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[CLJ-213] Invariants and the STM Created: 01/Dec/09  Updated: 26/Aug/13

Status: Open
Project: Clojure
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Anonymous Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: None


 Description   

(ticket requested here http://groups.google.com/group/clojure/browse_thread/thread/119311e89fa46806/4903ce25ff6deaa6#4903ce25ff6deaa6)

The general idea is to declare invariants inside a transaction and, when at commit time an invariant doesn't hold anymore, the transaction retries.
So it can both act as a kind of soft ensure or to specify actions that "partially commute".
Thus it would enable coarser refs.

See the attached file for quick prototype.

User code would looks like:

(invariant (@world :key))
(commute world update-in [:key] val-transform-fn)

This means the commute will occur only if (@world :key) returns the same value in-transaction and at commit point.



 Comments   
Comment by Assembla Importer [ 24/Aug/10 7:23 AM ]

Converted from http://www.assembla.com/spaces/clojure/tickets/213
Attachments:
invariants.patch - https://www.assembla.com/spaces/clojure/documents/dd4kUS3MWr3QvMeJe5aVNr/download/dd4kUS3MWr3QvMeJe5aVNr

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