括弧付きの式に対応

BNF.txt

@@ -1,3 +1,4 @@
 program = add
 add = mul ("+" mul | "-" mul)*
-mul = num ("*" num | "/" num)*
+mul = primary ("*" primary | "/" primary)*
+primary = num | "(" add ")"

parser.cpp

@@ -1,5 +1,6 @@
 #include <cstdlib>
 #include <cstring>
+#include <iostream>
 #include <vector>
 #include "parser.hpp"
 #include "rook.hpp"
@@ -39,21 +40,33 @@ Node* Parser::add(void)
 
 Node* Parser::mul(void)
 {
-	Node* node = num();
+	Node* node = primary();
 
 	while(1){
 		if(consume("*")){
-			node = new Node{ ND_MUL, node, num() };
+			node = new Node{ ND_MUL, node, primary() };
 		}
 		else if(consume("/")){
-			node = new Node{ ND_DIV, node, num() };
+			node = new Node{ ND_DIV, node, primary() };
 		}
 		else{
 			return node;
 		}
 	}
 };
 
+Node* Parser::primary(void)
+{
+	if(consume("(")){
+		Node* addNode = add();
+		expect(")");
+		return addNode;
+	}
+	else{
+		return num();
+	}
+};
+
 bool Parser::consume(const char* str)
 {
 	if(TK_EOF == token->kind) return false;
@@ -66,6 +79,17 @@ bool Parser::consume(const char* str)
 	return false;
 };
 
+void Parser::expect(const char* str)
+{
+	if(TK_EOF == token->kind || strncmp(str, token->str, token->len)){
+		cerr << "Error : expect \"" << str << "\"" << endl;
+		exit(1);
+	}
+	else{
+		token++;
+	}
+};
+
 Node* Parser::parse(vector<Token>& tokens)
 {
 	token = tokens.begin();

parser.hpp

@@ -15,8 +15,10 @@ class Parser
 	Node* num(void);
 	Node* add(void);
 	Node* mul(void);
+	Node* primary(void);
 
 	bool consume(const char* str);
+	void expect(const char* str);
 
 public:
 	Node* parse(vector<Token>& tokens);

rook.hpp

@@ -8,7 +8,7 @@
 // トークン関連の定義
 typedef enum {
 	TK_NUM,			// 数値
-	TK_OP,			// 演算子
+	TK_RESERVED,	// 記号
 	TK_EOF,			// 終端
 } TokenKind;
 

test.sh

@@ -24,5 +24,9 @@ test 8 "2 * 4"
 test 3 "12 / 4"
 test 10 "5 * 3 - 5"
 test 9 "2 + 2 * 5 - 3"
+test 1 "(1)"
+test 8 "2*(1+3)"
+test 5 "1+(2*4)-(2*2)"
+test 2 "(2*(1+1)+2)/3"
 
 echo "OK"

tokenizer.cpp

@@ -17,22 +17,32 @@ vector<Token> Tokenizer::tokenize(char* input)
 			input++;
 		}
 		else if(strncmp(input, "+", 1) == 0){
-			Token token = { TK_OP, input, 1 };
+			Token token = { TK_RESERVED, input, 1 };
 			tokens.push_back(token);
 			input++;
 		}
 		else if(strncmp(input, "-", 1) == 0){
-			Token token = { TK_OP, input, 1 };
+			Token token = { TK_RESERVED, input, 1 };
 			tokens.push_back(token);
 			input++;
 		}
 		else if(strncmp(input, "*", 1) == 0){
-			Token token = { TK_OP, input, 1 };
+			Token token = { TK_RESERVED, input, 1 };
 			tokens.push_back(token);
 			input++;
 		}
 		else if(strncmp(input, "/", 1) == 0){
-			Token token = { TK_OP, input, 1 };
+			Token token = { TK_RESERVED, input, 1 };
+			tokens.push_back(token);
+			input++;
+		}
+		else if(strncmp(input, "(", 1) == 0){
+			Token token = { TK_RESERVED, input, 1 };
+			tokens.push_back(token);
+			input++;
+		}
+		else if(strncmp(input, ")", 1) == 0){
+			Token token = { TK_RESERVED, input, 1 };
 			tokens.push_back(token);
 			input++;
 		}