Have a look at my JOOP'99 article because I explain how to develop
instance specific behavior.
Stef
Le 24/7/16 à 17:14, Eric Velten de Melo a écrit :
Actually I wanted to have many different object instances with
different behaviours picked at random from a list of available
behaviours, but didn't find practical to create a class for each
different method implementation and delegating to it, since there are
many, possibly unlimited valid behaviours.
So maybe changing method implementation at runtime is not what I want
because the method implementation will be shared among all instances.
What I had in mind was a functionality similar to prototyped languages
like Self and Javascript in which you could change the behaviour
inside the object and not the class/prototype.
2016-07-23 7:35 GMT-03:00 Norbert Hartl <norb...@hartl.name
<mailto:norb...@hartl.name>>:
Can you elaborate on the reason why want to modify behaviour? And
how you would like it to happen?
If the code you want to modify is your own code than you can solve
that most of time with the things you already have. Your example
using a block might be altered to be a strategy pattern. That
means you keep one ore more instance variables for strategy
objects. Then you delegate parts of your behaviour to those
objects. You can based on context exchange those objects to adjust
behaviour.
If it is not feasible to change the internal state of an object
but you know all possible variants you can implement all
variations as methods in the object. The right method can be
invoked by doing a double dispatch with another object providing
contextual information.
There are plenty of possibilities so you need to know what is the
context that is responsible for switching behaviour and the
requirements of the behaviour modifications. Can you alter the
object? Is the number of modifications a fixed number? Does the
modification need to be thread safe?
Norbert
> Am 23.07.2016 um 00:41 schrieb Eric Velten de Melo
<ericvm...@gmail.com <mailto:ericvm...@gmail.com>>:
>
> Hello,
>
> One thing I try to do often is changing the behaviour of a
method dynamically at runtime. The current way I do this is by
having a block as an instance variable and having the method call
this block, but I find this approach a bit cumbersome. Is there
some other way or is this the recommended approach?
>
> I mean, I suppose methods could be changed dynamically by means
of reflection somehow, but is this an easy or recommended way of
programming in Smalltalk? Should slots make things easier?
>
> Eric
