Re: Token types with constructor

[Akim Demaille]

>>> "Martin" == Martin Trautmann <address@hidden> writes:

| What is the problem with the following code in the current bison
| version:
| class Token
| {
|   std::string str;
|   int i;
| };
| #define YYSTYPE Token

This is unrealistic:

- There are usually many more than merely two different entities.  So
  you're possibly wasting way too much space.

- From the C++ point of view, it's even worse: you're calling n
  different ctor and dtor for each symbol!  Not to mention the cost of
  the copy.

There is just no decent way to store different object types, you have
to store pointers (there are nice proposals for Variant types in
future C++es, but that's not for tomorrow).  Also, introducing an
artificial common root to all the symbols often breaks the AST design,
or worse, weakens types hence type safety.