Re: why use flex?

>> [ re C++ in bison ]
>> Pardon me, but what kind of C++ support would you like to expect from
>> Flex and Bison? I have used Flex 2.5.4 and Bison 1.25 in two compiler
>> projects, both of which are written in C++. I use the tools in the
>> traditional C mode; only the semantic actions contain C++ code.
>
>C++ forbids putting objects into unions. This makes the yylval
>techniques of passing tokens values rather inadequate for C++.
>Another thing that would be nice is using exceptions for error
>recovery (with the hope of nice cleaning of the created objects).


    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.


Later,

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