Transience of .front in input vs. forward ranges

[Andrei Alexandrescu]

On 11/6/12 6:49 AM, Tommi wrote:
> On Tuesday, 6 November 2012 at 04:31:56 UTC, H. S. Teoh wrote:
>> The problem is that you can't do this in generic code, because generic
>> code by definition doesn't know how to copy an
>> arbitrary type.
>
> I'm not familiar with that definition of generic code. But I do feel
> that there's a pretty big problem with a language design if the language
> doesn't provide a generic way to make a copy of a variable. To be fair,
> e.g. C++ doesn't provide that either.

Languages commonly have trouble defining comparison and copying 
generically. More often than not user intervention is needed (e.g. see 
Java's clone, Lisp's many comparison operators etc).

Andrei