16 Nov
2010
16 Nov
'10
9:22 p.m.
I'm using some option descriptions. For resolving possible options of to be referenced
objects I use something like
options: [ HRExampleObject instances ] magritteDynamicObject;
Now I'm trying to avoid using globals. Especially when dealing with gemstone it is not
advizable to have class side instances management. Is there a way to specify some lookup
environment to lookup something like the above?
Norbert
17 Nov
17 Nov
10:34 a.m.
On 16.11.2010, at 21:22, Norbert Hartl wrote:
I'm using some option descriptions. For resolving
possible options of to be referenced objects I use something like
options: [ HRExampleObject instances ] magritteDynamicObject;
Now I'm trying to avoid using globals. Especially when dealing with gemstone it is
not advizable to have class side instances management. Is there a way to specify some
lookup environment to lookup something like the above?
Well, the question was maybe too unspecific. At first I'm looking for a
possibility to create options from the instance side while dealing with components. On my
custom components I could do that easily by overwriting availableList. I'm just
looking for a more generically applicable solution that does not force me to build a
custom component for every case.
thanks,
Norbert
5:56 p.m.
On 17/11/10 4:34 AM, Norbert Hartl wrote:
Well, the question was maybe too unspecific. At first I'm looking for
a possibility to create options from the instance side while dealing
with components.
I don't fully understand what you're trying to achieve, but how about
you override #description on the instance side. Something like:
description
| desc instanceSpecificDesc |
desc := super description copy. "Copy, else per class cache altered"
desc add: (instanceSpecificDesc := self descriptionInstanceSpecific).
instanceSpecificDesc optionsAndLabels: self buildOptionsAndLabels.
"instanceSpecificDesc options: self buildOptions."
A variation, to have all the descriptions documented on the class side,
is as follows:
description
| desc customizedDesc |
desc := super description copy.
customizedDesc := desc detect: [:each | each label = 'Customized'].
customizedDesc options: self customOptions.
^ desc
6:21 p.m.
The way Magritte builds descriptions by default has become quite a
nuisance. Of course you can always do your own thing as Yanni
describes, but I think that at some point Magritte should be improved
in that regard. I wrote a proposal this summer of want to proceed on
that, but of course I had to finish my writing and never actually
found the time to implement it:
--------------------
I propose to perform the following (non-backward compatible) changes
in the Magritte 2 code-base to resolve some major annoyances and
issues that keep on reoccurring:
- Move descriptions from class-side to instance-side. This resolves
various issues such as cache-invalidation, instance specific
descriptions, dynamic descriptions, context dependent descriptions,
etc. Furthermore the descriptions will be closer to the code they
describe and it will be possible to describe class- and instance-side
of an object, not just the instance-side.
- Rename the method #description as the default entry point into
Magritte to #magritteDescription. This avoids common problems where
the domain model already defines such a method.
- Instead of using a naming convention for description methods, use a
pragma called <magritte> to annotate the methods. And to extend and
change existing descriptions use <magritte: aSelector>. Finally all
Smalltalk implementation reached a consensus of pragmas that can be
safely used cross-platform.
All in all the "new" Magritte would look like in the following
example. Imagine a shop item with the accessor #place:
Item>>place
^ place
Item>>place: aString
place := aString
The meta-description is defined on the instance-side and annotated. It
can refer to itself for the possible places:
Item>>placeDescription
<magritte>
^ MASingleOptionDescription new
options: self possiblePlaces;
label: 'Place of Item';
accessor: #place;
yourself
Class extensions can modify a description using:
Item>>placeDescriptionXmlStorage: aDescription
<magritte: #placeDescription>
^ placeDescription xmlTag: 'xname'
Since these changes are not backward compatible I'll try to provide
automatic refactorings for most parts. Moving existing code to the new
codebase will certainly cause some problems, but in the long run I
believe this to be a much better approach than the current one. If
people have any feedback, concerns or other changes that would be
important in the same run I am happy to hear them.
--------------------
On 17 November 2010 13:56, Yanni Chiu <yanni(a)rogers.com> wrote:
On 17/11/10 4:34 AM, Norbert Hartl wrote:
--
Lukas Renggli
www.lukas-renggli.ch
Well, the question was maybe too unspecific. At first I'm looking for
a possibility to create options from the instance side while dealing
with components.
I don't fully understand what you're trying to achieve, but how about you
override #description on the instance side. Something like:
description
| desc instanceSpecificDesc |
desc := super description copy. "Copy, else per class cache altered"
desc add: (instanceSpecificDesc := self descriptionInstanceSpecific).
instanceSpecificDesc optionsAndLabels: self buildOptionsAndLabels.
"instanceSpecificDesc options: self buildOptions."
A variation, to have all the descriptions documented on the class side, is
as follows:
description
| desc customizedDesc |
desc := super description copy.
customizedDesc := desc detect: [:each | each label = 'Customized'].
customizedDesc options: self customOptions.
^ desc
_______________________________________________
Magritte, Pier and Related Tools ...
https://www.iam.unibe.ch/mailman/listinfo/smallwiki
7 p.m.
Hi Lukas,
This sounds really useful.
Since these changes are not backward compatible I'll try to provide
automatic refactorings for most parts. Moving existing
code to the new
codebase will certainly cause some problems, but in the long run I
believe this to be a much better approach than the current one. If
people have any feedback, concerns or other changes that would be
important in the same run I am happy to hear them.
I am using similar tricks to the ones Yanni indicated above to build
instance specific instances - so it looks like your proposal would simplify
that code considerably. I've also been bitten by the name clash with
#description.
One specific annoyance I have is with class extension description methods
that are installed by addons that I can't disable (I currently delete the
methods). Specifically:
PRCase>>descriptionDocumentTagCloud: aDescription
^ aDescription beTagCloud
PRStructure>>descriptionNameTagCloud: aDescription
^ aDescription beTagCloud
I use the TagCloud addon, but don't want the structure name to be included
and instead of document I use plain text (arguably the plain text change
might be more widely applicable, but probably the first is more specific to
my use cases)
Perhaps it's overcomplicating to be able to disable class extension
descriptions - without making the code incomprehensible.
---
The other issue is with Magritte description caching and Gemstone. After I
change a description in Gemstone I have to remember to flush the description
cache. This seems to be due to a combination of Gemstone's classHistory and
lack of support for weak collections(?). Is this on your radar?
----
I imagine your proposed changes will require some effort to rework Pier - as
it uses Magritte extensively - I guess we can all pitch in to try to make it
happen smoothly - perhaps we could organise a Camp Magritte/Pier??
----
Nick
8:37 p.m.
On 17.11.2010, at 17:56, Yanni Chiu wrote:
On 17/11/10 4:34 AM, Norbert Hartl wrote:
Thanks Yanni,
this came to mind as well. I was asking if there is a better idea to achieve the same.
Norbert
Well, the question was maybe too unspecific. At first I'm looking for
a possibility to create options from the instance side while dealing
with components.
I don't fully understand what you're trying to achieve, but how about you
override #description on the instance side. Something like:
description
| desc instanceSpecificDesc |
desc := super description copy. "Copy, else per class cache altered"
desc add: (instanceSpecificDesc := self descriptionInstanceSpecific).
instanceSpecificDesc optionsAndLabels: self buildOptionsAndLabels.
"instanceSpecificDesc options: self buildOptions."
A variation, to have all the descriptions documented on the class side, is as follows:
description
| desc customizedDesc |
desc := super description copy.
customizedDesc := desc detect: [:each | each label = 'Customized'].
customizedDesc options: self customOptions.
^ desc
18 Nov
18 Nov
7:31 a.m.
On 17/11/10 12:21 PM, Lukas Renggli wrote:
Since these changes are not backward compatible I'll try to provide
automatic refactorings for most parts. Moving existing code to the new
codebase will certainly cause some problems, but in the long run I
believe this to be a much better approach than the current one. If
people have any feedback, concerns or other changes that would be
important in the same run I am happy to hear them.
I like the proposed changes. I've run into all those problems that would
be fixed. The pragma usage is something I'll have to get used to.
It's not clear whether your plan is to start with the Magritte2 code
base, and create, say, a Magritte3. Or is it to make the changes
directly to the Magritte2 code base. Changing Magritte2 directly would
mean one less branch to be maintained. Either way is fine with me.
4930
days inactive
4932
days old
6 comments
4 participants
participants (4)
-
Lukas Renggli -
Nick Ager -
Norbert Hartl -
Yanni Chiu