use more consistent types

lexer.h

@@ -7,7 +7,7 @@
 
 namespace usql {
 
-    enum class TokenType {
+enum class TokenType {
 	undef,
 	identifier,
 	plus,
@@ -69,17 +69,17 @@ namespace usql {
 	newline,
 	comment,
 	eof
-    };
+};
 
-    struct Token {
+struct Token {
 	std::string token_string;
 	TokenType type;
 
 	Token(const std::string &token_str, TokenType typ);
-    };
+};
 
-    class Lexer {
-    public:
+class Lexer {
+public:
 	Lexer();
 
 	void parse(const std::string &code);
@@ -108,7 +108,7 @@ namespace usql {
 
 	static bool isArithmeticalOperator(TokenType token_type);
 
-    private:
+private:
 	TokenType type(const std::string &token);
 
 	static std::string stringLiteral(std::string token);
@@ -116,16 +116,16 @@ namespace usql {
 	static std::string typeToString(TokenType token_type);
 
 
-    private:
+private:
 	std::string m_code_str;
 	std::vector<Token> m_tokens;
-	int m_index = 0;
+	size_t m_index = 0;
 
 	std::regex k_words_regex;
 	std::regex k_int_regex;
 	std::regex k_int_underscored_regex;
 	std::regex k_double_regex;
 	std::regex k_identifier_regex;
-    };
+};
 
-}
+}	// namespace