modified structure

source/Ast.h

@@ -18,92 +18,92 @@ using namespace llvm;
 // Abstract Syntax Tree (aka Parse Tree)
 //===----------------------------------------------------------------------===//
 namespace ast{
-// struct instantiated by the 'main' to access data structures if llvm IR.
-struct AstTree {
-public:
-  static std::unique_ptr<llvm::Module> TheModule;
-  static llvm::IRBuilder<> Builder;
-  static std::map<std::string, llvm::Value *> NamedValues;
-  static void InitializeModuleAndPassManager();
-};
-
-/// ExprAST - Base class for all expression nodes.
-
-class ExprAST {
-public:
-  virtual ~ExprAST() {}
-  virtual llvm::Value *codegen() = 0;
-};
-
-/// NumberExprAST - Expression class for numeric literals like "1.0".
-class NumberExprAST : public ExprAST {
-  double Val;
-
-public:
-  NumberExprAST(double Val) : Val(Val) {}
-  Value *codegen() override;
-};
-
-/// 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;
-};
-
-/// 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)
+  // struct instantiated by the 'main' to access data structures if llvm IR.
+  struct AstTree {
+  public:
+    static std::unique_ptr<llvm::Module> TheModule;
+    static llvm::IRBuilder<> Builder;
+    static std::map<std::string, llvm::Value *> NamedValues;
+    static void InitializeModuleAndPassManager();
+  };
+
+  /// ExprAST - Base class for all expression nodes.
+
+  class ExprAST {
+  public:
+    virtual ~ExprAST() {}
+    virtual llvm::Value *codegen() = 0;
+  };
+
+  /// NumberExprAST - Expression class for numeric literals like "1.0".
+  class NumberExprAST : public ExprAST {
+    double Val;
+
+  public:
+    NumberExprAST(double Val) : Val(Val) {}
+    Value *codegen() override;
+  };
+
+  /// 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;
+  };
+
+  /// 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)
       : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
-  Value *codegen() override;
-};
-
-/// 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)) {}
-  Value *codegen() override;
-};
-
-/// PrototypeAST - This class represents the "prototype" for a function,
-/// which captures its name, and its argument names (thus implicitly the number
-/// of arguments the function takes).
-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)) {}
-  Function *codegen();
-  const std::string &getName() const { return Name; }
-};
-
-/// 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)
-      : Proto(std::move(Proto)), Body(std::move(Body)) {}
-  Function *codegen();
-};
-
-// method added from chapter 3 of the tutorial
-} // end anonymous namespace
-
-#endif
+      Value *codegen() override;
+    };
+
+    /// 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)) {}
+        Value *codegen() override;
+      };
+
+      /// PrototypeAST - This class represents the "prototype" for a function,
+      /// which captures its name, and its argument names (thus implicitly the number
+      /// of arguments the function takes).
+      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)) {}
+        Function *codegen();
+        const std::string &getName() const { return Name; }
+      };
+
+      /// 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)
+          : Proto(std::move(Proto)), Body(std::move(Body)) {}
+          Function *codegen();
+        };
+
+        // method added from chapter 3 of the tutorial
+      } // end anonymous namespace
+
+      #endif

source/CMakeLists.txt

@@ -13,7 +13,7 @@ add_compile_options(-std=c++14 -g -O3)
 include_directories(${LLVM_INCLUDE_DIRS})
 add_definitions(${LLVM_DEFINITIONS})
 
-add_executable(kaleidoscope LexerParser.cpp Ast.cpp)
+add_executable(kaleidoscope Main.cpp Lexer.cpp Parser.cpp Ast.cpp)
 
 # Find the libraries that correspond to the LLVM components
 # that we wish to use

source/Lexer.cpp

@@ -0,0 +1,54 @@
+#include "Lexer.h"
+
+/// gettok - Return the next token from standard input.
+namespace lexer{
+  int gettok() {
+    static int LastChar = ' ';
+
+    // Skip any whitespace.
+    while (isspace(LastChar))
+    LastChar = getchar();
+
+    if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
+      IdentifierStr = LastChar;
+      while (isalnum((LastChar = getchar())))
+      IdentifierStr += LastChar;
+
+      if (IdentifierStr == "def")
+      return tok_def;
+      if (IdentifierStr == "extern")
+      return tok_extern;
+      return tok_identifier;
+    }
+
+    if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+
+      std::string NumStr;
+      do {
+        NumStr += LastChar;
+        LastChar = getchar();
+      } while (isdigit(LastChar) || LastChar == '.');
+
+      NumVal = strtod(NumStr.c_str(), nullptr);
+      return tok_number;
+    }
+
+    if (LastChar == '#') {
+      // Comment until end of line.
+      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;
+
+    // Otherwise, just return the character as its ascii value.
+    int ThisChar = LastChar;
+    LastChar = getchar();
+    return ThisChar;
+  }
+}

source/Lexer.h

@@ -0,0 +1,32 @@
+#ifndef LEXER_H
+#define LEXER_H
+
+#include <cctype>
+#include <cstdio>
+#include <map>
+#include <string>
+#include <vector>
+#include "Ast.h"
+
+namespace lexer{
+// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
+// of these for known things.
+enum Token {
+  tok_eof = -1,
+
+  // commands
+  tok_def = -2,
+  tok_extern = -3,
+
+  // primary
+  tok_identifier = -4,
+  tok_number = -5
+};
+
+static std::string IdentifierStr; // Filled in if tok_identifier
+static double NumVal;
+
+int gettok();
+}
+
+#endif

source/LexerParser.cpp

@@ -1,399 +0,0 @@
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/Verifier.h"
-#include <cctype>
-#include <cstdio>
-#include <map>
-#include <string>
-#include <vector>
-#include "Ast.h"
-
-using namespace llvm;
-using namespace ast;
-
-
-namespace helper {
-// Cloning make_unique here until it's standard in C++14.
-// Using a namespace to avoid conflicting with MSVC's std::make_unique (which
-// ADL can sometimes find in unqualified calls).
-template <class T, class... Args>
-static
-    typename std::enable_if<!std::is_array<T>::value, std::unique_ptr<T>>::type
-    make_unique(Args &&... args) {
-  return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
-}
-}
-
-//===----------------------------------------------------------------------===//
-// Lexer
-//===----------------------------------------------------------------------===//
-
-// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
-// of these for known things.
-enum Token {
-  tok_eof = -1,
-
-  // commands
-  tok_def = -2,
-  tok_extern = -3,
-
-  // primary
-  tok_identifier = -4,
-  tok_number = -5
-};
-
-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() {
-  static int LastChar = ' ';
-
-  // Skip any whitespace.
-  while (isspace(LastChar))
-    LastChar = getchar();
-
-  if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
-    IdentifierStr = LastChar;
-    while (isalnum((LastChar = getchar())))
-      IdentifierStr += LastChar;
-
-    if (IdentifierStr == "def")
-      return tok_def;
-    if (IdentifierStr == "extern")
-      return tok_extern;
-    return tok_identifier;
-  }
-
-  if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+
-    std::string NumStr;
-    do {
-      NumStr += LastChar;
-      LastChar = getchar();
-    } while (isdigit(LastChar) || LastChar == '.');
-
-    NumVal = strtod(NumStr.c_str(), nullptr);
-    return tok_number;
-  }
-
-  if (LastChar == '#') {
-    // Comment until end of line.
-    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;
-
-  // Otherwise, just return the character as its ascii value.
-  int ThisChar = LastChar;
-  LastChar = getchar();
-  return ThisChar;
-}
-
-//===----------------------------------------------------------------------===//
-// Parser
-//===----------------------------------------------------------------------===//
-
-/// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
-/// 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(); }
-
-/// BinopPrecedence - This holds the precedence for each binary operator that is
-/// defined.
-static std::map<char, int> BinopPrecedence;
-
-/// GetTokPrecedence - Get the precedence of the pending binary operator token.
-static int GetTokPrecedence() {
-  if (!isascii(CurTok))
-    return -1;
-
-  // Make sure it's a declared binop.
-  int TokPrec = BinopPrecedence[CurTok];
-  if (TokPrec <= 0)
-    return -1;
-  return TokPrec;
-}
-
-/// Error* - These are little helper functions for error handling.
-std::unique_ptr<ExprAST> Error(const char *Str) {
-  fprintf(stderr, "Error: %s\n", Str);
-  return nullptr;
-}
-std::unique_ptr<PrototypeAST> ErrorP(const char *Str) {
-  Error(Str);
-  return nullptr;
-}
-
-static std::unique_ptr<ExprAST> ParseExpression();
-
-/// numberexpr ::= number
-static std::unique_ptr<ExprAST> ParseNumberExpr() {
-  auto Result = helper::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.
-
-  if (CurTok != '(') // Simple variable ref.
-    return helper::make_unique<VariableExprAST>(IdName);
-
-  // Call.
-  getNextToken(); // eat (
-  std::vector<std::unique_ptr<ExprAST>> Args;
-  if (CurTok != ')') {
-    while (1) {
-      if (auto Arg = ParseExpression())
-        Args.push_back(std::move(Arg));
-      else
-        return nullptr;
-
-      if (CurTok == ')')
-        break;
-
-      if (CurTok != ',')
-        return Error("Expected ')' or ',' in argument list");
-      getNextToken();
-    }
-  }
-
-  // Eat the ')'.
-  getNextToken();
-
-  return helper::make_unique<CallExprAST>(IdName, std::move(Args));
-}
-
-/// primary
-///   ::= identifierexpr
-///   ::= numberexpr
-///   ::= 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();
-  }
-}
-
-/// binoprhs
-///   ::= ('+' primary)*
-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();
-
-    // 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
-
-    // Parse the primary expression after the binary operator.
-    auto RHS = ParsePrimary();
-    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;
-    }
-
-    // Merge LHS/RHS.
-    LHS = helper::make_unique<BinaryExprAST>(BinOp, std::move(LHS),
-                                             std::move(RHS));
-  }
-}
-
-/// expression
-///   ::= primary binoprhs
-///
-static std::unique_ptr<ExprAST> ParseExpression() {
-  auto LHS = ParsePrimary();
-  if (!LHS)
-    return nullptr;
-
-  return ParseBinOpRHS(0, std::move(LHS));
-}
-
-/// prototype
-///   ::= id '(' id* ')'
-static std::unique_ptr<PrototypeAST> ParsePrototype() {
-  if (CurTok != tok_identifier)
-    return ErrorP("Expected function name in prototype");
-
-  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 helper::make_unique<PrototypeAST>(FnName, std::move(ArgNames));
-}
-
-/// definition ::= 'def' prototype expression
-static std::unique_ptr<FunctionAST> ParseDefinition() {
-  getNextToken(); // eat def.
-  auto Proto = ParsePrototype();
-  if (!Proto)
-    return nullptr;
-
-  if (auto E = ParseExpression())
-    return helper::make_unique<FunctionAST>(std::move(Proto), std::move(E));
-  return nullptr;
-}
-
-/// toplevelexpr ::= expression
-static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
-  if (auto E = ParseExpression()) {
-    // Make an anonymous proto.
-    auto Proto = helper::make_unique<PrototypeAST>("__anon_expr",
-                                                   std::vector<std::string>());
-    return helper::make_unique<FunctionAST>(std::move(Proto), std::move(E));
-  }
-  return nullptr;
-}
-
-/// external ::= 'extern' prototype
-static std::unique_ptr<PrototypeAST> ParseExtern() {
-  getNextToken(); // eat extern.
-  return ParsePrototype();
-}
-
-//===----------------------------------------------------------------------===//
-// Top-Level parsing
-//===----------------------------------------------------------------------===//
-
-static void HandleDefinition() {
-  if (auto FnAST = ParseDefinition()) {
-    if (auto *FnIR = FnAST->codegen()) {
-      fprintf(stderr, "Read function definition:");
-      FnIR->dump();
-    }
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-static void HandleExtern() {
-  if (auto ProtoAST = ParseExtern()) {
-    if (auto *FnIR = ProtoAST->codegen()) {
-      fprintf(stderr, "Read extern: ");
-      FnIR->dump();
-    }
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-static void HandleTopLevelExpression() {
-  // Evaluate a top-level expression into an anonymous function.
-  if (auto FnAST = ParseTopLevelExpr()) {
-    if (auto *FnIR = FnAST->codegen()) {
-      fprintf(stderr, "Read top-level expression:");
-      FnIR->dump();
-    }
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-/// top ::= definition | external | expression | ';'
-static void MainLoop() {
-  while (1) {
-    fprintf(stderr, "ready> ");
-    switch (CurTok) {
-    case tok_eof:
-      return;
-    case ';': // ignore top-level semicolons.
-      getNextToken();
-      break;
-    case tok_def:
-      HandleDefinition();
-      break;
-    case tok_extern:
-      HandleExtern();
-      break;
-    default:
-      HandleTopLevelExpression();
-      break;
-    }
-  }
-}
-
-//===----------------------------------------------------------------------===//
-// Main driver code.
-//===----------------------------------------------------------------------===//
-
-int main() {
-  // Install standard binary operators.
-  // 1 is lowest precedence.
-  BinopPrecedence['<'] = 10;
-  BinopPrecedence['+'] = 20;
-  BinopPrecedence['-'] = 20;
-  BinopPrecedence['*'] = 40; // highest.
-
-  // Prime the first token.
-  fprintf(stderr, "ready> ");
-  getNextToken();
-
-  // Run the main "interpreter loop" now.
-  MainLoop();
-
-  AstTree::TheModule->dump();
-
-  return 0;
-}

source/Main.cpp

@@ -0,0 +1,51 @@
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Verifier.h"
+#include <cctype>
+#include <cstdio>
+#include <map>
+#include <string>
+#include <vector>
+#include "Ast.h"
+#include "Lexer.h"
+#include "Parser.h"
+
+using namespace llvm;
+using namespace ast;
+using namespace lexer;
+using namespace parser;
+
+
+namespace helper {
+// Cloning make_unique here until it's standard in C++14.
+// Using a namespace to avoid conflicting with MSVC's std::make_unique (which
+// ADL can sometimes find in unqualified calls).
+template <class T, class... Args>
+static
+    typename std::enable_if<!std::is_array<T>::value, std::unique_ptr<T>>::type
+    make_unique(Args &&... args) {
+  return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
+}
+}
+
+
+//===----------------------------------------------------------------------===//
+// Main driver code.
+//===----------------------------------------------------------------------===//
+
+int main() {
+  
+
+  // Prime the first token.
+  fprintf(stderr, "ready> ");
+  getNextToken();
+
+  // Run the main "interpreter loop" now.
+  parser::MainLoop();
+
+  AstTree::TheModule->dump();
+
+  return 0;
+}

source/Parser.cpp

@@ -0,0 +1,286 @@
+#include "Parser.h"
+
+using namespace lexer;
+namespace parser{
+  //===----------------------------------------------------------------------===//
+  // Parser
+  //===----------------------------------------------------------------------===//
+
+  /// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
+  /// token the parser is looking at.  getNextToken reads another token from the
+  /// lexer and updates CurTok with its results.
+  int getNextToken() { return CurTok = gettok(); }
+
+  /// BinopPrecedence - This holds the precedence for each binary operator that is
+  /// defined.
+
+  /// GetTokPrecedence - Get the precedence of the pending binary operator token.
+  static int GetTokPrecedence() {
+    if (!isascii(CurTok))
+      return -1;
+
+    // Make sure it's a declared binop.
+    int TokPrec = BinopPrecedence[CurTok];
+    if (TokPrec <= 0)
+      return -1;
+    return TokPrec;
+  }
+
+  /// Error* - These are little helper functions for error handling.
+  std::unique_ptr<ExprAST> Error(const char *Str) {
+    fprintf(stderr, "Error: %s\n", Str);
+    return nullptr;
+  }
+
+  std::unique_ptr<PrototypeAST> ErrorP(const char *Str) {
+    Error(Str);
+    return nullptr;
+  }
+
+  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.
+
+    if (CurTok != '(') // Simple variable ref.
+      return llvm::make_unique<VariableExprAST>(IdName);
+
+    // Call.
+    getNextToken(); // eat (
+    std::vector<std::unique_ptr<ExprAST>> Args;
+    if (CurTok != ')') {
+      while (1) {
+        if (auto Arg = ParseExpression())
+          Args.push_back(std::move(Arg));
+        else
+          return nullptr;
+
+        if (CurTok == ')')
+          break;
+
+        if (CurTok != ',')
+          return Error("Expected ')' or ',' in argument list");
+        getNextToken();
+      }
+    }
+
+    // Eat the ')'.
+    getNextToken();
+
+    return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
+  }
+
+  /// primary
+  ///   ::= identifierexpr
+  ///   ::= numberexpr
+  ///   ::= 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();
+    }
+  }
+
+  /// binoprhs
+  ///   ::= ('+' primary)*
+  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();
+
+      // 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
+
+      // Parse the primary expression after the binary operator.
+      auto RHS = ParsePrimary();
+      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;
+      }
+
+      // Merge LHS/RHS.
+      LHS =
+          llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
+    }
+  }
+
+  /// expression
+  ///   ::= primary binoprhs
+  ///
+  static std::unique_ptr<ExprAST> ParseExpression() {
+    auto LHS = ParsePrimary();
+    if (!LHS)
+      return nullptr;
+
+    return ParseBinOpRHS(0, std::move(LHS));
+  }
+
+  /// prototype
+  ///   ::= id '(' id* ')'
+  static std::unique_ptr<PrototypeAST> ParsePrototype() {
+    if (CurTok != tok_identifier)
+      return ErrorP("Expected function name in prototype");
+
+    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>(FnName, std::move(ArgNames));
+  }
+
+  /// definition ::= 'def' prototype expression
+  static std::unique_ptr<FunctionAST> ParseDefinition() {
+    getNextToken(); // eat def.
+    auto Proto = ParsePrototype();
+    if (!Proto)
+      return nullptr;
+
+    if (auto E = ParseExpression())
+      return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
+    return nullptr;
+  }
+
+  /// toplevelexpr ::= expression
+  static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
+    if (auto E = ParseExpression()) {
+      // Make an anonymous proto.
+      auto Proto = llvm::make_unique<PrototypeAST>("__anon_expr",
+                                                   std::vector<std::string>());
+      return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
+    }
+    return nullptr;
+  }
+
+  /// external ::= 'extern' prototype
+  static std::unique_ptr<PrototypeAST> ParseExtern() {
+    getNextToken(); // eat extern.
+    return ParsePrototype();
+  }
+  //===----------------------------------------------------------------------===//
+  // Top-Level parsing and JIT Driver
+  //===----------------------------------------------------------------------===//
+
+  static void HandleDefinition() {
+    if (auto FnAST = ParseDefinition()) {
+      if (auto *FnIR = FnAST->codegen()) {
+        fprintf(stderr, "Read function definition:");
+        FnIR->dump();
+      }
+    } else {
+      // Skip token for error recovery.
+      getNextToken();
+    }
+  }
+
+  static void HandleExtern() {
+    if (auto ProtoAST = ParseExtern()) {
+      if (auto *FnIR = ProtoAST->codegen()) {
+        fprintf(stderr, "Read extern: ");
+        FnIR->dump();
+      }
+    } else {
+      // Skip token for error recovery.
+      getNextToken();
+    }
+  }
+
+  static void HandleTopLevelExpression() {
+    // Evaluate a top-level expression into an anonymous function.
+    if (auto FnAST = ParseTopLevelExpr()) {
+      if (auto *FnIR = FnAST->codegen()) {
+        fprintf(stderr, "Read top-level expression:");
+        FnIR->dump();
+      }
+    } else {
+      // Skip token for error recovery.
+      getNextToken();
+    }
+  }
+
+  /// top ::= definition | external | expression | ';'
+  void MainLoop() {
+    // Install standard binary operators.
+    // 1 is lowest precedence.
+    BinopPrecedence['<'] = 10;
+    BinopPrecedence['+'] = 20;
+    BinopPrecedence['-'] = 20;
+    BinopPrecedence['*'] = 40; // highest.
+    while (1) {
+      fprintf(stderr, "ready> ");
+      switch (CurTok) {
+      case tok_eof:
+        return;
+      case ';': // ignore top-level semicolons.
+        getNextToken();
+        break;
+      case tok_def:
+        HandleDefinition();
+        break;
+      case tok_extern:
+        HandleExtern();
+        break;
+      default:
+        HandleTopLevelExpression();
+        break;
+      }
+    }
+  }
+
+
+}

source/Parser.h

@@ -0,0 +1,40 @@
+#ifndef PARSER_H
+#define PARSER_H
+
+#include <cstdio>
+#include <map>
+#include <string>
+#include <vector>
+#include "Lexer.h"
+#include "Ast.h"
+
+using namespace ast;
+
+namespace parser{
+
+  static int CurTok;
+  static std::map<char, int> BinopPrecedence;
+
+  int getNextToken();
+  static int GetTokPrecedence();
+  std::unique_ptr<ExprAST> Error(const char *Str);
+  std::unique_ptr<PrototypeAST> ErrorP(const char *Str);
+  static std::unique_ptr<ExprAST> ParseExpression();
+  static std::unique_ptr<ExprAST> ParseNumberExpr();
+  static std::unique_ptr<ExprAST> ParseParenExpr();
+  static std::unique_ptr<ExprAST> ParseIdentifierExpr();
+  static std::unique_ptr<ExprAST> ParsePrimary();
+  static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
+                                                std::unique_ptr<ExprAST> LHS);
+  static std::unique_ptr<PrototypeAST> ParsePrototype();
+  static std::unique_ptr<FunctionAST> ParseDefinition();
+  static std::unique_ptr<FunctionAST> ParseTopLevelExpr();
+  static std::unique_ptr<PrototypeAST> ParseExtern();
+  static void HandleDefinition();
+  static void HandleExtern();
+  static void HandleTopLevelExpression();
+  void MainLoop();
+
+}
+
+#endif