Smalltalk › Pharo › Pharo Smalltalk Developers

[bloc] why redefining new is not enough?

_‹ Previous Topic Next Topic _›

Classic

List

Threaded

14 messages Options

stepharo

[bloc] why redefining new is not enough?

BlElement class>>basicNew
"Redefined to set the space of the element"

^ super basicNew basicSpace: BlUniverse default runningSpace

why redefining new is not enough?

Ok now back to the mooc videos :(

EstebanLM

Re: [bloc] why redefining new is not enough?

this is bad… redefining basicNew should not be done, never, never, never.
that’s why we have new and basicNew :)

Esteban

> On 25 Feb 2016, at 09:52, stepharo <[hidden email]> wrote:
>
> BlElement class>>basicNew
> "Redefined to set the space of the element"
>
> ^ super basicNew basicSpace: BlUniverse default runningSpace
>
> why redefining new is not enough?
>
> Ok now back to the mooc videos :(
>
>

Pharo Smalltalk Developers mailing list

Re: [bloc] why redefining new is not enough?

> On 25 févr. 2016, at 11:49, Esteban Lorenzano <[hidden email]> wrote:
>
> this is bad… redefining basicNew should not be done, never, never, never.
why ?

> that’s why we have new and basicNew :)

the space may be needed during #initialize.
this is why the initialization of the space is done in
basicNew.
But ok, we will fix that.
Thanks
Alain

>
> Esteban
>
>> On 25 Feb 2016, at 09:52, stepharo <[hidden email]> wrote:
>>
>> BlElement class>>basicNew
>> "Redefined to set the space of the element"
>>
>> ^ super basicNew basicSpace: BlUniverse default runningSpace
>>
>> why redefining new is not enough?
>>
>> Ok now back to the mooc videos :(
>>
>>
>
>

Clément Béra

Re: [bloc] why redefining new is not enough?

Hi,

when redefining new you don't have to use super:

BlElement class>>new
^ self basicNew

basicSpace: BlUniverse default runningSpace;

initialize;

yourself

IMO that's a better practice that redefining basicNew.

Usually basicNew is only redefined when you cannot instantiate the objects using the normal API because it is not supported by the runtime (SmallInteger, Context, etc.)

2016-02-25 12:33 GMT+01:00 Alain Plantec via Pharo-dev <[hidden email]>:

---------- Message transféré ----------
From: Alain Plantec <[hidden email]>
To: Pharo Development List <[hidden email]>
Cc:
Date: Thu, 25 Feb 2016 12:37:59 +0100
Subject: Re: [Pharo-dev] [bloc] why redefining new is not enough?

> On 25 févr. 2016, at 11:49, Esteban Lorenzano <[hidden email]> wrote:
>
> this is bad… redefining basicNew should not be done, never, never, never.
why ?

> that’s why we have new and basicNew :)

the space may be needed during #initialize.
this is why the initialization of the space is done in
basicNew.
But ok, we will fix that.
Thanks
Alain

>
> Esteban
>
>> On 25 Feb 2016, at 09:52, stepharo <[hidden email]> wrote:
>>
>> BlElement class>>basicNew
>> "Redefined to set the space of the element"
>>
>> ^ super basicNew basicSpace: BlUniverse default runningSpace
>>
>> why redefining new is not enough?
>>
>> Ok now back to the mooc videos :(
>>
>>
>
>

Stephan Eggermont-3

Re: [bloc] why redefining new is not enough?

In reply to this post by Pharo Smalltalk Developers mailing list

On 25-02-16 12:31, Alain Plantec via Pharo-dev wrote:
>the space may be needed during #initialize.

I would strongly advice against that. That makes it untestable

Stephan

EstebanLM

Re: [bloc] why redefining new is not enough?

In reply to this post by Pharo Smalltalk Developers mailing list

On 25 Feb 2016, at 12:32, Alain Plantec via Pharo-dev <[hidden email]> wrote:

From: Alain Plantec <[hidden email]>
Subject: Re: [Pharo-dev] [bloc] why redefining new is not enough?
Date: 25 February 2016 at 12:37:59 GMT+1
To: Pharo Development List <[hidden email]>

On 25 févr. 2016, at 11:49, Esteban Lorenzano <[hidden email]> wrote:

this is bad… redefining basicNew should not be done, never, never, never.
why ?

well… is not forbidden, of course…

but many frameworks use basicNew as a way of obtain *explicitly* non-initialized objects (voyage does that, for instance).

that’s why we have new and basicNew :)

the space may be needed during #initialize.
this is why the initialization of the space is done in
basicNew.
But ok, we will fix that.

you can define new as:

new

^ self basicNew

basicSpace: BlUniverse default runningSpace;

initialize;

yourself

that’s perfectly fine :)

other possibility is to lazy initialise space with the default universe.

Esteban

Thanks
Alain

Esteban

On 25 Feb 2016, at 09:52, stepharo <[hidden email]> wrote:

BlElement class>>basicNew
"Redefined to set the space of the element"

^ super basicNew basicSpace: BlUniverse default runningSpace

why redefining new is not enough?

Ok now back to the mooc videos :(

EstebanLM

Re: [bloc] why redefining new is not enough?

In reply to this post by Clément Béra

On 25 Feb 2016, at 13:34, Clément Bera <[hidden email]> wrote:

Hi,

when redefining new you don't have to use super:

BlElement class>>new
^ self basicNew
basicSpace: BlUniverse default runningSpace;
initialize;
yourself

IMO that's a better practice that redefining basicNew.

I just sent the same example ;)

Usually basicNew is only redefined when you cannot instantiate the objects using the normal API because it is not supported by the runtime (SmallInteger, Context, etc.)

2016-02-25 12:33 GMT+01:00 Alain Plantec via Pharo-dev <[hidden email]>:

---------- Message transféré ----------
From: Alain Plantec <[hidden email]>
To: Pharo Development List <[hidden email]>
Cc:
Date: Thu, 25 Feb 2016 12:37:59 +0100
Subject: Re: [Pharo-dev] [bloc] why redefining new is not enough?

> On 25 févr. 2016, at 11:49, Esteban Lorenzano <[hidden email]> wrote:
>
> this is bad… redefining basicNew should not be done, never, never, never.
why ?

> that’s why we have new and basicNew :)

the space may be needed during #initialize.
this is why the initialization of the space is done in
basicNew.
But ok, we will fix that.
Thanks
Alain

>
> Esteban
>
>> On 25 Feb 2016, at 09:52, stepharo <[hidden email]> wrote:
>>
>> BlElement class>>basicNew
>> "Redefined to set the space of the element"
>>
>> ^ super basicNew basicSpace: BlUniverse default runningSpace
>>
>> why redefining new is not enough?
>>
>> Ok now back to the mooc videos :(
>>
>>
>
>

Pharo Smalltalk Developers mailing list

Re: [bloc] why redefining new is not enough?

In reply to this post by EstebanLM

well… is not forbidden, of course…
but many frameworks use basicNew as a way of obtain *explicitly* non-initialized objects (voyage does that, for instance).

that’s why we have new and basicNew :)

the space may be needed during #initialize.
this is why the initialization of the space is done in
basicNew.
But ok, we will fix that.

you can define new as:

new
^ self basicNew
basicSpace: BlUniverse default runningSpace;
initialize;
yourself

that’s perfectly fine :)

this is how I intended to fix it.

other possibility is to lazy initialise space with the default universe.

maybe, I don’t know.

thanks

Alain

Esteban

Thanks
Alain

Esteban

On 25 Feb 2016, at 09:52, stepharo <[hidden email]> wrote:

BlElement class>>basicNew
"Redefined to set the space of the element"

^ super basicNew basicSpace: BlUniverse default runningSpace

why redefining new is not enough?

Ok now back to the mooc videos :(

Pharo Smalltalk Developers mailing list

Re: [bloc] why redefining new is not enough?

In reply to this post by Stephan Eggermont-3

Hello Stephan,
> On 25 Feb 2016, at 13:30, Stephan Eggermont <[hidden email]> wrote:
>
> On 25-02-16 12:31, Alain Plantec via Pharo-dev wrote:
> >the space may be needed during #initialize.
>
> I would strongly advice against that. That makes it untestable

interesting.
can you elaborate ?
thanks

Alain

>
> Stephan
>
>

Aliaksei Syrel

Re: [bloc] why redefining new is not enough?

In reply to this post by stepharo

Well, it is not *important* for design what method is redefined new or basicNew in order to set space. My question is why do we need at all to set space? It means that element created (not added) while spaceA is running can not be used in or added to spaceB.
The only reason that I know is a possibility to add global event listener to space while initializing an element. This must be fixed by having lazy addition of global event listeners.

On Feb 25, 2016 9:55 AM, "stepharo" <[hidden email]> wrote:

BlElement class>>basicNew
"Redefined to set the space of the element"

^ super basicNew basicSpace: BlUniverse default runningSpace

why redefining new is not enough?

Ok now back to the mooc videos :(

Aliaksei Syrel

Re: [bloc] why redefining new is not enough?

An we need NullSpace to be default value.

On Feb 25, 2016 2:06 PM, "Aliaksei Syrel" <[hidden email]> wrote:

Well, it is not *important* for design what method is redefined new or basicNew in order to set space. My question is why do we need at all to set space? It means that element created (not added) while spaceA is running can not be used in or added to spaceB.
The only reason that I know is a possibility to add global event listener to space while initializing an element. This must be fixed by having lazy addition of global event listeners.

On Feb 25, 2016 9:55 AM, "stepharo" <[hidden email]> wrote:
BlElement class>>basicNew
"Redefined to set the space of the element"

^ super basicNew basicSpace: BlUniverse default runningSpace

why redefining new is not enough?

Ok now back to the mooc videos :(

Stephan Eggermont-3

Re: [bloc] why redefining new is not enough?

In reply to this post by Pharo Smalltalk Developers mailing list

On 25-02-16 14:00, Alain Plantec via Pharo-dev wrote:
>interesting.
>can you elaborate ?

Basically it says I can only be tested when I have a valid space, and
you get a really complex one to test with, the one where everything else
is running in. Having that space, it tends to be difficult not to depend
on that space (and why would you, as it is the space you want).
For testing, I mostly don't want the space to be one that can be
easily changed behind my back. Basically,the arguments from an old
smalltalker [GOOS]

Stephan

[GOOS] Nat Pryce, Steve Freeman (2009) Growing Object-Oriented Software,
Guided By Tests

stepharo

Re: [bloc] why redefining new is not enough?

In reply to this post by Aliaksei Syrel

Can you create a bug entry? we should log the bloc design improvements to not forget them.

Le 25/2/16 14:08, Aliaksei Syrel a écrit :

An we need NullSpace to be default value.

On Feb 25, 2016 2:06 PM, "Aliaksei Syrel" <[hidden email]> wrote:

Well, it is not *important* for design what method is redefined new or basicNew in order to set space. My question is why do we need at all to set space? It means that element created (not added) while spaceA is running can not be used in or added to spaceB.
The only reason that I know is a possibility to add global event listener to space while initializing an element. This must be fixed by having lazy addition of global event listeners.

On Feb 25, 2016 9:55 AM, "stepharo" <[hidden email]> wrote:

BlElement class>>basicNew
"Redefined to set the space of the element"

^ super basicNew basicSpace: BlUniverse default runningSpace

why redefining new is not enough?

Ok now back to the mooc videos :(

stepharo

Re: [bloc] why redefining new is not enough?

In reply to this post by Aliaksei Syrel

Aliaksei

can you log this action somewhere?
in a bloc bug entry?

Stef

Le 25/2/16 14:06, Aliaksei Syrel a écrit :

Well, it is not *important* for design what method is redefined new or basicNew in order to set space. My question is why do we need at all to set space? It means that element created (not added) while spaceA is running can not be used in or added to spaceB.
The only reason that I know is a possibility to add global event listener to space while initializing an element. This must be fixed by having lazy addition of global event listeners.

On Feb 25, 2016 9:55 AM, "stepharo" <[hidden email]> wrote:

BlElement class>>basicNew
"Redefined to set the space of the element"

^ super basicNew basicSpace: BlUniverse default runningSpace

why redefining new is not enough?

Ok now back to the mooc videos :(