SICP to the rescue
http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-24.html#%_sec_3.5.2

Probably inspiring in the context of this thread.
Bye
Enrico

On Wed, Feb 10, 2010 at 8:16 AM, Levente Uzonyi <leves at elte.hu> wrote:

> On Tue, 9 Feb 2010, Andreas Raab wrote:
>
>  Colin Putney wrote:
>>
>>> Also, Stephen Pair posted an implementation here in December:
>>> http://n4.nabble.com/ANN-CoroutineReadStream-tt963004.html#a963004
>>>
>>
>> Brilliant! That's the ticket! Once I got down the right path it's even
>> simpler than that. I put a version of Generator into the inbox for people to
>> play with and give feedback. With 5 methods total you get to do fun stuff
>> like:
>>
>> | gen max |
>> max := 10000000.
>> gen := Generator on:[:yield| Integer primesUpTo: max do: yield].
>> 'Computing primes' displayProgressAt: Sensor cursorPoint
>>        from: 1 to: max during:[:bar| | prime |
>>                [prime := gen next] whileNotNil:[bar value: prime].
>>        ].
>>
>> I think we should add support for Generators. They are so incredibly
>> useful where you have complex operations that you don't want to spend the
>> upfront effort on to compute everything (like primes) before you can do some
>> work with the results.
>>
>
> I wonder how can you use generators to generate primes efficiently _and_ on
> the fly.
>
>
> Levente
>
>
>> Cheers,
>>  - Andreas
>>
>>
>>
>


-- 
Enrico Spinielli
"Do Androids dream of electric sheep?"— Philip K. Dick
"Hear and forget; see and remember;do and understand."—Mitchel Resnick
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