implemented improved hold stack with convenience functions

new HoldStack class based on QStack with drop(), to pop the top item
with out returning it, and push() with token and first token to put in
the new item pushed to the stack

tokenhandlers.cpp

@@ -378,7 +378,7 @@ TokenStatus CloseParen_Handler(Translator &t, Token *&token)
 			// if topToken was not changed, pop it now
 			if (topToken == t.m_holdStack.top().token)
 			{
-				t.m_holdStack.resize(t.m_holdStack.size() - 1);
+				t.m_holdStack.drop();
 			}
 			delete token;		// delete close paren token
 			token = topToken;  // set token with error
@@ -387,7 +387,7 @@ TokenStatus CloseParen_Handler(Translator &t, Token *&token)
 	}
 
 	// now pop the top token
-	t.m_holdStack.resize(t.m_holdStack.size() - 1);
+	t.m_holdStack.drop();
 
 	return Good_TokenStatus;
 }

translator.cpp

@@ -249,9 +249,7 @@ TokenStatus Translator::addToken(Token *&token)
 
 		// push null token to be last operator on stack
 		// to prevent from popping past bottom of stack
-		m_holdStack.resize(m_holdStack.size() + 1);
-		m_holdStack.top().token = m_table.newToken(Null_Code);
-		m_holdStack.top().first = NULL;
+		m_holdStack.push(m_table.newToken(Null_Code));
 
 		m_state = OperandOrEnd_State;
 	}
@@ -445,9 +443,7 @@ TokenStatus Translator::processOperand(Token *&token)
 			m_countStack.top().nExpected = 0;
 		}
 
-		m_holdStack.resize(m_holdStack.size() + 1);
-		m_holdStack.top().token = token;
-		m_holdStack.top().first = NULL;
+		m_holdStack.push(token);
 		// leave state == Operand
 		m_state = Operand_State;  // make sure not OperandOrEnd
 	}
@@ -552,9 +548,7 @@ bool Translator::processUnaryOperator(Token *&token, TokenStatus &status)
 		}
 		token->setDataType(dataType);
 		// push open parentheses right on stack and return
-		m_holdStack.resize(m_holdStack.size() + 1);
-		m_holdStack.top().token = token;
-		m_holdStack.top().first = NULL;
+		m_holdStack.push(token);
 		m_state = Operand_State;
 
 		// add a null counter to prevent commas
@@ -672,7 +666,7 @@ TokenStatus Translator::processOperator(Token *&token)
 		// it will be reset upon next open parentheses)
 		m_lastPrecedence = m_table.precedence(topToken->code());
 
-		m_holdStack.resize(m_holdStack.size() - 1);
+		m_holdStack.drop();
 	}
 
 	// check for special token processing
@@ -720,10 +714,8 @@ TokenStatus Translator::processFirstOperand(Token *&token)
 		}
 	}
 
-	// push it onto the holding stack
-	m_holdStack.resize(m_holdStack.size() + 1);
-	m_holdStack.top().token = token;
-	m_holdStack.top().first = first;  // attach first operand
+	// push it onto the holding stack and attach first operand
+	m_holdStack.push(token, first);
 
 	// expecting another operand next
 	m_state = Translator::Operand_State;

translator.h

@@ -72,6 +72,23 @@ class Translator
 		Token *token;				// token pointer on hold stack
 		Token *first;				// operator token's first operand pointer
 	};
+	class HoldStack : public QStack<HoldItem>
+	{
+	public:
+		// drop the top item on stask (pop with no return)
+		void drop(void)
+		{
+			resize(size() - 1);
+		}
+		// push new item with token and first token
+		void push(Token *token, Token *first = NULL)
+		{
+			resize(size() + 1);
+			top().token = token;
+			top().first = first;
+		}
+	};
+
 	struct DoneItem
 	{
 		RpnItem *rpnItem;			// pointer to RPN item
@@ -98,7 +115,7 @@ class Translator
 	Table &m_table;					// reference to the table instance
 	Parser *m_parser;				// pointer to parser instance
 	RpnList *m_output;				// pointer to RPN list output
-	QStack<HoldItem> m_holdStack;	// operator/function holding stack
+	HoldStack m_holdStack;			// operator/function holding stack
 	QStack<DoneItem> m_doneStack;	// items processed stack
 	Token *m_pendingParen;			// closing parentheses token is pending
 	int m_lastPrecedence;			// precedence of last op added during paren