Re: [boost] Proposal: static_string library
>From: "Beman Dawes" <[EMAIL PROTECTED]> > At 05:58 PM 3/5/2003, Robert Klarer wrote: > > >The purpose of the static_string library is to offer an alternative to > >string literals and the standard type const std::string. A > >static_string uses no dynamically allocated memory, and is more > >efficient at execution time than either string literals or > >basic_strings. > > Yes, agreed. That would be useful. IIRC, the C++ committee's performance > working groups has talked about such a string in the past. > > There are questions that come to mind: > > * Can you come up with a small, workable language extension that eases > those problems? Josuttis/Vandevoorde mentions being able to pass string literals as template parameters as a possible future extension. That would be a clean way to handle it. Possibly could there also be a general solution regarding passing compound values. At the moment, values of class type can't be passed as template parameters. > * Can you come up with an alternate design that gives up a tiny bit of > efficiency (one pointer indirection perhaps) but then allows reasonable > construction and internationalization? If run-time computation is ok, and that one only wants to avoid dynamical allocation, then one might do something like I used in another posting in this thread: template class fixed_size_string; template fixed_size_string operator+(const fixed_size_string &s1, const fixed_size_string &s2); etc. Regards, Terje ___ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
Re: [boost] Proposal: static_string library
Beman Dawes <[EMAIL PROTECTED]> writes: > Lack of internationalization support is also a serious concern. What would internationalization support look like on a static string?! > There are questions that come to mind: > > * Can you come up with a small, workable language extension that eases > those problems? > > * Can you come up with an alternate design that gives up a tiny bit of > efficiency (one pointer indirection perhaps) but then allows > reasonable construction and internationalization? That's potentially a huge difference. With a truly static string you can do computations at compile-time. -- Dave Abrahams Boost Consulting www.boost-consulting.com ___ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
Re: [boost] Proposal: static_string library
At 05:58 PM 3/5/2003, Robert Klarer wrote: >There's already been some discussion of this library under the thread >"Proposal: strings as template parameters," but static_string hasn't >been the subject of its own thread, so I'm starting this one. I'd like >to solicit opinions about this project. Is it worthwhile? > >The purpose of the static_string library is to offer an alternative to >string literals and the standard type const std::string. A >static_string uses no dynamically allocated memory, and is more >efficient at execution time than either string literals or >basic_strings. Yes, agreed. That would be useful. IIRC, the C++ committee's performance working groups has talked about such a string in the past. But... >The syntax for declaring a static_string is unfortunate... > > boost::static_string<'s', 't', 'a', 't', 'i', 'c', '_'> StrType1; Unfortunate? Is that one of those understatement jokes Canadians are known for? I'd say it is way worse that "unfortunate" - it is ugly and error prone. Lack of internationalization support is also a serious concern. There are questions that come to mind: * Can you come up with a small, workable language extension that eases those problems? * Can you come up with an alternate design that gives up a tiny bit of efficiency (one pointer indirection perhaps) but then allows reasonable construction and internationalization? Wondering-out-loud, --Beman ___ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
[boost] Proposal: static_string library
There's already been some discussion of this library under the thread
"Proposal: strings as template parameters," but static_string hasn't
been the subject of its own thread, so I'm starting this one. I'd like
to solicit opinions about this project. Is it worthwhile?
The purpose of the static_string library is to offer an alternative to
string literals and the standard type const std::string. A
static_string uses no dynamically allocated memory, and is more
efficient at execution time than either string literals or
basic_strings.
The syntax for declaring a static_string is unfortunate, but once it has
been declared, a static_string's interface is (almost*) the same as that
of a const std::string.
* A static_string does not allocate memory, so it has no allocator_type.
Similarly, since a static_string can only be used with characters of
type char, no traits_type is necessary.
//Example 1: declaring and using a static_string
//
#include
int main()
{
typedef boost::static_string<'s', 't', 'a', 't', 'i', 'c', '_'>
StrType1;
StrType1 str1;
std::cout << "string one is: \'" << str1 << "\'\n";
std::cout << "length of string one is: " << str1.length() << '\n';
std::cout << "remove \'a\': ";
std::ostream_iterator oi(std::cout);
std::remove_copy(str1.begin(), str1.end(), oi, 'a'); // prints
"sttic_"
std::cout << std::endl;
}
A static_string cannot be modified, so all of the iterator types nested
within static_string behave as const_iterators. Internally, these
iterators are represented using pointers to const char, and are
therefore random access iterators.
Since the contents of a static_string are known at compile time, many
operations involving static_strings can be computed at program compile
time so that they are essentially free at program execution time
(assuming inlining).
//Example 2: free lunch?
//
#include
#include
int main()
{
typedef boost::static_string<'s', 't', 'a', 't', 'i', 'c', '_'>
StrType1;
typedef boost::static_string<'s', 't', 'r', 'i', 'n', 'g'> StrType2;
StrType1 str1;
StrType2 str2;
std::cout << "Strings one and two are "
<< (str1.compare(str2) ? "not " : "") // cost of this call
is nil
<< "equal" << std::endl;
}
As well, number of metafunctions are defined for static_string. Any
operation that be performed by means of a call to one of static_string's
member functions can be performed by one of these metafunctions.
//Example 3: metafunction interface
//
#include
#include
int main()
{
typedef boost::static_string<'s', 't', 'a', 't', 'i', 'c', '_'>
StrType1;
typedef boost::static_string<'s', 't', 'r', 'i', 'n', 'g'> StrType2;
typedef StrType1::concat_static::apply::value StrType3;
std::cout << "Concatenation of strings one and two: "
<< StrType3::c_str_static::apply::value
<< std::endl;
}
Thanks for considering my proposal.
___
Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
