[boost] Re: Possible boost addition: sub string and const s tring.

[Vincent Finn]

Alexei Novakov wrote:

"Vincent Finn" <[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...

Forwarded to main Boost list - that's the more appropriate venue for
discussions of possible additions.

-- Jim Hyslop boost-users moderator.

> -----Original Message-----
> From: alexei_novakov [mailto:[EMAIL PROTECTED]]
> Sent: Monday, November 18, 2002 7:05 PM
> To: [EMAIL PROTECTED]
> Subject: [Boost-Users] Possible boost addition: sub string and const
> string.
>
>
> Hello everyone.
>
> I have two classes which I found pretty handy: sub_string (behaves as
> a mirror of the portion of master basic_string) and const_string (C-
> string wrapper). Nice thing about these two is they implemented as
> template specialization of basic_string which has advantages:
> a) familiar interface;
> b) possibility to reuse the code written for basic_string (like
> string streams, lexical casts, etc).
>
> Any interest?
>
> Regards.
>
> Alexei Novakov

Sounds interesting, like slice on a valarray

When I have to do a lot of manipulation of sub string and can't afford
to copy back and forward I normally resort to using vector<char>; this
sounds a lot handier

How does it work ?

Vin

The idea is simple. Sub string is declared as basic_string template
specialization:

template <typename CHAR, typename TRAITS, typename ALLOCATOR>
class basic_string<CHAR, TRAITS, basic_string<CHAR, TRAITS, ALLOCATOR> >

The interfase is the same as for basic_string (except constructors). Sub
string instances contain reference to master string and boundaries (start
and size). One can use it like this:

// Start
typedef basic_string<string::value_type, string::traits_type, string>
sub_string;

string str("1234567890");
sub_string ss(str, 2, 5); // master string, start position, size

assert(lexical_cast<int>(ss) == 34567);

ss = "$$";

assert(str == "12$$890");
// End

All the basic_string operators (like +, ==, !=, <, >, <=, >=) are overloaded
to be used for both strings and sub strings.

Similar approach is used for const_string (C string wrapper), but only const
methods of basic_string are implemented.

Alexei.

Cool, I'd definitely use it
Seeing as there is a move to submit a library of string helpers at the moment it might be worth submitting this at the same time!

Vin



_______________________________________________
Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost