Re: [boost] range processing extension(s)

From: Rainer Deyke (root_at_[hidden])
Date: 2001-12-22 08:55:16

----- Original Message -----
From: "James Mitchell" <jimdesu_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Saturday, December 22, 2001 2:23 AM
Subject: [boost] range processing extension(s)

> template <typename B, typename E>
> class range
> {
>   B begin_;
>   E end_;
> public:
>   template< typename T>
>   range(T container): begin_(container.begin()),
> end_(container.end()){};
>   range(B begin, E end):begin_(begin), end_(end){};
>   /* canonical entries here */
>   operator*() { return *begin_; }
>   operator bool() { return begin_ == end_ };
>   /* incrementers and decrementers here */
>   B begin();
>   E end();
> };

Several problems:

 - I can't think of any real-life case where separate types for 'begin_' and
'end_' would be useful, and having to secify the same iterator type twice is
not good.
 - The first constructor as written here is obviously broken. (It need to
take its argument by reference.)
 - It is unclear how this class should be used.  If used simply to hold two
iterator, 'operator*' and the incerementers/decrementers are unnecessary.
If used directly for iteration, it needs to expose the full functionality of
the underlying iterators (including random access for random access
iterators).

--
Rainer Deyke (root_at_[hidden])
Shareware computer games           -           http://rainerdeyke.com
"In ihren Reihen zu stehen heisst unter Feinden zu kaempfen" - Abigor