private static Expression ParseBaseExpression(Scanner scanner)
{
int intvalue;
string strvalue;
if (scanner.TryGetIdentifier("null"))
{
return(new NullExpression());
}
else if (scanner.TryGetIdentifier("true"))
{
return(new TrueExpression());
}
else if (scanner.TryGetIdentifier("false"))
{
return(new FalseExpression());
}
else if (scanner.TryGetIdentifier("new"))
{
scanner.GetIdentifier(out strvalue);
//return new NewExpression(strvalue);
throw new NotImplementedException();
}
else if (scanner.TryGetIdentifier(out strvalue))
{
return(new VariableExpression(strvalue));
}
else if (scanner.TryGetInteger(out intvalue))
{
return(new IntegerLiteralExpression(intvalue));
}
else if (scanner.TryGetString(out strvalue))
{
return(new StringLiteralExpression(strvalue));
}
else if (scanner.TryGetSpecial(out strvalue))
{
return(new EnvironmentExpression(strvalue));
}
else if (scanner.TryGetDelimiter("("))
{
Expression expression = ParseExpression(scanner);
scanner.GetDelimiter(")");
return(expression);
}
else
{
throw new ApplicationException();
}
}
private static Expression ParseBaseExpression(Scanner scanner)
{
int intvalue;
string strvalue;
if (scanner.TryGetIdentifier("null"))
{
return new NullExpression();
}
else if (scanner.TryGetIdentifier("true"))
{
return new TrueExpression();
}
else if (scanner.TryGetIdentifier("false"))
{
return new FalseExpression();
}
else if (scanner.TryGetIdentifier("new"))
{
scanner.GetIdentifier(out strvalue);
//return new NewExpression(strvalue);
throw new NotImplementedException();
}
else if (scanner.TryGetIdentifier(out strvalue))
{
return new VariableExpression(strvalue);
}
else if (scanner.TryGetInteger(out intvalue))
{
return new IntegerLiteralExpression(intvalue);
}
else if (scanner.TryGetString(out strvalue))
{
return new StringLiteralExpression(strvalue);
}
else if (scanner.TryGetSpecial(out strvalue))
{
return new EnvironmentExpression(strvalue);
}
else if (scanner.TryGetDelimiter("("))
{
Expression expression = ParseExpression(scanner);
scanner.GetDelimiter(")");
return expression;
}
else
{
throw new ApplicationException();
}
}