private void handleOperator(Token token) {
//If the current op has higher precedence, add to the stack
//true if the last operator on the stack has precedence over the current operator
while (operatorStack.Count() > 0 && operatorStack.First().TokenType == TokenType.arithmeticOp
&& precedenceTest(operatorStack.First().TokenString, token.TokenString)) {
tokens.Add(operatorStack.Pop());
}
operatorStack.Push(token);
}
private void testForOperationInference(Token tokenToAdd)
{
if (tokens.Count() > 0) {
//When a minus or plus sign is read as a negative number, add a plus sign before the number
if (tokenToAdd.TokenType == TokenType.number
&& (tokens.Last().TokenType == TokenType.number || tokens.Last().TokenType == TokenType.closedBrace)
&& (tokenToAdd.TokenString[0] == '-' || tokenToAdd.TokenString[0] == '+')) {
tokens.Add(new Token("+", TokenType.arithmeticOp));
}
//Infer a multiplication sign between two sets of parenthesis
if (tokenToAdd.TokenType == TokenType.openBrace && tokens.Last().TokenType == TokenType.closedBrace) {
tokens.Add(new Token("*", TokenType.arithmeticOp));
}
//Infer a multiplication sign between parenthesis and a number (that doesn't start with a minus sign)
if (tokenToAdd.TokenType == TokenType.openBrace && tokens.Last().TokenType == TokenType.number) {
tokens.Add(new Token("*", TokenType.arithmeticOp));
}
if (tokenToAdd.TokenType == TokenType.number && tokens.Last().TokenType == TokenType.closedBrace && tokenToAdd.TokenString[0] != '-') {
tokens.Add(new Token("*", TokenType.arithmeticOp));
}
}
}
public Token AddChar(currentChar c)
{
Token tokenToReturn = null;
//check if the char is legal in this context
if (syntaxIllegalCharTypes.Contains(c.currentCharTokenType)) {
throw new Exception("Illegal char placement");
}
//The char is legal. Check we if we should publish the current string
if (!charsThatAppendToCurrentString.Contains(c.currentCharTokenType) && tokenString.Count() > 0) {
tokenToReturn = new Token(tokenString, currentStringTokenType);
tokenString = string.Empty;
}
//Append Char
tokenString += c.val;
//Depending on the current char type:
//Set the local string type and other currenttoken state values
//Set publication types and char legal types
switch (c.currentCharTokenType) {
case CharType.arithmeticOp:
//Set local string type
if (c.val == '=')
currentStringTokenType = TokenType.equalSign;
else
currentStringTokenType = TokenType.arithmeticOp;
//Set the value of the publication type, etc.
//Publish on every char type
charsThatAppendToCurrentString = new HashSet<CharType>() {};
syntaxIllegalCharTypes = new HashSet<CharType>() { CharType.arithmeticOp, CharType.syntaxChar };
break;
case CharType.brace:
if(c.val == ')')
currentStringTokenType = TokenType.closedBrace;
if (c.val == '(')
currentStringTokenType = TokenType.openBrace;
charsThatAppendToCurrentString = new HashSet<CharType>() {};
syntaxIllegalCharTypes = new HashSet<CharType>() { };
break;
case CharType.letter:
currentStringTokenType = TokenType.charString;
charsThatAppendToCurrentString = new HashSet<CharType>() { CharType.letter, CharType.number };
syntaxIllegalCharTypes = new HashSet<CharType>() { };
break;
case CharType.number:
//We're not dealing with a word - we're dealing with a number or +/-
if (currentStringTokenType != TokenType.charString) {
currentStringTokenType = TokenType.number;
charsThatAppendToCurrentString = new HashSet<CharType>() { CharType.number, CharType.letter, CharType.period };
syntaxIllegalCharTypes = new HashSet<CharType>() { };
} else {
currentStringTokenType = TokenType.charString;
charsThatAppendToCurrentString = new HashSet<CharType>() { CharType.letter, CharType.number };
syntaxIllegalCharTypes = new HashSet<CharType>() { };
}
break;
case CharType.plusOrMinusSign:
currentStringTokenType = TokenType.arithmeticOp;
charsThatAppendToCurrentString = new HashSet<CharType>() { CharType.number };
syntaxIllegalCharTypes = new HashSet<CharType>() { CharType.arithmeticOp, CharType.syntaxChar };
break;
case CharType.syntaxChar:
currentStringTokenType = TokenType.syntaxChar;
charsThatAppendToCurrentString = new HashSet<CharType>() { };
syntaxIllegalCharTypes = new HashSet<CharType>() { CharType.arithmeticOp, CharType.syntaxChar };
break;
case CharType.whitespace:
tokenString = string.Empty;
break;
}
return tokenToReturn;
}
public override void Add(Token token) {
tokens.Add(token);
}
public virtual void Add(Token token)
{
testForOperationInference(token);
tokens.Add(token);
}