diff --git a/headers/private/shared/ExpressionParser.h b/headers/private/shared/ExpressionParser.h
index 95df720db4..b180b87e17 100644
--- a/headers/private/shared/ExpressionParser.h
+++ b/headers/private/shared/ExpressionParser.h
@@ -14,8 +14,6 @@
 #include <String.h>
 
 
-class Tokenizer;
-
 class ParseException {
  public:
 	ParseException(const char* message, int32 position)
@@ -35,10 +33,10 @@ class ParseException {
 };
 
 struct Function;
-struct Token;
 class MAPM;
 
 class ExpressionParser {
+
  public:
 								ExpressionParser();
 								~ExpressionParser();
@@ -52,6 +50,10 @@ class ExpressionParser {
 			int64				EvaluateToInt64(const char* expressionString);
 			double				EvaluateToDouble(const char* expressionString);
 
+ private:
+			struct Token;
+			class Tokenizer;
+
  private:
 			MAPM				_ParseBinary();
 			MAPM				_ParseSum();
diff --git a/src/kits/shared/ExpressionParser.cpp b/src/kits/shared/ExpressionParser.cpp
index c49c67d3a2..b75c0e2c79 100644
--- a/src/kits/shared/ExpressionParser.cpp
+++ b/src/kits/shared/ExpressionParser.cpp
@@ -47,7 +47,7 @@ enum {
 	TOKEN_END_OF_LINE
 };
 
-struct Token {
+struct ExpressionParser::Token {
 	Token()
 		: string(""),
 		  type(TOKEN_NONE),
@@ -89,7 +89,7 @@ struct Token {
 };
 
 
-class Tokenizer {
+class ExpressionParser::Tokenizer {
  public:
 	Tokenizer()
 		: fString(""),
@@ -594,7 +594,7 @@ ExpressionParser::_ParseFunction(const Token& token)
 	if (strcmp("e", token.string.String()) == 0)
 		return _ParseFactorial(MAPM(MM_E));
 	else if (strcasecmp("pi", token.string.String()) == 0
-		|| ((unsigned char)token.string.String()[0] == 0xCF 
+		|| ((unsigned char)token.string.String()[0] == 0xCF
 			&& (unsigned char)token.string.String()[1] == 0x80)) {
 		// UTF-8 small greek letter PI
 		return _ParseFactorial(MAPM(MM_PI));