uniquer

import std.array : array;
assertEqual( [1,1,1,1].uniquer.array, [1] );
assertEqual( [1].uniquer.array, [1] );
assertEqual( "".uniquer.array, [] );
assertEqual( [1,2,1,3].uniquer.array, [1,2,3] );
assertEqual( [1,2,1,3,1,2].uniquer.array, [1,2,3] );
assertEqual( [1,2,3].uniquer.array, [1,2,3] );
assertEqual( ["a","b","a","c","a","c"].uniquer.array, ["a","b","c"] );

import std.typecons : tuple;
assertEqual( [tuple(1,"a"),tuple(1,"b"),tuple(2,"b"),tuple(1,"b")]
        .uniquer.array, [tuple(1,"a"),tuple(1,"b"),tuple(2,"b")] );