HKU PL Group

We are a group of programming language researchers who study topics about functional language design, type theory, compilers and program analysis.
The University of Hong Kong

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Disjoint Intersection Types

Calculi about disjoint intersection types enable an highly modular and compositional programming style that addresses the Expression Problem naturally, and allows for a much more dynamic form of inheritance.

Compositional Programming

Those works present a novel modular programming style.

Gradual Typing

This work presents a generalized definition of consistent subtyping that works for polymorphic types.

Dependent Types

Those works propose a unified syntax that accounts for types and terms which still preserves decidable type-checking.

Higher-Ranked Polymorphism

This paper provides the first mechanized formalization of type inference for higher-ranked polymorphism.

Kind Inference

This work proposes a solution of challenge of kind inference for datatype declarations for Haskell98 and modern Haskell.

Subtyping for Iso-recursive Types

A new iso-recursive subtyping formulation which takes advantage over other designs on both theoretical side and implementation side.

Bi-directional Type Checking

This paper presents a variant of bi-directional type checking where the type information flows from arguments to functions.

Intersection and Union Types

This paper proposes a novel methodology for designing subtyping relations that exploits duality between intersection types and union types.

Type-directed Operational Semantics

Type-directed operational semantics(TDOS) is a variant of small-step operational semantics. In TDOS, type annotations become operationally relevant and can affect the result of a program.

Seminar

  • Compositional Programming
    May 4, 2021
    In the recently accepted TOPLAS paper, we proposed a new statically typed modular programming style called compositional programming. It offers an alternative way to model data structures that differs from...

  • Some discussions about type classes
    Apr 27, 2021
    In this problem session we are going to have a shallow peek at the state of one of the signature features of the modern haskell, the type classes. Hopefully it’s...

  • Formalized Higher-Ranked Polymorphic Type Inference Algorithms
    Apr 20, 2021
    This is a practice talk of Jimmy’s Ph.D. thesis defense examination.

  • Type Directed Operational Semantics for Gradual Typing
    Mar 30, 2021
    The semantics of gradually typed languages is typically given indirectly via an elaboration into a cast calculus. This contrasts with more conventional formulations of programming language semantics, where the semantics...

  • Polymorphic Subtyping and Dependent Types
    Jan 19, 2021
    Abstract: The polymorphic subtyping relation, which captures the more-general-than relation between polymorphic and monomorphic types, is one of the main ways modern functional programming languages handles parametric polymorphisms (generic types)...

Gallery

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    Lab dinner 2019