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February 11, 2007
Re: Using typedefed types as covariant return types
Bill Baxter Wrote:

> What are you reading that makes you think CFStringRef is "derived" from 
> CFTypeRef?

It seems to be implied by the "Implicit Conversions" section of <http://www.digitalmars.com/d/type.html>:

"A typedef or enum can be implicitly converted to its base type, but going the other way requires an explicit conversion. "
February 12, 2007
Re: Using typedefed types as covariant return types
Rick Mann wrote:
> Bill Baxter Wrote:
> 
>> What are you reading that makes you think CFStringRef is "derived" from 
>> CFTypeRef?
> 
> It seems to be implied by the "Implicit Conversions" section of <http://www.digitalmars.com/d/type.html>:
> 
> "A typedef or enum can be implicitly converted to its base type, but going the other way requires an explicit conversion. "

Implicitly convertible doesn't mean a type is a subtype of another. 
Altough in this case of typedef and enums I think they could be subtypes 
of the base type.

-- 
Bruno Medeiros - MSc in CS/E student
http://www.prowiki.org/wiki4d/wiki.cgi?BrunoMedeiros#D
February 12, 2007
Re: Using typedefed types as covariant return types
Bruno Medeiros wrote:
> Rick Mann wrote:
>> Bill Baxter Wrote:
>> "A typedef or enum can be implicitly converted to its base type, but 
>> going the other way requires an explicit conversion. "
> 
> Implicitly convertible doesn't mean a type is a subtype of another. 
> Altough in this case of typedef and enums I think they could be subtypes 
> of the base type.

Perhaps he meant the "to its base type" part? I could see someone mixing 
that up with the same term used in class hierarchies...
February 12, 2007
Re: Using typedefed types as covariant return types
Frits van Bommel wrote:
> Bruno Medeiros wrote:
>> Rick Mann wrote:
>>> Bill Baxter Wrote:
>>> "A typedef or enum can be implicitly converted to its base type, but 
>>> going the other way requires an explicit conversion. "
>>
>> Implicitly convertible doesn't mean a type is a subtype of another. 
>> Altough in this case of typedef and enums I think they could be 
>> subtypes of the base type.
> 
> Perhaps he meant the "to its base type" part? I could see someone mixing 
> that up with the same term used in class hierarchies...

True enough, that may cause some confusion.

-- 
Bruno Medeiros - MSc in CS/E student
http://www.prowiki.org/wiki4d/wiki.cgi?BrunoMedeiros#D
February 17, 2007
Re: Using typedefed types as covariant return types
Frits van Bommel Wrote:

> Bruno Medeiros wrote:
> > Rick Mann wrote:
> >> Bill Baxter Wrote:
> >> "A typedef or enum can be implicitly converted to its base type, but 
> >> going the other way requires an explicit conversion. "
> > 
> > Implicitly convertible doesn't mean a type is a subtype of another. 
> > Altough in this case of typedef and enums I think they could be subtypes 
> > of the base type.
> 
> Perhaps he meant the "to its base type" part? I could see someone mixing 
> that up with the same term used in class hierarchies...

In that case, I'd like to make it a feature request. It seems only natural to be able to use typedefs in this manner. Should I file a formal request via bug?
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