapter3/toy.cpp b/examples/Kaleidoscope/Chapter3/toy.cpp
index d425b101b51..29914aa0331 100644
--- a/examples/Kaleidoscope/Chapter3/toy.cpp
+++ b/examples/Kaleidoscope/Chapter3/toy.cpp
@@ -21,14 +21,16 @@ enum Token {
   tok_eof = -1,
 
   // commands
-  tok_def = -2, tok_extern = -3,
+  tok_def = -2,
+  tok_extern = -3,
 
   // primary
-  tok_identifier = -4, tok_number = -5
+  tok_identifier = -4,
+  tok_number = -5
 };
 
-static std::string IdentifierStr;  // Filled in if tok_identifier
-static double NumVal;              // Filled in if tok_number
+static std::string IdentifierStr; // Filled in if tok_identifier
+static double NumVal;             // Filled in if tok_number
 
 /// gettok - Return the next token from standard input.
 static int gettok() {
@@ -43,12 +45,14 @@ static int gettok() {
     while (isalnum((LastChar = getchar())))
       IdentifierStr += LastChar;
 
-    if (IdentifierStr == "def") return tok_def;
-    if (IdentifierStr == "extern") return tok_extern;
+    if (IdentifierStr == "def")
+      return tok_def;
+    if (IdentifierStr == "extern")
+      return tok_extern;
     return tok_identifier;
   }
 
-  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
+  if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+
     std::string NumStr;
     do {
       NumStr += LastChar;
@@ -61,13 +65,14 @@ static int gettok() {
 
   if (LastChar == '#') {
     // Comment until end of line.
-    do LastChar = getchar();
+    do
+      LastChar = getchar();
     while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
-    
+
     if (LastChar != EOF)
       return gettok();
   }
-  
+
   // Check for end of file.  Don't eat the EOF.
   if (LastChar == EOF)
     return tok_eof;
@@ -92,6 +97,7 @@ public:
 /// NumberExprAST - Expression class for numeric literals like "1.0".
 class NumberExprAST : public ExprAST {
   double Val;
+
 public:
   NumberExprAST(double Val) : Val(Val) {}
   Value *Codegen() override;
@@ -100,6 +106,7 @@ public:
 /// VariableExprAST - Expression class for referencing a variable, like "a".
 class VariableExprAST : public ExprAST {
   std::string Name;
+
 public:
   VariableExprAST(const std::string &Name) : Name(Name) {}
   Value *Codegen() override;
@@ -109,10 +116,11 @@ public:
 class BinaryExprAST : public ExprAST {
   char Op;
   std::unique_ptr<ExprAST> LHS, RHS;
+
 public:
   BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
                 std::unique_ptr<ExprAST> RHS)
-    : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
+      : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
   Value *Codegen() override;
 };
 
@@ -120,10 +128,11 @@ public:
 class CallExprAST : public ExprAST {
   std::string Callee;
   std::vector<std::unique_ptr<ExprAST>> Args;
+
 public:
   CallExprAST(const std::string &Callee,
               std::vector<std::unique_ptr<ExprAST>> Args)
-    : Callee(Callee), Args(std::move(Args)) {}
+      : Callee(Callee), Args(std::move(Args)) {}
   Value *Codegen() override;
 };
 
@@ -133,10 +142,10 @@ public:
 class PrototypeAST {
   std::string Name;
   std::vector<std::string> Args;
+
 public:
   PrototypeAST(const std::string &Name, std::vector<std::string> Args)
-    : Name(Name), Args(std::move(Args)) {}
-  
+      : Name(Name), Args(std::move(Args)) {}
   Function *Codegen();
 };
 
@@ -144,11 +153,11 @@ public:
 class FunctionAST {
   std::unique_ptr<PrototypeAST> Proto;
   std::unique_ptr<ExprAST> Body;
+
 public:
   FunctionAST(std::unique_ptr<PrototypeAST> Proto,
               std::unique_ptr<ExprAST> Body)
-    : Proto(std::move(Proto)), Body(std::move(Body)) {}
-  
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
   Function *Codegen();
 };
 } // end anonymous namespace
@@ -161,9 +170,7 @@ public:
 /// token the parser is looking at.  getNextToken reads another token from the
 /// lexer and updates CurTok with its results.
 static int CurTok;
-static int getNextToken() {
-  return CurTok = gettok();
-}
+static int getNextToken() { return CurTok = gettok(); }
 
 /// BinopPrecedence - This holds the precedence for each binary operator that is
 /// defined.
@@ -173,10 +180,11 @@ static std::map<char, int> BinopPrecedence;
 static int GetTokPrecedence() {
   if (!isascii(CurTok))
     return -1;
-  
+
   // Make sure it's a declared binop.
   int TokPrec = BinopPrecedence[CurTok];
-  if (TokPrec <= 0) return -1;
+  if (TokPrec <= 0)
+    return -1;
   return TokPrec;
 }
 
@@ -196,19 +204,39 @@ std::unique_ptr<FunctionAST> ErrorF(const char *Str) {
 
 static std::unique_ptr<ExprAST> ParseExpression();
 
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return Error("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
 /// identifierexpr
 ///   ::= identifier
 ///   ::= identifier '(' expression* ')'
 static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
   std::string IdName = IdentifierStr;
-  
-  getNextToken();  // eat identifier.
-  
+
+  getNextToken(); // eat identifier.
+
   if (CurTok != '(') // Simple variable ref.
     return llvm::make_unique<VariableExprAST>(IdName);
-  
+
   // Call.
-  getNextToken();  // eat (
+  getNextToken(); // eat (
   std::vector<std::unique_ptr<ExprAST>> Args;
   if (CurTok != ')') {
     while (1) {
@@ -217,7 +245,8 @@ static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
       else
         return nullptr;
 
-      if (CurTok == ')') break;
+      if (CurTok == ')')
+        break;
 
       if (CurTok != ',')
         return Error("Expected ')' or ',' in argument list");
@@ -227,28 +256,8 @@ static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
 
   // Eat the ')'.
   getNextToken();
-  
-  return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
-}
 
-/// numberexpr ::= number
-static std::unique_ptr<ExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return std::move(Result);
-}
-
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken();  // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-  
-  if (CurTok != ')')
-    return Error("expected ')'");
-  getNextToken();  // eat ).
-  return V;
+  return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
 }
 
 /// primary
@@ -257,10 +266,14 @@ static std::unique_ptr<ExprAST> ParseParenExpr() {
 ///   ::= parenexpr
 static std::unique_ptr<ExprAST> ParsePrimary() {
   switch (CurTok) {
-  default: return Error("unknown token when expecting an expression");
-  case tok_identifier: return ParseIdentifierExpr();
-  case tok_number:     return ParseNumberExpr();
-  case '(':            return ParseParenExpr();
+  default:
+    return Error("unknown token when expecting an expression");
+  case tok_identifier:
+    return ParseIdentifierExpr();
+  case tok_number:
+    return ParseNumberExpr();
+  case '(':
+    return ParseParenExpr();
   }
 }
 
@@ -271,31 +284,33 @@ static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
   // If this is a binop, find its precedence.
   while (1) {
     int TokPrec = GetTokPrecedence();
-    
+
     // If this is a binop that binds at least as tightly as the current binop,
     // consume it, otherwise we are done.
     if (TokPrec < ExprPrec)
       return LHS;
-    
+
     // Okay, we know this is a binop.
     int BinOp = CurTok;
-    getNextToken();  // eat binop
-    
+    getNextToken(); // eat binop
+
     // Parse the primary expression after the binary operator.
     auto RHS = ParsePrimary();
-    if (!RHS) return nullptr;
-    
+    if (!RHS)
+      return nullptr;
+
     // If BinOp binds less tightly with RHS than the operator after RHS, let
     // the pending operator take RHS as its LHS.
     int NextPrec = GetTokPrecedence();
     if (TokPrec < NextPrec) {
-      RHS = ParseBinOpRHS(TokPrec+1, std::move(RHS));
-      if (!RHS) return nullptr;
+      RHS = ParseBinOpRHS(TokPrec + 1, std::move(RHS));
+      if (!RHS)
+        return nullptr;
     }
-    
+
     // Merge LHS/RHS.
-    LHS = llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS),
-                                           std::move(RHS));
+    LHS =
+        llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
   }
 }
 
@@ -304,8 +319,9 @@ static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
 ///
 static std::unique_ptr<ExprAST> ParseExpression() {
   auto LHS = ParsePrimary();
-  if (!LHS) return nullptr;
-  
+  if (!LHS)
+    return nullptr;
+
   return ParseBinOpRHS(0, std::move(LHS));
 }
 
@@ -317,28 +333,28 @@ static std::unique_ptr<PrototypeAST> ParsePrototype() {
 
   std::string FnName = IdentifierStr;
   getNextToken();
-  
+
   if (CurTok != '(')
     return ErrorP("Expected '(' in prototype");
-  
+
   std::vector<std::string> ArgNames;
   while (getNextToken() == tok_identifier)
     ArgNames.push_back(IdentifierStr);
   if (CurTok != ')')
     return ErrorP("Expected ')' in prototype");
-  
+
   // success.
-  getNextToken();  // eat ')'.
-  
-  return llvm::make_unique<PrototypeAST>(std::move(FnName),
-                                         std::move(ArgNames));
+  getNextToken(); // eat ')'.
+
+  return llvm::make_unique<PrototypeAST>(FnName, std::move(ArgNames));
 }
 
 /// definition ::= 'def' prototype expression
 static std::unique_ptr<FunctionAST> ParseDefinition() {
-  getNextToken();  // eat def.
+  getNextToken(); // eat def.
   auto Proto = ParsePrototype();
-  if (!Proto) return nullptr;
+  if (!Proto)
+    return nullptr;
 
   if (auto E = ParseExpression())
     return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
@@ -349,8 +365,8 @@ static std::unique_ptr<FunctionAST> ParseDefinition() {
 static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
   if (auto E = ParseExpression()) {
     // Make an anonymous proto.
-    auto Proto = llvm::make_unique<PrototypeAST>("",
-                                                 std::vector<std::string>());
+    auto Proto =
+        llvm::make_unique<PrototypeAST>("", std::vector<std::string>());
     return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
   }
   return nullptr;
@@ -358,7 +374,7 @@ static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
 
 /// external ::= 'extern' prototype
 static std::unique_ptr<PrototypeAST> ParseExtern() {
-  getNextToken();  // eat extern.
+  getNextToken(); // eat extern.
   return ParsePrototype();
 }
 
@@ -366,11 +382,14 @@ static std::unique_ptr<PrototypeAST> ParseExtern() {
 // Code Generation
 //===----------------------------------------------------------------------===//
 
+Value *ErrorV(const char *Str) {
+  Error(Str);
+  return nullptr;
+}
+
 static Module *TheModule;
 static IRBuilder<> Builder(getGlobalContext());
-static std::map<std::string, Value*> NamedValues;
-
-Value *ErrorV(const char *Str) { Error(Str); return nullptr; }
+static std::map<std::string, Value *> NamedValues;
 
 Value *NumberExprAST::Codegen() {
   return ConstantFP::get(getGlobalContext(), APFloat(Val));
@@ -385,18 +404,23 @@ Value *VariableExprAST::Codegen() {
 Value *BinaryExprAST::Codegen() {
   Value *L = LHS->Codegen();
   Value *R = RHS->Codegen();
-  if (!L || !R) return nullptr;
-  
+  if (!L || !R)
+    return nullptr;
+
   switch (Op) {
-  case '+': return Builder.CreateFAdd(L, R, "addtmp");
-  case '-': return Builder.CreateFSub(L, R, "subtmp");
-  case '*': return Builder.CreateFMul(L, R, "multmp");
+  case '+':
+    return Builder.CreateFAdd(L, R, "addtmp");
+  case '-':
+    return Builder.CreateFSub(L, R, "subtmp");
+  case '*':
+    return Builder.CreateFMul(L, R, "multmp");
   case '<':
     L = Builder.CreateFCmpULT(L, R, "cmptmp");
     // Convert bool 0/1 to double 0.0 or 1.0
     return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
                                 "booltmp");
-  default: return ErrorV("invalid binary operator");
+  default:
+    return ErrorV("invalid binary operator");
   }
 }
 
@@ -405,74 +429,75 @@ Value *CallExprAST::Codegen() {
   Function *CalleeF = TheModule->getFunction(Callee);
   if (!CalleeF)
     return ErrorV("Unknown function referenced");
-  
+
   // If argument mismatch error.
   if (CalleeF->arg_size() != Args.size())
     return ErrorV("Incorrect # arguments passed");
 
-  std::vector<Value*> ArgsV;
+  std::vector<Value *> ArgsV;
   for (unsigned i = 0, e = Args.size(); i != e; ++i) {
     ArgsV.push_back(Args[i]->Codegen());
-    if (!ArgsV.back()) return nullptr;
+    if (!ArgsV.back())
+      return nullptr;
   }
-  
+
   return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
 }
 
 Function *PrototypeAST::Codegen() {
   // Make the function type:  double(double,double) etc.
-  std::vector<Type*> Doubles(Args.size(),
-                             Type::getDoubleTy(getGlobalContext()));
-  FunctionType *FT = FunctionType::get(Type::getDoubleTy(getGlobalContext()),
-                                       Doubles, false);
-  
-  Function *F = Function::Create(FT, Function::ExternalLinkage, Name,
-                                 TheModule);
-  
+  std::vector<Type *> Doubles(Args.size(),
+                              Type::getDoubleTy(getGlobalContext()));
+  FunctionType *FT =
+      FunctionType::get(Type::getDoubleTy(getGlobalContext()), Doubles, false);
+
+  Function *F =
+      Function::Create(FT, Function::ExternalLinkage, Name, TheModule);
+
   // If F conflicted, there was already something named 'Name'.  If it has a
   // body, don't allow redefinition or reextern.
   if (F->getName() != Name) {
     // Delete the one we just made and get the existing one.
     F->eraseFromParent();
     F = TheModule->getFunction(Name);
-    
+
     // If F already has a body, reject this.
     if (!F->empty()) {
       ErrorF("redefinition of function");
       return nullptr;
     }
-    
+
     // If F took a different number of args, reject.
     if (F->arg_size() != Args.size()) {
       ErrorF("redefinition of function with different # args");
       return nullptr;
     }
   }
-  
+
   // Set names for all arguments.
   unsigned Idx = 0;
   for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
        ++AI, ++Idx) {
     AI->setName(Args[Idx]);
-    
+
     // Add arguments to variable symbol table.
     NamedValues[Args[Idx]] = AI;
   }
-  
+
   return F;
 }
 
 Function *FunctionAST::Codegen() {
   NamedValues.clear();
-  
+
   Function *TheFunction = Proto->Codegen();
   if (!TheFunction)
     return nullptr;
-  
+
   // Create a new basic block to start insertion into.
   BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
   Builder.SetInsertPoint(BB);
-  
+
   if (Value *RetVal = Body->Codegen()) {
     // Finish off the function.
     Builder.CreateRet(RetVal);
@@ -482,7 +507,7 @@ Function *FunctionAST::Codegen() {
 
     return TheFunction;
   }
-  
+
   // Error reading body, remove function.
   TheFunction->eraseFromParent();
   return nullptr;
@@ -534,27 +559,25 @@ static void MainLoop() {
   while (1) {
     fprintf(stderr, "ready> ");
     switch (CurTok) {
-    case tok_eof:    return;
-    case ';':        getNextToken(); break;  // ignore top-level semicolons.
-    case tok_def:    HandleDefinition(); break;
-    case tok_extern: HandleExtern(); break;
-    default:         HandleTopLevelExpression(); break;
+    case tok_eof:
+      return;
+    case ';': // ignore top-level semicolons.
+      getNextToken();
+      break;
+    case tok_def:
+      HandleDefinition();
+      break;
+    case tok_extern:
+      HandleExtern();
+      break;
+    default:
+      HandleTopLevelExpression();
+      break;
     }
   }
 }
 
 //===----------------------------------------------------------------------===//
-// "Library" functions that can be "extern'd" from user code.
-//===----------------------------------------------------------------------===//
-
-/// putchard - putchar that takes a double and returns 0.
-extern "C" 
-double putchard(double X) {
-  putchar((char)X);
-  return 0;
-}
-
-//===----------------------------------------------------------------------===//
 // Main driver code.
 //===----------------------------------------------------------------------===//
 
@@ -566,14 +589,15 @@ int main() {
   BinopPrecedence['<'] = 10;
   BinopPrecedence['+'] = 20;
   BinopPrecedence['-'] = 20;
-  BinopPrecedence['*'] = 40;  // highest.
+  BinopPrecedence['*'] = 40; // highest.
 
   // Prime the first token.
   fprintf(stderr, "ready> ");
   getNextToken();
 
   // Make the module, which holds all the code.
-  std::unique_ptr<Module> Owner = llvm::make_unique<Module>("my cool jit", Context);
+  std::unique_ptr<Module> Owner =
+      llvm::make_unique<Module>("my cool jit", Context);
   TheModule = Owner.get();
 
   // Run the main "interpreter loop" now.
diff --git a/examples/Kaleidoscope/Chapter4/toy.cpp b/examples/Kaleidoscope/Chapter4/toy.cpp
index f0665f29831..eba0ab1f27d 100644
--- a/examples/Kaleidoscope/Chapter4/toy.cpp
+++ b/examples/Kaleidoscope/Chapter4/toy.cpp
@@ -106,6 +106,7 @@ public:
 /// NumberExprAST - Expression class for numeric literals like "1.0".
 class NumberExprAST : public ExprAST {
   double Val;
+
 public:
   NumberExprAST(double Val) : Val(Val) {}
   Value *Codegen() override;
@@ -114,6 +115,7 @@ public:
 /// VariableExprAST - Expression class for referencing a variable, like "a".
 class VariableExprAST : public ExprAST {
   std::string Name;
+
 public:
   VariableExprAST(const std::string &Name) : Name(Name) {}
   Value *Codegen() override;
@@ -123,6 +125,7 @@ public:
 class BinaryExprAST : public ExprAST {
   char Op;
   std::unique_ptr<ExprAST> LHS, RHS;
+
 public:
   BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
                 std::unique_ptr<ExprAST> RHS)
@@ -134,6 +137,7 @@ public:
 class CallExprAST : public ExprAST {
   std::string Callee;
   std::vector<std::unique_ptr<ExprAST>> Args;
+
 public:
   CallExprAST(const std::string &Callee,
               std::vector<std::unique_ptr<ExprAST>> Args)
@@ -147,9 +151,10 @@ public:
 class PrototypeAST {
   std::string Name;
   std::vector<std::string> Args;
+
 public:
-  PrototypeAST(const std::string &name, std::vector<std::string> Args)
-      : Name(name), Args(std::move(Args)) {}
+  PrototypeAST(const std::string &Name, std::vector<std::string> Args)
+      : Name(Name), Args(std::move(Args)) {}
   Function *Codegen();
 };
 
@@ -157,10 +162,11 @@ public:
 class FunctionAST {
   std::unique_ptr<PrototypeAST> Proto;
   std::unique_ptr<ExprAST> Body;
+
 public:
   FunctionAST(std::unique_ptr<PrototypeAST> Proto,
               std::unique_ptr<ExprAST> Body)
-    : Proto(std::move(Proto)), Body(std::move(Body)) {}
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
   Function *Codegen();
 };
 } // end anonymous namespace
@@ -207,6 +213,26 @@ std::unique_ptr<FunctionAST> ErrorF(const char *Str) {
 
 static std::unique_ptr<ExprAST> ParseExpression();
 
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return Error("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
 /// identifierexpr
 ///   ::= identifier
 ///   ::= identifier '(' expression* ')'
@@ -243,26 +269,6 @@ static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
   return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
 }
 
-/// numberexpr ::= number
-static std::unique_ptr<ExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return std::move(Result);
-}
-
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken(); // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-
-  if (CurTok != ')')
-    return Error("expected ')'");
-  getNextToken(); // eat ).
-  return V;
-}
-
 /// primary
 ///   ::= identifierexpr
 ///   ::= numberexpr
@@ -312,8 +318,8 @@ static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
     }
 
     // Merge LHS/RHS.
-    LHS = llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS),
-                                           std::move(RHS));
+    LHS =
+        llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
   }
 }
 
@@ -368,8 +374,8 @@ static std::unique_ptr<FunctionAST> ParseDefinition() {
 static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
   if (auto E = ParseExpression()) {
     // Make an anonymous proto.
-    auto Proto = llvm::make_unique<PrototypeAST>("",
-                                                 std::vector<std::string>());
+    auto Proto =
+        llvm::make_unique<PrototypeAST>("", std::vector<std::string>());
     return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
   }
   return nullptr;
@@ -806,9 +812,9 @@ static void MainLoop() {
     switch (CurTok) {
     case tok_eof:
       return;
-    case ';':
+    case ';': // ignore top-level semicolons.
       getNextToken();
-      break; // ignore top-level semicolons.
+      break;
     case tok_def:
       HandleDefinition();
       break;
@@ -832,6 +838,12 @@ extern "C" double putchard(double X) {
   return 0;
 }
 
+/// printd - printf that takes a double prints it as "%f\n", returning 0.
+extern "C" double printd(double X) {
+  printf("%f\n", X);
+  return 0;
+}
+
 //===----------------------------------------------------------------------===//
 // Main driver code.
 //===----------------------------------------------------------------------===//
diff --git a/examples/Kaleidoscope/Chapter5/toy.cpp b/examples/Kaleidoscope/Chapter5/toy.cpp
index 042d974626d..c191d61d562 100644
--- a/examples/Kaleidoscope/Chapter5/toy.cpp
+++ b/examples/Kaleidoscope/Chapter5/toy.cpp
@@ -123,6 +123,7 @@ public:
 /// NumberExprAST - Expression class for numeric literals like "1.0".
 class NumberExprAST : public ExprAST {
   double Val;
+
 public:
   NumberExprAST(double Val) : Val(Val) {}
   Value *Codegen() override;
@@ -131,6 +132,7 @@ public:
 /// VariableExprAST - Expression class for referencing a variable, like "a".
 class VariableExprAST : public ExprAST {
   std::string Name;
+
 public:
   VariableExprAST(const std::string &Name) : Name(Name) {}
   Value *Codegen() override;
@@ -140,6 +142,7 @@ public:
 class BinaryExprAST : public ExprAST {
   char Op;
   std::unique_ptr<ExprAST> LHS, RHS;
+
 public:
   BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
                 std::unique_ptr<ExprAST> RHS)
@@ -151,6 +154,7 @@ public:
 class CallExprAST : public ExprAST {
   std::string Callee;
   std::vector<std::unique_ptr<ExprAST>> Args;
+
 public:
   CallExprAST(const std::string &Callee,
               std::vector<std::unique_ptr<ExprAST>> Args)
@@ -161,6 +165,7 @@ public:
 /// IfExprAST - Expression class for if/then/else.
 class IfExprAST : public ExprAST {
   std::unique_ptr<ExprAST> Cond, Then, Else;
+
 public:
   IfExprAST(std::unique_ptr<ExprAST> Cond, std::unique_ptr<ExprAST> Then,
             std::unique_ptr<ExprAST> Else)
@@ -172,6 +177,7 @@ public:
 class ForExprAST : public ExprAST {
   std::string VarName;
   std::unique_ptr<ExprAST> Start, End, Step, Body;
+
 public:
   ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
              std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
@@ -187,9 +193,10 @@ public:
 class PrototypeAST {
   std::string Name;
   std::vector<std::string> Args;
+
 public:
-  PrototypeAST(const std::string &name, std::vector<std::string> Args)
-      : Name(name), Args(std::move(Args)) {}
+  PrototypeAST(const std::string &Name, std::vector<std::string> Args)
+      : Name(Name), Args(std::move(Args)) {}
   Function *Codegen();
 };
 
@@ -197,10 +204,11 @@ public:
 class FunctionAST {
   std::unique_ptr<PrototypeAST> Proto;
   std::unique_ptr<ExprAST> Body;
+
 public:
   FunctionAST(std::unique_ptr<PrototypeAST> Proto,
               std::unique_ptr<ExprAST> Body)
-    : Proto(std::move(Proto)), Body(std::move(Body)) {}
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
   Function *Codegen();
 };
 } // end anonymous namespace
@@ -247,6 +255,26 @@ std::unique_ptr<FunctionAST> ErrorF(const char *Str) {
 
 static std::unique_ptr<ExprAST> ParseExpression();
 
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return Error("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
 /// identifierexpr
 ///   ::= identifier
 ///   ::= identifier '(' expression* ')'
@@ -283,26 +311,6 @@ static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
   return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
 }
 
-/// numberexpr ::= number
-static std::unique_ptr<ExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return std::move(Result);
-}
-
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken(); // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-
-  if (CurTok != ')')
-    return Error("expected ')'");
-  getNextToken(); // eat ).
-  return V;
-}
-
 /// ifexpr ::= 'if' expression 'then' expression 'else' expression
 static std::unique_ptr<ExprAST> ParseIfExpr() {
   getNextToken(); // eat the if.
@@ -434,8 +442,8 @@ static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
     }
 
     // Merge LHS/RHS.
-    LHS = llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS),
-                                           std::move(RHS));
+    LHS =
+        llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
   }
 }
 
@@ -490,8 +498,8 @@ static std::unique_ptr<FunctionAST> ParseDefinition() {
 static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
   if (auto E = ParseExpression()) {
     // Make an anonymous proto.
-    auto Proto = llvm::make_unique<PrototypeAST>("",
-                                                 std::vector<std::string>());
+    auto Proto =
+        llvm::make_unique<PrototypeAST>("", std::vector<std::string>());
     return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
   }
   return nullptr;
@@ -624,23 +632,22 @@ Value *IfExprAST::Codegen() {
   return PN;
 }
 
+// Output for-loop as:
+//   ...
+//   start = startexpr
+//   goto loop
+// loop:
+//   variable = phi [start, loopheader], [nextvariable, loopend]
+//   ...
+//   bodyexpr
+//   ...
+// loopend:
+//   step = stepexpr
+//   nextvariable = variable + step
+//   endcond = endexpr
+//   br endcond, loop, endloop
+// outloop:
 Value *ForExprAST::Codegen() {
-  // Output this as:
-  //   ...
-  //   start = startexpr
-  //   goto loop
-  // loop:
-  //   variable = phi [start, loopheader], [nextvariable, loopend]
-  //   ...
-  //   bodyexpr
-  //   ...
-  // loopend:
-  //   step = stepexpr
-  //   nextvariable = variable + step
-  //   endcond = endexpr
-  //   br endcond, loop, endloop
-  // outloop:
-
   // Emit the start code first, without 'variable' in scope.
   Value *StartVal = Start->Codegen();
   if (!StartVal)
@@ -676,7 +683,7 @@ Value *ForExprAST::Codegen() {
     return nullptr;
 
   // Emit the step value.
-  Value *StepVal;
+  Value *StepVal = nullptr;
   if (Step) {
     StepVal = Step->Codegen();
     if (!StepVal)
@@ -691,7 +698,7 @@ Value *ForExprAST::Codegen() {
   // Compute the end condition.
   Value *EndCond = End->Codegen();
   if (!EndCond)
-    return EndCond;
+    return nullptr;
 
   // Convert condition to a bool by comparing equal to 0.0.
   EndCond = Builder.CreateFCmpONE(
@@ -849,9 +856,9 @@ static void MainLoop() {
     switch (CurTok) {
     case tok_eof:
       return;
-    case ';':
+    case ';': // ignore top-level semicolons.
       getNextToken();
-      break; // ignore top-level semicolons.
+      break;
     case tok_def:
       HandleDefinition();
       break;
@@ -875,6 +882,12 @@ extern "C" double putchard(double X) {
   return 0;
 }
 
+/// printd - printf that takes a double prints it as "%f\n", returning 0.
+extern "C" double printd(double X) {
+  printf("%f\n", X);
+  return 0;
+}
+
 //===----------------------------------------------------------------------===//
 // Main driver code.
 //===----------------------------------------------------------------------===//
diff --git a/examples/Kaleidoscope/Chapter6/toy.cpp b/examples/Kaleidoscope/Chapter6/toy.cpp
index ba308af5120..87048bb2da4 100644
--- a/examples/Kaleidoscope/Chapter6/toy.cpp
+++ b/examples/Kaleidoscope/Chapter6/toy.cpp
@@ -131,6 +131,7 @@ public:
 /// NumberExprAST - Expression class for numeric literals like "1.0".
 class NumberExprAST : public ExprAST {
   double Val;
+
 public:
   NumberExprAST(double Val) : Val(Val) {}
   Value *Codegen() override;
@@ -139,6 +140,7 @@ public:
 /// VariableExprAST - Expression class for referencing a variable, like "a".
 class VariableExprAST : public ExprAST {
   std::string Name;
+
 public:
   VariableExprAST(const std::string &Name) : Name(Name) {}
   Value *Codegen() override;
@@ -159,6 +161,7 @@ public:
 class BinaryExprAST : public ExprAST {
   char Op;
   std::unique_ptr<ExprAST> LHS, RHS;
+
 public:
   BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
                 std::unique_ptr<ExprAST> RHS)
@@ -170,6 +173,7 @@ public:
 class CallExprAST : public ExprAST {
   std::string Callee;
   std::vector<std::unique_ptr<ExprAST>> Args;
+
 public:
   CallExprAST(const std::string &Callee,
               std::vector<std::unique_ptr<ExprAST>> Args)
@@ -180,6 +184,7 @@ public:
 /// IfExprAST - Expression class for if/then/else.
 class IfExprAST : public ExprAST {
   std::unique_ptr<ExprAST> Cond, Then, Else;
+
 public:
   IfExprAST(std::unique_ptr<ExprAST> Cond, std::unique_ptr<ExprAST> Then,
             std::unique_ptr<ExprAST> Else)
@@ -191,12 +196,13 @@ public:
 class ForExprAST : public ExprAST {
   std::string VarName;
   std::unique_ptr<ExprAST> Start, End, Step, Body;
+
 public:
   ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
              std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
              std::unique_ptr<ExprAST> Body)
-    : VarName(VarName), Start(std::move(Start)), End(std::move(End)),
-      Step(std::move(Step)), Body(std::move(Body)) {}
+      : VarName(VarName), Start(std::move(Start)), End(std::move(End)),
+        Step(std::move(Step)), Body(std::move(Body)) {}
   Value *Codegen() override;
 };
 
@@ -208,11 +214,12 @@ class PrototypeAST {
   std::vector<std::string> Args;
   bool IsOperator;
   unsigned Precedence; // Precedence if a binary op.
+
 public:
   PrototypeAST(const std::string &Name, std::vector<std::string> Args,
                bool IsOperator = false, unsigned Prec = 0)
-    : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
-      Precedence(Prec) {}
+      : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
+        Precedence(Prec) {}
 
   bool isUnaryOp() const { return IsOperator && Args.size() == 1; }
   bool isBinaryOp() const { return IsOperator && Args.size() == 2; }
@@ -231,8 +238,10 @@ public:
 class FunctionAST {
   std::unique_ptr<PrototypeAST> Proto;
   std::unique_ptr<ExprAST> Body;
+
 public:
-  FunctionAST(std::unique_ptr<PrototypeAST> Proto, std::unique_ptr<ExprAST> Body)
+  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
+              std::unique_ptr<ExprAST> Body)
       : Proto(std::move(Proto)), Body(std::move(Body)) {}
   Function *Codegen();
 };
@@ -280,6 +289,26 @@ std::unique_ptr<FunctionAST> ErrorF(const char *Str) {
 
 static std::unique_ptr<ExprAST> ParseExpression();
 
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return Error("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
 /// identifierexpr
 ///   ::= identifier
 ///   ::= identifier '(' expression* ')'
@@ -316,26 +345,6 @@ static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
   return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
 }
 
-/// numberexpr ::= number
-static std::unique_ptr<ExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return std::move(Result);
-}
-
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken(); // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-
-  if (CurTok != ')')
-    return Error("expected ')'");
-  getNextToken(); // eat ).
-  return V;
-}
-
 /// ifexpr ::= 'if' expression 'then' expression 'else' expression
 static std::unique_ptr<ExprAST> ParseIfExpr() {
   getNextToken(); // eat the if.
@@ -453,7 +462,8 @@ static std::unique_ptr<ExprAST> ParseUnary() {
 
 /// binoprhs
 ///   ::= ('+' unary)*
-  static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec, std::unique_ptr<ExprAST> LHS) {
+static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
+                                              std::unique_ptr<ExprAST> LHS) {
   // If this is a binop, find its precedence.
   while (1) {
     int TokPrec = GetTokPrecedence();
@@ -482,7 +492,8 @@ static std::unique_ptr<ExprAST> ParseUnary() {
     }
 
     // Merge LHS/RHS.
-    LHS = llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
+    LHS =
+        llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
   }
 }
 
@@ -579,7 +590,8 @@ static std::unique_ptr<FunctionAST> ParseDefinition() {
 static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
   if (auto E = ParseExpression()) {
     // Make an anonymous proto.
-    auto Proto = llvm::make_unique<PrototypeAST>("", std::vector<std::string>());
+    auto Proto =
+        llvm::make_unique<PrototypeAST>("", std::vector<std::string>());
     return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
   }
   return nullptr;
@@ -612,7 +624,10 @@ Value *NumberExprAST::Codegen() {
 Value *VariableExprAST::Codegen() {
   // Look this variable up in the function.
   Value *V = NamedValues[Name];
-  return V ? V : ErrorV("Unknown variable name");
+  if (!V)
+    return ErrorV("Unknown variable name");
+
+  return V;
 }
 
 Value *UnaryExprAST::Codegen() {
@@ -654,7 +669,7 @@ Value *BinaryExprAST::Codegen() {
   Function *F = TheModule->getFunction(std::string("binary") + Op);
   assert(F && "binary operator not found!");
 
-  Value *Ops[] = { L, R };
+  Value *Ops[] = {L, R};
   return Builder.CreateCall(F, Ops, "binop");
 }
 
@@ -732,23 +747,22 @@ Value *IfExprAST::Codegen() {
   return PN;
 }
 
+// Output for-loop as:
+//   ...
+//   start = startexpr
+//   goto loop
+// loop:
+//   variable = phi [start, loopheader], [nextvariable, loopend]
+//   ...
+//   bodyexpr
+//   ...
+// loopend:
+//   step = stepexpr
+//   nextvariable = variable + step
+//   endcond = endexpr
+//   br endcond, loop, endloop
+// outloop:
 Value *ForExprAST::Codegen() {
-  // Output this as:
-  //   ...
-  //   start = startexpr
-  //   goto loop
-  // loop:
-  //   variable = phi [start, loopheader], [nextvariable, loopend]
-  //   ...
-  //   bodyexpr
-  //   ...
-  // loopend:
-  //   step = stepexpr
-  //   nextvariable = variable + step
-  //   endcond = endexpr
-  //   br endcond, loop, endloop
-  // outloop:
-
   // Emit the start code first, without 'variable' in scope.
   Value *StartVal = Start->Codegen();
   if (!StartVal)
@@ -784,7 +798,7 @@ Value *ForExprAST::Codegen() {
     return nullptr;
 
   // Emit the step value.
-  Value *StepVal;
+  Value *StepVal = nullptr;
   if (Step) {
     StepVal = Step->Codegen();
     if (!StepVal)
@@ -799,7 +813,7 @@ Value *ForExprAST::Codegen() {
   // Compute the end condition.
   Value *EndCond = End->Codegen();
   if (!EndCond)
-    return EndCond;
+    return nullptr;
 
   // Convert condition to a bool by comparing equal to 0.0.
   EndCond = Builder.CreateFCmpONE(
@@ -964,9 +978,9 @@ static void MainLoop() {
     switch (CurTok) {
     case tok_eof:
       return;
-    case ';':
+    case ';': // ignore top-level semicolons.
       getNextToken();
-      break; // ignore top-level semicolons.
+      break;
     case tok_def:
       HandleDefinition();
       break;
diff --git a/examples/Kaleidoscope/Chapter7/toy.cpp b/examples/Kaleidoscope/Chapter7/toy.cpp
index 3c988ac9aa2..a900c5f7b16 100644
--- a/examples/Kaleidoscope/Chapter7/toy.cpp
+++ b/examples/Kaleidoscope/Chapter7/toy.cpp
@@ -136,6 +136,7 @@ public:
 /// NumberExprAST - Expression class for numeric literals like "1.0".
 class NumberExprAST : public ExprAST {
   double Val;
+
 public:
   NumberExprAST(double Val) : Val(Val) {}
   Value *Codegen() override;
@@ -144,6 +145,7 @@ public:
 /// VariableExprAST - Expression class for referencing a variable, like "a".
 class VariableExprAST : public ExprAST {
   std::string Name;
+
 public:
   VariableExprAST(const std::string &Name) : Name(Name) {}
   const std::string &getName() const { return Name; }
@@ -154,6 +156,7 @@ public:
 class UnaryExprAST : public ExprAST {
   char Opcode;
   std::unique_ptr<ExprAST> Operand;
+
 public:
   UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
       : Opcode(Opcode), Operand(std::move(Operand)) {}
@@ -164,6 +167,7 @@ public:
 class BinaryExprAST : public ExprAST {
   char Op;
   std::unique_ptr<ExprAST> LHS, RHS;
+
 public:
   BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
                 std::unique_ptr<ExprAST> RHS)
@@ -175,6 +179,7 @@ public:
 class CallExprAST : public ExprAST {
   std::string Callee;
   std::vector<std::unique_ptr<ExprAST>> Args;
+
 public:
   CallExprAST(const std::string &Callee,
               std::vector<std::unique_ptr<ExprAST>> Args)
@@ -185,6 +190,7 @@ public:
 /// IfExprAST - Expression class for if/then/else.
 class IfExprAST : public ExprAST {
   std::unique_ptr<ExprAST> Cond, Then, Else;
+
 public:
   IfExprAST(std::unique_ptr<ExprAST> Cond, std::unique_ptr<ExprAST> Then,
             std::unique_ptr<ExprAST> Else)
@@ -196,6 +202,7 @@ public:
 class ForExprAST : public ExprAST {
   std::string VarName;
   std::unique_ptr<ExprAST> Start, End, Step, Body;
+
 public:
   ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
              std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
@@ -209,25 +216,29 @@ public:
 class VarExprAST : public ExprAST {
   std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
   std::unique_ptr<ExprAST> Body;
+
 public:
-  VarExprAST(std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames,
-             std::unique_ptr<ExprAST> Body)
-    : VarNames(std::move(VarNames)), Body(std::move(Body)) {}
+  VarExprAST(
+      std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames,
+      std::unique_ptr<ExprAST> Body)
+      : VarNames(std::move(VarNames)), Body(std::move(Body)) {}
   Value *Codegen() override;
 };
 
 /// PrototypeAST - This class represents the "prototype" for a function,
-/// which captures its argument names as well as if it is an operator.
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes), as well as if it is an operator.
 class PrototypeAST {
   std::string Name;
   std::vector<std::string> Args;
   bool IsOperator;
   unsigned Precedence; // Precedence if a binary op.
+
 public:
   PrototypeAST(const std::string &Name, std::vector<std::string> Args,
                bool IsOperator = false, unsigned Prec = 0)
-    : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
-      Precedence(Prec) {}
+      : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
+        Precedence(Prec) {}
 
   bool isUnaryOp() const { return IsOperator && Args.size() == 1; }
   bool isBinaryOp() const { return IsOperator && Args.size() == 2; }
@@ -248,8 +259,10 @@ public:
 class FunctionAST {
   std::unique_ptr<PrototypeAST> Proto;
   std::unique_ptr<ExprAST> Body;
+
 public:
-  FunctionAST(std::unique_ptr<PrototypeAST> Proto, std::unique_ptr<ExprAST> Body)
+  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
+              std::unique_ptr<ExprAST> Body)
       : Proto(std::move(Proto)), Body(std::move(Body)) {}
   Function *Codegen();
 };
@@ -297,6 +310,26 @@ std::unique_ptr<FunctionAST> ErrorF(const char *Str) {
 
 static std::unique_ptr<ExprAST> ParseExpression();
 
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return Error("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
 /// identifierexpr
 ///   ::= identifier
 ///   ::= identifier '(' expression* ')'
@@ -333,26 +366,6 @@ static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
   return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
 }
 
-/// numberexpr ::= number
-static std::unique_ptr<ExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return std::move(Result);
-}
-
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken(); // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-
-  if (CurTok != ')')
-    return Error("expected ')'");
-  getNextToken(); // eat ).
-  return V;
-}
-
 /// ifexpr ::= 'if' expression 'then' expression 'else' expression
 static std::unique_ptr<ExprAST> ParseIfExpr() {
   getNextToken(); // eat the if.
@@ -521,7 +534,8 @@ static std::unique_ptr<ExprAST> ParseUnary() {
 
 /// binoprhs
 ///   ::= ('+' unary)*
-  static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec, std::unique_ptr<ExprAST> LHS) {
+static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
+                                              std::unique_ptr<ExprAST> LHS) {
   // If this is a binop, find its precedence.
   while (1) {
     int TokPrec = GetTokPrecedence();
@@ -550,7 +564,8 @@ static std::unique_ptr<ExprAST> ParseUnary() {
     }
 
     // Merge LHS/RHS.
-    LHS = llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
+    LHS =
+        llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
   }
 }
 
@@ -647,7 +662,8 @@ static std::unique_ptr<FunctionAST> ParseDefinition() {
 static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
   if (auto E = ParseExpression()) {
     // Make an anonymous proto.
-    auto Proto = llvm::make_unique<PrototypeAST>("", std::vector<std::string>());
+    auto Proto =
+        llvm::make_unique<PrototypeAST>("", std::vector<std::string>());
     return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
   }
   return nullptr;
@@ -716,7 +732,7 @@ Value *BinaryExprAST::Codegen() {
     // This assume we're building without RTTI because LLVM builds that way by
     // default.  If you build LLVM with RTTI this can be changed to a
     // dynamic_cast for automatic error checking.
-    VariableExprAST *LHSE = static_cast<VariableExprAST*>(LHS.get());
+    VariableExprAST *LHSE = static_cast<VariableExprAST *>(LHS.get());
     if (!LHSE)
       return ErrorV("destination of '=' must be a variable");
     // Codegen the RHS.
@@ -759,7 +775,7 @@ Value *BinaryExprAST::Codegen() {
   Function *F = TheModule->getFunction(std::string("binary") + Op);
   assert(F && "binary operator not found!");
 
-  Value *Ops[] = { L, R };
+  Value *Ops[] = {L, R};
   return Builder.CreateCall(F, Ops, "binop");
 }
 
@@ -837,27 +853,26 @@ Value *IfExprAST::Codegen() {
   return PN;
 }
 
+// Output for-loop as:
+//   var = alloca double
+//   ...
+//   start = startexpr
+//   store start -> var
+//   goto loop
+// loop:
+//   ...
+//   bodyexpr
+//   ...
+// loopend:
+//   step = stepexpr
+//   endcond = endexpr
+//
+//   curvar = load var
+//   nextvar = curvar + step
+//   store nextvar -> var
+//   br endcond, loop, endloop
+// outloop:
 Value *ForExprAST::Codegen() {
-  // Output this as:
-  //   var = alloca double
-  //   ...
-  //   start = startexpr
-  //   store start -> var
-  //   goto loop
-  // loop:
-  //   ...
-  //   bodyexpr
-  //   ...
-  // loopend:
-  //   step = stepexpr
-  //   endcond = endexpr
-  //
-  //   curvar = load var
-  //   nextvar = curvar + step
-  //   store nextvar -> var
-  //   br endcond, loop, endloop
-  // outloop:
-
   Function *TheFunction = Builder.GetInsertBlock()->getParent();
 
   // Create an alloca for the variable in the entry block.
@@ -894,7 +909,7 @@ Value *ForExprAST::Codegen() {
     return nullptr;
 
   // Emit the step value.
-  Value *StepVal;
+  Value *StepVal = nullptr;
   if (Step) {
     StepVal = Step->Codegen();
     if (!StepVal)
@@ -907,7 +922,7 @@ Value *ForExprAST::Codegen() {
   // Compute the end condition.
   Value *EndCond = End->Codegen();
   if (!EndCond)
-    return EndCond;
+    return nullptr;
 
   // Reload, increment, and restore the alloca.  This handles the case where
   // the body of the loop mutates the variable.
@@ -1137,9 +1152,9 @@ static void MainLoop() {
     switch (CurTok) {
     case tok_eof:
       return;
-    case ';':
+    case ';': // ignore top-level semicolons.
       getNextToken();
-      break; // ignore top-level semicolons.
+      break;
     case tok_def:
       HandleDefinition();
       break;
diff --git a/examples/Kaleidoscope/Chapter8/toy.cpp b/examples/Kaleidoscope/Chapter8/toy.cpp
index ed2d9b427ff..b39a5a215af 100644
--- a/examples/Kaleidoscope/Chapter8/toy.cpp
+++ b/examples/Kaleidoscope/Chapter8/toy.cpp
@@ -17,7 +17,6 @@
 #include "llvm/Transforms/Scalar.h"
 #include <cctype>
 #include <cstdio>
-#include <iostream>
 #include <map>
 #include <string>
 #include <vector>
@@ -109,7 +108,7 @@ struct SourceLocation {
   int Col;
 };
 static SourceLocation CurLoc;
-static SourceLocation LexLoc = { 1, 0 };
+static SourceLocation LexLoc = {1, 0};
 
 static int advance() {
   int LastChar = getchar();
@@ -196,30 +195,32 @@ static int gettok() {
 //===----------------------------------------------------------------------===//
 namespace {
 
-std::ostream &indent(std::ostream &O, int size) {
+raw_ostream &indent(raw_ostream &O, int size) {
   return O << std::string(size, ' ');
 }
 
 /// ExprAST - Base class for all expression nodes.
 class ExprAST {
   SourceLocation Loc;
+
 public:
+  ExprAST(SourceLocation Loc = CurLoc) : Loc(Loc) {}
+  virtual ~ExprAST() {}
+  virtual Value *Codegen() = 0;
   int getLine() const { return Loc.Line; }
   int getCol() const { return Loc.Col; }
-  ExprAST(SourceLocation Loc = CurLoc) : Loc(Loc) {}
-  virtual std::ostream &dump(std::ostream &out, int ind) {
+  virtual raw_ostream &dump(raw_ostream &out, int ind) {
     return out << ':' << getLine() << ':' << getCol() << '\n';
   }
-  virtual ~ExprAST() {}
-  virtual Value *Codegen() = 0;
 };
 
 /// NumberExprAST - Expression class for numeric literals like "1.0".
 class NumberExprAST : public ExprAST {
   double Val;
+
 public:
   NumberExprAST(double Val) : Val(Val) {}
-  std::ostream &dump(std::ostream &out, int ind) override {
+  raw_ostream &dump(raw_ostream &out, int ind) override {
     return ExprAST::dump(out << Val, ind);
   }
   Value *Codegen() override;
@@ -228,11 +229,12 @@ public:
 /// VariableExprAST - Expression class for referencing a variable, like "a".
 class VariableExprAST : public ExprAST {
   std::string Name;
+
 public:
   VariableExprAST(SourceLocation Loc, const std::string &Name)
       : ExprAST(Loc), Name(Name) {}
   const std::string &getName() const { return Name; }
-  std::ostream &dump(std::ostream &out, int ind) override {
+  raw_ostream &dump(raw_ostream &out, int ind) override {
     return ExprAST::dump(out << Name, ind);
   }
   Value *Codegen() override;
@@ -242,10 +244,11 @@ public:
 class UnaryExprAST : public ExprAST {
   char Opcode;
   std::unique_ptr<ExprAST> Operand;
+
 public:
   UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
       : Opcode(Opcode), Operand(std::move(Operand)) {}
-  std::ostream &dump(std::ostream &out, int ind) override {
+  raw_ostream &dump(raw_ostream &out, int ind) override {
     ExprAST::dump(out << "unary" << Opcode, ind);
     Operand->dump(out, ind + 1);
     return out;
@@ -257,11 +260,12 @@ public:
 class BinaryExprAST : public ExprAST {
   char Op;
   std::unique_ptr<ExprAST> LHS, RHS;
+
 public:
   BinaryExprAST(SourceLocation Loc, char Op, std::unique_ptr<ExprAST> LHS,
                 std::unique_ptr<ExprAST> RHS)
       : ExprAST(Loc), Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
-  std::ostream &dump(std::ostream &out, int ind) override {
+  raw_ostream &dump(raw_ostream &out, int ind) override {
     ExprAST::dump(out << "binary" << Op, ind);
     LHS->dump(indent(out, ind) << "LHS:", ind + 1);
     RHS->dump(indent(out, ind) << "RHS:", ind + 1);
@@ -274,11 +278,12 @@ public:
 class CallExprAST : public ExprAST {
   std::string Callee;
   std::vector<std::unique_ptr<ExprAST>> Args;
+
 public:
   CallExprAST(SourceLocation Loc, const std::string &Callee,
               std::vector<std::unique_ptr<ExprAST>> Args)
       : ExprAST(Loc), Callee(Callee), Args(std::move(Args)) {}
-  std::ostream &dump(std::ostream &out, int ind) override {
+  raw_ostream &dump(raw_ostream &out, int ind) override {
     ExprAST::dump(out << "call " << Callee, ind);
     for (const auto &Arg : Args)
       Arg->dump(indent(out, ind + 1), ind + 1);
@@ -290,11 +295,13 @@ public:
 /// IfExprAST - Expression class for if/then/else.
 class IfExprAST : public ExprAST {
   std::unique_ptr<ExprAST> Cond, Then, Else;
+
 public:
   IfExprAST(SourceLocation Loc, std::unique_ptr<ExprAST> Cond,
             std::unique_ptr<ExprAST> Then, std::unique_ptr<ExprAST> Else)
-    : ExprAST(Loc), Cond(std::move(Cond)), Then(std::move(Then)), Else(std::move(Else)) {}
-  std::ostream &dump(std::ostream &out, int ind) override {
+      : ExprAST(Loc), Cond(std::move(Cond)), Then(std::move(Then)),
+        Else(std::move(Else)) {}
+  raw_ostream &dump(raw_ostream &out, int ind) override {
     ExprAST::dump(out << "if", ind);
     Cond->dump(indent(out, ind) << "Cond:", ind + 1);
     Then->dump(indent(out, ind) << "Then:", ind + 1);
@@ -308,13 +315,14 @@ public:
 class ForExprAST : public ExprAST {
   std::string VarName;
   std::unique_ptr<ExprAST> Start, End, Step, Body;
+
 public:
   ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
              std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
              std::unique_ptr<ExprAST> Body)
       : VarName(VarName), Start(std::move(Start)), End(std::move(End)),
         Step(std::move(Step)), Body(std::move(Body)) {}
-  std::ostream &dump(std::ostream &out, int ind) override {
+  raw_ostream &dump(raw_ostream &out, int ind) override {
     ExprAST::dump(out << "for", ind);
     Start->dump(indent(out, ind) << "Cond:", ind + 1);
     End->dump(indent(out, ind) << "End:", ind + 1);
@@ -329,11 +337,13 @@ public:
 class VarExprAST : public ExprAST {
   std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
   std::unique_ptr<ExprAST> Body;
+
 public:
-  VarExprAST(std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames,
-             std::unique_ptr<ExprAST> Body)
+  VarExprAST(
+      std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames,
+      std::unique_ptr<ExprAST> Body)
       : VarNames(std::move(VarNames)), Body(std::move(Body)) {}
-  std::ostream &dump(std::ostream &out, int ind) override {
+  raw_ostream &dump(raw_ostream &out, int ind) override {
     ExprAST::dump(out << "var", ind);
     for (const auto &NamedVar : VarNames)
       NamedVar.second->dump(indent(out, ind) << NamedVar.first << ':', ind + 1);
@@ -344,19 +354,21 @@ public:
 };
 
 /// PrototypeAST - This class represents the "prototype" for a function,
-/// which captures its argument names as well as if it is an operator.
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes), as well as if it is an operator.
 class PrototypeAST {
   std::string Name;
   std::vector<std::string> Args;
   bool IsOperator;
   unsigned Precedence; // Precedence if a binary op.
   int Line;
+
 public:
   PrototypeAST(SourceLocation Loc, const std::string &Name,
                std::vector<std::string> Args, bool IsOperator = false,
                unsigned Prec = 0)
-    : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
-      Precedence(Prec), Line(Loc.Line) {}
+      : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
+        Precedence(Prec), Line(Loc.Line) {}
 
   bool isUnaryOp() const { return IsOperator && Args.size() == 1; }
   bool isBinaryOp() const { return IsOperator && Args.size() == 2; }
@@ -378,12 +390,13 @@ public:
 class FunctionAST {
   std::unique_ptr<PrototypeAST> Proto;
   std::unique_ptr<ExprAST> Body;
+
 public:
   FunctionAST(std::unique_ptr<PrototypeAST> Proto,
               std::unique_ptr<ExprAST> Body)
       : Proto(std::move(Proto)), Body(std::move(Body)) {}
 
-  std::ostream &dump(std::ostream &out, int ind) {
+  raw_ostream &dump(raw_ostream &out, int ind) {
     indent(out, ind) << "FunctionAST\n";
     ++ind;
     indent(out, ind) << "Body:";
@@ -436,10 +449,30 @@ std::unique_ptr<FunctionAST> ErrorF(const char *Str) {
 
 static std::unique_ptr<ExprAST> ParseExpression();
 
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return Error("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
 /// identifierexpr
 ///   ::= identifier
 ///   ::= identifier '(' expression* ')'
-  static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
+static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
   std::string IdName = IdentifierStr;
 
   SourceLocation LitLoc = CurLoc;
@@ -454,10 +487,10 @@ static std::unique_ptr<ExprAST> ParseExpression();
   std::vector<std::unique_ptr<ExprAST>> Args;
   if (CurTok != ')') {
     while (1) {
-      auto Arg = ParseExpression();
-      if (!Arg)
+      if (auto Arg = ParseExpression())
+        Args.push_back(std::move(Arg));
+      else
         return nullptr;
-      Args.push_back(std::move(Arg));
 
       if (CurTok == ')')
         break;
@@ -474,26 +507,6 @@ static std::unique_ptr<ExprAST> ParseExpression();
   return llvm::make_unique<CallExprAST>(LitLoc, IdName, std::move(Args));
 }
 
-/// numberexpr ::= number
-static std::unique_ptr<ExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return std::move(Result);
-}
-
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken(); // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-
-  if (CurTok != ')')
-    return Error("expected ')'");
-  getNextToken(); // eat ).
-  return V;
-}
-
 /// ifexpr ::= 'if' expression 'then' expression 'else' expression
 static std::unique_ptr<ExprAST> ParseIfExpr() {
   SourceLocation IfLoc = CurLoc;
@@ -664,7 +677,8 @@ static std::unique_ptr<ExprAST> ParseUnary() {
 
 /// binoprhs
 ///   ::= ('+' unary)*
-static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec, std::unique_ptr<ExprAST> LHS) {
+static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
+                                              std::unique_ptr<ExprAST> LHS) {
   // If this is a binop, find its precedence.
   while (1) {
     int TokPrec = GetTokPrecedence();
@@ -795,8 +809,8 @@ static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
   SourceLocation FnLoc = CurLoc;
   if (auto E = ParseExpression()) {
     // Make an anonymous proto.
-    auto Proto =
-      llvm::make_unique<PrototypeAST>(FnLoc, "main", std::vector<std::string>());
+    auto Proto = llvm::make_unique<PrototypeAST>(FnLoc, "main",
+                                                 std::vector<std::string>());
     return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
   }
   return nullptr;
@@ -909,7 +923,7 @@ Value *BinaryExprAST::Codegen() {
     // This assume we're building without RTTI because LLVM builds that way by
     // default.  If you build LLVM with RTTI this can be changed to a
     // dynamic_cast for automatic error checking.
-    VariableExprAST *LHSE = static_cast<VariableExprAST*>(LHS.get());
+    VariableExprAST *LHSE = static_cast<VariableExprAST *>(LHS.get());
     if (!LHSE)
       return ErrorV("destination of '=' must be a variable");
     // Codegen the RHS.
@@ -952,7 +966,7 @@ Value *BinaryExprAST::Codegen() {
   Function *F = TheModule->getFunction(std::string("binary") + Op);
   assert(F && "binary operator not found!");
 
-  Value *Ops[] = { L, R };
+  Value *Ops[] = {L, R};
   return Builder.CreateCall(F, Ops, "binop");
 }
 
@@ -1034,27 +1048,26 @@ Value *IfExprAST::Codegen() {
   return PN;
 }
 
+// Output for-loop as:
+//   var = alloca double
+//   ...
+//   start = startexpr
+//   store start -> var
+//   goto loop
+// loop:
+//   ...
+//   bodyexpr
+//   ...
+// loopend:
+//   step = stepexpr
+//   endcond = endexpr
+//
+//   curvar = load var
+//   nextvar = curvar + step
+//   store nextvar -> var
+//   br endcond, loop, endloop
+// outloop:
 Value *ForExprAST::Codegen() {
-  // Output this as:
-  //   var = alloca double
-  //   ...
-  //   start = startexpr
-  //   store start -> var
-  //   goto loop
-  // loop:
-  //   ...
-  //   bodyexpr
-  //   ...
-  // loopend:
-  //   step = stepexpr
-  //   endcond = endexpr
-  //
-  //   curvar = load var
-  //   nextvar = curvar + step
-  //   store nextvar -> var
-  //   br endcond, loop, endloop
-  // outloop:
-
   Function *TheFunction = Builder.GetInsertBlock()->getParent();
 
   // Create an alloca for the variable in the entry block.
@@ -1093,7 +1106,7 @@ Value *ForExprAST::Codegen() {
     return nullptr;
 
   // Emit the step value.
-  Value *StepVal;
+  Value *StepVal = nullptr;
   if (Step) {
     StepVal = Step->Codegen();
     if (!StepVal)
@@ -1106,7 +1119,7 @@ Value *ForExprAST::Codegen() {
   // Compute the end condition.
   Value *EndCond = End->Codegen();
   if (!EndCond)
-    return EndCond;
+    return nullptr;
 
   // Reload, increment, and restore the alloca.  This handles the case where
   // the body of the loop mutates the variable.
@@ -1369,9 +1382,9 @@ static void MainLoop() {
     switch (CurTok) {
     case tok_eof:
       return;
-    case ';':
+    case ';': // ignore top-level semicolons.
       getNextToken();
-      break; // ignore top-level semicolons.
+      break;
     case tok_def:
       HandleDefinition();
       break;
@@ -1473,7 +1486,7 @@ int main() {
   OurFPM.add(createGVNPass());
   // Simplify the control flow graph (deleting unreachable blocks, etc).
   OurFPM.add(createCFGSimplificationPass());
-  #endif
+#endif
   OurFPM.doInitialization();
 
   // Set the global so the code gen can use this.