design question

[Andrei Alexandrescu]

dsimcha wrote:
> == Quote from Andrei Alexandrescu (SeeWebsiteForEmail at erdani.org)'s article
>> I think the stability request could be better encoded as a wrapper of
>> the range making the request. For example:
>> auto p = partition!("(a & 1) == 0")(keepStable(arr));
>> So in order to tell partition you want stability, you just wrap the
>> range with a call to keepStable. (The runtime cost is negligible).
>> Similarly, say you want a stable sort. You'd say:
>> sort(keepStable(arr));
>> instead of:
>> sort!(SwapStrategy.stable)(arr);
> 
> Can you elaborate a little?  In particular, would the KeepStable wrapper actually _do_ anything in itself to
> make modifications to the underlying range stable, or would it just wrap the range in a new type so that
> you could stick a static if statement in the sort algorithm to decide what to?

keepStable is a template function that simply wraps the range in a 
different type. It's a way to pass information about the range (e.g., 
"keep this stable", or "this is sorted already"), to the function 
understanding it.

Andrei