🚀 go-pugleaf

Steve Clamage wrote:
> 
> In article 6AF5@cs.tu-berlin.de, Roman Lechtchinsky <wolfro@cs.tu-berlin.de> writes:
> >Steve Clamage wrote:
> >
> >> A converting constructor is one which can be called with a single parameter.
> >> The default constructor isn't a converting constructor except in the
> >> case of a constructor with all parameters having default values.
> >>
> >> If a constructor has no parameters, declaring it "explicit" has no effect,
> >> since it can never be invoked for a conversion.
> >
> >> If a constructor's parameters all have default values, it can be a
> >> converting constructor, and declaring it "explicit" prevents it from
> >> being invoked implicitly.
> >
> >Yes, I've had this in mind, too. In the following case:
> >
> >class A
> >{
> > explicit A( int x=0 );
> >};
> >
> >how do you call the default constructor?
> 
> The same way you always did before. The default constructor is one which
> requires no parameters. If implicitly or explicitly invoked with no
> parameters, no conversion is taking place, and it is a non-converting
> constructor.

Sorry for posting another article on this topic ( I wasn't going to, honest ) 
but I'm really not happy with this section of the DWP ( you might remember 
the thread about copy constructors ). However, you agree that a default 
constructor is a non-converting constructor. Then I read this passage in the 
DWP:

  A  nonconverting  constructor  constructs objects just like converting
  constructors, but does so only where a constructor call is  explicitly
  indicated by the syntax. [class.conv.ctor]

Do you see how this can be interpreted? A default constructor is 
non-converting, so it constructs objects only if its call is "explicitly 
indicated". The DWP doesn't say that this section deals only with 
constructors that could be converting or are invoked for a conversion. BTW, 
I'm talking only about the definitions in the DWP, not about the language 
itself (i.e. I'm not confused how to call default constructors). So, if we 
argue strictly on the basis of the DWP, where am I wrong?

> 
> > An explicit call would rather be
> >
> >A a();
> 
> No, that declares 'a' to be a function with no parameters returning an
> 'A' by value.

Oops. Sure. Sorry. Probably I should get some sleep.

Bye

Roman


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