[boost] Re: 'function' idea

[Dirk Gerrits]

Aleksey Gurtovoy wrote:

Dirk Gerrits wrote:

>I still don't get it. Have I used to few widget libraries? ;)


OK, we are drifting from the actual topic here, but I really don't like the
fact that I can't express myself clearly tonight :). So, here we go:

class widget_model
{
public:
// ...
typedef boost::function bool_arg_t;

self_t& is_enabled(bool_arg_t a_enabled)
{
is_enabled_ = a_enabled;
return *this;
}

bool is_enabled() const
{
return is_enabled_();
}

private:
bool_arg_t is_enabled_;
};


class win32_widget_impl
{
public:
win32_widget_impl( /* ... */)
{
// setup this->on_idle() to be called, well, on idle
}

void on_idle()
{
// sync itself with the model
::EnableWindow(hwnd_, model_->is_enabled());
}

private:
HWND hwnd_;
ref_ptr model_;
};

Since the model is passive here, everything works as per my first example
(given 'widget' -> 'widget_model' substitution).

Ahh, now I understand. Looks cool indeed. However I'm not sure how often this might be useful. Perhaps smarter people than I can think of more examples?

Dirk



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