On Tue, Feb 17, 2015 at 4:50 PM, François Laupretre <franc...@php.net>
wrote:
> HI Dmitry,
>
> Question : in which scope do you evaluate the PHP expression ?
>
We don't evaluate expressions. We just store them. Evaluation and/or
modification is a subject for future development.
>
> Example :
>
> <DbC.requires($a > 0);>
> <DbC.ensures(__RETURN__ > 0);>
>
> function foo($a)
> {
> ...
>
> How can you know from this that the first expression must be evaluated at
> function entry, that the second one must be interpreted when function
> exits, let alone the question of __RETURN__ replacement and external switch
> to authorize/disable DbC evaluations.
>
If we will support such DbC approach, then an additional extension may use
this attributes to insert their code into appropriate places of main
function.
Thanks. Dmitry.
> Several people rightly stated that expression would be computed at compile
> time. That's a way to solve the scope question as it practically means that
> expressions are evaluated in the global scope, but DbC must evaluate its
> expressions at runtime. Does it mean we should write '<DbC.requires('$a >
> 0')> ? Not very intuitive but that's probably the only solution.
>
> Something else : I am not sure I understand, but do you intend evaluating
> annotation expressions everytime you parse the file. Or would you provide a
> global switch ?
>
> > Any one can use doc-block now and later, but php core won't parse
> doc-blocks. It's a task for external tools.
>
> I understand. Actually, DbC is not the perfect use case for annotations.
> It would be fine to find a good use case because neither of DbC, AOP,
> Doctrine, or phpdoc fit so well.
>
> There comes my last question : is it so interesting and mandatory to
> implement annotations in the core, instead of an extension which would
> parse doc blocks when needed, and would return bare strings through a
> reflection-like API ? I know most want to put annotations in the core, but
> what's the real benefit, if we don't consider performance ? Do we have use
> cases comparing both approaches ?
>
> The fact that we voluntarily make it incompatible with phpdoc and doctrine
> 'annotations' saddens me a bit too because people used to the current
> 'annotation' meaning will have to integrate that a new PHP native
> 'annotation' feature, totally different from what they've been using for
> years. And doctrine is not an edge-case. If there are good reasons, why
> not, but I don't see them yet.
>
> Regards
>
> François
>
>
>
>
