[Newbies] Re: Best way to implement two-dimensional array

John Almberg jalmberg at identry.com
Tue Sep 4 22:31:47 UTC 2007

Yes, that's clear, and I do intend to initialize this big table with  
code, mainly to make it easy for me to spot and fix typos. However,  
it's still cool to gain a sense of the concreteness of Smalltalk  

And I find myself trying out code in a Workspace to see how things  
work, before encoding it in a method. I suspect interactively  
tweaking a class might help me figure things out before committing it  
to an initialize method.

-- John

On Sep 4, 2007, at 5:29 PM, nicolas cellier wrote:

> However, Classes and methods are Objects which have well defined  
> tools to help them migrating from an image to another, even to  
> another Smalltalk dialect. This ease code sharing.
> This is less clear for arbitrary objects...
> That's why I restrict myself to initialize these class vars in an  
> initialize method in the class side, and loose some of the power of  
> the image...
> But there is a better reason:
> if you construct your object with some snippets of code, say in an  
> inspector or a debugger:
> 	MyTable at: 1 put: 30 degreesToRadians cos * 4
> Then your image will loose the history of construction.
> All it retains is 3.464101615137755 which is somehow less expressive.
> Nicolas
> Bert Freudenberg a écrit :
>> Seems you've made the first step to truly understanding Smalltalk :)
>> Also you must realize that the browser is just a view into that  
>> live system of objects we call classes and is simply modifying  
>> those live objects. You could do that in an inspector as well, but  
>> the class browser is more specialized so it is easier to use for  
>> that purpose.
>> Welcome to Real Objects.
>> - Bert -
>> On Sep 4, 2007, at 12:19 , John Almberg wrote:
>>> Whoa... that worked, but the implications are a bit hard to  
>>> digest...
>>> So MyClass is an object in my Smalltalk image, and it can have  
>>> variables that I can set interactively, and the values contained  
>>> therein are now part of the class...
>>> I keep reading that classes are objects, but this is the first  
>>> time I've seen something that makes me realize that they are  
>>> fundamentally different than objects in other languages. I guess  
>>> because they are 'live', in some sense, in the Smalltalk  
>>> environment. That is, not just source code, but an instantiated  
>>> object.
>>> Talk about paradigm whiplash... I'm going to have to think about  
>>> this, a bit :-)
>>> Thanks!
>>> -- John
>>>> Type "MyClass", select it, press Cmd-i (or Alt-i). You get an  
>>>> inspector on a class - which of course is the instance of  
>>>> another class, as everything is an object (and hence an instance  
>>>> of a class) in Smalltalk. Anyway, you should see a reference to  
>>>> the superclass, a dictionary of all the methods, the list of  
>>>> instance variables and subclasses etc. Class variables are  
>>>> simply held in a Dictionary in the "classPool" instance variable  
>>>> of that class. So by inspecting that and drilling down into your  
>>>> class var you can modify it.
>>>> A simpler way to get at the contents of your class var is just  
>>>> selecting its name in a browser showing any method of your  
>>>> class, and press Cmd-i there. That works because in the browser,  
>>>> code is evaluated in the context of the selected class.
>>>> - Bert -
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