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Date: Wed, 8 Mar 2017 19:50:07 +0100
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To: Andrea Faulds <ajf@ajf.me>
Cc: PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [Discussion] is_string(), string type
 andobjectsimplementing __toString()
From: nikita.ppv@gmail.com (Nikita Popov)

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On Wed, Mar 8, 2017 at 7:44 PM, Andrea Faulds <ajf@ajf.me> wrote:

> Fleshgrinder wrote:
>
>> On 3/8/2017 7:36 PM, Andrea Faulds wrote:
>>
>>> Hi,
>>>
>>> Andrey Andreev wrote:
>>>
>>>> The question is rather "is this value a string?", only with the added
>>>> assumption that __toString() objects are treated as "string objects"
>>>> and thus fulfill the condition (another reason why I went for an
>>>> is_string() parameter).
>>>>
>>>
>>> This is a faulty assumption. The presence of __toString() doesn't mean
>>> the object is a string, or intended to be used like one.
>>>
>>>
>> What is it then in your book?
>>
>>
> It means the object can be converted to a string. But such a conversion
> may entail a loss of information and not be equivalent to the object
> itself. It might be a =E2=80=9Chuman-readable=E2=80=9D form, for instance=
.
>

To give an example: Exceptions implement __toString(), which contains the
exception message, location information and backtrace. Of course,
exceptions are rather different from strings and treating an exceptions as
a string is usually incorrect.

Nikita

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