private AExpression CalcTerm()
{
var result = CalcFactor();
while (CurrentChar() == '+' || CurrentChar() == '-')
{
char curChar = CurrentChar();
NextChar();
AExpression right = CalcFactor();
result = new Expression(curChar, result, right);
}
return(result);
}
private AExpression CalcFactor()
{
var result = ParsePrimary();
while (CurrentChar() == '/' || CurrentChar() == '*')
{
char curChar = CurrentChar();
NextChar();
AExpression right = ParsePrimary();
result = new Expression(curChar, result, right);
}
return(result);
}
private AExpression ParsePrimary()
{
AExpression result = null;
if (IsDigit(CurrentChar()))
{
result = ParseInteger();
}
else if (CurrentChar() == '(')
{
NextChar();
result = CalcAll();
SkipNextChar();
}
else
{
Console.WriteLine("Error: unexpected symbol " + CurrentChar() + " at " + cursor);
}
return(result);
}
public Expression(char oper, AExpression result, AExpression right2)
{
op = oper;
left = result;
right = right2;
}