> Am 31.07.2018 um 06:57 schrieb Richard O'Keefe <rao...@gmail.com>: > > 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. > You could delegate the transaction list and other objects to a process specific variable. But the biggest problem with a copy approach is that all identity checks fail with the copied objects
Norbert >> 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 >
