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digitalmars.D - Parens

reply "Janice Caron" <caron800 googlemail.com> writes:
On 10/05/2008, Dee Girl <deegirl noreply.com> wrote:

  void main(string[] args)
  {
     auto c = new const C;
  }

  Does not compile. But if I change to const(C) it does compile. It is a bit
unusual that parens make such a big difference. Thank you, Dee Girl



When it comes to parens-version versus non-parens-version, it's not
really a problem if one of the two doesn't compile. It would be a
bigger problem if both compile, but behave differently.

But I agree with you. "new const C" should behave like "new const(C)".

However, what you probably should have written is:

    const c = new C;

because "auto" is what you use in the absence of any other attribute.
In this case, it suffices to create a new C, and then assign it to a
const-thereafter variable.
May 09 2008
parent reply Dee Girl <deegirl noreply.com> writes:
Janice Caron Wrote:


 On 10/05/2008, Dee Girl <deegirl noreply.com> wrote:

  void main(string[] args)
  {
     auto c = new const C;
  }

  Does not compile. But if I change to const(C) it does compile. It is a bit
unusual that parens make such a big difference. Thank you, Dee Girl



 When it comes to parens-version versus non-parens-version, it's not
 really a problem if one of the two doesn't compile. It would be a
 bigger problem if both compile, but behave differently.
 
 But I agree with you. "new const C" should behave like "new const(C)".
 
 However, what you probably should have written is:
 
     const c = new C;
 
 because "auto" is what you use in the absence of any other attribute.
 In this case, it suffices to create a new C, and then assign it to a
 const-thereafter variable.



I respectfully disagree, Janice-san. The const subject is of big interest to me
and I read many times on the website about it. I think in general it is better
to write new const(C) but not new C and then use it to assign a const. It is
similar to invariant(C) and it is impossible to construct a new C and then
assign it to invariant(C) object. In Andres document from ACCU he shows how
invariant constructor must know that object being constructed is invariant. And
the same a const constructor could know that the object being constructed is
const and use that information. Thank you, Dee Girl
May 09 2008
next sibling parent reply Ty Tower <towerty msn.com.au> writes:
Dee Girl Wrote:


 Janice Caron Wrote:
 

 On 10/05/2008, Dee Girl <deegirl noreply.com> wrote:

  void main(string[] args)
  {
     auto c = new const C;
  }

  Does not compile. But if I change to const(C) it does compile. It is a bit
unusual that parens make such a big difference. Thank you, Dee Girl



 When it comes to parens-version versus non-parens-version, it's not
 really a problem if one of the two doesn't compile. It would be a
 bigger problem if both compile, but behave differently.
 
 But I agree with you. "new const C" should behave like "new const(C)".
 
 However, what you probably should have written is:
 
     const c = new C;
 
 because "auto" is what you use in the absence of any other attribute.
 In this case, it suffices to create a new C, and then assign it to a
 const-thereafter variable.



 I respectfully disagree, Janice-san. The const subject is of big interest to
me and I read many times on the website about it. I think in general it is
better to write new const(C) but not new C and then use it to assign a const.
It is similar to invariant(C) and it is impossible to construct a new C and
then assign it to invariant(C) object. In Andres document from ACCU he shows
how invariant constructor must know that object being constructed is invariant.
And the same a const constructor could know that the object being constructed
is const and use that information. Thank you, Dee Girl




Ahh the Japs . Exponents of the art of seeming respectful whilst telling you
you are a bloody idiot . This ones not so good at it though.
May 10 2008
next sibling parent reply "Koroskin Denis" <2korden gmail.com> writes:
On Sat, 10 May 2008 12:35:22 +0400, Ty Tower <towerty msn.com.au> wrote:=



 Dee Girl Wrote:


 Janice Caron Wrote:


 On 10/05/2008, Dee Girl <deegirl noreply.com> wrote:

  void main(string[] args)
  {
     auto c =3D new const C;
  }

  Does not compile. But if I change to const(C) it does compile. I=














 is a bit unusual that parens make such a big difference. Thank you, D=








 Girl

 When it comes to parens-version versus non-parens-version, it's not=










 really a problem if one of the two doesn't compile. It would be a
 bigger problem if both compile, but behave differently.

 But I agree with you. "new const C" should behave like "new const(C=










 However, what you probably should have written is:

     const c =3D new C;

 because "auto" is what you use in the absence of any other attribut=










 In this case, it suffices to create a new C, and then assign it to =










 const-thereafter variable.



 I respectfully disagree, Janice-san. The const subject is of big  =







 interest to me and I read many times on the website about it. I think=








 in general it is better to write new const(C) but not new C and then =








 use it to assign a const. It is similar to invariant(C) and it is  =







 impossible to construct a new C and then assign it to invariant(C)  =







 object. In Andres document from ACCU he shows how invariant construct=








 must know that object being constructed is invariant. And the same a =








 const constructor could know that the object being constructed is con=








 and use that information. Thank you, Dee Girl




 Ahh the Japs . Exponents of the art of seeming respectful whilst telli=





 you you are a bloody idiot . This ones not so good at it though.



Please, stop it.
May 10 2008
next sibling parent downs <default_357-line yahoo.de> writes:
Koroskin Denis wrote:

 On Sat, 10 May 2008 12:35:22 +0400, Ty Tower <towerty msn.com.au> wrote:
 

 Ahh the Japs . Exponents of the art of seeming respectful whilst
 telling you you are a bloody idiot . This ones not so good at it though.



 Please, stop it.



The original message seems to have been deleted (thanks W!), so I'll have to
answer to your post instead.


 downs wrote:
 Ahh the Ty. Insulting people whilst somehow avoiding getting their messages
kicked off the list. This one's not so good at it though.
May 10 2008
prev sibling parent Yigal Chripun <yigal100 gmail.com> writes:
Koroskin Denis wrote:

 On Sat, 10 May 2008 12:35:22 +0400, Ty Tower <towerty msn.com.au> wrote:
 

 Dee Girl Wrote:


 Janice Caron Wrote:


 On 10/05/2008, Dee Girl <deegirl noreply.com> wrote:

  void main(string[] args)
  {
     auto c = new const C;
  }

  Does not compile. But if I change to const(C) it does compile.






 you, Dee Girl

 When it comes to parens-version versus non-parens-version, it's not
 really a problem if one of the two doesn't compile. It would be a
 bigger problem if both compile, but behave differently.

 But I agree with you. "new const C" should behave like "new const(C)".

 However, what you probably should have written is:

     const c = new C;

 because "auto" is what you use in the absence of any other attribute.
 In this case, it suffices to create a new C, and then assign it to a
 const-thereafter variable.



 I respectfully disagree, Janice-san. The const subject is of big
 interest to me and I read many times on the website about it. I think
 in general it is better to write new const(C) but not new C and then
 use it to assign a const. It is similar to invariant(C) and it is
 impossible to construct a new C and then assign it to invariant(C)
 object. In Andres document from ACCU he shows how invariant
 constructor must know that object being constructed is invariant. And
 the same a const constructor could know that the object being
 constructed is const and use that information. Thank you, Dee Girl




 Ahh the Japs . Exponents of the art of seeming respectful whilst
 telling you you are a bloody idiot . This ones not so good at it though.



 Please, stop it.



let me just post my thanks to the Mozilla foundation for making
Thunderbird such a good product that filters out garbage like the above.
Denis, You really should not answer his posts cause then innocent people
get exposed to his posts, quoted in your replies. Why would you help him
in such a way, huh?
please add a filter to your newsreader. it's simple and much more
environment friendly.
--Yigal
May 10 2008
prev sibling parent reply BCS <ao pathlink.com> writes:
Reply to ty,


 Ahh the Japs . Exponents of the art of seeming respectful whilst
 telling you you are a bloody idiot . This ones not so good at it
 though.
 



You overstate your case. I have see the suffix -san used by more non Japanese 
than otherwise. And IIRC a  number of us yanks around here speek the language 
as well.
May 10 2008
parent reply Yigal Chripun <yigal100 gmail.com> writes:
BCS wrote:

 Reply to ty,
 

 Ahh the Japs . Exponents of the art of seeming respectful whilst
 telling you you are a bloody idiot . This ones not so good at it
 though.



 You overstate your case. I have see the suffix -san used by more non
 Japanese than otherwise. And IIRC a  number of us yanks around here
 speek the language as well.
 



I'm starting to feel disappointed. Why do people continue to respond to
this message? common people! what's the point in filtering if people
consider that type of message worthy of a response and a quote?
Maybe we should move to a registration-required model whereby ty's login
would be removed and blocked a long time ago since it's hardly his first
racist remark.

--Yigal
May 10 2008
parent reply "Me Here" <p9e883002 sneakemail.com> writes:
Yigal Chripun wrote:


 BCS wrote:

 Reply to ty,
 

 Ahh the Japs . Exponents of the art of seeming respectful whilst
 telling you you are a bloody idiot . This ones not so good at it
 though.
 



 You overstate your case. I have see the suffix -san used by more non
 Japanese than otherwise. And IIRC a  number of us yanks around here
 speek the language as well.
 



 I'm starting to feel disappointed. Why do people continue to respond to
 this message? common people! what's the point in filtering if people
 consider that type of message worthy of a response and a quote?
 Maybe we should move to a registration-required model whereby ty's login
 would be removed and blocked a long time ago since it's hardly his first
 racist remark.
 
 --Yigal





--
May 10 2008
next sibling parent Derek Parnell <derek psych.ward> writes:
On Sun, 11 May 2008 01:19:43 +0000 (UTC), Me Here wrote:

[snipped: witty copy of stuff that should not have been copied in the first
place ]

ROTFLMAO



-- 
Derek Parnell
Melbourne, Australia
skype: derek.j.parnell
May 10 2008
prev sibling parent Yigal Chripun <yigal100 gmail.com> writes:
Me Here wrote:

 Yigal Chripun wrote:

 I'm starting to feel disappointed. Why do people continue to respond to
 this message? common people! what's the point in filtering if people
 consider that type of message worthy of a response and a quote?
 Maybe we should move to a registration-required model whereby ty's login
 would be removed and blocked a long time ago since it's hardly his first
 racist remark.

 --Yigal






I guess I made the same mistake I've complained about. I'm sorry for
that. to my defense, I'll say that it was like 3 at night so I was tired
and didn't notice.
I've also just spotted a typo in there :)
this is my last reply to this thread. hopefully, no one will answer it
and it'll go the way of the dodo.

--Yigal
May 11 2008
prev sibling parent reply "Bruce Adams" <tortoise_74 yeah.who.co.uk> writes:
On Sat, 10 May 2008 06:51:21 +0100, Dee Girl <deegirl noreply.com> wrote=
:


 Janice Caron Wrote:


 On 10/05/2008, Dee Girl <deegirl noreply.com> wrote:

  void main(string[] args)
  {
     auto c =3D new const C;
  }

  Does not compile. But if I change to const(C) it does compile. It =











 a bit unusual that parens make such a big difference. Thank you, Dee =








 Girl

 When it comes to parens-version versus non-parens-version, it's not
 really a problem if one of the two doesn't compile. It would be a
 bigger problem if both compile, but behave differently.

 But I agree with you. "new const C" should behave like "new const(C)"=







 However, what you probably should have written is:

     const c =3D new C;

 because "auto" is what you use in the absence of any other attribute.=







 In this case, it suffices to create a new C, and then assign it to a
 const-thereafter variable.



 I respectfully disagree, Janice-san. The const subject is of big  =




 interest to me and I read many times on the website about it. I think =





 general it is better to write new const(C) but not new C and then use =





 to assign a const. It is similar to invariant(C) and it is impossible =





 construct a new C and then assign it to invariant(C) object. In Andres=





 document from ACCU he shows how invariant constructor must know that  =




 object being constructed is invariant. And the same a const constructo=





 could know that the object being constructed is const and use that  =




 information. Thank you, Dee Girl



It could know and use that but is that really a good idea?
I can imagine a class which had an invariant constructor that set up som=
e  =

sort
of mutex to prevent modification whereas its mutable counterpart did not=
.
I would hate to try and unravel code like that while debugging.
Its the sort of thing only the compier should need to know about.
That being the case the equals is just syntactic sugar like in C++.

const c =3D new C;

is identically equivalent to

const c(new C);

and:

const c(new const c);
May 10 2008
parent Dee Girl <deegirl noreply.com> writes:
Bruce Adams Wrote:


 On Sat, 10 May 2008 06:51:21 +0100, Dee Girl <deegirl noreply.com> wrote:
 

 Janice Caron Wrote:


 On 10/05/2008, Dee Girl <deegirl noreply.com> wrote:

  void main(string[] args)
  {
     auto c = new const C;
  }

  Does not compile. But if I change to const(C) it does compile. It is  



 Girl

 When it comes to parens-version versus non-parens-version, it's not
 really a problem if one of the two doesn't compile. It would be a
 bigger problem if both compile, but behave differently.

 But I agree with you. "new const C" should behave like "new const(C)".

 However, what you probably should have written is:

     const c = new C;

 because "auto" is what you use in the absence of any other attribute.
 In this case, it suffices to create a new C, and then assign it to a
 const-thereafter variable.



 I respectfully disagree, Janice-san. The const subject is of big  
 interest to me and I read many times on the website about it. I think in  
 general it is better to write new const(C) but not new C and then use it  
 to assign a const. It is similar to invariant(C) and it is impossible to  
 construct a new C and then assign it to invariant(C) object. In Andres  
 document from ACCU he shows how invariant constructor must know that  
 object being constructed is invariant. And the same a const constructor  
 could know that the object being constructed is const and use that  
 information. Thank you, Dee Girl



 It could know and use that but is that really a good idea?
 I can imagine a class which had an invariant constructor that set up some  
 sort
 of mutex to prevent modification whereas its mutable counterpart did not.
 I would hate to try and unravel code like that while debugging.
 Its the sort of thing only the compier should need to know about.



There could be a simpler case. A const C can have more sharing than an not
const C. If the constructor does not know this will be const then it must
assume this will be mutated.

And there is one other case. If a const(C) is constructed the invariant
constructor can work because invariant is a subtype of const.


 That being the case the equals is just syntactic sugar like in C++.
 
 const c = new C;
 
 is identically equivalent to
 
 const c(new C);
 
 and:
 
 const c(new const c);



Is that true? I tried to compile these codes and it does not work. Thank you,
Dee Girl
May 10 2008