Reflections on isPalindrome

["Nordlöw" via Digitalmars-d-learn]

On Friday, 24 October 2014 at 22:29:12 UTC, Peter Alexander wrote:
> On Friday, 24 October 2014 at 21:56:20 UTC, Nordlöw wrote:
>> bool isPalindrome(R)(in R range) @safe pure
>
> Aside: for templates, just let the compiler infer @safe and 
> pure. You don't know whether the range operations on R are pure 
> or not.
>
> As for the actual algorithm, there's no need for the random 
> access version, and you bidirectional version does twice as 
> much as necessary:
>
> Just do:
>
> while (!range.empty)
> {
>   if (range.front != range.back) return false;
>   range.popFront();
>   if (range.empty) break;
>   range.popBack();
> }
> return true;
>
> This automatically handles narrow strings.
>
>
>> Further, I would like to extend isPalindrome() with a minimum 
>> length argument minLength that for string and wstring does
>>
>> import std.uni: byDchar;
>> range.byDchar.array.length >= minLength.
>>
>> AFAIK this will however prevent my algorithm from being 
>> single-pass right?
>
> I'm not sure what you are saying here, but hopefully the above 
> code obviates this anyway.

Clever. Thx!