Modularizing Cross-Cutting Concerns with Aspect-Oriented Extensions for Solidity

Over the past few years, blockchain technology has attracted much attention. The smart contract is a computer program that implements and executes transactions and business logic on the blockchain. Unlike traditional general-purpose programming languages, the modularization techniques of programming languages for the smart contracts are still immature. Specifically, a suitable modularization mechanism for cross-cutting concerns is still not available. From a software engineering perspective, the modularization of cross-cutting concerns is a fundamental issue that can dramatically affect the contracts' maintainability and readability. As a result, reducing the redundant cross-cutting logic is still a challenging task. This paper proposes a practically viable approach that supports Aspect-Oriented Programming (AOP) for smart contract development on Ethereum-based blockchains. We suggest a set of extension to Solidity, a programming language that runs on the Ethereum-based blockchains, that facilitates AOP semantics and behaviors. As a proof of concept, we also realize the weaving module for the extension. The feasibility of the proposed approach is demonstrated by a case study.