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Subject: Re: [PHP-DEV] [RFC] Default expression
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Date: Sun, 25 Aug 2024 11:49:42 +0200
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From: php-internals_nospam@adviesenzo.nl (Juliette Reinders Folmer)

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(resending as I accidentally originally send a private reply instead of 
sending the below to the list)

On 24-8-2024 18:49, Bilge wrote:
> Hi gang,
>
> New RFC just dropped: https://wiki.php.net/rfc/default_expression. I 
> think some of you might enjoy this one. Hit me with any feedback.
>
> This one already comes complete with working implementation that I've 
> been cooking for a little while. Considering I don't know C or PHP 
> internals, one might think implementing this feature would be 
> prohibitively difficult, but considering the amount of help and 
> guidance I received from Ilija, Bob and others, it would be truer to 
> say it would have been more difficult to fail! Huge thanks to them.
>
> Cheers,
> Bilge
>

Hi Bilge,

I like the idea, but see some potential for issues with ambiguity, which 
I don't see mentioned in the RFC as "solved".

Example 1:
```php
function foo($paramA, $default = false) {}
foo( default: default ); // <= Will this be handled correctly ?
```

Example 2:
```php
callme(
     match($a) {
         10 => $a * 10,
         20 => $a * 20,
         default => $a * default, // <= Based on a test in the PR this 
should work. Could you confirm ?
     }
);
```

Example 3:
```php
switch($a) {
     case 'foo':
         return callMe($a, default); // I presume this shouldn't be a 
problem, but might still be good to have a test for this ?
     default:
         return callMe(10, default); // I presume this shouldn't be a 
problem, but might still be good to have a test for this ?
}
```

On that note, might it be an idea to introduce a separate token for the 
`default` keyword when used as a default expression in a function call 
to reduce ambiguity ?

Smile,
Juliette


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    <div class="moz-cite-prefix">(resending as I accidentally originally
      send a private reply instead of sending the below to the list)<br>
      <br>
      On 24-8-2024 18:49, Bilge wrote:<br>
    </div>
    <blockquote
      cite="mid:0c8ed5d6-5507-4c41-8d7f-05d14ba8aa4c@scriptfusion.com"
      type="cite">Hi gang, <br>
      <br>
      New RFC just dropped: <a class="moz-txt-link-freetext"
        href="https://wiki.php.net/rfc/default_expression">https://wiki.php.net/rfc/default_expression</a>.
      I think some of you might enjoy this one. Hit me with any
      feedback. <br>
      <br>
      This one already comes complete with working implementation that
      I've been cooking for a little while. Considering I don't know C
      or PHP internals, one might think implementing this feature would
      be prohibitively difficult, but considering the amount of help and
      guidance I received from Ilija, Bob and others, it would be truer
      to say it would have been more difficult to fail! Huge thanks to
      them. <br>
      <br>
      Cheers, <br>
      Bilge <br>
      <br>
    </blockquote>
    <br>
    Hi Bilge,<br>
    <br>
    I like the idea, but see some potential for issues with ambiguity,
    which I don't see mentioned in the RFC as "solved".<br>
    <br>
    Example 1:<br>
    ```php<br>
    function foo($paramA, $default = false) {}<br>
    foo( default: default ); // &lt;= Will this be handled correctly ?<br>
    ```<br>
    <br>
    Example 2:<br>
    ```php<br>
    callme(<br>
        match($a) {<br>
            10 =&gt; $a * 10,<br>
            20 =&gt; $a * 20,<br>
            default =&gt; $a * default, // &lt;= Based on a test in the
    PR this should work. Could you confirm ?<br>
        }<br>
    );<br>
    ```<br>
    <br>
    Example 3:<br>
    ```php<br>
    switch($a) {<br>
        case 'foo':<br>
            return callMe($a, default); // I presume this shouldn't be a
    problem, but might still be good to have a test for this ?<br>
        default:          <br>
            return callMe(10, default); // I presume this shouldn't be a
    problem, but might still be good to have a test for this ?<br>
    }<br>
    ```<br>
    <br>
    On that note, might it be an idea to introduce a separate token for
    the `default` keyword when used as a default expression in a
    function call to reduce ambiguity ?<br>
    <br>
    Smile,<br>
    Juliette<br>
    <br>
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