1,698 research outputs found
Linear Haskell: practical linearity in a higher-order polymorphic language
Linear type systems have a long and storied history, but not a clear path
forward to integrate with existing languages such as OCaml or Haskell. In this
paper, we study a linear type system designed with two crucial properties in
mind: backwards-compatibility and code reuse across linear and non-linear users
of a library. Only then can the benefits of linear types permeate conventional
functional programming. Rather than bifurcate types into linear and non-linear
counterparts, we instead attach linearity to function arrows. Linear functions
can receive inputs from linearly-bound values, but can also operate over
unrestricted, regular values.
To demonstrate the efficacy of our linear type system - both how easy it can
be integrated in an existing language implementation and how streamlined it
makes it to write programs with linear types - we implemented our type system
in GHC, the leading Haskell compiler, and demonstrate two kinds of applications
of linear types: mutable data with pure interfaces; and enforcing protocols in
I/O-performing functions
Specification and verification challenges for sequential object-oriented programs
The state of knowledge in how to specify sequential programs in object-oriented languages such as Java and C# and the state of the art in automated verification tools for such programs have made measurable progress in the last several years. This paper describes several remaining challenges and approaches to their solution
Blockchain Software Verification and Optimization
In the last decade, blockchain technology has undergone a strong evolution. The maturity reached and the consolidation obtained have aroused the interest of companies and businesses, transforming it into a possible response to various industrial needs. However, the lack of standards and tools for the development and maintenance of blockchain software leaves open challenges and various possibilities for improvements. The goal of this thesis is to tackle some of the challenges proposed by blockchain technology, to design and implement analysis, processes, and architectures that may be applied in the real world. In particular, two topics are addressed: the verification of the blockchain software and the code optimization of smart contracts. As regards the verification, the thesis focuses on the original developments of tools and analyses able to detect statically, i.e. without code execution, issues related to non-determinism, untrusted cross-contracts invocation, and numerical overflow/underflow. Moreover, an approach based on on-chain verification is investigated, to proactively involve the blockchain in verifying the code before and after its deployment. For the optimization side, the thesis describes an optimization process for the code translation from Solidity language to Takamaka, also proposing an efficient algorithm to compute snapshots for fungible and non-fungible tokens. The results of this thesis are an important first step towards improving blockchain software development, empirically demonstrating the applicability of the proposed approaches and their involvement also in the industrial field
Specification and verification challenges for sequential object-oriented programs
The state of knowledge in how to specify sequential programs in object-oriented languages such as Java and C# and the state of the art in automated verification tools for such programs have made measurable progress in the last several years. This paper describes several remaining challenges and approaches to their solutio
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