Personally, I believed that traits are a *compile time injection* to a
class, so that at runtime a class behaves completely as it would if trait
methods were implemented directly in the class. That said, everything like
trait requirements for a certain interface, should be done at compile time
and constructions like abstract foo(); in a trait serve that purpose. IMHO.
2010/12/10 Stefan Marr <p...@stefan-marr.de>
> Hi Nathan:
>
>
> On 09 Dec 2010, at 23:42, Nathan Nobbe wrote:
> > What I'm getting at is the scenario when a trait is designed to be used
> in
> > concert with the class in which it is being used. In this case the trait
> > expects certain functions to be available on the class in which it is
> used
> > with. If the methods aren't there (or checked for at runtime) a fatal
> error
> > is raised.
> >
> > A quick example
> > <?php
> > class A {
> > use AHelper;
> >
> > function blah() {}
> > }
> >
> > trait AHelper {
> > function meh() {
> > // hoping we get used w/ instances of A ...
> > return $this->blah() * 5;
> > }
> > }
> >
> > class B {
> > use AHelper;
> >
> > /// waiting for a runtime error if blah() is ever called ..
> > }
> > ?>
> >
> > Do you see what I mean?
> No, do not really see what you are getting at.
>
> How is your approach using the instanceof checks (from the first mail)
> different from changing AHelper to require blah() by stating this
> requirement using an abstract method definition?
> For the trait it is not important where that method is implemented, it just
> has to be in the final composed class.
>
> So, why don't you want the following trait?
>
> trait AHelper {
> abstract function blah();
>
> function meh() {
> // hoping we get used w/ instances of A ...
> return $this->blah() * 5;
> }
>
> }
>
> You want to avoid the fatal error during runtime, right?
>
> Do you prefer dynamic checks over compile time checks?
>
> Best regards
> Stefan
>
> --
> Stefan Marr
> Software Languages Lab
> Vrije Universiteit Brussel
> Pleinlaan 2 / B-1050 Brussels / Belgium
> http://soft.vub.ac.be/~smarr
> Phone: +32 2 629 2974
> Fax: +32 2 629 3525
>
>
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С уважением,
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