DynamicObjects



On 2020-04-18, at 11:16 AM, Jakob Reschke <[hidden email]> wrote:

Would be nice for mock objects indeed. For everything else, well it is not so much Smalltalk, rather Self or JavaScript, but without their syntax (and maybe without prototype inheritance). Could be interesting and I am not particularly against it, but users should know that this is not basic Smalltalk. It might "delude" beginners if they get confronted with it too early.

Yeah; this seems a good place to remind people of the old but very important programming aphorism -
"Debugging is at least twice as hard as writing code. So if you write the cleverest code you can..."

My advice - if you can't create a tool to help use a neat new trick you just came up with, that will allow other more mortals to make sense of it; don't foist the neat trick on us. We already have way too many things that are hard to follow, find, understand, use, etc  - and that's just in the squeak image!

tim
--
tim Rowledge; [hidden email]; http://www.rowledge.org/tim
Strange OpCodes: LOW: Launch on Warning

Such a constructed DynamicObject would be useful for Raven. The plan is to extend ASN1 de/encoding to callback to the Scope for each object in the graph being serialized to check for substitution. So using ASN1 to encode between machines. Consider a machine at level 1 and another machine who has advanced to level 3. Level 3 knows about #passByCopy objects that the level 1 machine knows not.

DynamicObject use cases, A) model an unknown class' instance, B) class generation & C)dynamic code loading

A) Level 3 machine sends such an advanced class to the level 1 machine. As this class structure gets decoded, without such a class available, construct as a DynamicObject and set the modeled instance variables with values. I am assuming that in addition to methods, instance variables can be defined with the DynamicObject, to model the ASN1 encoded object.

B) At this point level 1 does not know what to do about the level 3 dynamicObject. During development, an engineer could convert this DynamicObject to a class. So class definition meta-protocol will be needed.

C) During deployment, the DynamicObject could lookup the code Monticello package on the code server, for this new instance's class, and load it. In this fashion a network of nodes can stay updated.

Anyways, here are my use cases for DynamicObject or a similar construct.

K, r

Uhh! This feels like JavaScript ... :o) I would rather work on improving Squeak's meta-object protocol and with it class construction and refinement. Especially for tests. Let's not undermine the idea of having classes in Smalltalk.

-1 for DynamicObject.

Objects in Squeak/Smalltalk are quite dynamic already. That name is misleading. :-)

Best,

Marcel

Am 18.04.2020 19:55:05 schrieb Thiede, Christoph [hidden email]:

d := DynamicObject withMethods: {

#origin -> [2 @ 3].

#corner -> [3 @ 7] } asDictionary.

d origin "2@3"

Did we already have something like this for Squeak? May this become a pattern for situations where you actually don't need a class (e. g., when writing very small mock objects for tests)?

d := DynamicObject new.

d xxxMethodAt: #foo put: [self inform: 'Hi!'].

d xxxMethodAt: #foo: put: [:x | x halt].

d foo: 3.

Best,

Christoph

-- 
Kindly,
Robert

Yalp! Sure, already have what I need, right?

So define:

ASN1Value subclass: #ASN1DomainObject
    instanceVariableNames: 'className'
    classVariableNames: ''
    poolDictionaries: ''
    category: 'CryptographyASN1-Objects'

Then whenever we have an unknown object to write or reading in the same, output in ASN1 a class structure, with className (let us say #SessionConfig and instance variables:  '

• selectedCipherName
• selectedEncoderName
• cryptoCiphers
• dataEncoders
• protocolMap
• preferredProtocol '

So using ASN1WrapperConstructedType or ASN1ExplicitContextValue,

ASN1WrapperType subclass: #ASN1WrapperConstructedType
    instanceVariableNames: ''
    classVariableNames: ''
    poolDictionaries: ''
    category: 'CryptographyASN1-Types'

Dynamically create a subclass of ASN1DomainObject, with the right ivars (className in the superclass) and accessors:

ASN1DomainObject subclass: #ASN1DOSessionConfig
    instanceVariableNames: 'selectedCipherName selectedEncoderName cryptoCiphers dataEncoders protocolMap preferredProtocol'
    classVariableNames: ''
    poolDictionaries: ''
    category: 'CryptographyASN1-Types'

Thus we dynamically defined a domain object class for the unknown #SessionConfig structure. This meets the needs of A, B & C.

K, r

On 2020-04-20, at 2:03 AM, Marcel Taeumel [hidden email] wrote:

Uhh! This feels like JavaScript ... :o) I would rather work on improving Squeak's meta-object protocol and with it class construction and refinement. Especially for tests. Let's not undermine the idea of having classes in Smalltalk.

-1 for DynamicObject.

Objects in Squeak/Smalltalk are quite dynamic already. That name is misleading. :-)

I agree.


tim
--
tim Rowledge; [hidden email]; http://www.rowledge.org/tim
CChheecckk yyoouurr dduupplleexx sswwiittcchh..

-- 
Kindly,
Robert