private static YCodeNode DigitNode(char c)
{
YCodeNode node = new YCodeNode();
node.type = TokenType.CONST;
while (char.IsDigit(c) || c == '.')
{
tokenBuffer += c;
c = GetChar();
}
BackSpaceChar();
node.lexicon = tokenBuffer;
float v;
if (!float.TryParse(node.lexicon, out v))
{
///The Number is invalid. Set the value to null and generate error message.
node.value = null;
AppendErrorMessage(node, ErrorType.InvalidNumber);
}
else
{
node.value = v;
}
return(node);
}
private static YCodeNode LetterNode(char c)
{
YCodeNode node = new YCodeNode();
while (char.IsLetterOrDigit(c))
{
tokenBuffer += c;
c = GetChar();
}
BackSpaceChar();
if (c == '(')
{
///This is a Function.
node.type = TokenType.FUNC;
}
else
{
///This is a Variable.
node.type = TokenType.VAR;
}
node.lexicon = tokenBuffer;
node.value = YCodeVariableBuffer.GetVariable(node.lexicon);
return(node);
}
public static YCodeNode CompareNode(char c)
{
YCodeNode node = new YCodeNode();
tokenBuffer += c;
switch (c)
{
case '>':
c = GetChar();
if (c == '=')
{
node.type = TokenType.MOREEQ;
tokenBuffer += '=';
}
else
{
node.type = TokenType.MORE;
BackSpaceChar();
}
break;
case '<':
c = GetChar();
if (c == '=')
{
node.type = TokenType.LESSEQ;
tokenBuffer += '=';
}
else
{
node.type = TokenType.LESS;
BackSpaceChar();
}
break;
case '=':
c = GetChar();
if (c == '=')
{
node.type = TokenType.EQUALEQ;
tokenBuffer += '=';
}
else
{
node.type = TokenType.EQUAL;
BackSpaceChar();
}
break;
}
node.lexicon = tokenBuffer;
return(node);
}
public static YCodeNode ExprNode(char c)
{
YCodeNode node = new YCodeNode();
node.type = TokenType.EXPR;
tokenBuffer += c;
c = GetChar();
int lBracket = 1, rBracket = 0;
while (lBracket != rBracket && c != '\0')
{
if (c == '(')
{
lBracket++;
}
else if (c == ')')
{
rBracket++;
}
tokenBuffer += c;
c = GetChar();
}
if (c != '\0')
{
BackSpaceChar();
}
if (lBracket != rBracket)
{
node.value = null;
}
else
{
node.value = (float)0f;
}
node.lexicon = tokenBuffer;
return(node);
}
/// <summary>
/// Get the nearest node according to the currentPointer.
/// Meanwhile generates error messages.
/// </summary>
/// <returns>The node.</returns>
private static YCodeNode GetNode()
{
YCodeNode node;
tokenBuffer = "";
char c = GetChar();
if (char.IsLetter(c))
{
node = LetterNode(c);
}
else if (char.IsDigit(c))
{
node = DigitNode(c);
}
else if (c == '&' || c == '|' || c == '!')
{
node = LogicNode(c);
}
else if (c == '+' || c == '-' || c == '*' || c == '/' || c == '^')
{
node = OperatorNode(c);
}
else if (c == '>' || c == '=' || c == '<')
{
node = CompareNode(c);
}
else if (c == '(')
{
node = ExprNode(c);
}
else
{
node = new YCodeNode(TokenType.ERRTOKEN, ")", null);
///Call for generating Error.
}
return(node);
}
/// <summary>
/// Appends the Error Message to the List.
/// </summary>
/// <param name="node">Node.</param>
/// <param name="errType">Error type.</param>
public static void AppendErrorMessage(YCodeNode node, ErrorType errType)
{
}
public static YCodeNode OperatorNode(char c)
{
YCodeNode node = new YCodeNode();
tokenBuffer += c;
node.value = (float)0f;
switch (c)
{
case '+':
c = GetChar();
if (c == '=')
{
node.type = TokenType.PLUSEQ;
tokenBuffer += '=';
}
else
{
node.type = TokenType.PLUS;
BackSpaceChar();
}
break;
case '-':
c = GetChar();
if (c == '=')
{
node.type = TokenType.MINUSEQ;
tokenBuffer += '=';
}
else
{
node.type = TokenType.MINUS;
BackSpaceChar();
}
break;
case '*':
c = GetChar();
if (c == '=')
{
node.type = TokenType.MULEQ;
tokenBuffer += '=';
}
else
{
node.type = TokenType.MUL;
BackSpaceChar();
}
break;
case '/':
c = GetChar();
if (c == '=')
{
node.type = TokenType.DIVEQ;
tokenBuffer += '=';
}
else
{
node.type = TokenType.DIV;
BackSpaceChar();
}
break;
case '^':
c = GetChar();
if (c == '=')
{
node.type = TokenType.POWEQ;
tokenBuffer += '=';
}
else
{
node.type = TokenType.POW;
BackSpaceChar();
}
break;
}
node.lexicon = tokenBuffer;
return(node);
}
public static YCodeNode LogicNode(char c)
{
YCodeNode node = new YCodeNode();
node.value = (float)0f;
tokenBuffer += c;
switch (c)
{
case '&':
node.type = TokenType.AND;
c = GetChar();
if (c != '&')
{
node.value = null;
BackSpaceChar();
///Error Message.
}
else
{
tokenBuffer += c;
}
break;
case '|':
node.type = TokenType.OR;
c = GetChar();
if (c != '|')
{
node.value = null;
BackSpaceChar();
///Error Message.
}
else
{
tokenBuffer += c;
}
break;
case '!':
c = GetChar();
if (c == '=')
{
node.type = TokenType.NOTEQUAL;
tokenBuffer += c;
}
else
{
node.type = TokenType.NOT;
BackSpaceChar();
}
break;
default:
///Actually, this is impossible ...
break;
}
node.lexicon = tokenBuffer;
return(node);
}