## PHP Internals Reading
*Reading materials related to the PHP internals or performance.*

* [Disproving the Single Quotes Myth](http://nikic.github.io/2012/01/09/Disproving-the-Single-Quotes-Performance-Myth.html) - An article about performance of single and double quoted strings.
* [How Big Are PHP Arrays (And Values) Really?](http://nikic.github.io/2011/12/12/How-big-are-PHP-arrays-really-Hint-BIG.html) - An article about array internals.
* [How Foreach Works](http://stackoverflow.com/questions/10057671/how-does-php-foreach-actually-work/14854568#14854568) - A detailed StackOverflow answer about foreach.
* [How Long is a Piece of String](http://blog.golemon.com/2006/06/how-long-is-piece-of-string.html) - An article about string internals.
* [PHP Evaluation Order](https://gist.github.com/nikic/6699370) - An article about evaluation order in PHP.
* [PHP Internals Book](http://www.phpinternalsbook.com) - An online book about PHP internals, written by three core developers.
* [PHP RFCs](https://wiki.php.net/rfc) - The home of PHP RFCs (Request for Comments).
* [Print vs Echo, Which One is Faster?](http://fabien.potencier.org/print-vs-echo-which-one-is-faster.html) - An article about print and echo performance.
* [The PHP Ternary Operator. Fast or Not?](http://fabien.potencier.org/the-php-ternary-operator-fast-or-not.html) - An article ternary performance.
* [Understanding OpCodes](http://blog.golemon.com/2008/01/understanding-opcodes.html) - An article about opcodes.
* [When Does Foreach Copy?](http://nikic.github.io/2011/11/11/PHP-Internals-When-does-foreach-copy.html) - An article about the internals of foreach.
* [Why Objects (Usually) Use Less Memory Than Arrays](https://gist.github.com/nikic/5015323) - An article about object and array internals.
* [You're Being Lied To](http://blog.golemon.com/2007/01/youre-being-lied-to.html) - An article about internal ZVALs.