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digitalmars.D.learn - Meaning of Scoped! ??

reply Ron Tarrant <rontarrant gmail.com> writes:
Some things are almost impossible to research. For instance, in 
the GtkD wrapper code—specifically the Widget.d file—the 
following function definition appears:


	gulong addOnDraw(bool delegate(Scoped!Context, Widget) dlg, 
ConnectFlags connectFlags=cast(ConnectFlags)0)
	{
		return Signals.connect(this, "draw", dlg, connectFlags ^ 
ConnectFlags.SWAPPED);
	}


With contemporary search engines, it's impossible to search for 
'!' and get meaningful results. And searching for 'Scoped!' 
results in every variation of the word 'scope' and ignores the 
'!' altogether, even with Google's Verbatim tool turned on. 
Worse, Google ignores case as well.

I also searched all three D-language books and found nothing.

Here are my questions:

1) What exactly does the '!' mean? For instance, '=' means "is 
equal to," but I don't know what words to 'think' while looking 
at a '!'

2) What does 'Scoped' mean?

3) In the specific instance above, what does 'Scoped!Context' 
mean as opposed to just 'Context'? In other words, what are the 
differences between 'Scoped!Context' and 'Context'?

The last question needs more explanation...

In Widget.d, there are two overloads of addOnDraw(), the one 
cited above and this one:


	deprecated gulong addOnDraw(bool delegate(Context, Widget) dlg, 
ConnectFlags connectFlags=cast(ConnectFlags)0)
	{
		return Signals.connect(this, "draw", dlg, connectFlags ^ 
ConnectFlags.SWAPPED);
	}


The former works, but the latter spits out a 'deprecated' error 
(naturally).
Jul 30 2019
next sibling parent rikki cattermole <rikki cattermole.co.nz> writes:
On 30/07/2019 9:33 PM, Ron Tarrant wrote:

 Some things are almost impossible to research. For instance, in the GtkD 
 wrapper code—specifically the Widget.d file—the following function 
 definition appears:
 
 
      gulong addOnDraw(bool delegate(Scoped!Context, Widget) dlg, 
 ConnectFlags connectFlags=cast(ConnectFlags)0)
      {
          return Signals.connect(this, "draw", dlg, connectFlags ^ 
 ConnectFlags.SWAPPED);
      }
 
 
 With contemporary search engines, it's impossible to search for '!' and 
 get meaningful results. And searching for 'Scoped!' results in every 
 variation of the word 'scope' and ignores the '!' altogether, even with 
 Google's Verbatim tool turned on. Worse, Google ignores case as well.
 
 I also searched all three D-language books and found nothing.
 
 Here are my questions:
 
 1) What exactly does the '!' mean? For instance, '=' means "is equal 
 to," but I don't know what words to 'think' while looking at a '!'


Template

https://dlang.org/spec/template.html


 2) What does 'Scoped' mean?


Its a type defined by GtkD by the looks.

https://github.com/gtkd-developers/GtkD/blob/e14091fb2df4d05348061f274c131700af89fb16/generated/gtkd/glib/c/types.d#L56


 3) In the specific instance above, what does 'Scoped!Context' mean as 
 opposed to just 'Context'? In other words, what are the differences 
 between 'Scoped!Context' and 'Context'?


Auto destruction of the argument and you cannot copy its value around.
Jul 30 2019
prev sibling next sibling parent reply Andrea Fontana <nospam example.com> writes:
On Tuesday, 30 July 2019 at 09:33:04 UTC, Ron Tarrant wrote:

 Some things are almost impossible to research. For instance, in 
 the GtkD wrapper code—specifically the Widget.d file—the 
 following function definition appears:


 	gulong addOnDraw(bool delegate(Scoped!Context, Widget) dlg, 
 ConnectFlags connectFlags=cast(ConnectFlags)0)
 	{
 		return Signals.connect(this, "draw", dlg, connectFlags ^ 
 ConnectFlags.SWAPPED);
 	}


Scoped is a struct defined here:
https://github.com/gtkd-developers/GtkD/blob/e14091fb2df4d05348061f274c131700af89fb16/generated/gtkd/glib/c/types.d#L56

Looking at its source code, it seems it's a way to force the call 
of "destroy" method of wrapped object (Context in your case) when 
the struct goes out of its scope (and d-tor is called)

Andrea
Jul 30 2019
parent Ron Tarrant <rontarrant gmail.com> writes:
On Tuesday, 30 July 2019 at 09:46:07 UTC, Andrea Fontana wrote:


 Looking at its source code, it seems it's a way to force the 
 call of "destroy" method of wrapped object (Context in your 
 case) when the struct goes out of its scope (and d-tor is 
 called)

 Andrea


Thanks, Andrea (and rikki). I actually learned this a while back 
(even wrote about it in a blog post) but I've noticed my memory 
is playing tricks on me lately.

In fact, don't be surprised if I ask this same question (or a 
close variation of it) next month. (sigh)
Jul 30 2019
prev sibling parent =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 07/30/2019 02:33 AM, Ron Tarrant wrote:


 With contemporary search engines, it's impossible to search for '!' and
 get meaningful results.


I recommend this Index section for such cases:

   http://ddili.org/ders/d.en/ix.html

Like most of Phobos, Scoped is not there but the "!, template instance" 
entry answers the other question. :)

Ali
Jul 31 2019