On Sep 30, 2016 09:50, "Nicolas Cellier" nicolas.cellier.aka.nice@gmail.com wrote:
2016-09-30 14:57 GMT+02:00 Jakob Reschke jakob.reschke@student.hpi.de:
Hello,
Looks good to me as an outline. I have the following comments, questions or doubts:
- 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.
- 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?
- 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...
I wrote Control to do pretty much that: give a nice interface through which to create and change delimited dynamic variables (and delimited continuations). I would link to it (it's on SS3) but my phone is a bit limited...
frank
2016-09-30 13:29 GMT+02:00 H. Hirzel hannes.hirzel@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@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@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@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
- Subclass MorphicProject --- MyMorphicProject
- Subclass PasteUpMorph --- MyPasteUpMorph
- Override #initialize in MyMorphicProject and use MyPasteUpMorph
- ... 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
subclass Object with a #Hello class.
compile a class method #say the method should write 'Hello' to the
Transcript
run Hello say
The result should be 'Hello' on the Transcript
create a new Environment called "myEnvironment".
import the Smalltalk environmnet into myEnvironment
subclass Object with a #Hello class in myEnvironment
compile a method #say the method should write 'Buenas dias' to the
Transcript
run Hello say
Result should be
30-Sept-2016Starting 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@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@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@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
- Subclass MorphicProject --- MyMorphicProject
- Subclass PasteUpMorph --- MyPasteUpMorph
- Override #initialize in MyMorphicProject and use MyPasteUpMorph
- ... 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
subclass Object with a #Hello class.
compile a class method #say the method should write 'Hello' to the
Transcript
run Hello say
The result should be 'Hello' on the Transcript
create a new Environment called "myEnvironment".
import the Smalltalk environmnet into myEnvironment
subclass Object with a #Hello class in myEnvironment
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
Leave environment called 'myEnvironment'
run Hello say
The result should be this time 'Hello' on the Transcript
Any comments on these steps?