Re: why use flex?

> >C++ forbids putting objects into unions. ...
> Actually you can put C++ objects into Unions as long as they don't
> have copy-constructors or some nonsense like that. My solution was to
> create a class called SemanticValue which could contain objects of
> different types (a class that acts like a Union). A bit messy, but on
> the plus side, I used assignment operator overloading for simple types
> like boolean, string, etc which makes the lexer code look real nice.


A much better solution is to define semantic value as a pointer to
some base C++ class. This gives you type-safety, polymorphism etc. I
did that once. The only problem was to arrange for some sort of
garbage collection which I did simply by keeping a list of all
nodes. It worked (and I hope it still works) and it wasn't messy at
all.




Dmitri

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