Re: [Pharo-dev] STON updates/improvements

Oct. 12, 2018


      On ven. 12 oct. 2018 at 11:38, Sven Van Caekenberghe <sven@stfx.eu> wrote:
...
Hi,
I have consolidated all repositories where STON code lives so that they
are now all in sync, and in sync with changes from Pharo 7.
http://ss3.gemtalksystems.com/ss/STON/
 http://smalltalkhub.com/mc/SvenVanCaekenberghe/STON/main/
 https://github.com/svenvc/ston
There are 2 CI builds
https://travis-ci.org/svenvc/ston
 https://ci.inria.fr/pharo-contribution/job/STON/
The project's format will remain FileTree (until Tonel is supported on
other Smalltalk implementations).
Last week I applied a couple of changes that I wanted to apply for a long
time.
Traits are no longer used in the implementation (which should help porting
to other Smalltalk implementations).
More specifically the following are used (again)
- Class>>#stonOn:
- ClassDescription>>#stonContainsSubObjects
- Metaclass>>#stonName
- Metaclass>>#stonOn:
instead of
- TClass>>#stonOn:
- TClassDescription>>#stonContainsSubObjects
- TApplyingOnClassSide>>#stonName
- TApplyingOnClassSide>>#stonOn:
use #instanceSide instead of #theNonMetaClass in MetaClass>>#stonOn:
Reorganised the packages with sub tags.
Add support for Fraction and ScaledDecimal literals (not in JSON mode).
Previously a float conversion meant there was a loss of information.
Change the representation of Date to include a timezone offset (since the
current Date implementation is sensitive to this).
2018-10-11Z
 2018-10-11+00:00
 2018-10-11+02:00
A missing timezone offset is interpreted as being the local timezone
offset.
Add more special representations for common value style objects. One of
STON's goals is to be a human readable and human editable representation of
an object graph while remaining 100% correct (not losing information). The
following were added for this reason:
MimeType and URL using ZnMimeType and ZnUrl respectively as simplified
values.
MimeType['application/json']
 URL['https://pharo.org']
Color
Color[#red]
 Color{#red:1.0,#green:0.0,#blue:0.0,#alpha:0.4}
FileReferences to the DiskFileSystem (effectively normal files)
FILE['/tmp/foo.txt']
Here is an example of how much difference that makes. Given the following
Dictionary
{
  #background->Color red.
  #workdir->'/tmp/pharo/work/' asFileReference.
  #home->'https://pharo.org/experimental' asUrl.
  #datatype->'application/json' asMIMEType } asDictionary
Which contains real objects as its values.
was serialised by STON BEFORE the changes as
{
        #datatype : ZnMimeType {
                #main : 'application',
                #sub : 'json'
        },
        #background : Color {
                #rgb : 1072693248,
                #cachedDepth : 32,
                #cachedBitPattern : Bitmap [
                        4294901760
                ],
                #alpha : 255
        },
        #home : ZnUrl {
                #scheme : #https,
                #host : 'pharo.org',
                #segments : OrderedCollection [
                        'experimental'
                ]
        },
        #workdir : FileReference {
                #filesystem : FileSystem {
                        #store : MacStore {
                                #maxFileNameLength : 255
                        }
                },
                #path : AbsolutePath [ 'tmp', 'pharo', 'work' ]
        }
}
which is 100% correct, but not very human friendly.
Now, AFTER the changes, the STON serialisation looks as follows:
{
        #datatype : MimeType [ 'application/json' ],
        #background : Color [ #red ],
        #home : URL [ 'https://pharo.org/experimental' ],
        #workdir : FILE [ '/tmp/pharo/work' ]
}
which is a huge improvement, IMO.
What do you think ? Comments, feedback, remarks ?
Any other suggestions for other object that could use this treatment ?
This is great thank you! In some projects I had some hacks for the export
of FileReferences in a readable way, it is great to know have a readable
export by default in ston.
...
Sven
--
Cyril Ferlicot
https://ferlicot.fr