D2 GUI Libs

[Nick Sabalausky]

"Eldar Insafutdinov" <e.insafutdinov at gmail.com> wrote in message 
news:hg3g6u$11so$1 at digitalmars.com...
> Nick Sabalausky Wrote:
>
>> "Nick Sabalausky" <a at a.a> wrote in message
>> news:hg394f$mr1$1 at digitalmars.com...
>> > "Eldar Insafutdinov" <e.insafutdinov at gmail.com> wrote in message
>> > news:hg2p87$2ttj$1 at digitalmars.com...
>> >>
>> >> 1) You may know the concept of signals and slots in Qt. Consider the
>> >> following snippet:
>> >>
>> >> class Test : QObject
>> >> {
>> >>    mixin Signal!("signal_1(string)");
>> >>
>> >>    mixin Slot!("slot_1(string str)");
>> >>    void slot_1(string str)
>> >>    {
>> >>        writefln("slot_1 invoked with ~ " str);
>> >>    }
>> >>
>> >>    mixin Q_OBJECT;
>> >> }
>> >>
>> >> In Qt objects, that inherit from QObject are capable of having signals
>> >> and slots and participate in connections. In the current scheme mixins 
>> >> of
>> >> Signal and Slot template mix some static information into the class. 
>> >> The
>> >> class is then scanned when Q_OBJECT template is mixed in and the 
>> >> proper
>> >> meta-information is generated to register signals and slots in the Qt
>> >> type system.
>> >> As you see, this declaration is a bit ugly. In particular defining a 
>> >> slot
>> >> requires to duplicate its signature in a mixin. What would really be
>> >> awesome is a mechanism allowing something like:
>> >>
>> >>    @Slot
>> >>    void slot_1(string str)
>> >>    {
>> >>        writefln("slot_1 invoked with " ~ str);
>> >>    }
>> >> I.e we need annotations. But I am not sure how this will work. One of 
>> >> the
>> >> possible solutions will be that @Slot expands into mixin Slot!(symbol,
>> >> AnnotationArg1, ...).
>> >>
>> >
>>
>> Oops, slight typo:
>>
>> > Try string mixins, something like this:
>> >
>> > 1. Rename Slot to _Slot.
>> >
>> > 2. Do this:
>> >
>>
>> // Fixed:
>> template Slot(string decl, string body)
>> {
>>     const string Slot = "
>>         mixin _Slot!("~decl.stringof~");
>>         void slot_1(string str)
>>         {
>>             "~body.stringof~"
>>         }
>>     ";
>> }
>>
>> >
>> > class Test : QObject
>> > {
>> >    mixin Signal!("signal_1(string)");
>> >
>> >    mixin( Slot!("slot_1(string str)", q{
>> >        writefln("slot_1 invoked with ~ " str);
>> >    }) );
>> >
>> >   mixin Q_OBJECT;
>> > }
>> >
>> >
>>
>>
>
> Thank you for suggestion, but while reducing redundancy it became even 
> uglier! I'll better stay with the current syntax.

Yea, string mixins, powerful as they may be, are a bit of a poor-man's 
annotations.