On parsing annotations in docblocks: please don't. First of all, there are already plenty of established userland implementations - so there is really no need for this.
Whatever you decide on in terms of syntax, most likely won't satisfy every the needs of every userland annotation library, so at least some of them most likely won't use it. You'd be creating more work for the maintainers of these frameworks, and they don't standard to gain anything from that work. In terms of performance, there is nothing significant to gain here - any good annotation engine/framework already caches parsed annotations. On the other hand, I would be interested in having support for actual annotation syntax (not docblocks) added to PHP. Real annotation syntax could have benefits over parsing docblocks, starting with the fact that most of what's currently in docblocks is documentation, and thus not very interesting at run-time for anything other than documentation generators. (again, documentation generators already have working parsers, and don't stand to gain anything significant from switching to a native docblock parser.) - also mind the fact that docblocks are a loose standard with many more variations since annotation libraries came around. The only real downside (in terms of run-time) to adding custom syntax, is that existing useful annotations (such as @var for property-types) would not be useful - but in another sense, that's a good thing, because (for the most part) in existing codebases, these were written as documentation, not intended for run-time consumption. IDEs and documentation tools can add support for new annotation syntax, and treat these consistently and code, which itself can be documented using phpdoc blocks. I would support and encourage a C# style syntax and behavior, e.g.: use my\lib\DataType; [DataType('datetime')] public $published_date; In other words, DataType is a class, implementing an interface for initialization - everything between the parentheses is interpreted basically the same way as in an array() statement, and is passed to the annotation instance after construction via an initialization method defined by the interface. I could elaborate tons more on this subject, as it's something I have spent a lot of time researching in different languages, prior to writing my own annotation library. It may strike you as odd that someone who implemented an annotation library based on docblocks is actually against annotations in docblocks - I mainly chose that option because it was the best option at the time. I'm not a C programmer, and I do believe that docblocks are the best approach for a native PHP implementation. For a native implementation, I'd prefer to see a clear separation between non-functional documentation metadata and functional annotation objects. While there is some overlap between the two, much of what is currently written as documentation (for example @var annotations) could be written as functional annotations when these have a meaningful purpose. After all, existing code with phpdoc-annotations most likely was not written with the intent of consuming that metadata at runtime, unless written for use with an annotation library. I would be happy to involve myself deeper in this, if others agree and would like to work on a new RFC. - Rasmus Schultz