"stereotyping" (was: Strong Typing (Managing metadataabout attribute types) )

[ts]

>>>>> "G" == Gavin Sinclair <gsinclair@soyabean.com.au> writes:

G> Do both the :pre method wrappers get executed? If so, in what order?
G> If not, which one does? And why not execute both?

I really hope that ruby will give an message (method redefined) : I don't
want to learn a new language and you have module to do what you want.


Guy Decoux

[Gavin Sinclair]

On Saturday, November 22, 2003, 11:47:50 PM, ts wrote:

>>>>>> "G" == Gavin Sinclair <gsinclair@soyabean.com.au> writes:

G>> Do both the :pre method wrappers get executed? If so, in what order?
G>> If not, which one does? And why not execute both?

> I really hope that ruby will give an message (method redefined) : I don't
> want to learn a new language and you have module to do what you want.

Well, I'm not sure what I want in this case. Wrapping methods is a
great idea to satisfy a common idiom. I think it does seem a bit
wrong not to allow multiple wrappers, though. The idiom as it stands
(alias method to something else, and call alias from redefined method)
can be used to wrap a method several times if desired.

What method are you talking about? Oh, aspectr I suppose.

Gavin

[ts]

>>>>> "G" == Gavin Sinclair <gsinclair@soyabean.com.au> writes:

G> Well, I'm not sure what I want in this case. Wrapping methods is a
G> great idea to satisfy a common idiom. I think it does seem a bit
G> wrong not to allow multiple wrappers, though. The idiom as it stands

Perhaps in this case, you can also have multiple def in the same class :-)

G> What method are you talking about?

module B
def a:pre
end
end

class A
include B

def a:pre
end

def a
end
end


Guy Decoux

[Charles Hixson]

Yukihiro Matsumoto wrote:

>Hi,
>
>In message "Re: "stereotyping" (was: Re: Strong Typing (Re: Managing metadata about attribute types) )"
> on 03/11/21, "Sean O'Dell" <sean@celsoft.com> writes:
>
>|This is, I think, the clearest I can make the new proposal tonight:
>|
>|[url]http://www.rubygarden.org/ruby?InterfaceContracts[/url]
>
>...
>
> matz.
>p.s.
>Please do not use bad words everyone.
>

Perhaps one could make assertions about parameters / methods that could
be checked?
e.g.

class someclass < someOtherClass
assert .kind_of(someClass, Number)
def initialize (foo, bar)
assert.responds_to(foo, +)
assert.kind_of(bar, Number)
...
end
...
end

The only advantage I see of this over the normal responds_to? and
kind_of? is that it could be enabled or disabled by either a flag or by
a global variable ($DEBUG or possibly $ASSERT instead). assert
appears slightly special in that since it doesn't require any import
statement, it's probably added onto Object, and also I notice that the
"+" operator was considered as a normal method without being attached to
any variable (and methods would need to be able to go there too).
Perhaps that argument should be quoted?

This clearly doesn't answer all of the requirements, but it does answer
some of them, and might assist in debugging. (And it appears to me that
it would be simple for someone who understood Ruby better than I do to
implement.) Clearly if this were to be intended as a serious checking
tool it would need expansion, e.g. one would want a way to test that "+"
could take either one or two arguments, and that those arguments could
be numbers. A benefit of this approach is that it could probably be
bolted on without any change to the interpreter itself (at least until
it was decided to implement interpreter flags).