FlexSignal updated too (Re: sslot version 0.2)

[Bill Baxter]

Lutger wrote:
> Bill Baxter wrote:
>> In the mean time, I've also updated FlexSignal to support connecting a 
>> function like:
>>    bool foo_slot(char[] s) { ... }
>>
>> to the signal:
>>    FlexSignal!(int, char[], float);
>>
>> I.e. the foo_slot can be connected to only get the char[] argument if 
>> that's all it's interested in.  Unfortunately the syntax for this is a 
>> little cumbersome right now due to bug #540:
>>
>>     thesignal.fconnect!(typeof(&foo_slot),1)(&foo_slot);
>>
>> When/if #540 is fixed this can become:
>>
>>     thesignal.fconnect!(1)(&foo_slot);
>>
>> The '1' indicates foo_slot wants to skip the 1st argument emitted by 
>> the signal.
> 
> It's sort of a reverse bind? 

Yeh, it is sort of bind-like.

> Would it be possible to write a seperate 
> adapter so it could be used with std.signals and allow for garbage 
> collection / deletion before disconnection?

It does actually use a separate adaptor.  See the SlotAdaptor template 
in the code.
But right now the SlotAdaptor template only returns the pointer to the 
delegate it makes, not the class itself.  But I guess you could get that 
from the .ptr prop.



> Boost::signals works nicely with boost bind like this but it's a little 
> less flexible iirc.
> 
> Something like this perhaps:
> thesignal.connect(adapt(thesignal, &foo_slot, 1));

The problem with that is that it creates some adapted thingy but unless 
you keep a pointer to it yourself you won't have a way to disconnect it.

> and / or more concise:
> connect(thesignal, &foo_slot, 1);

That doesn't work because the '1' has to be a compile time constant in 
order to muck with the signal's argument tuple.  I don't think there's a 
way to convince D that it is constant without making it a template 
parameter.  At least I couldn't figure one out.

> btw. there is a way to get the type of the .ptr property of a delegate 
> but I was reluctant to use it as it seemed a little too hackish:
> http://www.digitalmars.com/d/archives/digitalmars/D/learn/delegate_type_info_5001.html

Ah yes.  I remember seeing that one go by.  Hopefully some official 
support for that will be added, or else the distinction between Object 
and non-object delegates will be removed.

--bb