Cast to left hand side

[ketmar via Digitalmars-d-learn]

On Sun, 09 Nov 2014 21:47:02 +0000
eles via Digitalmars-d-learn <digitalmars-d-learn at puremagic.com> wrote:

> On Sunday, 9 November 2014 at 19:00:01 UTC, tcak wrote:
> > In some cases, I need to cast right hand side expression to 
> > left hand side. While it looks/feels simple for basic data 
> > types, it requires long lines with duplication when flexible 
> > code is desired to be written.
> >
> > Example:
> >
> > int a = 7;
> > byte b;
> >
> > b = cast( byte )a;
> 
> I am also strongly in favor of introducing an "uncast". For 
> example, in C++'x const_cast and in D's cast for removing, for 
> example immutability:
> 
> immutable int* p = ...;
> int* q = cast(int*)p;
> 
> I think the goal is not clearly expressed with this cast. It does 
> not show that it's intension is to remove immutability and 
> otherwise let that type unchanged. If later a mismatch is 
> introduced between the left and the right type of data, that 
> inoffensive cast could create problems by hiding an error that 
> should have been spotted.
> 
> Something like that would be more expressive:
> 
> immutable int* p = ...;
> int* q = uncast(immutable)p;
> //or
> int* q = cast(~immutable)p;
> 
> This way, invalid implicit conversions from p's type to q's type 
> would be spotted.
i believe you can do this with some template magic.
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