Wich: opIndex overloading by return type

Steven Schveighoffer schveiguy at gmail.com
Sun Apr 19 17:16:29 UTC 2020


On 4/19/20 11:53 AM, Robert M. Münch wrote:
> Wouldn't it make a lot of sense to allow different opIndex 
> implementations based on return type?
> 
> class myC {
>      myT1 opIndex(int x)
>      myT2 opIndex(int x)
> }
> 
> Depending on the types involved myC[1] woudl return myT1 or myT2. 
> Use-case: I have a geomentry object and in one case I get x0,y0,x1,y1 
> and in the other case x,y,w,h
> 
> IMO that would make a lot of sense.
> 

D doesn't do overloading based on return type.

You can do some things like return an item that alias this'd to one of 
the two, and then use an accessor for the other.

Or you could provide indexers that operate with those types. e.g:

myC.asT1[1] => T1
myC.asT2[1] => T2

-Steve


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