2016-09-30 14:57 GMT+02:00 Jakob Reschke <jakob.reschke at student.hpi.de>:

> Hello,
>
> Looks good to me as an outline. I have the following comments,
> questions or doubts:
>
> 1. Currently, for me it does not feel like "entering" or "leaving" an
> Environment, as that works with dynamic scoping in a block. So step 8
> could turn out to be void.
>
> 2. Since all of this should go into a workspace, not into the browser,
> what is the shortest applicable snippet of code that, given a source
> code string and a class, creates a new method in that class?
>
> 3. I am not sure what will happen if you attempt to create a subclass
> that has the same name as another imported class. Generally,
> evaluating Superclass subclass: #Subclass ... a second time will
> replace the former Subclass by the new Subclass. 'myEnvironment' would
> have imported Hello from Smalltalk globals, so an "old" Hello is
> already visible. We have to check that evaluating the subclass
> expression will not try to update that existing Hello class, but
> create a new one instead. Here, the "shallow" lookup mechanism would
> be needed.
>
> Don't import: Smalltalk globals entirely, just from: Smalltalk globals
import: #Transcript.
and #Object too, depending in which environment you'll evaluate the message
for creating the class...


> Once I have figured out 2. I will try out and check 3. ;-)
>
> Kind regards,
> Jakob
>
>
Here is a snippet that works, but is not especially short.

| createHelloClass createHelloMethod english spanish |

"Straight but verbose code to create a Hello class and compile a say method.
 There's one trick: Environment current, otherwise Compiler would evaluate
in nil class environment, not good"
createHelloClass := [Object subclass: #Hello
            instanceVariableNames: ''
            classVariableNames: ''
            poolDictionaries: ''
            category: 'Test'].
createHelloMethod := [:greeting |
    | methodSource sourceCode |
    methodSource := 'say Transcript cr; show: ' , greeting printString.
    sourceCode := 'Hello class compile: ' , methodSource printString , '
classified: ' , 'test' printString.
    Compiler evaluate: sourceCode environment: Environment current].

"Create the english and spanish environments"
english := Smalltalk globals.
spanish := Environment withName: 'Spanish'.
spanish importSelf.
spanish from: english import: #Transcript.

"Create the class and compile the method in each environment:"

[createHelloClass value.
createHelloMethod value: 'Hello world'] on: CurrentEnvironment do: [:exc |
exc resume: english].

[createHelloClass value.
createHelloMethod value: 'Buenos dias'] on: CurrentEnvironment do: [:exc |
exc resume: spanish].

"Greet"
Compiler evaluate: 'Hello say' environment: english.
Compiler evaluate: 'Hello say' environment: spanish.
Compiler evaluate: 'Hello say' environment: english.

"Cleanup"
[Compiler evaluate: 'Hello removeFromSystem' environment: Environment
current] on: CurrentEnvironment do: [:exc | exc resume: english].
[Compiler evaluate: 'Hello removeFromSystem' environment: Environment
current] on: CurrentEnvironment do: [:exc | exc resume: spanish].

Yes, a DynamicVariable:
   CurrentEnvironment value: english during: ["load something"].
would be nicer than:
    ["load something"] on: CurrentEnvironment do: [:exc | exc resume:
english].
Otherwise we coulf fileIn some chunk format stream thru en
EnvironmentLoader for: english...


> 2016-09-30 13:29 GMT+02:00 H. Hirzel <hannes.hirzel at gmail.com>:
> > Starting a new thread, culled from the thread 'What are environments
> for'.
> >
> > There are many more good questions and thoughts in the  thread 'What
> > are environments for' but this thread is just about what the subject
> > says:
> >
> > How to create a 'Hello world' example for environments
> >
> > --Hannes
> >
> > On 9/29/16, David T. Lewis <lewis at mail.msen.com> wrote:
> >> On Thu, Sep 29, 2016 at 07:51:23AM +0200, H. Hirzel wrote:
> >>> On 9/29/16, Jakob Reschke <jakob.reschke at student.hpi.de> wrote:
> >>> > Hi Nicolas,
> >>> >
> >>> > First, thank you for answering me in the other thread.
> >>> >
> >>> > 2016-09-28 23:02 GMT+02:00 Nicolas Cellier
> >>> > <nicolas.cellier.aka.nice at gmail.com>:
> >>> >> Without clear goals or vision, fixing could essentially mean "let
> >>> >> Environment be transparent", that is let it remain a promise, a
> >>> >> potential,
> >>> >> whithout too many side effects... Not exactly YAGNI, just a bit of
> >>> >> over-engineered nice piece of code that might serve later. OK this
> >>> >> sounds
> >>> >> like a mandatory first step.
> >
> >
> >>> > I don't quite get what you mean by transparent, other than fixing it
> >>> > and enhancing the documentation to shed some light on what it is, why
> >>> > it is there and how to use it.
> > ..
> > ...
> >
> >>> Another maybe simple use case could be to have a project specific
> >>> environment set up when you enter a project
> >>> (http://wiki.squeak.org/squeak/1020).
> >>>
> >>> We now have very nicely cleaned up Project code in Squeak 5.1
> >>>
> >>> 1) Subclass MorphicProject --- MyMorphicProject
> >>> 2) Subclass PasteUpMorph  --- MyPasteUpMorph
> >>> 3) Override #initialize in MyMorphicProject and use MyPasteUpMorph
> >>> 4) ... some more adaptations ..... to enter a new Environment -- how?
> >>>
> >>
> >> I like this idea a lot.
> >>
> >> I would love to see a simple "hello world!" level example of
> Environments.
> >> If someone could make an EnvironmentsDemoProject that opens a new
> project
> >> with
> >> something that changes Duck>>speak ==> 'quack' to Duck>>speak ==> 'moo',
> >> I think it might really help me to understand how to use Environments.
> >>
> >> Dave
> >
> > So let's focus on a 'hello world' example for environments and do it
> > _slowly_ step by step so that people can catch up with the issues.
> >
> >
> >
> > Outline of steps of a 'Hello world' environments example
> > =============================================
> >
> > Steps
> >
> >
> > 1. subclass Object with a #Hello class.
> >
> > 2. compile a class method #say the method should write 'Hello' to the
> Transcript
> >
> > 3. run
> >     Hello say
> >
> >     The result should be 'Hello' on the Transcript
> >
> >
> > 4. create a new Environment called "myEnvironment".
> >
> > 5. import the Smalltalk environmnet into myEnvironment
> >
> > 6. subclass Object with a #Hello class in myEnvironment
> >
> > 7. compile a method #say the method should write 'Buenas dias' to the
> Transcript
> >
> >    run
> >         Hello say
> >
> >    Result should be
> >
> >         30-Sept-2016
> >
> > Starting a new thread, culled from the thread 'What are environments
> for'.
> >
> > There are many more good questions and thoughts in the  thread 'What
> > are environments for' but this thread is just about what the subject
> > says:
> >
> > How to create a 'Hello world' example for environments
> >
> > --Hannes
> >
> > On 9/29/16, David T. Lewis <lewis at mail.msen.com> wrote:
> >> On Thu, Sep 29, 2016 at 07:51:23AM +0200, H. Hirzel wrote:
> >>> On 9/29/16, Jakob Reschke <jakob.reschke at student.hpi.de> wrote:
> >>> > Hi Nicolas,
> >>> >
> >>> > First, thank you for answering me in the other thread.
> >>> >
> >>> > 2016-09-28 23:02 GMT+02:00 Nicolas Cellier
> >>> > <nicolas.cellier.aka.nice at gmail.com>:
> >>> >> Without clear goals or vision, fixing could essentially mean "let
> >>> >> Environment be transparent", that is let it remain a promise, a
> >>> >> potential,
> >>> >> whithout too many side effects... Not exactly YAGNI, just a bit of
> >>> >> over-engineered nice piece of code that might serve later. OK this
> >>> >> sounds
> >>> >> like a mandatory first step.
> >
> >
> >>> > I don't quite get what you mean by transparent, other than fixing it
> >>> > and enhancing the documentation to shed some light on what it is, why
> >>> > it is there and how to use it.
> > ..
> > ...
> >
> >>> Another maybe simple use case could be to have a project specific
> >>> environment set up when you enter a project
> >>> (http://wiki.squeak.org/squeak/1020).
> >>>
> >>> We now have very nicely cleaned up Project code in Squeak 5.1
> >>>
> >>> 1) Subclass MorphicProject --- MyMorphicProject
> >>> 2) Subclass PasteUpMorph  --- MyPasteUpMorph
> >>> 3) Override #initialize in MyMorphicProject and use MyPasteUpMorph
> >>> 4) ... some more adaptations ..... to enter a new Environment -- how?
> >>>
> >>
> >> I like this idea a lot.
> >>
> >> I would love to see a simple "hello world!" level example of
> Environments.
> >> If someone could make an EnvironmentsDemoProject that opens a new
> project
> >> with
> >> something that changes Duck>>speak ==> 'quack' to Duck>>speak ==> 'moo',
> >> I think it might really help me to understand how to use Environments.
> >>
> >> Dave
> >
> > So let's focus on a 'hello world' example for environments and do it
> > _slowly_ step by step so that people can catch up with the issues.
> >
> >
> >
> > Outline of steps of a 'Hello world' environments example
> > =============================================
> >
> > Steps
> >
> >
> > 1. subclass Object with a #Hello class.
> >
> > 2. compile a class method #say the method should write 'Hello' to the
> Transcript
> >
> > 3. run
> >     Hello say
> >
> >     The result should be 'Hello' on the Transcript
> >
> >
> > 4. create a new Environment called "myEnvironment".
> >
> > 5. import the Smalltalk environmnet into myEnvironment
> >
> > 6. subclass Object with a #Hello class in myEnvironment
> >
> > 7. compile a method #say the method should write 'Buenas dias' to the
> Transcript
> >
> >    run
> >         Hello say
> >
> >     The result should be 'Buenas dias' on the Transcript
> >
> >
> > 8. Leave environment called 'myEnvironment'
> >
> >
> > 9. run
> >     Hello say
> >
> >     The result should be this time 'Hello' on the Transcript
> >
> >
> >
> > Any comments on these steps?
> >
>
>
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