Basically, what you are talking about is Software Transactional Memory. According to https://en.wikipedia.org/wiki/Software_transactional_memory#Smalltalk there *is* STM support for Pharo at http://source.lukas-renggli.ch/transactional/ although the last version there is from 2012, and there have been major changes to Pharo since then, so it probably doesn't work any longer.
You could probably make a TransactionalObject class with a 'lastTransaction' instance variable, and a noteChange method that checks if lastTransaction == Transaction current, and if not, pushes self -> self shallowCopy onto a stack inside Transaction and sets lastTransaction to Transaction current. Then to roll back a transaction, peel back original -> backup records from the stack and do original copyFrom: backup for each of them. Please don't ask me to think about combining this with concurrency. On 31 July 2018 at 01:16, Peter Uhnák <i.uh...@gmail.com> wrote: > Hi, > > is there some library or approach how to do transactions in pharo? > And I don't mean database transactions, but directly in memory on Pharo > objects... e.g. > > p := Person new. > > transaction do: [ > p name: 'Nobody'. > p age: 70. > ] on: Error do: [ > transaction rollback. > ]. > > self assert: p name equals: 'Nobody'. > self assert: p age equals: 70. > > transaction do: [ > p name: 'Somebody'. > p age: 1 / 0. > ] on: Error do: [ > transaction rollback. > ]. > > self assert: p name equals: 'Nobody'. > self assert: p age equals: 70. > > Any pointers appreciated. > > Thanks, > Peter >
