Mattes Simeon
Though in comparison with C or C++ I can't figure out so clear the syntax...I seems realy strange, and I'm confused.
Surely a solution to this would be to use the standard types of Haskel for tuples and check out each time if I have just a number or a tuple. But this is how somebody thinks in imperative languages. Functional programming is something more...
The data declarations in Haskell are well-suited to pattern matching -- you have a compact way to express each alternative, so you can match on that alternative. The C++ way offers a *uniform* interface to every alternative, so you can do if-tests that will type check. The "do an if test at runtime" way is very general, but basically unoptimizable; whereas pattern matching is very specific, and can be optimized (see page 5 of Luca Cardelli's [Compiling ML]).
Sorry for beeing so naive, but although unions, enum, structure are just some tools in C, surely something more in C++, in Haskell they are seem to be a standard.
It's certainly true that Haskell elevates certain common data structures to the level of 'native citizens', providing short cut syntax and so forth. Personally, I think C's approach is an example of neglect in this domain, not sparseness; however, at the time C was introduced, I would not have said the same thing at all. -- _jsn [Compiling ML]: http://lucacardelli.name/Papers/CompilingML.pdf