Hi,

I want to use STON to enable the backup a graph of objects pertaining to an application.

Some of the objects in this graph include, in their state, a Map that is not supported by STON.

To write these objects, I would like to write via the standard procedure all the instance variables unless that pointing to such a map, and then add a modified version of that map by hand.��

To exclude the conflicting variable is easy, I just redefine #stonAllInstVarNames at the class side as follows:

�� ^self instVarNames reject: [ :theName | (theName = #references) ]

in this way, I do not need to modify the method if the state of these objects changes.

On the other hand, I found not easy to use the standard mechanism for the included instance variables. This mechanism is embedded in STONWriter>>writeObject: . I found no option but repeat the logic codified there, in the method #stonOn: of my class.

The easiest way to let STON integrate the standard mechanism to store the state of an object, with by-hand additions, is to slightly modify STONWriter>>writeObject:, adding just one line. Objects including instance variables would be written as follows:

self writeObject: anObject streamMap: [ :dictionary |��

instanceVariableNames do: [ :each |��

(anObject instVarNamed: each)

ifNotNil: [ :value |��

dictionary at: each asSymbol put: value ]

ifNil: [��

anObject stonShouldWriteNilInstVars��

ifTrue: [ dictionary at: each asSymbol put: nil ] ] ] .

anObject stonAdditionalInfoOn: dictionary . ]

the added line is the last one, the invocation to #stonAdditionalInfoOn:. Of course, the method #stonAdditionalInfoOn: should be added to the Object class.

By redefining this method in my class, I was able to easily add the modified, STON-compatlble value, to the values handled by the STON code.

I did not need to modify the STON code to read the STON String to generate a new object.

Do you think that doing this modification to STON could be a good idea?

Cordially - Carlos

PS: I envisaged as an alternative, to allow the following method in my class

�� stonOn:stonWriter

�� stonWriter writeObjectAsMap: self

�� do: [:mapWriter |��

�� // added code goes here

�� stonWriter writeInstVarsOf: self on: mapWriter

�� // added code goes here

�� ]

To this end, the methods #writeObjectAsMap:do: and #writeInstVarsOf:on should be added to STONWriter. The method��

�� writeInstVar: aSymbol ��of: anObject ��on: mapWriter

could be offered as well, to allow more fine-grained redefinitions of stonOn: , while keeping the ability to use the standard mechanism to store an instance variable.

I think that the option I described earlier is simpler, I include this one because maybe other people would prefere it.