arXiv subjects

Paulette Koronkevich

Publications and source records attributed to Paulette Koronkevich.

5 recordsLinked to original sources

arXiv2025

Dependent-Type-Preserving Memory Allocation

Dependently typed programming languages such as Coq, Agda, Idris, and F*, allow programmers to write detailed specifications of their programs and prove their programs meet these specifications. However, these specifications can be violated during compilation since they are erased after type checking. External programs linked with the compiled program can violate the specifications of the original program and change the behavior of the compiled program -- even when compiled with a verified compiler. For example, since Coq does not allow explicitly allocating memory, a programmer might link their Coq program with a C program that can allocate memory. Even if the Coq program is compiled with a verified compiler, the external C program can still violate the memory-safe specification of the Coq program by providing an uninitialized pointer to memory. This error could be ruled out by type checking in a language expressive enough to indicate whether memory is initialized versus uninitialized. Linking with a program with an uninitialized pointer could be considered ill-typed, and our linking process could prevent linking with ill-typed programs. To facilitate type checking during linking, we can use type-preserving compilation, which preserves the types through the compilation process. In this ongoing work, we develop a typed intermediate language that supports dependent memory allocation, as well as a dependent-type-preserving compiler pass for memory allocation.

cs.PL↗

arXiv2025

One Weird Trick to Untie Landin's Knot

In this work, we explore Landin's Knot, which is understood as a pattern for encoding general recursion, including non-termination, that is possible after adding higher-order references to an otherwise terminating language. We observe that this isn't always true -- higher-order references, by themselves, don't lead to non-termination. The key insight is that Landin's Knot relies not primarily on references storing functions, but on unrestricted quantification over a function's environment. We show this through a closure converted language, in which the function's environment is made explicit and hides the type of the environment through impredicative quantification. Once references are added, this impredicative quantification can be exploited to encode recursion. We conjecture that by restricting the quantification over the environment, higher-order references can be safely added to terminating languages, without resorting to more complex type systems such as linearity, and without restricting references from storing functions.

cs.PL↗

arXiv2024

Type Universes as Allocation Effects

In this paper, we explore a connection between type universes and memory allocation. Type universe hierarchies are used in dependent type theories to ensure consistency, by forbidding a type from quantifying over all types. Instead, the types of types (universes) form a hierarchy, and a type can only quantify over types in other universes (with some exceptions), restricting cyclic reasoning in proofs. We present a perspective where universes also describe \emph{where} values are allocated in the heap, and the choice of universe algebra imposes a structure on the heap overall. The resulting type system provides a simple declarative system for reasoning about and restricting memory allocation, without reasoning about reads or writes. We present a theoretical framework for equipping a type system with higher-order references restricted by a universe hierarchy, and conjecture that many existing universe algebras give rise to interesting systems for reasoning about allocation. We present 3 instantiations of this approach to enable reasoning about allocation in the simply typed $λ$-calculus: (1) the standard ramified universe hierarchy, which we prove guarantees termination of the language extended with higher-order references by restricting cycles in the heap; (2) an extension with an \emph{impredicative} base universe, which we conjecture enables full-ground references (with terminating computation but cyclic ground data structures); (3) an extension with \emph{universe polymorphism}, which divides the heap into fine-grained regions.

cs.PL↗

arXiv2020

PLIERS: A Process that Integrates User-Centered Methods into Programming Language Design

Programming language design requires making many usability-related design decisions. However, existing HCI methods can be impractical to apply to programming languages: they have high iteration costs, programmers require significant learning time, and user performance has high variance. To address these problems, we adapted both formative and summative HCI methods to make them more suitable for programming language design. We integrated these methods into a new process, PLIERS, for designing programming languages in a user-centered way. We evaluated PLIERS by using it to design two new programming languages. Glacier extends Java to enable programmers to express immutability properties effectively and easily. Obsidian is a language for blockchains that includes verification of critical safety properties. Summative usability studies showed that programmers were able to program effectively in both languages after short training periods.

cs.HC↗

arXiv2019

Obsidian: Typestate and Assets for Safer Blockchain Programming

Blockchain platforms are coming into broad use for processing critical transactions among participants who have not established mutual trust. Many blockchains are programmable, supporting smart contracts, which maintain persistent state and support transactions that transform the state. Unfortunately, bugs in many smart contracts have been exploited by hackers. Obsidian is a novel programming language with a type system that enables static detection of bugs that are common in smart contracts today. Obsidian is based on a core calculus, Silica, for which we proved type soundness. Obsidian uses typestate to detect improper state manipulation and uses linear types to detect abuse of assets. We describe two case studies that evaluate Obsidian's applicability to the domains of parametric insurance and supply chain management, finding that Obsidian's type system facilitates reasoning about high-level states and ownership of resources. We compared our Obsidian implementation to a Solidity implementation, observing that the Solidity implementation requires much boilerplate checking and tracking of state, whereas Obsidian does this work statically.

cs.PL↗