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Date: Sun, 23 Nov 2025 15:23:40 +0100
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Subject: Re: [PHP-DEV] [RFC][Discussion] use construct (Block Scoping)
To: "Rowan Tommins [IMSoP]" <imsop.php@rwec.co.uk>
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From: tim@bastelstu.be (=?UTF-8?Q?Tim_D=C3=BCsterhus?=)

Hi

On 11/12/25 10:53, Tim Düsterhus wrote:
>> I do see the advantage of forcing them to the start, though. Languages
>> in the Pascal family might be another comparison to explore - variables
>> are all declared in a separate block at the top of a function.
>> Off-hand, I'm not sure if any allow an arbitrary nested block just to
>> introduce additional variables.
> 
> We'll look into more research in that direction.

 From what I see in Pascal you would need to declare a “nested 
procedure” that can then access the variables of the outer prodecure, 
not dissimilar from a Closure with autocapturing.

We have now added a “Design Choices” section to the RFC explaining why 
we opted for “declarations need to be at the start of the scope”:

https://wiki.php.net/rfc/optin_block_scoping#design_choices

While it does not directly compare with any language (except for 
JavaScript), it mentions auto-vivification and scope-introspection 
functionality, which as far as we are aware doesn't exist to this extend 
in (similar) languages with block scoping and which is an important part 
of the requirement.

It also points out how it will not require additional nesting in 
practice. When there's already a block (particularly `if()`), one can 
put the block statement directly into the construct without additional 
braces.

Given the previous opinions of “please don't overload `use()` further”, 
we also renamed the keyword to `let()` which fits the “block scoping” 
semantics best, particularly when also considering the possible future 
scope for `foreach()` scoping.

Best regards
Tim Düsterhus