Re: any_function (callback) library

From: williamkempf_at_[hidden]
Date: 2001-04-11 08:41:45

--- In boost_at_y..., Jesse Jones <jesjones_at_h...> wrote:
> >  > 6) Trying to invoke an empty function seems like a precondition
> >>  violation to me. Asserting instead of throwing seems preferable.
> >
> >I disagree because using an assertion means that the check might 
be turned
> >off. If that happens, any_function will cause a segmentation 
violation. At
> >least throwing an exception gives some form of recovery.
> 
> Would you also throw if someone passed a nil char* into 
std::string's 
> ctor? Indexed past the end of a std::array? Passed bogus iterators 
> into std::find? Personally I don't think any of these should throw: 
> they should assert whenever possible and follow the normal code 
path 
> thereafter. This is *exactly* what asserts are for.

Indexing past the end of std::array does throw, at least when you use 
at() instead of [].  This kind of throws your whole argument here 
out.  I'm really learning to hate exceptions.  _NO ONE_ agrees on 
when they should be used.  Even people who think they have their own 
set of rules for when to use them seem to violate the rules 
themselves from what I've seen.

As for the argument that asserts should be used instead... an assert 
is a C concept that existed before exceptions.  In fact, other 
languages throw exceptions on failed assertions to further cloud this 
argument.  Saying that this is exactly what assertions are for does 
not help to argue your case, or to help people like me figure out 
when to use what kind of error handling.

Bill Kempf