C++Talk.NET

german diago · Guest

Hello. I've been thinking about the use of STL and some libraries from
other languages and its usage patterns.
In C++ you've got some data structures and then, the algorithms are
used from outside the class, which sometimes, is less natural than
approaches having algorithms inside classes.
In languages like Ruby or C#, you've got the algorithms inside the
classes.

I think it would be a very good adittion to the standard to be able to
reuse code from the STL (and other classes with such a style) inside a
class of a user-defined type as a member function or even to be able
to reuse it from anywhere.

The idea is the following: if your class meets the requirements of a
concept, then, the free function can be used as a member function. The
mapping would be that the first argument of the free function would be
*this inside the class.

You could do the following.

///This is a free function
namespace algo {

template<String S>
void trim(S s) {
...
}

//UpperCase howmany characters
template<String S>
void upper(std::size_t howmany) {
...
}

//UpperCase
template<String S>
void upper(S s)
{
...
}
}

//Meets string requirements.
class mystring {
public:
using algo::trim();

using algo::upper(std::size_t);
};

Then, you could do:

mystring s(" hello world!");
s.trim();

The syntax is the first thing I thought about, but you get the idea.
When the code is generated, the first argument passed to the function
is mystring and the code generated is the one for that class. With
this mapping, you have to write minimal code to add free algorithms to
your classes and it would be very easy to add a set of already
implemented functions to your class.
And with the overloading rules, the compiler could pick up the most
refined concept to generate code, generating always the best code for
your class, and without having class hierarchies with virtual
functions. You get the benefits of object-oriented programming with
optimal speed.
What do you think about the idea?

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Sebastian Redl · Guest

On Thu, 10 May 2007, german diago wrote:

Roman.Perepelitsa@gmail.c · Guest

===================================== MODERATOR'S COMMENT:

When replying to posts, please do quote enough context for your message
to make sense without needing to see other messages.

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approve comment When replying to posts, please do quote enough context for your message to make sense without needing to see other messages. 

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===================================== END OF MODERATOR'S COMMENT
There is no practical benefit in your proposal; it's just a syntax
sugar. And you know, "s.trim()" is one character longer than
"trim(s)" ;-)

Roman Perepelitsa.

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german diago · Guest

On 11 mayo, 02:12, e0226...@stud3.tuwien.ac.at (Sebastian Redl) wrote: