Most STM systems are poorly equipped to support libraries of concurrent data structures. One reason is that they typically detect conflicts by tracking transactions' read sets and write sets, an approach that often leads to false conflicts. A second is that existing data structures and libraries often need to be rewritten from scratch to support transactional conflict detection and rollback. This brief announcement introduces Proust, a framework for the design and implementation of transactional data structures. Proust is designed to maximize reuse of existing well-engineered libraries by providing transactional "wrappers" to make existing thread-safe concurrent data structures transactional. Proustian objects are also integrated with an underlying STM system, allowing them to take advantage of well-engineered STM conflict detection mechanisms. Proust generalizes and unifies prior approaches such as boosting and predication.

Modern cryptocurrency systems, such as Ethereum, permit complex financial transactions through scripts called smart contracts. These smart contracts are executed many, many times, always without real concurrency. First, all smart contracts are serially executed by miners before appending them to the blockchain. Later, those contracts are serially re-executed by validators to verify that the smart contracts were executed correctly by miners. Serial execution limits system throughput and fails to exploit today's concurrent multicore and cluster architectures. Nevertheless, serial execution appears to be required: contracts share state, and contract programming languages have a serial semantics.