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Date: Mon, 20 Jun 2011 20:38:28 +0200
Message-ID: <BANLkTi=oC_FQ=o0caf5pWu8YPa33kS4SRA@mail.gmail.com>
To: Todd Ruth <truth@proposaltech.com>
Cc: Stas Malyshev <smalyshev@sugarcrm.com>, 
	"internals@lists.php.net" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Re: foreach() for strings
From: robert@xarg.org (Robert Eisele)

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I really like the ideas shared here. It's a thing of consideration that
array-functions should also work with strings. Maybe this would be the way
to go, but I'm more excited about the OOP implementation of TextIterator an=
d
ByteIterator, which solves the whole problem at once (and is easier to
implement, as mentioned by Stas). As Jonathan  said, Database results with =
a
certain encoding could get iterated, too. The only way to workaround the
Text/Byte problem would be, offsetting >EVERY< string with 1-2 byte
"string-type" information or an additional type flag in the zval-strcuture.
Handling everything with zval's instead of objects would have the advantage=
,
that database-layers like mysqlnd could write the database-encoding directl=
y
into the zval and the user had no need to decide what encoding is used.

A new casting operator (binary) could then cast the string to a 1-byte
array. But this is syntactical sugar over OOP-implementations - I don't kno=
w
which one is the better choice.

For example:

$utf8_string =3D "J=E4germeister"; // information of utf8 ist stored in the=
 zval

foreach ($utf8_string as $k =3D> $v) // would iterate in byte mode

foreach ((binary)$utf8_string as $k =3D> $v) // would iterate in text mode

over this:
$utf8_obj =3D new ByteIterator("J=E4germeister");

foreach ($utf8_obj as $k =3D> $v)

foreach ($utf8_obj->toText() as $k =3D> $v)


I think the first one is easier and would be nicer to average developers
(and lazy programmers like me ;o) )

Todd, I don't like neither str_split() nor text_string_to_array(). Sure,
str_split could be optimized to return a different more optimized result
inside of foreach() but I would use rather one of the implementations,
mentioned above.


2011/6/20 Todd Ruth <truth@proposaltech.com>

> On Mon, 2011-06-20 at 10:06 -0700, Stas Malyshev wrote:
> > Hi!
> >
> > On 6/20/11 9:57 AM, Todd Ruth wrote:
> > > Iterators are nice.  Having a "text_string_to_array" function
> > > would also be fine.  For example:
> > >
> > > $s =3D 'hello';
> > > foreach (text_string_to_array($s) as $x) {
> > >      var_dump($x);
> > > }
> >
> >
> > text_to_array($s) =3D=3D str_split($s, 1)
>
> Does that have approximately the same performance as marking the
> string as being OK to use as an array?  For example,
>
> $s =3D file_get_contents($big_file);
> foreach (str_split($s, 1) as $x) {
>    f($x);
> }
>
> Are there performance issues with the above compared to:
>
> $s =3D file_get_contents($big_file);
> foreach (text_string_to_array($s) as $x) {
>     f($x);
> }
>
> assuming text_string_to_array could be implemented as marking
> the string OK to use as an array.
>
> Again, I don't know enough about the internals.  I'm just imagining
> a significant difference for very long strings between:
> $a1 =3D text_to_array('hello');
> and
> $a2 =3D array('h','e','l','l','o');
>
> $a1 and $a2 could act identically until a set occurred.  For example,
> "$a1['key'] =3D 5;" would first trigger $a1 becoming just like $a2 so
> that the set could take place.
>
> Any string that has not been hit with text_string_to_array would lead
> to all the usual error messages some of us know and love and
> any string that has been hit with text_string_to_array would allow all
> the fancy features some people are seeking.  I'm trying to find a
> way to please the people that want strings to act like arrays without
> ruining the day for those of us who are glad strings don't act like
> arrays.
>
> - Todd
>
>
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