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Date: Sun, 12 Jun 2022 15:25:54 -0500
To: "php internals" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Short Closures 2, aka auto-capture take 3
From: larry@garfieldtech.com ("Larry Garfield")

On Sun, Jun 12, 2022, at 12:54 PM, Mark Baker wrote:
> On 12/06/2022 19:21, Larry Garfield wrote:
>> On Thu, Jun 9, 2022, at 11:34 AM, Larry Garfield wrote:
>>
>> A little data:
>>
>> I used Nikita's project analyzer on the top 1000 projects to get a rough sense of how long-closures are used now.  All usual caveats apply about such survey data.  I was specifically looking at how many `use` statements a closure typically had, and how many statements it typically had.  Mainly, I am interested in how common "really long closures where the developer is likely to lose track of what is and isn't closed over" are.
>>
>> Total closures: 20052
>> Total used variables: 11534
>>
> Did many of those closures use "pass by reference" in the use clause, 
> because that's one real differentiator between traditional closures and 
> short lambdas. There's also the fact that use values are bound at the 
> point where the closure is defined, not where it's called (if they even 
> exist at all at that point), although that's probably more difficult to 
> determine.

New run to check for that:

Total used variables: 11534
ByRef used variables: 1833

So around 13% of used variables are by-ref, and thus would need to be explicitly used even with the new syntax.

> There's also the fact that use values are bound at the 
> point where the closure is defined, not where it's called (if they even 
> exist at all at that point), although that's probably more difficult to 
> determine.

I... don't see what relevance that has?  The potential for confusion is at the definition point, not call point.  If a closure is used inline then those are the same place, but if they're not, it's only the definition point that is relevant at the moment.

--Larry Garfield