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Date: Sat, 21 Feb 2015 15:36:27 +0000
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To: Markus Fischer <markus@fischer.name>
Cc: "internals@lists.php.net" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Make empty() a Variadic
From: danack@basereality.com (Dan Ackroyd)

On 21 February 2015 at 07:20, Markus Fischer <markus@fischer.name> wrote:
> On 21.02.15 06:11, Thomas Punt wrote:
> From the RFC:
>> Also, it will make empty() more inline with the not-too-disimillar isset(),
>
> Here I disagree.
>
> I would have assumed from the start that empty() would only return true
> if *all* of the entries are empty, i.e. AND things together.


The problem stems from the fact that 'empty' is a falsy statement as
it returns true when something is not set. Combining two positive
results in another positive statement. Combining two negative
statements results in a positive statement.....except when it doesn't.
You always have to think about what is the correct way to combine
them.

From the RFC:
> In PHP, it is not uncommon to see conditionals consisting of multiple empty()
> invocations. This is evident by simply browsing through some popular open
> source projects

This is subjective opinion, but at least two of those code examples
are horrible. In particular the phpBB code shows the problem of using
compound 'falsy' statements:

return !(
    empty($this->config['jab_enable']) ||
    empty($this->config['jab_host']) ||
    empty($this->config['jab_username']) ||
    empty($this->config['jab_password']) ||
    !@extension_loaded('xml')
);

Seriously, a double-negative at the end of a five piece statement that
combines falsy things? Making it easier to write bad (imo) code does
not seem a good reason for a change.

cheers
Dan