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Date: Fri, 27 Feb 2015 21:28:38 +0100
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To: Lester Caine <lester@lsces.co.uk>
Cc: "internals@lists.php.net" <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=001a11c39cf4a8c090051017b616
Subject: Re: [PHP-DEV] Coercive STH - some real world tests and updated RFC
From: damz@damz.org (Damien Tournoud)

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Hi Lester,

On Fri, Feb 27, 2015 at 6:51 PM, Lester Caine <lester@lsces.co.uk> wrote:

> This may not be what YOU want substr to do and it would perhaps be
> useful to ADD additional checks so that 'false' is returned when it
> can't created a string because of the 'invalid arguments', but type
> hints makes no difference to part of the jigsaw. What happens is exactly
> what one would expect ... nothing left in the string -> an empty string.
> Having then to check every time for a '0' string length got shortened to
> simply being able to check 'is there a string' yes/no, and if no you can
> do something else. There is nothing inconsistent ...
>

Please, read the examples again, the current behavior is nothing but
inconsistent:

  substr("a", 1) => FALSE
  substr("a", -300) => ""

But anyway, that's not even the point. The point is that return values that
"worked" in a world of transparent type-jungling will not work in a world
of stricter typing checks. Which means that we need:

(1) To accept that for now casting FALSE to the empty string is the right
thing to do;

until / unless:

(2) We fixed all the common functions in the standard library so that they
stop returning inconsistent types, in particular in the cases where it
should not even be a debate what is the right thing to do (for substr, if
the arguments point to an empty slice, return the empty string).

Damien

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