can we have something like in std.algorithm ?
it returns uniq elements in original order of appearance

Some cleanup may be needed, please send comments!

auto uniqStable(T)(T a) if(isRandomAccessRange!T){
	return zip(a,iota(a.length)).array.sort!q{a[0] < b[0]}.array.uniq!q{a[0]==b[0]}.array.sort!q{a[1]<b[1]}.map!q{a[0]}.array;
}

I forgot unittest:

unittest{
assert(uniqStable([1,3,1,0,2] ==[1, 3, 0, 2] ));
}
of course, it needs template on less, etc.

On Tuesday, 19 March 2013 at 02:09:06 UTC, timotheecour wrote:
> I forgot unittest:
>
> unittest{
> assert(uniqStable([1,3,1,0,2] ==[1, 3, 0, 2] ));
> }
> of course, it needs template on less, etc.

Stealing reply from Bearophile:
http://forum.dlang.org/post/rnsrrlmtguuayfxczsek@forum.dlang.org

He uses filter2 because filter doesn't cache results, but if you apply distinct() to a range where front() call is "stable" you can use filter.