Hi Andreas,

> This is well-known and lead to the invention of Ephemerons in
> VisualWorks. Unless you have something like Ephemerons you can get
> bitten in very weird ways.

Yes, ephemerons are a required.

> An annotation is called an annotation because it has no sematic effect
> for the execution of the method. What you have in your method is not an
> annotation but *code* (which does have an effect). To illustrate:
>
> Object>>yourself
> <returns: Object>
> ^self

if:
1.-it is not related with the message (selector, args & comment)
2.-is is not related with method's semantics.
we can consider them as text style; a cookie to be
 mantained by a tool, so we are not talking about
 methods here.

I follow an implementation where the annotation is
 not "inside" the method and are mantained by tools.

cheers,
Ale.


----- Original Message ----- 
From: "Andreas Raab" <andreas.raab at gmx.de>
To: "The general-purpose Squeak developers list"
<squeak-dev at lists.squeakfoundation.org>
Sent: Monday, August 29, 2005 12:50 AM
Subject: Re: Request for Comment: MethodAnnotations for 3.9alpha


> Alejandro F. Reimondo wrote:
> > Hello Marcus, and all;
> >
> > The properties can be implemented for all objects
> >  (e.g. Digitalk's Smalltalk saga has had implemented
> >   for +10years, and it is proved to be helpfull).
> > If done this way, CompiledMethods will not be
> >  "special objects"... with properties :-)
>
> Unfortunately, this also has some significant impacts on GC behavior.
> This is well-known and lead to the invention of Ephemerons in
> VisualWorks. Unless you have something like Ephemerons you can get
> bitten in very weird ways.
>
> >>2) Syntax for Method Annotations.
> >>     We can set annoations to methods using the syntax we already
> >>know for primitives (which are, in a sense, just an annotation):
> >>
> >>Object>>mumble
> >>    <hello: 4>
> >>
> >>Tweak uses these annotations to describe when a method should be
> >>activated.
> >
> > mmm... why to use a "primitive" mechanism?
> >
> > mumble
> >     ^thisContext method propertyAt: #hello
> > (or something like this using only objects and no syntax/architecture
sugar)
>
> An annotation is called an annotation because it has no sematic effect
> for the execution of the method. What you have in your method is not an
> annotation but *code* (which does have an effect). To illustrate:
>
> Object>>yourself
> <returns: Object>
> ^self
>
> Here, we have annotated the Method Object>>yourself with a sample
> annotation to indicate the type of the return value. We could retrieve
> this type by using:
>
>     (Object compiledMethodAt: #yourself) propertyValueAt: #returns.
>
> But the annotation does not change the execution of the method one bit.
> The method is still the same (a "quick return self"), the byte codes
> haven't changed.
>
> Cheers,
>    - Andreas
>