System F in Agda, for Fun and Profit

Chapman, James; Kireev, Roman; Nester, Chad; Wadler, Philip

doi:10.1007/978-3-030-33636-3_10

Cited by 18 publications

(14 citation statements)

References 26 publications

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“…They formalise and reason about their models in Agda. Chapman et al [14] formalise System F ωµ , which is polymorphic λ-calculus with higher-kinded and arbitrary recursive types, in Agda. System F ωµ correspondence to Plutus Core, which is the core of the smart contract language Plutus that is featured by the Cardano blockchain.…”

Section: Related Workmentioning

confidence: 99%

Verification of Bitcoin Script in Agda using Weakest Preconditions for Access Control

Alhabardi,

Beckmann,

Lazar

et al. 2022

Preprint

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This paper addresses the verification of Bitcoin smart contracts using the interactive theorem prover Agda. It focuses on two standard smart contracts that govern the distribution of Bitcoins, Pay to Public Key Hash (P2PKH) and Pay to Multisig (P2MS). Both are written in Bitcoin's low-level language script, and provide the security property of access control to the distribution of Bitcoins.The paper introduces an operational semantics of the script commands used in P2PKH and P2MS, and formalises it in the Agda proof assistant using Hoare triples. It advocates weakest preconditions in the context of Hoare triples as the appropriate notion for verifying access control. Two methodologies for obtaining human-readable weakest preconditions are discussed in order to close the validation gap between user requirements and formal specification of smart contracts:(1) a step-by-step approach, which works backwards instruction by instruction through a script, sometimes stepping over several instructions in one go; (2) symbolic execution of the code and translation into a nested case distinction, which allows to read off weakest preconditions as the disjunction of accepting paths. A syntax for equational reasoning with Hoare Triples is defined in order to formalise those approaches in Agda.

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Section: Related Workmentioning

confidence: 99%

Verification of Bitcoin Script in Agda using Weakest Preconditions for Access Control

Alhabardi,

Beckmann,

Lazar

et al. 2022

Preprint

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show abstract

“…This is because the Agda type system and its interactive programming environment provide greater assistance to the programmer that help speed up development on certain tasks. Building on the methodology described in this paper, Plutus Core (the compilation target for the Plutus language) has an executable specification written in Agda [CKNW19]. Plutus is a general purpose language for designing smart contracts that is closely related to Haskell.…”

Section: Upcoming Features: Smart Contracts Languages Plutus and Marlmentioning

confidence: 99%

Flexible Formality Practical Experience with Agile Formal Methods

Kant

Hammond

Coutts

et al. 2020

Lecture Notes in Computer Science

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Agile software development and Formal Methods are traditionally seen as being in conflict. From an Agile perspective, there is pressure to deliver quickly, building vertical prototypes and doing many iterations/sprints, refining the requirements; from a Formal Methods perspective, there is pressure to deliver correctly and any change in requirements often necessitates changes in the formal specification and might even impact all arguments of correctness. Over the years, the need to "be agile" has become a kind of mantra in software development management, and there is a prevalent prejudice that using formal methods was an impediment to being agile. In this paper, we contribute to the refutation of this stereotype, by providing a real-world example of using good practices from formal methods and agile software engineering to deliver software that is simultaneously reliable, effective, testable, and that can also be iterated and delivered rapidly. We thus present how a lightweight software engineering methodology, drawing from appropriate formal methods techniques and providing the benefits of agile software development, can look like. Our methodology is informed and motivated by practical experience. We have devised and adapted it in the light of experience in delivering a large-scale software system that needs to meet complex real-world requirements: the Cardano blockchain and its cryptocurrency ada. The cryptocurrency domain is a rather new application area for which no clear engineering habit exists, so it is fitting well for agile methods.

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“…Note that this means we really must perform a substitution rather than creating a let-binding, since that would simply create another abstract type. 8 Consider the following example:…”

Section: Non-recursive Datatype Bindingsmentioning

confidence: 99%

“…In this paper we construct an IR suitable for a powerful functional programming language like Haskell. We take as our lambda calculus System F µ ω (System F ω with indexed fixpoints: see [27,Chapter 30], formalized recently in [8]), which allows us to talk about higher-kinded recursive types, and extend it to an IR called FIR which adds the following features:…”

Section: Introductionmentioning

confidence: 99%

Unraveling Recursion: Compiling an IR with Recursion to System F

Jones¹,

Gkoumas²,

Kireev³

et al. 2019

Lecture Notes in Computer Science

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Lambda calculi are often used as intermediate representations for compilers. However, they require extensions to handle higherlevel features of programming languages. In this paper we show how to construct an IR based on System F µ ω which supports recursive functions and datatypes, and describe how to compile it to System F µ ω . Our IR was developed for commercial use at the IOHK company, where it is used as part of a compilation pipeline for smart contracts running on a blockchain.

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System F in Agda, for Fun and Profit

Cited by 18 publications

References 26 publications

Verification of Bitcoin Script in Agda using Weakest Preconditions for Access Control

Verification of Bitcoin Script in Agda using Weakest Preconditions for Access Control

Flexible Formality Practical Experience with Agile Formal Methods

Unraveling Recursion: Compiling an IR with Recursion to System F

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