Default implementation of opEquals

Stefan Koch via Digitalmars-d digitalmars-d at puremagic.com
Fri Oct 7 05:31:24 PDT 2016


On Friday, 7 October 2016 at 12:04:09 UTC, Mark wrote:
> I'm going over the Object class methods and I have a few 
> concerns about the opEquals method.
>
> First, what should be the default implementation of opEquals? 
> The specification (see 
> https://dlang.org/spec/operatoroverloading.html#eqcmp) reads:
>
> "If opEquals is not specified, the compiler provides a default 
> version that does member-wise comparison"
>
> But this doesn't appear to be the case (at least with dmd). So 
> I went and checked the module in 
> https://github.com/dlang/druntime/blob/master/src/object.d. It 
> implements opEquals by comparing references (obj1 is obj2), not 
> by member-wise comparison.
>
> Wouldn't member-wise comparison be a more intuitive default?

For structs it provides memberwise comparison for classes it uses 
pointer-identity


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