public List <NovelInstruction> ParseExpression(string text)
{
//Trim the expression
text = text.Trim();
//Create empty expression object
NovelExpression novelExpression = new NovelExpression();
//Declare instructions
List <NovelInstruction> instructions = new List <NovelInstruction>();
//For RPN algorithm purpose
string output = "";
string buffer = "";
for (int i = 0; i < text.Length; i++)
{
//Check if the i is pointing at operator name
var operatorIndex = IsOperator(text, i);
//operatorIndex = -1 means that its regular character
if (operatorIndex >= 0)
{
//Build expression here based on whats in buffer
if (!buffer.Equals(""))
{
if (IsDeclaredVariable(buffer))
{
buffer = buffer.Substring(3);
if (!Variables.ContainsVariable(buffer))
{
instructions.Add(new NovelExpandStack(1));
Variables.AddVaraible(buffer);
}
//TODO functions name
else
{
throw new NovelException("Variable or function name " + buffer + " already exists.", ParsedFile, ParsedLine);
}
}
//Handle the operands
novelExpression = HandleOperand(novelExpression, buffer);
//Push variable to the output
output += buffer;
buffer = "";
}
//Get the new operator
var op = Operators[operatorIndex];
//Parentheses close operator
if (op is NovelCloseCurvedParenthesesOperator)
{
//Pop all operators till (
while (OperatorStack.Count() > 0)
{
var opFromStack = OperatorStack.Pop();
if (opFromStack is NovelOpenCurvedParenthesesOperator)
{
var parentheses = parenthesesType.Pop();
if (parentheses == ParenthesesType.Function)
{
novelExpression.Term.Add(new NovelFunctionEndOperator());
}
break;
}
else
{
if (!(opFromStack is NovelOpenCurvedParenthesesOperator ||
opFromStack is NovelCloseCurvedParenthesesOperator))
{
novelExpression.Term.Add(opFromStack);
}
}
}
}
//If every other operator
else
{
//Iteratore over OperatorStack
while (OperatorStack.Count() > 0)
{
//If priority of new operator is lower or equal pop stack operators
//
if (op.GetPriority() <= OperatorStack.First().GetPriority() &&
!(op is NovelOpenCurvedParenthesesOperator))
{
var opFromStack = OperatorStack.Pop();
if (!(opFromStack is NovelOpenCurvedParenthesesOperator ||
opFromStack is NovelCloseCurvedParenthesesOperator))
{
novelExpression.Term.Add(opFromStack);
}
}
else
{
break;
}
}
}
//Now put the operator on the stack if not close curved
if (!(op is NovelCloseCurvedParenthesesOperator))
{
//If previous term part was function call
if (novelExpression.Term.Count >= 1 &&
op is NovelOpenCurvedParenthesesOperator &&
novelExpression.Term[novelExpression.Term.Count - 1] is NovelExpressionFunctionCall)
{
parenthesesType.Push(ParenthesesType.Function);
novelExpression.Term.Add(new NovelFunctionStartOperator());
}
//If normal paretheses
else if (op is NovelOpenCurvedParenthesesOperator)
{
parenthesesType.Push(ParenthesesType.Normal);
}
OperatorStack.Push(op);
}
//Move pointer by a length of operator
i += op.GetName().Length - 1;
}
//If its not an operator
else
{
if (text[i].Equals(' '))
{
continue;
}
else if (text[i].Equals('\t'))
{
continue;
}
else if (text[i].Equals('\r'))
{
continue;
}
else if (text[i].Equals('\n'))
{
continue;
}
//If its a quote
if (text[i].Equals('\"'))
{
int len = text.IndexOf('\"', i + 1) - i + 1;
buffer += text.Substring(i, len);
i += len - 1;
}
//If its not add single character
else
{
buffer += text[i];
}
}
}
//Empty buffer first
if (!buffer.Equals(""))
{
novelExpression = HandleOperand(novelExpression, buffer);
}
//Empty operator stack
while (OperatorStack.Count() > 0)
{
var opFromStack = OperatorStack.Pop();
if (!(opFromStack is NovelOpenCurvedParenthesesOperator ||
opFromStack is NovelCloseCurvedParenthesesOperator))
{
novelExpression.Term.Add(opFromStack);
}
}
Variables.AddScope();
int reservedVariables = Variables.GetStackVariables();
while (novelExpression.Term.Count > 0)
{
novelExpression = UnfoldOperations(novelExpression, ref instructions);
novelExpression = UnfoldArguments(novelExpression, ref instructions);
//For single variables or literals
if (novelExpression.Term.Count == 1)
{
var newExpression = new NovelExpression();
newExpression.Term.Add(novelExpression.Term[0]);
instructions.Add(newExpression);
novelExpression.Term.Clear();
}
}
//How many of temporary variables expression has
reservedVariables = Variables.GetStackVariables() - reservedVariables;
//Shrink stack to remove them
if (reservedVariables > 0)
{
instructions.Add(new NovelExpandStack(-reservedVariables));
}
Variables.RemoveScope();
foreach (var instruction in instructions)
{
string buff = "";
buff += " " + instruction;
Console.WriteLine(buff);
}
Console.WriteLine("");
return(instructions);
}