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Date: Wed, 02 Jun 2021 18:07:29 -0500
To: "php internals" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Regarding array_shift()/array_unshift()
From: larry@garfieldtech.com ("Larry Garfield")

On Wed, Jun 2, 2021, at 5:59 PM, Mike Schinkel wrote:
> > On Jun 2, 2021, at 4:25 AM, Jordi Boggiano <j.boggiano@seld.be> wrote:

> > IMO for unshift() it'd be fine to return a new array, but when processing a list of things in a FIFO pattern I often used array_shift() to get the first "job" out of the array. If $array->shift() returns a new array then how do I access the first item?
> 
> That is a really excellent point, something I did not think to consider 
> given how rarely I use array_shift().  
> 
> But your comment causes me to ponder a number of follow up questions, 
> some of which are tangential.  If any reader feels these tangents are 
> worth discussing please make another email and quote my relevant 
> comments so we can have a dedicated thread for each.
> 
> 1.) Given Nikita's position that it would only be viable to offer a 
> syntax that simulates method calling for arrays if the methods 
> themselves are immutable can you envision a solution for allowing  
> $array->shift() functionality that would address getting both element 
> and shifted array without resorting to by-reference parameters?

$list->head() (returns first item)
$list->tail() (returns all items but the first one)

Straight outa FP. :-)  Can probably do some internal optimizations to make them more efficient, but now we're back to the discussion of a List or Vector type built in, which always runs into the Generics discussion, so... yeah.

--Larry Garfield