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Re: Io N00B - basic questions

by spir :: Rate this Message:

Le Tue, 21 Apr 2009 10:47:12 -0700,
HowardP <how2paut@...> s'exprima ainsi:

> Thanks Jeremy - yes this is helpful.
>
> > Consider:
> > foo ::= 42
> > Creates a slot called "foo" with the value 42, and creates a "setFoo"
> which takes a single argument, the value to update the "foo" slot with.
>
> Then is a 'setWhatever' like a property encapsulation? In other words, if I
> use the " *::= *" operator/message, I *must* then use it for subsequent
> access to the 'foo' (or 'Whatever') slot? Or is " ::= " just allowing
> access to more of what goes on under the hood, that is " *:= " hides* the
> setWhatever, whereas "::=" bubbles it up so to speak?
>
> If I'm not totally off here, does that then mean then I'd have to use
>
> setFoo := 99 to get foo to be 99 - and that
>
> foo:=99 would be something else / or raise an exception?
>
> ( I'll test this of course, but thought it would be good to post the info
> anyway, as several of my programming pals are also fuzzy on this too. )

Io> x := Object clone
==> Object_0x9d7df60:

Io> x a ::= 1
==> 1
Io> x
==> Object_0x9d7df60:
a = 1
setA = method(...)

Io> x setA(2)
==> Object_0x9d7df60:
a = 2
setA = method(...)

Io> x a = 3
==> 3
Io> x
==> Object_0x9d7df60:
a = 3
setA = method(...)

Io> x a := 4
==> 4
Io> x
==> Object_0x9d7df60:
a = 4
setA = method(...)

While I wouldn't guess about the intention of Io developpers, I personly consider '::=' as a nicety that also sets a setter.
set* does not build a kind of property. Note:

Io> x m ::= method("m running")
==> m running
Io> x
==> Object_0x9d7df60:
a = 4
m = method(...)
setA = method(...)
setM = method(...)

Denis
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la vita e estrany

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