On Sep 11, 2012, at 8:41 PM, Camillo Bruni wrote:

On 2012-09-11, at 20:36, sergio_101 <sergio.rrd@gmail.com> wrote:

...

yes, i know this sounds simple.. but is it possible to instantiate an object with some parameters?

say i have a dictionary:

params := Dictionary new. params at: 'sound' put: 'bark'

dog := Dog new.

^^ at this point, i would like to just create a dog and send it 'params' all at once..

can i do this? what would the syntax look like?

sure :) in Smalltalk (almost) everything is a message-send :)

So you can do the following:

dog := Dog sound: 'wuff'.

then a class side method:

Dog class >> #sound: aString ^ self basicNew initializeWithSound: aString;

yourself. Otherwise you may have some strange behavior if the #initializeWithSound: message doesn't return the receiver :) Ben

then the initializeWithSound: methods on instance side

Dog >> #initializeWithSound: aString. self initialize. "now do the special initialization here..." " for instance set the sound" sound := aString.

Dog >> initialize "do the default initialization here" "for instance set a default sound" sound := 'bark'.

Hope that helps :)

On Sep 11, 2012, at 8:52 PM, Camillo Bruni wrote:

On 2012-09-11, at 20:50, Benjamin <benjamin.vanryseghem.pharo@gmail.com> wrote:

...

On Sep 11, 2012, at 8:41 PM, Camillo Bruni wrote:

...

On 2012-09-11, at 20:36, sergio_101 <sergio.rrd@gmail.com> wrote:

...

yes, i know this sounds simple.. but is it possible to instantiate an object with some parameters?

say i have a dictionary:

params := Dictionary new. params at: 'sound' put: 'bark'

dog := Dog new.

^^ at this point, i would like to just create a dog and send it 'params' all at once..

can i do this? what would the syntax look like?

sure :) in Smalltalk (almost) everything is a message-send :)

So you can do the following:

dog := Dog sound: 'wuff'.

then a class side method:

Dog class >> #sound: aString ^ self basicNew initializeWithSound: aString; yourself.

Otherwise you may have some strange behavior if the #initializeWithSound: message doesn't return the receiver :) well initialize.* usually returns self :) (it's like #initialize, where you never send #yourself)

Play with Morphic and then you will take this habit too :) Ben

Dog class>>newWithParams: aDictionary ^self new params: aDictionary

Dog>>params: aDictionary params := aDictionary

Is that something similar to what you were looking for?

yes! this is very close to what i am looking to do.. this is kind of where i figured it was going to go.. i was hoping it would be a one liner.. but i can live with this.. thanks! -- ---- peace, sergio photographer, journalist, visionary http://www.ThoseOptimizeGuys.com http://www.CodingForHire.com http://www.coffee-black.com http://www.painlessfrugality.com http://www.twitter.com/sergio_101 http://www.facebook.com/sergio101

But I don't really know what were you using that dictionary for and what was the intention (#params: is not a very nice name).

i have been intentionally being vague about what i am doing, as i am trying to understand the best smalltalk practice, without introducing an approach from another language. the idea i am after is something like this in rails.. i can make a hash like: dog_params = {:sound => 'bark', :food => 'steak'} and create a dog like: Dog.create(dog_params) and have a dog that with those params.. i just want to make sure i am not inventing a problem to solve.. and that there isn't a more 'smalltalky' way to do it. thanks! -- ---- peace, sergio photographer, journalist, visionary http://www.ThoseOptimizeGuys.com http://www.CodingForHire.com http://www.coffee-black.com http://www.painlessfrugality.com http://www.twitter.com/sergio_101 http://www.facebook.com/sergio101

This is a good guide:

http://www.amazon.com/Smalltalk-Best-Practice-Patterns-Kent/dp/013476904X

i actually just bought that, and am making my way through it now.. thanks! -- ---- peace, sergio photographer, journalist, visionary http://www.ThoseOptimizeGuys.com http://www.CodingForHire.com http://www.coffee-black.com http://www.painlessfrugality.com http://www.twitter.com/sergio_101 http://www.facebook.com/sergio101

sergio_101 wrote

...

But I don't really know what were you using that dictionary for and what was the intention (#params: is not a very nice name).

i have been intentionally being vague about what i am doing, as i am trying to understand the best smalltalk practice, without introducing an approach from another language.

the idea i am after is something like this in rails..

i can make a hash like: dog_params = {:sound => 'bark', :food => 'steak'}

and create a dog like: Dog.create(dog_params)

and have a dog that with those params.. i just want to make sure i am not inventing a problem to solve.. and that there isn't a more 'smalltalky' way to do it.

There is no other way to do what you want except using a dictionary/collection/etc. They keywords in Smalltalk must preserve the order because they're part of the method name, not its arguments. You could build your own way of passing "dynamic" parameters to the constructor, but most of the times if you need too many arguments for a constructor you might be needing to introduce a new abstraction, so take it as a sign to reify something. Syntax sugar in Smalltalk most of the times comes from better abstractions, not from the language's syntax. Regards, -- Esteban. -- View this message in context: http://forum.world.st/smalltalk-instantiate-an-object-with-parameters-tp4647... Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.