takeFront implementation is dangerous for ranges which invalidates their front value when popFront is called, for instance, File.byLine. Thus takeFront will have to be used with care: any range implement takeFront (because of the template and USFC), but it may not be valid. That makes the range interface more complicated: There is a takeFront property, but you have to check it is safe to use... how do you check that by the way?
Are there so many ranges that duplicate efforts in front and popFront, where there is no easy workarround? Would it be such an improvement in performance to add takeFront? strings being immutable, my guess would be that it is not that hard for the compiler to optimize a foreach loop (it should be easy to profile this...). Even if there is an efficiency issue, you could easily solve it by implementing a range wrapper or an opApply method to make foreach faster. -- Christophe
