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Date: Fri, 24 Apr 2020 05:22:11 +0200
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Subject: Re: [PHP-DEV] [DISCUSSION] Match expression
From: hubertnnn@gmail.com (HubertNNN)



> Hi!
>
>> I'm not quite sure what the way forward regarding that is. I can understand
>> the reluctance to propose the Rust-style block expression syntax, given its
> Speaking of which, what is the problem with that? I mean, if we just
> declare that the value of a block is the return of the last expression,
> would it break anything? Of course, by itself it'd be useless since we
> still aren't using blocks as expressions. But if we then had constructs
> that could accept both blocks and expressions - and we don't need to
> make everything that accepts expressions to accept blocks - we just need
> to make it make sense in those "dual" constructs.
>
I think that introducing a new construct like that would require its own RFC
Especially since there is a lot of confusion around how those blocks 
should work.
Eg. why should the fact that I use or not a semicolon depend on the fact 
what I will do with return value of the expression.

I think a much more sane solution would be to only allow expressions in 
match.

$x = match(true) {
     $a === 1 => foo(),
     $b > 2 => bar(),
}

$a = match($a) {
     1 => foo(),
     2 => bar(),
}

And then a block could be just an alias for a self calling anonymous 
function with all of its consequences:
- continue and break forbidden
- return being the keyword used to match the result instead of missing 
semicolon
- if no return was provided result defaults to null
- etc.

eg. this two are equal statements assigning result of baz() to $y:

$y = match($x) {
     1 => {
         foo();
         bar();
         return baz();
     },
     ...
}

$y = match($x) {
     1 => function() use(everything) {
         foo();
         bar();
         return baz();
     }(),
     ...
}


Also I think that suggestion that someone already made about making the 
parameter default to true is a really god idea,
I even believe that statements in this form are probably going to be 
more common than the standard one:

$y = match {
     $a < 10 => foo(),
     $a < 20 => bar(),
     ...
}