On the Zend Framework blog there's a new post from project lead Matthew Weier O'Phinney covering REST representations in Expressive and the release of two new components to help with their implementation.

We've been working towards our various Apigility on Expressive goals, and have recently published two new components: zend-problem-details and zend-expressive-hal.

These components provide response representations for APIs built with PSR-7 middleware. Specifically, they provide: Problem Details for HTTP APIs (RFC 7807) and Hypertext Application Language (HAL).

These two formats provide both JSON and XML representation options (the latter through a secondary proposal).

The post then goes on to talk about the idea of "representations" and how it relates back to the structure of the data returned and how the user knows what operations they can take on it. He also talks about the differences between normal responses and errors and gives example output helping to illustrate his points. The remainder of the post gets into the details of the two new components, their use and how to implement them in Expressive.

Nikita Popov has posted the second part of a series looking at how PHP 7 represents values internally. In the first part of the series the focus was on the major change from PHP 5: the zval updates and how they're allocated. This new post gets into more of the details on each of the types and how they're handled.

In the first part of this article, high level changes in the internal value representation between PHP 5 and PHP 7 were discussed. As a reminder, the main difference was that zvals are no longer individually allocated and don’t store a reference count themselves. Simple values like integers or floats can be stored directly in a zval, while complex values are represented using a pointer to a separate structure.

[...] In the following the details of the individual complex types will be discussed and compared to the previous implementation in PHP 5. One of the complex types are references, which were already covered in the previous part. Another type that will not be covered here are resources, because I don’t consider them to be interesting.

He goes through a few of the different types including strings and arrays and then gets into detail on how objects have changed from PHP 5 to PHP7. He also talks about "indirect zvals" (the IS_INDIRECT handling) that points to another zval instance rather than embedding it. Finally, he talks about two other constants, IS_CONSTANT and IN_CONSTANT_AST, and how they're used behind the scenes with some example code to illustrate.

Nikita Popov has a new post, the first part of a series, talking about the internal handling of variables in PHP7 and how it has changed from the current/past methods.

My last article described the improvements to the hashtable implementation that were introduced in PHP 7. This followup will take a look at the new representation of PHP values in general. Due to the amount of material to cover, the article is split in two parts: This part will describe how the zval (Zend value) implementation differs between PHP 5 and PHP 7, and also discuss the implementation of references. The second part will investigate the realization of individual types like strings or objects in more detail.

He starts with an introduction to the "zval" struct type and how it relates to the "zvalue" union. He goes on to talk about reference counting on zvals and some of the reasoning/desire to change how these are handled. Finally, he gets to the zval handling coming in PHP7 and the fundamental change in zval handling - they're no longer "individually heap-allocated and no longer store a refcount themselves". This change has several advantages and including improved refcount handling and less pointers involved in determining the actual value. He includes an example of how this new zval structure is defined in PHP7 compare to the previous version too. The remainder of the post looks at other related issues including memory management, supported types and a major change to how variable references are handled.