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Subject: Re: [PHP-DEV] [RFC] Generators
From: lester@lsces.co.uk (Lester Caine)

Nikita Popov wrote:

> I don't understand this argument. Generator functions are transparent
> to the user. You use a generator function just like you would use a
> function that returns an array. From a user point of view it does not
> matter whether getLinesFromFile() is just a function returning an
> array, or whether it is a generator (or maybe even returns a
> hand-implemented iterator). It's just all the same. The fact that the
> function uses `yield` internally is just an implementation detail, not
> something that has to be part of the public API. Actually you can swap
> between an array and generator implementation just by replacing one
> line in the function body (yield <=> $array[])...

Then I am now totally confused ...

I was under the impression that the IDEA was that EACH call to a generator would 
return the next value? So you do not get an array built. Just as one would with 
SUSPEND in an SQL query process. The only value available is the current one, 
and one processes that. So that the user of a generator needs to handle the 
results sequentially rather than simply accessing the array of results. There 
does not need to be an array of results, only the processed output of each cycle 
of the generator?

This of cause may still be confused thinking, since I would never be working in 
the way that this stuff is supposed to simplify. I WOULD be handling each 
element as I read it and building the details required from each cycle of the 
process. getLinesFromFile() would only ever return an array if that is what was 
needed to build the resulting page. It would normally be processed into a 
database, and later the required information selected from that. But that is a 
specialist iterator process just built with simple PHP.

-- 
Lester Caine - G8HFL
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