Re: Getting a range over a const Container

[Ali Çehreli]

On 07/19/2012 06:16 PM, Ali Çehreli wrote:

On 07/19/2012 06:09 PM, Ellery Newcomer wrote:

On 07/19/2012 02:51 AM, Artur Skawina wrote:

Range!Node opSlice() { return Range!Node(first); }
Range!(const Node) opSlice() const { return Range!(const Node)(first); }

anyone mind cluing me in on why this is possible?

It is the same as in C++. Considering the hidden non-const this and
const this parameters, one of the member functions is a better match for
each call:

Ha ha! The output is worthless when both functions print the same thing. :)

This is better:

import std.stdio;

struct S
{
    void foo(string name)
    {
        writeln("non-const foo called on ", name);
        assert(typeid(this) == typeid(S));
    }

    void foo(string name) const
    {
        writeln("const foo called on ", name);
        assert(typeid(this) == typeid(const S));
    }
}

void main()
{
    auto a = S();
    const b = S();

    a.foo("a");    // matches non-const foo()
    b.foo("b");    // matches const foo()
}

Now the output is different:

non-const foo called on a
const foo called on b

Ali