D Recurrences

[Ben Grabham]

On 10/06/11 05:43, Jonathan M Davis wrote:
> On 2011-06-09 20:35, Ben Grabham wrote:
>> On 09/06/11 20:15, Jonathan M Davis wrote:
>>> The save property of a forward range returns a copy of that range. In
>>> most cases, since ranges are generally restructs, it just returns the
>>> range. You use it when you want to save the original range and still be
>>> able pop elements off.
>>>
>>> auto orig = range.save;
>>>
>>> //pop off as many elements from range as I want.
>>> //orig still has all of its elements
>>>
>>> The elements aren't copied however, just the range. Regardless, it has
>>> nothing to do with returning an element from a range, so I don't
>>> understand your question about returning an index rather than a whole
>>> object. Ranges don't really use indicies. indexOf will tell you the
>>> index of a particular element, and you can increment a counter every
>>> time you pop off an element if you want to know how many elements you've
>>> consumed, but once an element has been popped off, it's not part of that
>>> range anymore (though it could be part of a saved range), so that could
>>> seriously affect by what you mean by index, depending on what you're
>>> doing.
>>>
>>> - Jonathan M Davis
>>
>> I want to make it so that foreach works but I'm storing an array which
>> when changed, want to keep it like that, even after the foreach, I just
>> want to reset the index to 0
>>
>> At the moment, I have to do:
>> foreach(i; 0..100)
>> 	...
>>
>> lazy._n = 0;
>>
>> foreach(i; 0..100)
>> 	...
>>
>> I want to do:
>> foreach(n; lazy)
>> 	...
>> foreach(n; lazy)
>> 	...
>
> 0 .. 100 has nothing to do with ranges. That's a built-in feature of foreach.
> This would use a range
>
> foreach(i; iota(0, 100))
>
> because iota generates one, but 0 .. 100 doesn't. But there's no array
> involved in
>
> foreach(i; 0 .. 100)
>
> anyway, and you state that you're storing an array as part of this, so I
> really don't know what you're trying to do. I'd need to see actual code to be
> of any help.
>
> - Jonathan M Davis

Sorry, didn't really make that clear.

Inside the foreach, I'm using popFront and front to get the values and 
then outside, I set the index (_n) back to 0. What I want to do is 
"save" the _n value and then restore it at the beginning and end of the 
foreach respectively.

I don't have the code on me atm, but when I get hold of it, I'll post it 
if you still need it.

Thanks,
Nebster