I note that #become: is not in the ANSI Smalltalk standard (am I the last person in the world to care about that? Probably) and that several of the Smalltalk systems I have on my machine don't support it. In Squeak 5.2, there were 17 references to #become:. Four of those were just testing it. One is just a mention in a collection of dangerous things to not be tried. Several are ways of changing an object's class. Several are ways of forcibly deleting an object by turning it into something trivial but safe. And a couple, I don't understand. Thing is, #become: is *not* something to do lightly, and the code that calls "x become: y" should "own" both x and y. (In fact one of them is often "self".)
About The Design Patterns Smalltalk Companion, draft chapters are available at http://sdmeta.gforge.inria.fr/FreeBooks/SmalltalkDesignPatternCompanion/ When I read the Gang of Four book, it seemed to me that most of it was about fighting the fact that C++ and Java aren't Smalltalk. Read a draft chapter or two to make up your own mind. One difference between the State pattern and #become: is that an object can be an instance of the State pattern in more than one way at the same time. On Thu, 17 Jan 2019 at 05:58, Ben Coman via Pharo-users < pharo-users@lists.pharo.org> wrote: > > > On Wed, 16 Jan 2019 at 17:16, Loïc Pagès <loic.pa...@inra.fr> wrote: > >> Dear Pharo users, >> >> I develop software dedicated to the simulation of plant development and >> 3D architecture. >> >> In the past, I used Java, > > but I am very interested in translating code >> in Pharo. I appreciated very much the language and the course. >> >> I have a question for you all : >> >> During plant development (ontogeny), new organs appear, that are >> gradually tranformed. For example, a bud can make a flower, and then a >> fruit. >> >> Organs are conveniently modelled as classes. During the course, I >> learned that it was better to make several classes (bud, flower, fruit) >> instead of a "fat class" such as "reproductive organ" with many >> attributes and stages (bud stage, flower stage, fruit stage). I wonder >> how to transform an object into another one, to represent for example >> the fact that the flower may become a fruit. >> >> Maybe a naive question ? >> > > Maybe #become: ... > https://gbracha.blogspot.com/2009/07/miracle-of-become.html > > but it might be a misuse for your purpose. The following book will > provide some good insights... > https://www.amazon.com/Design-Patterns-Smalltalk-Companion/dp/0201184621 > > cheers -ben > > > >
