shiny uno version, events / signals / slots

Stephan Bergmann sbergman at
Fri Jul 13 07:52:24 PDT 2012

On 07/13/2012 03:53 PM, Michael Meeks wrote:
> On Fri, 2012-07-13 at 14:27 +0200, Stephan Bergmann wrote:
>>> 	Sure - tools' IMPL_LINK - would be the broken, degenerate, gross
>>> case :-) More attractive versions would be g_signal or Qt's signals&
>>> slots[1], I've used the rather sweet C# bindings of these too to good
>>> effect; boost has a nice implementation as well anyhow checkout:
>> Not sure what improvements you are looking for over UNO's existing
>> listener mechanisms.
> 	Ease of declaration, use, type safe argument passing and succinctness.
> [snip]
> IDL:
> 	event somethingChanged([in] string aName, [in] long nValue);
> C++ to emit:
> 	inteface->somethingChanged.emit( "foo", 3 );
> C++ to listen:
> 	void handleChanged( const rtl::OUString &aName, long nValue);
> 	...
> 	interface->somethingChanged.connect(mem_func(*this, handleChanged));
> [/snip]
> 	Where the C++ piece is inspired by the std::sigc bindings - which are
> somewhat complicated, but potentially re-usable. The above is notably
> less verbose than the existing DECL_LINK horror, and should work nicely
> cross-platform too (like sigc).

...where DECL_LINK is independent of UNO

> 	IMHO that makes a rather pleasant contrast with the existing UNO
> listener implementation logic - but perhaps I'm missing something there;
> IIRC you need to declare and implement misc. interfaces on either side,
> your a custom listener interface, and more (?).

Right, what you save compared to current UNO is that on the listener's 
end you do not need to explicitly implement a specific UNO interface 
(instead, you only need to explicitly implement a function with a 
specific signature).

So what one would gain is improvement in ease of declaration and use (by 
increased succinctness).  Type safe argument passing would be just as 
type safe as today.


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