On Tue, Feb 17, 2015 at 5:06 PM, Nikita Popov <nikita....@gmail.com> wrote:
> On Mon, Feb 16, 2015 at 10:15 PM, Dmitry Stogov <dmi...@zend.com> wrote: > >> Hi Nikita, >> >> On Tue, Feb 17, 2015 at 12:07 AM, Nikita Popov <nikita....@gmail.com> >> wrote: >> >>> On Mon, Feb 16, 2015 at 10:02 PM, Dmitry Stogov <dmi...@zend.com> wrote: >>> >>>> >>>> >>>> On Mon, Feb 16, 2015 at 11:05 PM, Benjamin Eberlei <kont...@beberlei.de >>>> > wrote: >>>> >>>>> >>>>> >>>>> On Mon, Feb 16, 2015 at 12:07 PM, Dmitry Stogov <dmi...@zend.com> >>>>> wrote: >>>>> >>>>>> hi, >>>>>> >>>>>> During discussion of different ways of implementing "Design by >>>>>> Contract" we >>>>>> got an idea of using annotations. >>>>>> >>>>>> BTW: annotations are useful by their own and may be used for different >>>>>> purposes. Support for annotations was proposed long time ago: >>>>>> >>>>>> https://wiki.php.net/rfc/annotations >>>>>> https://wiki.php.net/rfc/annotations-in-docblock >>>>>> https://wiki.php.net/rfc/reflection_doccomment_annotations >>>>>> >>>>>> HHVM already implemented similar concept >>>>>> >>>>>> http://docs.hhvm.com/manual/en/hack.attributes.php >>>>>> >>>>>> I made a quick and dirty PoC that shows how we may implement >>>>>> annotations in >>>>>> PHP7 and how powerful they may be : >>>>>> https://gist.github.com/dstogov/dbf2a8f46e43719bd2c2 >>>>> >>>>> >>>>> How about not exposing the AST, and then the userland can pass context >>>>> to a method $reflection->getAnnotation($name, $context); >>>>> >>>>> https://gist.github.com/beberlei/0dc36d4412b8e3454912 >>>>> >>>>> That way AST is not exposed to userland. >>>>> >>>> >>>> Your example handles just particular use-case. >>>> I would like to provide a general solution. >>>> >>>> Thanks. Dmitry. >>>> >>> >>> Could you provide some more info on how you would imagine this to be >>> used for the DbC use case? As far as I see, this would require injecting >>> code into the method body based on the annotations. Does that mean that >>> annotations handlers will get the chance to modify the AST of the method >>> itself during compilation? Or how is this supposed to be realized? >>> >> >> In general, it must be possible to plug into compilation process using >> zend_ast_process() callback and modify function AST, inserting constraints >> validation in proper places. >> But for now, I'm thinking only about metadata syntax and representation. >> I just showed, how it can be used to represent DbC constraints. >> I don't think we need user-level interface to modify AST. >> > > To make sure I got it right: The AST-based annotations are only there to > allow handling by PHP extensions (or the engine itself), while evaluated > annotations are there for use by userland code? > > Nikita > I think yes, However, Alexander thinks differently https://wiki.php.net/rfc/parser-extension-api Of course this is not for 7.0 Thanks. Dmitry.
